Mock Exam

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What is the thickest and strongest tendon in the human body?

Achilles tendon

Pixel size in the phase direction of the image is determined by the _________ of the phase encoding gradient both positively and negatively.

Amplitude

The __________ of the phase-encoding gradient determines the degree of phase shift between two points along the gradient.

Amplitude

The _____________ of the frequency-encoding gradient determines the size of FOV in the frequency encoding direction.

Amplitude

The amount of current moving through the coil determines the ______________, strength, or slope of the gradient.

Amplitude

The smaller terminal branch of the popliteal artery is the ____________ _______ _______ leads into the dorsalis pedis artery.

Anterior tibial artery

The ____________ ___ _________contains cerebrospinal fluid (CSF), is within the mesencephalon (or midbrain) and connects the third ventricle in the diencephalon to the fourth ventricle, which is between the pons and cerebellum.

Aqueduct of Sylvius

3D TOF (time of flight) MRA is typically used to visualize ____________ vessels, and utilizes thinner slices, but yields less suppression of background tissues than 2D TOF. A. Larger B. Smaller

B (Smaller)

In an MRA sequence, the removal of signal from vessels is accomplished by: A. Spectral presaturation B. Spatial presaturation C. Gradient moment nulling D. B and C E. None of the above

B (Spatial presaturation)

Which of the following sequences is the most insensitive to magnetic field inhomogeneity? A. RF spoiled gradient echo B. Spin echo C. Steady state rephased gradient echo D. Echo planar

B (Spin echo)

The ligamentum flavum can be found in which part of the body? A. Abdomen B. Spine C. Thorax D. Neck E. Knee

B (Spine)

If the TR in a gradient echo sequence is less than the T2 (or T2*), the resulting condition is known as: A. Spin down B. Steady state C. Spin dephasement D. Thermal equilibrium

B (Steady state)

Question #57: The __________________ runs the length of the falx cerebri. A. Frontal sinus B. Superior sagittal sinus C. Transverse anterior sinus D. Lateral sinus E. Cerebral sinus

B (Superior sagittal sinus)

PC MRA (phase contrast) sequences use T2 gradient echoes that rely on velocity-induced phase shifts for vascular signal. A. T1 B. T2 C. PD D. DWI

B (T2)

PC MRA (phase contrast) sequences use ____ gradient echoes that rely on velocity-induced phase shifts for vascular signal. A. T1 B. T2 C. PD D. DWI

B (T2)

Superparamagnetic Iron Oxide (SPIO) and Ultrasmall Superparamagnetic Iron Oxide (USPIO) are used to reduce the _____ signals of absorbing tissues. A. T1 B. T2

B (T2)

A disadvantage of TOF MRA is high signal in some background tissues. To minimize signal from background tissues, ____ should be selected that enable the signals from fat and water to be out-of-phase. A. TR B. TE C. FA D. TI

B (TE)

Which of the following has been documented to cause muscle contractions, cardiac arrhythmias, mild cutaneous sensations and visual light flashes? A. Oscillating magnetic fields (RF -- radiofrequency) B. Time varying magnetic fields (TVMF -- gradient) C. Static magnetic fields (main magnet) D. Healthcare administration's recent demands

B (Time varying magnetic fields (TVMF -- gradient))

Phase contrast MRA techniques produce images in which the signal intensity within the vessel is dependent upon the: A. Shortening of the T1 time of blood B. Velocity of the flowing blood C. Larmor frequency of arterial versus venous blood D. Rate of gadolinium contrast injection E. Timing of gadolinium contrast injection F. A, D and E

B (Velocity of the flowing blood)

Defined as a factor in diffusion weighted imaging; the higher the factor, the stronger the diffusion weighting.

B-value

Defined as the static magnetic field of an MR system.

The difference in energy between high and low energy spins is directly related to what?

The __________ GE pulse sequence is a modification of the coherent GE sequence.

Balanced

________ _______ is a form of facial paralysis resulting from a dysfunction of the cranial nerve VII (the facial nerve) that results in the inability to control facial muscles on the affected side.

Bell's palsy

An integrated part of the magnet design that acts as its own transceiver coil, with large FOV capabilities, but lacking the high SNR of localized coils.

Body coil (Low SNR is due to the distance from the patient)

Increasing the flip angle: A. Doubles the SNR proportional to the angle increased B. Reduces SNR C. Increases SNR up to the Ernst angle D. Does not affect SNR

C (Increases SNR up to the Ernst angle)

When imaging the female pelvis, the most optimal view for evaluation of the uterus is the: A. Axial B. Coronal C. Sagittal D. None of the above

C (Sagittal)

Referencing the Centers for Disease Control and Prevention (CDC), what type of isolation precautions should be used for HIV-positive patients in the MRI suite? A. Respiratory B. Droplet C. Standard (universal) D. Enteric E. Contact

C (Standard (universal))

Referencing the White Paper on MRI safety, individuals identified as "Level 2" personnel include: A. Those with no MRI safety training B. Those with limited MRI safety training C. Those with extensive MRI safety training, including the magnetic, gradient and RF fields D. B and C E. None of the above

C (Those with extensive MRI safety training, including the magnetic, gradient and RF fields)

In a Fast Spin Echo (FSE) sequence, acquired with a short echo time (TE), yielding T1 or PD weighted images, blurring can be reduced by: A. Increasing the FOV B. Increasing NEX C. Using shorter ETL D. Using longer ETL E. Increasing phase encodings

C (Using shorter ETL)

Adjusting the ______ would aid in reducing chemical shift artifacts. A. TR B. TE C. rBw D. tBw

C (rBw - Increasing the rBw would reduce chemical shift artifacts but also decreases SNR)

Basic T1 perfusion imaging (pituitary or prostate dynamic sequences, longer acquisition times/dynamic compared to DSC).

DCE (Dynamic Contrast Enhancement)

T2* gradient echo perfusion imaging, utilized in Brain perfusion studies.

DSE (Dynamic Susceptibility Contrast)

Decreasing slice number in volume imaging will ___________ scan time and _________ SNR.

Decrease, decrease

Reducing the slice thickness will result in a ___________ in SNR, but will ___________ partial volume averaging.

Decrease, decrease

Decreasing the NSA will _______ the SNR, _________ scan time, and _________ signal averaging.

Decrease, decrease, decrease

Decreasing the TR will ________ the SNR, ________ scan time, _______ the number of slices, _________, and ________ the T1 contrast.

Decrease, decrease, decrease, increase

Decreasing the NSA will _____________ scan time, ____________ SNR, and __________ motion artifacts.

Decrease, decrease, increase

Decreasing the matrix (fixed FOV) will _________ spatial resolution, ___________ scan time, and _________ SNR if pixels are large.

Decrease, decrease, increase

Decreasing the phase matrix (fixed FOV) will __________ scan time, _________ spatial resolution, and _________ SNR.

Decrease, decrease, increase

In SE sequences, TOF effects DECREASE with a(n) ____________ in velocity, __________ in TE, and _____________ in slice thickness.

Decrease, decrease, increase

Decreasing the slice thickness will _________ the SNR, __________ the coverage, _________ slice resolution, and _________ partial volume averaging.

Decrease, decrease, increase, decrease

Decreasing the TE will _______ T2 contrast, and _________ the SNR.

Decrease, increase

Decreasing the TR will _________ scan time, __________ T1 contrast, __________ SNR, and _________ number of slices available.

Decrease, increase, decrease, decrease

Occurs after initial RF application, causing phase differences to appear between precessing spins, resulting in decay of transverse magnetization.

Dephasing

An effect resulting in a slightly weakened magnetic field when a substance in introduced into it. This material is considered to have a negative magnetic susceptibility.

Diamagnetism

The movement of atoms or molecules from an area of higher concentration to an area of lower concentration (Brownian motion).

Diffusion

Doubling the magnetic field strength will __________ the SNR.

Double

A spin echo sequence with two echoes, two generated images per slice location. Normally a PD and T2W image due to the need for a long TE.

Double echo

Immediately following the application of the 90° RF pulse, the precessing protons: A. Begin to precess in phase B. All move into a high energy state C. Tip into the transverse plane D. All of the above E. A and C only

E (A and C only -Immediately following the application of the 90° RF pulse, the precessing protons begin to precess in phase and tip into the transverse plane.)

Which of the following, in an MRA sequence, aids in minimizing the loss of signal due to dephasing within a voxel: A. Long TE B. Short TR C. Smaller voxel size D. Short TE E. C and D

E (C and D)

Force on an object in an magnetic environment depends on: I. Mass of the object II. Strength of the magnetic field III. Strength of the RF field IV. Ferromagnetic properties of the object A. I only B. II only C. I and II only D. I and III only E. I, II and IV F. I, II, III and IV

E (I, II and IV)

The number of gradient echoes in an EPI sequence acquired after the initial RF pulse; equating to the scan time acceleration factor.

EPI factor

In flow phenomenon, _____ is related to the excitation history of nuclei.

ESP

In flow phenomena, _____ tends to create flow-related enhancement of signal, whereby the lumen of a vessel appears hyperintense on the images.

ESP (Entery-slice phenomenon)

_________ tends to create flow-related enhancement of signal, thereby the lumen of the vessel appears _____________ on the image.

ESP, Hyperintense

In FSE, the longer the ____, the increased chance of blurring in the image.

ETL

The MR signal generated by an RF or a gradient pulse.

Echo

Very fast MR imaging technique where the complete image is acquired using a single selective excitation pulse, field gradients are periodically switched to generate a series or gradient echoes.

Echo Planar Imaging

Multiple echoes in sequence, each obtaining rows of k-space, shortening overall scan time, also reducing SNR with each additional one.

Echo Train

Distance between two echoes, as in Fast Spin Echo or EPI sequences. The shorter this is, the more compact the sequence timing and few artifacts result.

Echo spacing

The electrical currents generated in a conductor by changing magnetic fields or movement of the conductor within the magnetic field.

Eddy currents

Aliasing/wrap artifacts occur at the _______ of the image whereas parallel imaging artifacts occur at the ________ of the image.

Edge, center

In a pulse sequence, the contrast and overall SNR of an image determined by the position of the echo when the phase encoding gradient has the smallest amplitude (least amount of dephasing). At this time, the echo signal has the strongest signal and undergoes minimal dephasing.

Effective TE

Referring to prospective cardiac triggering techniques, the patient's heart rate controls the TR according to the BPM factor.

Effective TR

The electrical voltage created in a receiver coil as a result of a temporal change in the magnetic field.

Electromagnetic induction

Prevents or reduces motion artifacts in the MR images caused by the heartbeat or pulsating blood flow and enables the images to be acquired synchronized to cardiac movement.

Cardiac triggering

Blood flow velocities are greater at the __________ of a vessel.

Center

With respiratory compensation, when the chest movement is at rest, data is stored in the __________ lines of k-space.

Center

Ensures integrity of MR system operating frequency, at which all system coils will be tuned to.

Center frequency

Law that pertains to private legal rights and matters

Civil Law

A disease that is characterized by narrowing of the aorta is called an aortic _____________.

Coarctation

Maintaining a constant state of "in-phase" relationships between protons; located at the same phase cycle simultaneously.

Coherent

Law that pertains to crimes and their punishment

Criminal Law

Too small a slice gap for a given thickness and it can lead to ________-_______ artifacts.

Cross-talk

Occurs when slices are positioned too close together, causing signals from adjacent slices to affect one another. This affects T1 contrast, and is remedied by utilizing an interleaved slice profile or by increasing the slice gap.

Cross-talk artifact

Creating additional images in various planes from a 3D data set is accomplished by a technique known as: A. Subtraction B. Maximum intensity projection (MIP) C. Region of interest calculation(ROI) D. Multi-Planar reconstruction (MPR) E. Minimum Intensity Projection (MinIP)

D (Multi-Planar reconstruction (MPR))

A disadvantage of TOF MRA is high signal in some background tissues. To minimize signal from background tissues, TE should be selected that enable the signals from fat and water to be: A. Presaturated B. Nulled C. In phase D. Out of phase

D (Out of phase)

What protocol would be selected to rule out islet cell tumor? A. Pelvic floor laxity B. Liver for iron C. Adrenal glands with In/Out phase images D. Pancreas E. Soft tissue neck

D (Pancreas - Well or intermediately differentiated Pancreatic Neuroendocrine Tumors are sometimes called islet cell tumors, and are diagnosed with an abdominal MRI exam with attention to the pancreas.)

_______ is when only half the views of k-space are filled in the frequency axis. A. Anti aliasing B. Parallel imaging C. Half fourier D. Partial or fractional echo E. 1/2 TE (TAU)

D (Partial or fractional echo - Partial or fractional echo is when only half the views of k-space are filled in the frequency axis, an acceleration technique used to shorten TR and TE.)

Chemical or spectral fat suppression techniques suppress fat signal based on the: A. Presence of T1 relaxation in the tissue B. Presence of T2 relaxation in the tissue C. Amount of fat being imaged D. Precessional frequency of fat E. Precessional frequency of water

D (Precessional frequency of fat)

The _________ is defined as the resonant frequency, and is equal to the product of the magnetic field and the gyromagnetic ratio. A. RF excitation pulse B. Inversion recovery C. Presaturation pulse D. Precessional frequency

D (Precessional frequency)

In a cross sectional view of the MR magnet design, which coils are closest to the patient? A. Gradient coils B. Shim coils C. Main magnet D. Radiofrequency coils E. Surface coils

D (Radiofrequency coils)

The _____________ imaging plane would be the most optimal slice orientation for evaluation of Arnold Chiari Malformation and its inferior cerebellar tonsillar herniation. A. Axial B. Coronal C. Transverse D. Sagittal

D (Sagittal)

Permanent magnets with a vertical magnetic field use surface coils that are: A. Phased array B. Linear C. Quadrature D. Solenoids

D (Solenoids -Permanent magnets with a vertical magnetic field use surface coils that are solenoids because the secondary magnetic field (B1)created by the RF coil must be perpendicular to the orientation of B0.)

When a gradient echo sequence is selected for fast, breath hold dynamic contrast-enhanced imaging of the abdomen, _____________ is utilized. A. A refocussing 180° RF pulse B. An inverting RF pulse C. Presaturation D. Spoiling E. CSF nulling

D (Spoiling)

___________ could be used to line the walls and/or floors of the MR magnet room to reduce the fringe field, and is defined as __________ shielding. A. Copper; active B. Steel; active C. Copper; passive D. Steel; passive E. Lead; active

D (Steel; passive)

Active shielding can be defined as: A. Copper lining in the walls of the scanner room B. Performing robust prescan measurements for the purpose of field homogeneity C. Steel lining in the walls of the scanner room D. Superconducting windings within the MR scanner, reducing the fringe magnetic field E. Monthly adjustments made to the magnetic field for the purpose of field uniformity

D (Superconducting windings within the MR scanner, reducing the fringe magnetic field)

The gradient rise time is defined as the: A. Time it takes longitudinal magnetization to regrow B. Time between TI and initial RF pulse C. Speed rate of ascent or decent of a gradient from zero to its maximum amplitude D. Time it take for the gradient to reach its full amplitude

D (Time it take for the gradient to reach its full amplitude)

In a Fast Spin Echo (FSE) sequence, acquired with a long TE, yielding T2 weighted images, scan time can be reduced by: A. Increasing the FOV B. Increasing NEX C. Using shorter ETL D. Using longer ETL E. Increasing phase encodings

D (Using longer ETL)

When imaging a geriatric patient, while performing a PCA MRA sequence, what imaging parameter might the operator adjust? A. Field of view B. Presaturation band location C. Slice thickness D. VENC E. Contrast injection rate

D (VENC)

The ratio of the magnetic moment (field strength) of a rotating charged particle, such as an electron, to its angular momentum (frequency).

Gyromagnetic Ratio

In tissues where the ADC is low, the molecules are essentially stationary because their diffusion is limited. Magnetic moments of these spins acquire not net phase change after the gradients are applied. The results are therefore ______ signal.

High

Water has a _____ inherent energy and doesn't give up its energy freely to the surrounding lattice.

High

Water has a _____ molecular tumbling rate that does not match the larmor frequency so it does not efficient give it's energy to the surrounding molecular lattice.

High

As the TE is increased, I. The available number of slices is increased II. The available number of slices is decreased III. SNR increases IV. T1 contrast is maximized A. I only B. II only C. I and II only D. I and III only E. I, II, III and IV

II (The available number of slices is decreased)

The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the _____.

IVC

The common iliac veins join together to form the _________.

IVC

Mathematical computation converting the collected raw data signals into images using Fourier Transform.

Image reconstruction

The mathematical process of converting raw data into an image suitable for display.

Fourier Transform

In k-space, resolution is referred to as ___________ resolution because k-space is a spatial frequency domain.

Frequency

The _______ matrix is the number of data points in each row of k-space.

Frequency

The number of data points laid out in k-space is determined by the _________ matrix.

Frequency

The number of times that a periodic function or vibration repeats itself in a specified time.

Frequency

The process of locating an MR signal in one dimension by applying a magnetic field gradient along that dimension during the period when the signal is being received, utilizing differences in frequencies along the same row in order to spatially differentiate one location from another.

Frequency Encoding

The number of data points in each line of k-space determines what?

Frequency matrix

The sampling window determines what?

Frequency resolution (pixel size)

Slice-selection and frequency encoding rely on _______ change, while phase encoding relies on ______ change.

Frequency, phase

The transmit bandwidth of the RF pulse affects: A. Spatial resolution B. SNR C. Image contrast D. Slice thickness E. All of the above F. A and D only G. A, B and D only

G (A, B and D only)

Reducing the number of lines filled in k-space will produce an image: A. With a decrease in spatial resolution B. With a increase in spatial resolution C. With an decrease in overall SNR D. With an increase in overall SNR E. With a reduced overall scan time F. B, C and E only G. A, D and E only

G (A, D, and E Only. Reducing the number of lines filled in k-space reduces the number of phase encoding steps, resulting in shorter scan time, an increase in overall SNR, but a decrease in spatial resolution.)

A non-toxic paramagnetic contrast agent used in MR imaging. The infusion of gadolinium based paramagnetic contrast agents (GBCA's) shortens the T1 (and T2) times of tissue, dependent upon concentration.

Gadolinium

Timing the collection of MR data to physiological motion in order to minimize motion artifacts, used in cardiac and respiratory imaging.

Gating

Unit of magnetic induction in the centimeter-gram-second system of physical units. Used as a safety standard for the exclusion of implanted metallic devices.

Gauss

_________ is the term used to measure the magnetic field strength in the periphery of the magnet scan room.

Gauss

Increasing the TE will _______ T2 contrast, and _________ the SNR.

Increase, decrease

To correct for Gibbs truncation artifact, _________ the number of phase encodings or _________ the FOV (while maintaining matrix).

Increase, decrease

Decreasing the image matrix (fixed FOV) will _________ SNR, ________ the scan, and _________ spatial resolution.

Increase, decrease, decrease

Decreasing the slice thickness will _________ the spatial resolution, __________ the SNR, and __________ partial voluming averaging.

Increase, decrease, decrease

Increasing the FOV (fixed matrix) will __________ SNR, ___________ spatial resolution, ________ coverage, and __________ aliasing (pFOV).

Increase, decrease, increase decrease

Using a large coil will ________ area of received signal, _______ SNR, _______ sensitivity to artifacts, and __________ aliasing.

Increase, decrease, increase, increase

Decreasing the rBw will ___________ the sampling time and __________ the minimum TE.

Increase, increase

Increasing the NSA will _________ SNR and __________ scan time.

Increase, increase

In SE sequences, TOF effects INCREASE with a(n) ____________ in velocity, __________ in TE, and _____________ in slice thickness.

Increase, increase, decrease

Increasing the matrix (fixed FOV) will _________ spatial resolution, ___________ scan time, and _________ SNR if pixels are small.

Increase, increase, decrease

Increasing the slice thickness will _________ the SNR, __________ the coverage, _________ slice resolution, and _________ partial volume averaging.

Increase, increase, decrease, increase

Decreasing the rBw will _________ chemical shift, ________ minimum TE, and _________ SNR.

Increase, increase, increase

Decreasing the rBw will ____________ SNR, _________ the minimum TE, and ____________ chemical shift artifacts.

Increase, increase, increase

Increasing the NSA will _______ the SNR, _________ scan time, and _________ signal averaging.

Increase, increase, increase

Spatial resolution increases by either keeping the FOV the same and _____________ the image matrix, or by keeping the matrix the same and ______________ the FOV.

Increasing, decreasing

The TR in a SS sequence is equal to what?

Infinity

The ________ _____ is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver. It is usually formed by the confluence of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, gastric, and cystic veins.324860

Portal vein

The larger and more direct terminal branch of the popliteal artery is the __________ _______ ______, which supplies blood to the foot, and has a crucial branch known as the fibular, or peroneal artery.

Posterior tibial artery

A rotational motion about an axis of a vector whose origin is fixed at the origin of the coordinate system.

Precess

A technique employing repeated RF excitation of tissues outside the ROI for the purpose of reducing or eliminating their phase effect artifacts

Presaturation

___________ is an instrument (or document) that allows a patient to appoint an agent to make health care decisions in the event that the primary individual is incapable of executing such decisions.

Proxy

A set of specifically timed pulses and/or magnetic field gradients producing an image with specific characteristics based on the timing and duration of the pulses programmed

Pulse sequence

Utilizes the goal of maintaining a desired level of consistency and image quality requirements within Radiology.

QA (Asks the question, "Are we operating the devices or equipment correctly?")

Reflects the set of activities and/or techniques used to fulfill the requirements for quality.

QC ("Is the equipment operating correctly?")

A ________ refers to the sudden loss of superconductivity when its temperature is raised. In the superconducting state, the resistance of the magnet coil windings is zero and hence no energy is required to maintain current flow.

Quench

An event in a superconducting MR system causing a loss of superconductivity, a rapid loss of the magnet cryogens, potentially creating a hazard for patients / operators in the magnet room

Quench

Cardiac triggering monitors cardiac motion by coordinating the RF excitation pulse with the ____ wave of cardiac systole.

A frequency band in the electromagnetic spectrum with frequencies in the millions of cycles per second.

The _____ field is by design closest to the patient inside the scanner.

The _____________ results s in the system centering itself in the center of k-space.

RF pulse

The location of the coils installed in the MRI scanner, from the inner point closest to the patient to the outer most edge, are:

RF, gradient, shim, B0

A coil, or antenna used to detect the NMR signal. Types of receiver coils include solenoid, quadrature and phased array coils

Receiver coil

MRI equipment device that detects and amplifies the RF signals picked up by the receiver coil.

Recevier

GMN works best on what type of flow?

Laminar (First order motion)

Blood flow that is at different but consistent velocities across a vessel.

Laminar flow

Applying the phase encoding gradient many times would result in a ______ phase matrix.

Large

Thin slices produced when a _______ amount of current is applied to the slice-select gradient.

Large

Steep phase-encoding gradients produce _____ phase shifts across a given distance along the gradient and are able to encode ______ spatial frequencies.

Large, high

An equation stating that the frequency of precession of nuclear magnetic moment is directly proportional to the product of the magnetic field strength(B0) and the gyromagnetic ratio.

Larmor equation

The specific frequency at which magnetic resonance in a nucleus can be excited and detected, and varies directly with magnetic field strength.

Larmor frequency

The internal cerebral vein drain what cerebral structure?

Lateral ventricle

The magnetic and thermal environment through which nuclei exchange energy in longitudinal (T1) relaxation.

Lattice

Frequency encoding gradient negative, K space is traversed _______ to _________

Right, left

The gradient _______________ is defined as the time it takes for the gradient to reach its full amplitude, measured in microseconds --- mT/m (milliTesla/meter) or G/cm (Gauss/centimeter).

Rise time

The ____________ _______ are ligaments which connect the laminae of adjacent vertebrae, from the C1/2 axis to the first segment of the sacrum (C2 to S1).

Ligamentum Flavum

Return of longitudinal magnetization to its equilibrium value after RF excitation due to the exchange of energy between the nuclear spins and the lattice.

Longitudinal relaxation

Fat has a ____ inherent energy and gives up it's energy freely to the surrounding lattice.

Low

Fat has a ____ molecular tumbling rate that closely matches the larmor frequency and allows for efficient exchange of energy to the molecular lattice.

Low

In DWI, normal tissue that has a high ADC has a _____ signal intensity than abnormal tissue that has a low ADC.

Low

In a Fast Spin Echo sequence, the effective TE are the echoes that are encoded with a _______ amplitude phase encoding gradient.

Low

In areas of restricted diffusion, the ADC is _____ because the extracellular space is small.

Low

In human tissue, muscle does not have parity, therefore it returns ______ signal in the steady state.

Low

A truncation artifacts creates a _______ intensity band running through a _____ intensity area.

Low, high

Areas with low PD will have _____ SI while areas with high PD will have _____ high SI.

Low, high

At thermal equilibrium, there are more ______ energy spins than there are _____ energy spins.

Low, high

Biphasic agents (e.g. water, polyethylene glycol, dilute barium with sorbitol) demonstrate _____ signal intensity on T1 and _____ signal intensity on T2 images.

Low, high

What is the second branch of the abdominal aorta?

SMA

Ratio between the amplitude of the received signal and background noise.

SNR

T2 weighted images normally have low ____, but high _____.

SNR, CNR

In this technique, half the lines of K-space are acquired in one TR and the other half is transposed.

SS-FSE

A gradient echo sequence in which a non-zero steady state develops for both transverse and longitudinal components of magnetization.

SSFP

Technique used to suppress fluids, utilizing a long TE coupled with a long TI.

STIR (Short Tau Inversion Recovery)

Defined as the mode of operation of the MR equipment in which one or more output reach a value that can produce significant risk for subjects, for which explicit ethical approval is required according to local requirements.

Second-level controlled operating mode

MR technique utilized to image flowing blood and specific vasculature structures.

MRA

MR technique which quantitatively assesses the mechanical properties of tissues, based on the propagation of shear waves.

MRE

Magnetic lines of force which extend from a north and south pole to form a closed loop around the outside of a magnetic material. A magnetic field has properties of both magnitude (strength) and direction.

Magnetic field

In PC-MRA, ___________ images offer the normal anatomical-looking appearance with high-signal against a black background.

Magnitude

How many times each line of k-space data is acquired during the scan, or how many times each slice is repeated to gain signal and reduce noise, improving SNR.

NEX

A vector which represents the sum of the magnetization from a spin system; the magnitude and direction of the magnetization resulting from the collection of atomic nuclei.

NMV

TOF on a SE sequence will produce _____ signal due to spins being present for one RF pulse, but not the other.

Vessels in SE TOF sequences will have ____ signal, whereby vessels in GE TOF sequences will have _______ signal.

No, High

Described as personnel with little or no training in MRI safety.

Non-MR

Defined as the mode of operation in which none of the outputs have a value that would be anticipated to cause physiological stress to subjects.

Normal operating mode

A plane or section that is perpendicular to the X,Y, or Z axes.

Orthogonal

With respiratory compensation, when the chest movement is at its highest data is stored in the __________ lines of k-space.

Outer

How well a material attracts the imaginary lines of the magnetic field.

Permeability

ESP is seen when nuclei flow is ___________ to the slice and it is most prominent in the ______ slice in the stack.

Perpendicular, first

Zipper artifacts appear in the image ______________ to the ________ encoding direction.

Perpendicular, frequency

A coherent GE uses the ________ gradient to rewind all transverse magnetization so that it coherency is maintained.

Phase

An angular relationship describing the degree of synchronism between sinusoidal waveforms of the same frequency.

Phase

In PC-MRA, _________ images demonstrate the direction of flow as being white (when in the same direction of VENC) or black (when in the opposite direction of VENC).

Phase

The _______ matrix depends on how many lines of k-space are filled with data points and it is therefore the total number of data points in each column of data in k-space.

Phase

The only gradient to change it's amplitude during the acquisition is the ________ encoding gradient. All others utilize the same amplitude.

Phase

Term describing the degree to which precessing nuclear spins are synchronous.

Phase coherence

The process of locating an MR signal along the phase axis, directly correlating spatial resolution and scan time with the number of phase encodings in an MR image.

Phase encoding

The number of data points in each column of k-space determines what?

Phase matrix

Blood flow within a vessel that is characterized by different velocities that fluctuate randomly.

Turbulent flow

The Nyquist theorem states that a frequency must be sampled at least _______ in order to reproduce it reliably

Twice

When digitizing a signal with a range of analogue frequencies (frequencies represented by a waveform), the highest frequency must be sampled at least _________ ____ _______ to accurately digitize or represent it

Twice as fast

Refers to the practice, in medicine, of avoiding contact with patients' bodily fluids, by means of the wearing of nonporous articles such as medical gloves, goggles and face shields, regardless of any known transmittable diseases.

Universal precautions

Formula for the temporal change of the magnetic field, especially important with regards to patient safety in relation to gradients. This is due to the electrical field generated in conductive materials, as in human tissue.

dB/dt

Increasing the __________ value will allow more arterial vessels to be visualized

VENC (velocity encodings)

When imaging the extremities, _____________ tablets could be used as a marker to delineate the area of interest for both radiologist and referring physician.

Vitamin E

Blood flow that is initially laminar, then intersects a vessel stenosis or stricture, becoming high velocity central flow and spiral near the walls of the vessel.

Vortex flow

If a sagittal slice plane has been selected, the ___ gradient is enabled to alter the magnetic field around the patient's body.

In axial images, the long axis of the anatomy lies along the ____ axis

In coronal images, the short axis of the anatomy lies along the ____ axis

In axial images the long axis of the anatomy usually lies along the horizontal axis of the magnet and therefore, the ___ Gradient performs the frequency encoding. However, in the head the long axis usually lies along the anterior-posterior axis of the magnet so the ___ Gradient performs the frequency encoding.

X, Y

In axial images of the head, the long axis of the anatomy lies along the ____ axis.

In sagittal images, the short axis of the anatomy lies along the ____ axis

The sagittal images usually lie along the vertical axis of the magnet, therefore the ___ gradient performs the phase encoding

The axial images usually lie along the vertical axis of the magnet, therefore the ___ gradient performs the phase encoding. When imaging the head, the short axis of the anatomy lies along the horizontal axis of the magnet and therefore the __ gradient performs the phase encoding

Y, X

To achieve thick slices, a _______ slice-select slope and/or _________ tBw is applied.

Shallow, wide

Coils positioned near the main magnetic field that have a small current, and are used to provide localized magnetic fields improving homogeneity

Shim coils

The process of improving the homogeneity of the magnetic field, either through active shimming (use of shim coils) or passive shimming (adding or removing steel from the magnet).

Shimming

Incoherent GE is a steady state sequence that utilizes a _____ TR and a ____ FA.

Short, medium

The speed rate of ascent or descent of a gradient from zero to its maximum amplitude, either positive or negative.

Slew rate

The amplitude of the slice-select gradient and transmit bandwidth determines what?

Slice thickness (and slice gap)

In balanced GE, gradients are applied in the _______ and _______ axes.

Slice, frequency

Applying the phase encoding gradient few times would result in a ______ phase matrix.

Small

Thick slices produced when a _______ amount of current is applied to the slice-select gradient.

Small

To minimize T1 contrast in a GE pulse sequence, a ____ FA and _____ TR would be used.

Small, Long

MDH increases the amplitude of the ___ wave, thus hindering correct R peak detection. This often results in unreliable triggering and poor image quality.

IR is typically used to produce heavily weighted ____ images.

____ contrast is likely to occur if vectors do not fully recover their longitudinal magnetization between RF pulses.

The FID tends to create contrast that relies on ____/____ effects because it does not contain residual transverse magnetization.

T1/PD

Coherent (rewound) GE pulse sequences can be used to create T1, PD, or T2* weighted images, but they are traditionally used to produce ____ weighted image.

T2*

Coherent GE pulse sequences yield images with ____ weighting whereas incoherent GE pulse sequences yield images with more ___ weighting.

T2, T1

The stimulated echo contains mainly ___/___ weighted information because it is generated from residual transverse magnetization.

T2/T2*

The time between the initial 180º RF and the 90º RF excitation pulse in an Inversion Recovery sequence.

MRA technique relying on flow related enhancement to distinguish between stationary spins and flowing spins.

TOF

In flow phenomena, ______ tends to cause high-velocity signal loss whereby the lumen of the vessel appears less hyperintense on the image as the velocity of flow increases.

TOF (Time-of-flight)

_________ tends to cause HVSL whereby the lumen of the vessel appears less ______________ on the image as the velocity of flow increases.

TOF, hyperintense

The time between successive pulse sequences applied to the same slice, the time between consecutive 90º RF excitation pulses. TR is the controlling factor of T1 contrast, and a factor in MR scan time.

What equation is used to calculate scan time in a 2D GE pulse sequence?

TR x Phase x NEX

What equation is used to calculate scan time in a FSE pulse sequence?

TR x Phase x NEX / ETL

What equation is used to calculate scan time in a 3D GE pulse sequence?

TR x Phase x NEX x slice number

What equation is used to calculate scan time in a SE pulse sequence?

TR x phase x NEX

In a reverse echo GE pulse sequence, only the __________ _____ is sampled, and due to its repoistioning, the TE of this echo is long enough to inclued __ contrast.

Stimulated echo, T2

When the direction and velocity of flow are jerky, it is defined as _______ -order motion.

Third

A _________, in common law jurisdictions, is a wrong that involves a breach of a civil duty (other than a contractual duty) owed to someone else. It is differentiated from a crime, which involves a breach of a duty owed to society in general.

Tort

What is the slew rate measured in?

mT/m/ms (or G/cm/s)

T2 decay times are measured in ______ whereas T1 relaxation times are measured in _______.

ms, s

When the Nyquist principles are obeyed, the _____ has the same numerical value as the digital sampling frequency.

rBW

The _____ is determined by applying a filter to the frequencies encoded by the frequency-encoding gradient.

rBw

What are the units of K space?

radians/cm

TI times are _________ proportional to the magnetic field strength of the scanner. A. Directly B. Inversely

A (Directly)

The energy used to form MRI images is ____________ the patient's tissues. A. Emitted from B. Attenuated by C. Amplified from D. Reflected off

A (Emitted from)

Steep phase encoding slopes produce ____ spatial frequencies. A. High B. Low

A (High)

The larmor frequency of MR-active nuclei is proportional to B0. If a H nucleus lies in an area of inhomogeneity with higher field strength, the precessional frequency of its magnetic moment will be _________. A. Higher B. Lower

A (Higher)

The smaller the voxel, the _______ the spatial resolution. A. Higher B. Lower

A (Higher)

_____________ field strengths will realize more chemical shift artifacts due to the increased separation of fat and water frequencies. A. Higher B. Lower

A (Higher)

As the thickness of the slice decreases, the TOF phenomenon _____________. A. Increases B. Decreases

A (Increases)

Decreasing the rBw __________ the sampling time. A. Increases B. Decreases

A (Increases)

Decreasing the receiver bandwidth ___________ chemical shift. A. Increases B. Decreases

A (Increases)

Reducing the rBw ___________ chemical shift artifacts. A. Increases B. Decreases

A (Increases)

Reducing the rBw ___________ the minimum TE. A. Increases B. Decreases

A (Increases)

A small FOV requires a ____________ frequency-encoding gradient. A. Steep B. Shallow

A (Steep)

An extracranial time-of-flight MRA of the carotid arteries for arterial blood flow would require a presaturation pulse to be placed ___________ to the slice group. A. Superior B. Inferior

A (Superior)

TOF (Time-of-Flight) MRA sequences use ________ gradient echoes with TR and FA (flip angle) selections to suppress signal from stationary tissues, visualizing flowing blood by flow-related enhancement. A. T1 B. T2 C. PD D. DWI

A (T1)

Blood flow velocities are greater at the center of a vessel. A. True B. False

A (True)

EKG triggering should be used when imaging the chest, heart, and great vessels. A. True B. False

A (True)

If the sampling interval doubles, it's the same as halving the rBw. A. True B. False

A (True)

Larger FAs create more saturation. 1. True 2. False

A (True)

T2 decay in fat is short because the molecules are closely packed together, allowing for efficient exchange of energy. A. True B. False

A (True)

TE indirectly affects scan time. A. True B. False

A (True)

The FID decays at a rate of T2*. A. True B. False

A (True)

The lentiform nucleus consists of the putamen and the globus pallidus. A. True B. False

A (True)

The lumbar region is the spinal region that is LEAST affected by cerebrospinal fluid (CSF) pulsation. A. True B. False

A (True)

The net longitudinal magnetization in thermodynamical equilibrium is due to a tiny excess of protons in the lower energy state. This gives a net polarization parallel to the external field. A. True B. False

A (True)

The sampling rate determines the time interval between each data point. A. True B. False

A (True)

The two main advantages of selecting parallel imaging options are the reduction in gradient switching and the lack of additional RF power required performing the acceleration technique. A. True B. False

A (True)

The _____________________ is part of the computer system that converts the analog acquired MR signal into a digital signal.

ADC

In the spine, the _____ is a broad, sturdy band of fiberous tissue joining the vertebral bodies and intervertebral discs anteriorly and laterally.

ALL

An _____ is defined as an abnormal tangling or connection between arteries and veins, usually formed before birth.

AVM (arterio-venous malformation)

The water molecules clearly move in a preferred direction and is displayed BRIGHT on the image.

Anisotropic diffusion

Also known as cusp artifacts, the feather-like bright signal primarily occurs in the phase encoding direction, and can be corrected by simply de-selecting the element(s) outside the scanning range.

Annefact

The internal carotid artery supplies blood to the ___________ ________.

Anterior brain

SAR is proportional to the power of ___ for the resonant frequency. A. 1 B. 2 C. 3 D. 4

B (2)

To achieve a low phase matrix, the phase-encoding gradient is applied _________ times during the pulse sequence. A. Many B. Fewer

B (Fewer)

What element in the body is the principal nucleus utilized in clinical MR imaging? A. Helium B. Hydrogen C. Oxygen D. Calcium

B (Hydrogen)

______ TR leads to higher SARs. A. Longer B. Shorter

B (Shorter)

Long echo trains lead to more _____ weighting. A. T1 B. T2 C. PD D. DW

B (T2)

Objects exhibiting paramagnetism have ________ electrons. A. Paired B. Unpaired

B (Unpaired)

The alternating magnetic field generated by the RF in a transceiver coil, perpendicular to B0.

Defined as the range or spectrum of frequencies (minimum to maximum processed frequency) of a pulse sequence acquired by an RF system.

Bandwidth

To be continuous, or having a continuous range of values. A. Digital B. Frequency C. Analog D. Array

C (Analog)

Magnetic susceptibility artifacts are more prominent with _____________ sequences. A. Inversion recovery B. Spin echo C. Gradient echo D. Fast spin echo

C (Gradient echo)

The MRI system component that provides the ability to perform spatial encoding is the: A. Shim system B. Main magnet C. Gradient system D. Radiofrequency system

C (Gradient system)

In the image, the FOV is calculated by _________ the pixel size by the number of pixels. A. Adding B. Subtracting C. Multiplying D. Dividing

C (Multiplying)

Utilizes the reduced T1 relaxation time of blood through the use of an IV injected Gd contrast agent.

CE MRA

_____ is probably the most critical factor affecting image quality, as it directly determines the eye's ability to distinguish areas of high signal from areas of low signal.

CNR

What are the two prerequisites to parallel imaging?

Calibration scan and phased array coil

The _________ _______ artifact only occurs when water and fat coexist in the same voxel.

Chemical shift

Can be defined as the signal strength differences between two adjacent tissue types.

Contrast

Increasing the rBw will _________ chemical shift, ________ minimum TE, and _________ SNR.

Decrease, decrease, decrease

Using a small coil will ________ area of received signal, _______ SNR, _______ sensitivity to artifacts, and __________ aliasing.

Decrease, increase, decrease, decrease

Decreasing the FOV (fixed matrix) will __________ SNR, ___________ spatial resolution, ________ coverage, and __________ aliasing (pFOV).

Decrease, increase, decrease, increase

If a sequence with a matrix of 256 x 512 is adjusted to 512 x 512, the SNR will _________, the scan time will __________, and spatial resolution will ___________.

Decrease, increase, increase

ESP will DECREASE with a(n) ___________ in the TR, _______ in the FA, ___________ in the slice thickness, __________ in velocity of flow, and when flow is in the __________ direction of the slice.

Decrease, increase, increase, decrease, same

As sampling frequency increases, SNR __________

Decreases

Flow-related enhancement increases as the velocity of flow ___________, TE __________, and slice thickness _____________.

Decreases, decreases, increases

Liquids that are supercooled (4 degrees Kelvin) in order to maintain the superconductivity of the magnet coils.

Cyrogens

If the flip angle is doubled, RF deposition increases by a factor of: A. 1 B. 2 C. 3 D. 4 E. 6 F. 8

D (4)

Another term used for "fever" is: A. Hypothermia B. Apnea C. Dystonia D. Febrile

D (Febrile)

When imaging a hemorrhagic infarct in the brain, which pulse sequence would demonstrate the magnetic susceptibility effects better? A. Spin echo B. Fast spin echo C. Inversion recovery D. Gradient echo E. Multi echo spin echo F. FLAIR

D (Gradient echo)

The B1 magnetic field is produced by a: A. Shim coil B. Main magnet coil C. Gradient coil D. Radiofrequency coil

D (Radiofrequency coil)

In a superconducting magnet, the magnetic field strength is increased by increasing the: A. Temperature B. Patient body weight C. Cryogen content D. Turns of wire E. Tuning to a higher frequency

D (Turns of wire)

Displays the mobility of water molecules in all three coordinates.

Diffusion tensor

The smaller terminal branch of the popliteal artery, the anterior tibial artery leads into the _________ ______ artery.

Doralis pedis

What equation can be used to calculate the sampling time?

Frequency/rBw

Acquiring a bit more than half the phase k-space samples, then interpolating the data with zeroes for the remaining half is a technique known as: A. Half Fourier B. Fast spin echo C. Zero Fill D. Spoiled Gradient Echo E. All of the above F. A, C and/or D only G. A and/or C only

G (A and/or C only)

__________ law of induction states that a changing magnetic field will induce a voltage.

Faraday's

The property of being strongly attracted to either pole of a magnet.

Ferromagnetism

The linear increased or decreased change in the magnetic field of a certain orientation. Defines the strength and orientation of change of a magnitude in space.

Gradient

__________ is the most commonly reported contrast reaction.

Headache

Double and triple IR prep sequence would be used in imaging what part of the body?

Heart (Double IR can null blood, triple IR can null blood and fat.)

The major bifurcation of the abdominal aorta is the right and left common ________ arteries.

Iliac

This is determined by the number of data points in k-space.

Image matrix

A _________ tumor is a tumor primarily found in pediatric kidneys.

Wilms

In axial images of the head, the short axis of the anatomy lies along the ____ axis

Corrective measures for parallel imaging artifacts are to __________ FOV or ___________ the parallel imaging factor.

Increase, decrease

Corrective measures for parallel imaging artifacts are to ___________ the FOV or __________ the parallel imaging factor.

Increase, decrease

Decreasing the FOV (fixed matrix) will __________ spatial resolution, and __________ SNR.

Increase, decrease

Decreasing the TE will _______ SNR and ___________ T2 contrast.

Increase, decrease

Increasing the FOV (fixed matrix) will __________ the SNR and _________ spatial resolution.

Increase, decrease

ESP will INCREASE with a(n) ___________ in the TR, _______ in the FA, ___________ in the slice thickness, __________ in velocity of flow, and when flow is in the __________ direction of the slice.

Increase, decrease, decrease, increase, opposite

Increasing the slice thickness will _________ the SNR, ________ the spatial resolution, and ____________ partial volume averaging.

Increase, decrease, increase

Increasing the image matrix (fixed FOV) will ________ spatial resolution, _________ SNR, and ___________ scan time.

Increase, decrease, increase (phase matrix)

Increasing the TR will ________ the SNR, ________ scan time, _______ the number of slices, _________, and ________ the T1 contrast.

Increase, increase, increase, decrease

Increasing the TR will _________ the SNR, ________ scan time, ________ the number of slices available, and ___________ T1 contrast.

Increase, increase, increase, decrease

HVSL increases as the velocity of flow _________, TE ___________, and slice thickness ___________.

Increases, Increases, decreases

The prostate gland is located ________ and __________ to the bladder in the male pelvis.

Inferior, posterior

__________ consent is a phrase often used in law to indicate that the consent a person gives meets certain minimum standards.

Informed

Lack of homogeneity or uniformity in the main magnetic field.

Inhomogeneity

An _____________ MRA exam is defined as an MRA of the Circle of Willis, or head MRA.

Intracranial

A location within the magnet bore assigned coordinates X-0, Y-0, Z-0, and having magnetic field strength B0 and center frequency relative to field strength.

Isocenter

Any signal that demonstrates a zero change in phase and frequency must be coming from where?

Isocenter

Atomic nuclei that contain the same number of protons but differ in the number of neutrons in the nucleus of the atom.

Isotope

Water molecules move the same way in every direction and is displayed DARK on the image.

Isotropic diffusion

Data acquisition matrix containing raw image data prior to image processing.

K-space

Filling the outer lines of K-space before the arrival of Gd, then filling the central thereafter is a K-space filling technique referred to as what?

Keyhole

_______________ disease is a condition of osteomalacia in the lunate bone of the wrist, an avascular necrosis (death and fracture of bone tissue due to interruption of blood supply) with fragmentation and collapse of the lunate.

Kienbock's

In a T1 GE, the FA is _______ and the TR is ______ to allow for maximum T1 contrast.

Large, short

Stage of disease when symptoms are not present.

Latent

Most inferior part of the heart is the ____ ventricle, most superior is the _______ atrium

Left, Right

Frequency encoding gradient positive, K space is traversed _______ to _______.

Left, right

Longer ETLs mean that ______ slices can be acquired per scan.

Less

Reducing the rBw results in ______ noise sampled relative to the signal.

Less

Described as those with limited training in MRI safety (education about the magnetic field).

Level 1

Described as those with extensive training in MRI safety, including a vast knowledge of the main magnetic field as well as the RF and gradient fields, and the risks and biological effects of these three magnetic fields.

Level 2

A __________ can mean something that is a hindrance or puts an individual or group at a disadvantage, or something that someone is responsible for, or something that increases the chance of something occurring.

Liability

In the spine, the _________ _____ are broad, pale yellow bands of elastic tissue.

Ligamenta flava

If the acquisition window is increased, the frequency encoding gradient is switched on for a _______- amount of time. Hence the peak of the echo occurs later, increasing the time from the peak of the echo to the RF excitation pulse that created it. The TE is therefore __________.

Longer,

The Z component of the net magnetization vector in the direction of the static magnetic field. Following RF excitation, this vector returns to its equilibrium value at a rate characterized by the time constant T1.

Longitudinal magnetization

____________ ____________is professional negligence by act or omission by a health care provider in which the treatment provided falls below the accepted standard of practice in the medical community and causes injury or death to the patient, with most cases involving medical error, simply defined as a failure to render proper services through reprehensible ignorance or negligence.

Medical malpractice

Airborne, droplet, contact are all what?

Method of transmission

A crime that is punishable by a fine and/or up to one year in jail

Misdemeanor

Medical asepsis is the removing or killing of ______ microorganisms, whereas surgical asepsis is the removing or killing of ____ microorganisms completely

Most, All

An MR technique using a series of echoes following a single excitation pulse, usually in the form of 180º RF pulses that generate images.

Multi-echo imaging

_____________ is a failure to exercise the care that a reasonably prudent person would exercise in like circumstances.

Negligence

An uncharged neutral particle located in the nucleus of most atoms which serves as a stabilizer.

Neutron

To triple the SNR requires a _______fold increase in NSA and scan time.

Nine

Infections acquired during a hospital stay or while receiving some type of medical treatment.

Nosocomial infections

An imaging technique which produces images along planes that are not perpendicular to the X,Y, or Z axes.

Oblique

An MRA technique based on the speed of the vessels of interest, utilizing velocity encoding (VENC)

_____ MRA is the most useful technique to evaluate slow flow within a vessel.

An image minimizing T1 and T2 effects, with contrast primarily dependent upon the density of protons in the imaging volume.

With a long TR, the differences in T1 contrast primarily rely on what intrinsic parameter?

With a TR of 4000ms and an ETL of 16, echoes collected early on would exhibit ____ weighting while echoes collected towards the end would exhibit heavy _____ weighting.

PD, T2

In the spine, the _____ runs withing the vertebral canal aling the dorsal border of the vertebral bodies, primarily attaching to the intervertebral discs. It is much more narrow and weak compared to the ALL.

PLL

Drug route that is any route other than by mouth (PO) or rectal.

Parenteral

Cause of disease

Pathogen

_______________ magnets are blocks of ferromagnetic plates used to generate a magnetic field, and are typically heavy.

Permanent

A magnet designed with blocks of ferromagnetic materials to generate a magnetic field, typically heavy in construction. No supercooling or additional electrical power required, typically low field.

Permanent magnet

An artificial object that can be imaged to test the performance and quality of a magnetic resonance system.

Phantom

What equation is used to calculate voxel volume?

Pixel area (phase x freq ^2) x slice thickness

The vertebral artery supplies blood to the _________ _____.

Posterior brain

Frequency is a change of phase over _______.

Time

Part of the QC test that provides information relating to the proper flip angles.

Transmit gain

Quantity that has both magnitude and direction.

Vector

Gradient rise time is measured in what?

mT/m (Or G/cm)

In the steady state, image contrast is not due to to differences in the T1 recovery or T2 decay times of tissues but rather due to the _______ of T1 recovery and T2 decay time.

Ratio

The components of the magnetization in the imaging object after excitation, sampled from the receiver coil signal and stored as a function of time during the data acquisition of an MR imaging sequence

Raw data

Magnetic field gradient applied during the moment when the echo is formed, and is responsible for frequency encoding in the image

Readout gradient

Where the pathogen grows

Reservior

The ability to differentiate adjacent tissue structures.

Resolution

GE sequences keep their residual trans mag coherent by a process known as _____________.

Rewinding

To achieve large pixels a ______ slope of the phase encoding gradient is applied.

Shallow

The gradient _________ ______ is the speed rate of ascent or descent of a gradient from zero to its maximum amplitude, either positive or negative.

Slew rate

Shallow phase-encoding gradients produce _____ phase shifts across a given distance along the gradient and are able to encode ______ spatial frequencies.

Small, low

To decrease magnetic susceptibility, utilize ________ voxels, _________ TE, and___________ receiver bandwidth.

Smaller, decrease, increase

Resolution increases with a ________ FOV, _________ matrix, and ___________ slices

Smaller, larger, thinner

______________ is a technique that enables evaluation of tissues metabolism by looking at its molecular and chemical structures.

Spectroscopy

MR technique generating a spectrum of metabolites in a specific volume of interest.

Spectroscopy (MRS)

Blood flow where the direction of flow is spiral.

Spiral flow

To achieve a small FOV in the frequency direction, a _____ frequency-encoding gradient is applied.

Steep

To achieve small pixels a ______ slope of the phase encoding gradient is applied.

Steep

To achieve thin slices, a _______ slice-select slope and/or _________ tBw is applied.

Steep, narrow

Pathogens grow in locations where they are stronger than the host they occupy.

Susceptible host

The medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone

Syncope

In CSF flow studies, the bright "white" signal within CSF spaces confirms craniocaudal flow during __________, while the "black" signal voids indicate flow during ___________.

Systole, diastole

Short echo trains lead to more ___/___ weighting.

T1/PD

The time between the excitation pulse of a sequence and the resulting echo used as the MR signal.

TE (Time to echo)

The time between the pulses (btwn 90ºRF - 180ºRF and 180ºRF - echo) in spin echo (also known as 1/2 TE).

Tau

A receive bandwidth of 32KHz represents ___KHz above the center frequency to ____KHz below the center frequency

16, 16

Oxygen is considered a medication and in order to be administered, must be prescribed by a physician. A technologist may administer oxygen in an emergency situation. The most frequent rate used is __L/min, with the average being __-___L/min administered via nasal cannula or a face mask.

2, 1-4

SAR is proportional to the power of ___ for the resonant frequency - doubling field strength results in ______fold increase in SAR potential.

2, four

Aliasing occurs due to tissues outside the FOV experiencing either higher or lower frequency that do not match the Nyquist frequency. They are therefore undersampled and placed in the wrong area on the image. A. True B. False

A (True)

All scan time equations use either multiplication or division. A. True B. False

A (True)

An informed consent can be said to have been given based upon a clear appreciation and understanding of the facts, implications, and future consequences of an action. A. True B. False

A (True)

Anatomy outside the FOV still experiences the effects of the gradients and produce a signal if it is within the volume of the receiver coil. A. True B. False

A (True)

Anything that affects signal amplitude, affects SNR. A. True B. False

A (True)

As long as the highest frequency present is sampled twice, it is represented correctly. A. True B. False

A (True)

Cables from local RF coils and gating leads should be braided and positioned straight in the bore, NEVER in direct contact with the patient's skin. A. True B. False

A (True)

Compensatory gradients are applied for the slice-select and frequency encoding process so that at the end, there is no net phase change. A. True B. False

A (True)

Contrast in Diffusion Weighted Imaging (DWI) depends on the degree to which molecular mobility is impaired (water restriction), the sensitivity of the sequence to Brownian motion, and the direction of water diffusion. A. True B. False

A (True)

Cyclical ionic Gad compounds are considered the least likely to release the Gad ion and hence the safest. A. True B. False

A (True)

GMN is more effective on veinous flow vs arterial flow due to arterial flow being pulsatile. A. True B. False

A (True)

Gating is when we select a threshold (gate) that only allows data through when a certain condition is met. A. True B. False

A (True)

Ghosting is less obvious with distance from the source. A. True B. False

A (True)

Gradient echo sequences use flip angles to control saturation effects. In a gradient echo, reducing the flip angle while maintaining the TR reduces saturation. A. True B. False

A (True)

Gradients with a shorter echo spacing will have better resolution capabilities and more available Trapezoidal gradient pulse utilized in conventional pulse sequences slices per TR period. A. True B. False

A (True)

Handwashing is the most effective method of preventing the spread of pathogens. A. True B. False

A (True)

High risk patients are often pre-medicated with Prednisone or Benadryl to help reduce the chance of having a serious anaphylactic reaction. A. True B. False

A (True)

STIR and FLAIR sequences are commonly fast IR sequences. A. True B. False

A (True)

Sequences requiring metal artifact reduction would also be candidates for parallel imaging, as the calibration scan required for parallel imaging is gradient echo based. A. True B. False

A (True)

The FDA recommends posting warning signs to indicate the ___ Gauss line.

The general public is limited to a magnetic field of ____ Gauss.

The MR technologist's approach to scanning MS patients would be to acquire thin slice FLAIR high resolution Axial and Sagittal sequences through the brain, as well as delaying post contrast T1 weighted imaging to allow accurate contrast visualization. A. True B. False

A (True)

The RF rephasing pulse results in a point in k-space flipped to the mirror point on the opposite side of k-space. A. True B. False

A (True)

The SNR in an image utilizing half-scan will be lower due to less data being acquired. A. True B. False

A (True)

The amount of chemical shift is always independent of the main field strength and is equal to 3.5ppm A. True B. False

A (True)

The amount of current passing through a coil determines the amplitude, strength, and slope of the gradient. A. True B. False

A (True)

The amplitude of any gradient is determined by how much current is passed through it. A. True B. False

A (True)

The primary biological effect of radiofrequency fields is tissue heating. A. True B. False

A (True)

A narrow rBw _________ chemical shift artifacts. A. Increase B. Decreases

A. (Increase)

Calculate the voxel volume for the following pulse sequence: TR 2000, TE 85, FOV 24cm, Matrix 272 x 320, 3mm slice thickness, 3 NSA. A. 0.66mm3 B. 0.75mm3 C. 1.98mm3 D. 4.91mm3 E. 4.98mm3

C (1.98mm3)

The difference in chemical shift is approximately ______ parts-per-million. A. 1.5 B. 2.5 C. 3.5 D. 4.5 E. 5.5

C (3.5)

Which parameter combination will yield the best spatial resolution? A. 3mm slice thickness, 192 x 256 matrix B. 3mm slice thickness, 224 x 256 matrix C. 3mm slice thickness, 256 x 256 matrix D. 5mm slice thickness, 192 x 256 matrix E. 3mm slice thickness, 208 x 256 matrix

C (3mm slice thickness, 256 x 256 matrix)

The 180° RF pulse is __x the power of the initial 90° RF pulse. A. 2 B. 3 C. 4 D. 5

C (4)

The hippocampus is located in the medial temporal lobe of the brain, and is best seen cross-sected with a __________ oblique imaging plane. A. Axial B. Sagittal C. Coronal

C (Coronal)

The optimal imaging plane to demonstrate the carpal bones and the interosseous ligaments would be the _________ plane. A. Axial B. Sagittal C. Coronal

C (Coronal)

As the number of phase encodings is increased from 256 to 512, SNR (signal to noise ratio): A. Increases B. Decreases C. Doubles D. Does not change E. Quadruples

C (Decreases)

Due to the difference in resonant frequencies between fat and water, causing a phase shift in voxels containing fat and water. This artifact only occurs in the frequency encoding direction.

Chemical shift

In order to generate thin slices, a ___________ is used. I. Steep slice selection gradient II. High amplitude slice select gradient III. Low amplitude slice select gradient IV. Narrow transmit bandwidth (tBW) V. Wide transmit bandwidth (tBW) VI. Narrow receiver bandwidth (rBW) A. I, III, IV and VI B. I, II and IV C. I and II only D. I, II, IV and V

B (I, II and IV)

In order to acquire intracranial MR venogram images, a presaturation pulse would be applied __________ to the slice group in order to null signal from intracranial arterial blood flow. A. Anterior B. Inferior

B (Inferior)

SNR is ___________ proportional to the TE A. Directly B. Inversely

B (Inversely)

To produce an image based on differences in T1, the time interval between 90° excitation pulses should be: A. Long B. Short C. Refocussed D. Inverted

B (Short)

ESP is more pronounced in ________ slices. A. Thick B. Thin

B (Thin)

Diseases, such as malaria, in which microorganisms are transferred via an insect, come under the classification of __________ infections. A. Indirect contact B. Vector borne C. Nosocomial D. Common vehicle

B (Vector borne)

As the TE is increased, the available number of slices is ___________. A. Increased B. Decreased

B (decreased (longer TE means fewer slices can fit into the TR period))

Dynamic enhanced MRA sequences of the mesenteric arteries are performed using: A. T2* gradient echo B. Steady-state gradient echo C. Coherent gradient echo D. Incoherent gradient echo

D (Incoherent gradient echo)

Gradient echo sequences requiring high signal from fluid are known as all of the following EXCEPT: A. T2* gradient echo B. Steady-state gradient echo C. Coherent gradient echo D. Incoherent gradient echo

D (Incoherent gradient echo)

A narrow receiver bandwidth: A. Should be used in the presence of metal artifacts B. Reduces SNR C. Decreases susceptibility artifact D. Increases susceptibility artifact E. B and D

D (Increases susceptibility artifact)

Gradient echo sequences can yield either T1 or T2* characteristics, with influences caused by all of the following EXCEPT: A. Chemical shift B. Inhomogeneity C. Susceptibility D. Inversion time

D (Inversion time)

On a T2 weighted image, edema appears bright because it has a _________ relaxation time. A. Short T1 B. Short T2 C. Long T1 D. Long T2

D (Long T2)

A magnetic vector possesses attributes of both __________ and _____________. A. Strength; magnitude B. Direction; purpose C. Strength; flow D. Magnitude; direction

D (Magnitude; direction)

The ___________ valve lies between the left atrium (LA) and the left ventricle (LV). A. Aortic B. Pulmonary C. Tricuspid D. Mitral E. Septic

D (Mitral)

The gradient slew rate is the: A. Time it takes longitudinal magnetization to regrow B. Time between TI and initial RF pulse C. Time it takes for the gradient to reach its full amplitude D. Rate of speed of ascent or descent of a gradient from zero to its maximum amplitude

D (Rate of speed of ascent or descent of a gradient from zero to its maximum amplitude)

In order to acquire an intracranial arterial blood flow sequence, a presaturation pulse would be applied in which location? A. Below the heart B. Anterior to brain C. Inferior to slice group D. Superior to slice group

D (Superior to slice group)

Which fissure divides the frontal and parietal lobes from the temporal lobes? A. Anterior fissure B. Longitudinal fissure C. Cerebellar fissure D. Sylvian fissure E. Insular fissure

D (Sylvian fissure)

________ sequences use T1 gradient echoes with TR and FA selections to suppress signal from stationary tissues, visualizing flowing blood by flow-related enhancement, whereas __________ sequences use T2 gradient echoes with parameter selections that suppress stationary tissue and rely on velocity-induced phase shifts for vascular signal. A. CE MRA; PC MRA B. TOF MRA; CE MRA C. PC MRA; TOF MRA D. TOF MRA; PC MRA E. PC MRA; CE MRA

D (TOF MRA; PC MRA)

An _____________ MRA exam is defined as an MRA of the carotid and vertebral arteries.

Extracranial

Reducing the FOV (field of view) only will result in: A. Decreased spatial resolution B. Increased signal-to-noise C. Decreased signal-to-noise D. Increased T1 contrast E. More slices per TR F. A and C

F (A and C)

_______ sequences are performed to suppress CSF (cerebro-spinal fluid)and aid in the detection of demyelination. A. T1 weighted B. STIR C. T2 weighted D. Gradient echo E. Spin density F. FLAIR

F. (FLAIR)

TR controls the amount of T1 contrast in a SE sequence, but TR and ____ control the amount of T1 in an GE sequence.

SE sequences have more signal than GE sequences for what two reasons?

FA (the longitudinal mag is converted into transverse mag by the 90 flip angle; GE only convert a proportion of the long mag into transverse) and 180 RF pulse (the § rephasing pulse is more efficient at rephasing than the rephasing gradient of GE sequences, and so the resultant echo has greater signal amplitude)

Gradient moment nulling is most effective on ______ -order motion.

First

When the direction and velocity of flow are constant, it is defined as _______ -order motion.

First

Flow compensation (GMN) is only used to correct for _______ order motion and _________ velocity.

First, constant

The angle to which the longitudinal magnetization is tipped into the transverse plane, following the initial RD excitation pulse.

Flip angle (FA)

An MR technique used to reduce artifacts from spin phase effects through the use of additional gradient pulse. Also known as Gradient Moment Nulling.

Flow compensation

The invisible lines of force that extend around a magnetic field, with the greatest strength/force being at the two poles/ends of the magnet.

Flux

Echo generated by switching a pair of dephasing and rephasing gradients, without the use of a 180° refocusing pulse (seen in spin echo sequences).

Reducing the FOV by a factor of 2 will reduce the voxel volume by a factor of: A. 1.41 B. √2 C. √4 D. 2 E. 4

E (4)

Which of the following parameter adjustments will SHORTEN scan time in an MR pulse sequence? I. Decrease TR II. Increase TR III. Increase ETL IV. Decrease ETL V. Decrease NEX VI. Increase NEX VII. Enable Half-fourier VIII. Increase parallel imaging factor IX. Decrease parallel imaging factor X. Enable anti-aliasing A. I, III, IV and VII B. I, II, III and IV C. I, II, IV, VI, VII and IX D. I, II, IV, V, VII and X E. I, III, V, VII and VIII F. I, III, IV, VI, VIII and IX

E (I, III, V, VII and VIII)

All of the following yield a higher signal-to-noise ratio EXCEPT: A. Increase in TR B. Larger FOV C. Higher NEX D. Decrease in ETL E. Increase in TE F. Reduction in phase matrix

E (Increase in TE)

All of the following are examples of INTRINSIC contrast parameters in tissues EXCEPT: A. Proton density B. ADC (apparent diffusion coefficient) C. T2 time of tissue D. T1 time of tissue E. TR

E (TR)

T2 weighted FLAIR (fluid attenuated inversion recovery) sequences are typically used for evaluation of: A. Intra-articular cartilage B. Adrenal adenoma C. Fatty liver D. Musculoskeletal chondroma E. White matter disease

E (White matter disease)

The radiofrequency pulse used to disturb the equilibrium of the NMV; the higher the energy, the greater the flip angle.

Excitation pulse

Normal blood pressure is ___/___ mm Hg.

120/80

ACR recommended Zone __ signage designates an area intended for the general public

FDA guidelines dictate a level of concern when RF energy absorption produces an increase in body temperature of __° Celsius.

Doubling the NSA will increase the SNR by _____.

1.4

1 T = ___________ Gauss.

10,000

T1 recovery takes approximately ___-___ times longer than T2 decay.

10-15

Fat has a T2 time of ____ ms.

100

White matter has a T2 time of _____ ms.

100

1 T/m = what?

100 G/cm

_____________ consent is a controversial form of consent which is not expressly granted by a person, but rather inferred from a person's actions and the facts and circumstances of a particular situation (or in some cases, by a person's silence or inaction).

Implied

What GE pulse sequence samples only the FID?

Incoherent (Spoiled GE)

Acquires data from an entire volume of tissue, rather than in separate slices. The excitation pulse is not slice selective, and the whole prescribed imaging volume is excited describes what type of acquisition?

3D volumetric

ACR recommended Zone ___ signage designates an area intended for screened patients under constant direct supervision of trained MR personnel

Reducing the FOV by a factor of 2 will reduce the voxel volume by a factor of ___.

The 180° RF pulse is __x the power of the initial 90° RF pulse.

A loss of resolution due to excessively large voxels, typically caused by slices that are too thick.

Partial volume averaging

In large voxels, individual signal intensities are averaged together and not represented as distinct within the voxel which describes what?

Partial volume averaging

In large voxels, individual signal intensities are averaged together and not represented as distinct within the voxel. This is known as what?

Partial volume averaging

Using thinner slices will decrease SNR, but it was also decrease what?

Partial volume averaging

In FSE images, image weighting is controlled by _____ _______ so that data from echoes at or around the effective TE are placed in the signal and contrast areas of k-space.

Phase reordering

The amplitude of the steepest phase-encoding gradient positively and negatively determines what?

Phase resolution (pixel size)

Any two 90 degree excitation pulse create a ________ echo in the steady state.

Hahn

The width of the RF pulse should be _____ its amplitude, but this normally varies up to ___%.

Half, 10

FDA limits for whole body SAR is ___ W/kg over ___ minutes of scanning and Head limits are 3 W/kg over 10 minutes of scanning.

4, 15

The intensity limit for a static magnetic field in clinical use is limited by the Food and Drug Administration (FDA) to __ Tesla (T) field strength for all patients, but __ Tesla for all patients over 1 month of age.

4, 8

Acquiring all the data from slice 1 and then go on to acquire all the data from slice 2 (all lines of K space are filled in slice 1 and then all the lines of k space are filled for slice 2), describes what type of acquisition?

Sequential

To achieve a large FOV in the frequency direction, a _____ frequency-encoding gradient is applied.

Shallow

A coherent GE is a steady state sequence that utilizes a ___ TR and ____ FA.

Short, medium

Any two RF pulses with varying amplitude (FA) create a _______ echo in the steady state.

Stimulated

Produces a banding artifact at the interfaces of high and low signal. Results from undersampling of data so that interfaces of high and low signal are incorrectly represented on the image. Occurs only in the phase direction.

Truncation (Gibbs)

The coronal images usually lie along the horizontal axis of the magnet therefore the ___ gradient performs the phase encoding.

If a coronal slice plane has been selected, the ___ gradient is enabled to alter the magnetic field around the patient's body.

In axial images, the short axis of the anatomy lies along the ____ axis

The number of Watts of RF energy per kilogram of body weight in an imaging sequence.

SAR

What is the chemical shift at 3T.

440 Hz

In PC-MRAs, a VENC of __cm/s is commonly used to evaluate both venous and arterial flow.

The TR for a PD weighted image is typically ____-____ms and the TE is typically ____-____ms.

1500-3000, 10-30

What is the sampling time for a 512 frequency matrix and 32 kHz rBw?

16 ms

If a rBw of 16 KHz is selected, then the echo is sampled ________ times per second during the sampling window.

16,000

Diffusion-weighted imaging (DWI) can be performed by using diffusion gradients on each side of the _____° pulse when using very fast, single-shot spin-echo echo-planar varying b-values. The first pulse dephases the spins, and the second pulse rephases the spins if no net movement occurs.

180

ACR recommended Zone __ signage designates an area intended for unscreened MRI patients

SAR is proportional to the power of ___ for the resonant frequency.

CSF has a T1 time of ____ ms.

2000

The TR for a T2 weighted image is typically ____-____ms and the TE is typically ____-____ms.

2000-6000, 70-120

Water has a T1 time of ____ ms.

2500

Water has a T2 time of ____ ms.

2500

If the frequency matrix is 256, how many data points must be collected?

256

Filling one line of K space for slice 1 and then going on to fill the same line of K space for slice 2, etc describes what type of acquisition?

2D volumetic

ACR recommended Zone ___ signage designates an area intended for screened MRI patients/personnel

A 6 inch surface coil is able to receive signal ____ inches deep into the patient.

3 (SNR penetration depth = ½ coil diameter)

Smaller FAs contribute more ___ weighting. 1. T1 2. T2 3. T2* 4. PD

3 (T2* less long mag, and FA modulation if exclusive to GE pulse sequences)

FDA limits for whole body SAR is 4 W/kg over 15 minutes of scanning and Head limits are __ W/kg over ___ minutes of scanning.

3, 10

The difference in chemical shift is approximately _____ parts-per-million (ppm)

3.5

Cross-excitation can be reduced by insuring that there is at least a ___% gap between the slices.

3.5 T/m = _____ G/cm.

350 (3.5 x 100)

The TR for a T1 weighted image is typically ____-____ms and the TE is typically ____-____ms.

350-700, 10-30

The liquid cryogens are cooled in a superconducting magnet at a temperature of ___ Kelvin.

To double SNR we would need to increase the NEX and the scan time by a factor of ___.

4 (Not the best way to increase SNR.)

Halving rBw improves SNR by ~_____%

When going from a linear coil to a quadrature coil, SNR is increased by _____%.

Halving the rBw increases the SNR by about ___%, but ____________ the sampling window.

40, increases

Doubling FOV increases SNR to _____% of the original value, due to the pixel size increase by a factor of 4 (phase and frequency dimensions)

400

What is the precessional frequency of hydrogen?

42.57

What is the gyromagnetic ratio of hydrogen at 1 T?

42.57 MHz

A typical Fast Spin Echo sequence can have an echo spacing of anywhere between ___ ms and ___ ms, approximately.

5, 20

White matter has a T1 time of ____ ms.

500

With respiratory gating, up to ____% of data acquired can be thrown out due to it not meeting the necessary conditions, thus increasing scan time.

Normal pulse rate should be about ___-___ beats / minute.

60-100

If a rBw of 64 KHz is selected, then the echo is sampled ________ times per second during the sampling window.

64,000

Consistent room temperature of ___-___°F, humidity of 50-70%, and sufficient air flow in the MR scan room.

65-75

The TI required to null signal from a tissue is always 0.__ times its T1 relaxation time.

What is the sampling time for a 256 frequency matrix and 32 kHz rBw?

8 ms

A gradient echo sequence in which all the remaining residual transverse magnetization is removed prior to the next excitation pulse is known as: A. Incoherent or spoiled B. Steady state C. Magnetization prepped D. Dual IR

A (Incoherent or spoiled)

To sample this higher frequency accurately, the sampling frequency must _____________. A. Increase B. Decrease

A (Increase - if not, aliasing results)

A remedy for a Gibbs truncation artifact would be: A. Increase the field of view B. Reduce the number of phase encodings C. Increase the number of phase encodings D. Decrease the TE

A (Increase the field of view)

A 90 degree FA in SE or the Ernst angle in GE pulse sequences will ___________ the SNR. A. Increase B. Decrease

A (Increase)

A high/fine image matrix will _______ spatial resolution. A. Increase B. Decrease

A (Increase)

A large FOV will ________ the SNR. A. Increase B. Decrease

A (Increase)

A long TE will __________ the TOF phenomenon. A. Increase B. Decrease

A (Increase)

A long TR and short TE will __________ the SNR. A. Increase B. Decrease

A (Increase)

A narrow rBw will _________ the SNR. A. Increase B. Decrease

A (Increase)

A very long TR and TE will ________ CNR. A. Increase B. Decrease

A (Increase)

If a frequency matrix increases from 256 to 512 while the rBw of 32 kHz remains unchanged, the sampling time will _____________. A. Increase B. Decrease

A (Increase)

Increasing the field strength will ____________ the T1 recovery time. A. Increase B. Decrease

A (Increase)

Increasing the sampling time will ___________ the minimum TE. A. Increase B. Decrease

A (Increase)

Increasing the temp of the tissue will ____________ the T1 recovery time. A. Increase B. Decrease

A (Increase)

Paramagnetic substances _____ to the applied magnetic field. A. Increase B. Decrease

A (Increase)

Partial volume averaging increases when there is a(n) ___________ in slice thickness. A. Increase B. Decrease

A (Increase)

Thick slices will _________ the SNR. A. Increase B. Decrease

A (Increase)

Thin slices will __________ spatial resolution. A. Increase B. Decrease

A (Increase)

To remedy for Gibbs artifacts, one must _________ the number of phase encoding steps. A. Increase B. Decrease

A (Increase)

_________ in NEX and/or the enabling of Flow Compensation can correct for FID (Free Induction Decay) artifacts. A. Increase B. Decrease

A (Increase)

As the velocity of flow increase, TOF phenomenon _____________. A. Increases B. Decreases

A (Increases - High velocity signal loss)

As the digital sampling frequency increases, the noise in the image _____________. A. Increases B. Decreases

A (Increases)

If the system must perform extra gradient tasks, more time must elapse before it is ready to read the echo, thus _______ the minimum TE. A. increasing B. Decreasing

A (Increasing)

Spatial resolution increases by keeping the FOV the same and _________the image matrix. A. Increasing B. Decreasing

A (Increasing)

2D TOF (time of flight) MR angiography is typically used for _______ areas of coverage, with thicker slices used. (TOF MRA relies on flow related enhancement to distinguish between stationary spins and flowing spins) A. Large B. Small

A (Large)

A coarse matrix results in ________ pixels. A. Large B. Small

A (Large)

2D TOF (time of flight) MR angiography is typically used for ________ areas of coverage, with thicker slices used. (TOF MRA relies on flow related enhancement to distinguish between stationary spins and flowing spins). A. Larger B. Smaller

A (Larger)

Brought on by eddy currents, especially at high field strengths and large FOV's, there is no real correction to dielectric effects outside of placing patients on lower field strength systems, employing dielectric pads or utilizing a __________ FOV. A. Larger B. Smaller

A (Larger)

In the lentiform nucleus, the putamen lies more ____________ than the globus pallidus. A. Lateral B. Medial

A (Lateral)

Which type of blood cell is responsible for phagocytosis? A. Leukocyte B. Erythrocyte C. Lymphocyte D. Platelet

A (Leukocyte)

Water has a __________ T1 relaxation time and a ________ T2 relaxation time. A. Long; long B. Short; short C. Short; long D. Long; short

A (Long; long)

By the application of an imaging option known as gradient moment nulling (flow compensation), it is required that a ___________ minimum TE is used due to the use of additional gradients. A. Longer B. Shorter

A (Longer)

Steep gradient take a __________ amount of time to apply than shallow ones. A. Longer B. Shorter

A (Longer)

The _________ the TE, the more time given for intravoxel dephasing, resulting in signal loss from within the vessel. Larger voxels lead to an increase in inhomogeneities within the voxel, increasing intravoxel dephasing and reducing signal intensity. A. Longer B. Shorter

A (Longer)

RF energy used in MRI is classified as: A. Low energy, nonionizing radiation B. Low energy, ionizing radiation C. High energy, nonionizing radiation D. High energy, ionizing radiation

A (Low energy, nonionizing radiation)

High ADC corresponds to _______ SI. A. High B. Low

A (Low)

To achieve a high phase matrix, the phase-encoding gradient is applied _________ times during the pulse sequence. A. Many B. Fewer

A (Many)

If the combination of FA and TR causes saturation of the vectors (they never fully recover their longitudinal magnetization during the TR period) then T1 contrast is _______________. A. Maximized B. Minimized

A (Maximized)

Higher field strengths means that ________ energy is required to excite H nuclei. A. More B. Less

A (More - This leads to higher SAR)

The echo of the effective TE will have the _______ signal, greatest magnitude. A. Most B. Least

A (Most)

Objects exhibiting diamagnetism have ________ electrons. A. Paired B. Unpaired

A (Paired)

In cardiac imaging, a two chamber view is acquired where the slices are selected _________ to the inter-ventricular septum. A. Parallel B. Perpendicular

A (Parallel)

The net longitudinal magnetization in thermodynamical equilibrium is due to a tiny excess of protons in the lower energy state. This gives a net polarization ____________ to the external field. A. Parallel B. Anti-parallel

A (Parallel)

In a medical malpractice lawsuit, the ______ must be able to prove medical malpractice. A. Patient plaintiff B. Technologist who performed the scan C. Hospital's risk manager D. Radiologist defense lawyer

A (Patient plaintiff)

Phase mismapping is produced by anatomy moving across the _________-encoding gradient during the pulse sequence. A. Phase B. Frequency

A (Phase)

The slice thickness is _____________ to the transmit bandwidth. A. Proportional B. Inversely proportional

A (Proportional)

To achieve a small pixel, the highest or lowest step in the ladder is selected using a ___________ phase-encoding gradient. A. Steep B. Shallow

A (Steep)

An extracranial time-of-flight MRA of the carotid arteries for arterial blood flow would require a presaturation pulse to be placed ____________ to the slice group above the cerebellum/brain stem. The purpose of this presaturation pulse is to null the signal from venous blood flow. A. Superior B. Inferior

A (Superior)

In order to acquire an intracranial arterial blood flow MRA, a presaturation pulse would be applied ___________ to the slice group in in order to null signal from intracranial venous blood flow. A. Superior B. Inferior

A (Superior)

Larger FAs contribute more ___ weighting. 1. T1 2. T2 3. T2* 4. PD

A (T1 - more long mag)

Manganese chelates such as Mn-DPDP enhance the _____ signal and have been used for the detection of liver lesions. A. T1 B. T2

A (T1)

TOF (Time-of-Flight) MRA sequences use ____ gradient echoes with TR and FA (flip angle) selections to suppress signal from stationary tissues, visualizing flowing blood by flow-related enhancement. A. T1 B. T2 C. T2* D. PD

A (T1)

·Steep slopes stress the gradient coils more than shallow slopes which increases the minimum TE. A. True B. False

A (True - Steep slopes stress the gradient coils more than shallow slopes; which increases the minimum TE as the system cannot collect signal until all the gradient functions have been completed.)

Fat will remain bright on T2W images using a FSE due to J coupling. A. True B. False

A (True - The multiple 180 degree RF pulses reduce the effects of spin-spin interactions)

FSE sequences are best for T2 weighted images. A. True B. False

A (True - because large turbo factor for a T1 or PD image will place too much T2 weighting in the image so a shorter turbo factor must be used)

STIR should not be used in conjunction with contrast enhancements. A. True B. False

A (True - enhancing tissues will be nulled)

A paraplegic patient is one that is paralyzed from the waist down. A quadriplegic is one that is paralyzed in the upper and lower extremities. A. True B. False

A (True)

A wide rBw means that the echo is sampled more frequently than when it is narrow. A. True B. False

A (True)

According to the FDA, a severe reaction to MR contrast would be described as life threatening or permanently disabling. A. True B. False

A (True)

By saturating normal anatomy (which often contains fat), pathology (which is mainly water) is often seen more clearly especially if it has high intensity. A. True B. False

A (True)

Current FDA guidance limits the Time Rate of Change of Magnetic Field (dB/dt) to levels which do not result in painful peripheral nerve stimulation. A. True B. False

A (True)

Decreasing bandwidth by factor of 2 increases SNR by √2 (approximately 40%). A. True B. False

A (True)

Doubling field strength results in fourfold increase in SAR potential. A. True B. False

A (True)

Each data point contains information for the whole slice, as spatial frequencies come from the whole echo, and the echo comes from the whole slice. A. True B. False

A (True)

Education for patients and staff is the most important aspect of providing a safe MR environment. A. True B. False

A (True)

Every TR, a different line of k-space is filled with the same number of data points determined by the frequency matrix. A. True B. False

A (True)

FDA safety levels for RF exposure during MR examination are defined by SAR restrictions, which are imposed to reduce the risk of systemic and/or thermal injury to patient. A. True B. False

A (True)

Fast or turbo versions on the traditional GE sequences use strategies such as ramped sampling and fractional echo to reduce scan times. A. True B. False

A (True)

Fat molecules are closely packed together and have a tumbling rate that matches the Larmor frequency. This means they are efficient at exchanging energy. A. True B. False

A (True)

Field strength in MRI is the barometer of the potential for image quality. A. True B. False

A (True)

Functional imaging techniques are used to image the function or physiology of a system rather than its anatomy. A. True B. False

A (True)

If a brain exam is being performed and the request is made to rule out acoustic neuroma, a protocol with thin cuts through the IAC's (Internal Auditory Canals, or 7th and 8th Cranial Nerves) should be performed. A. True B. False

A (True)

If a patient has to be monitored with an electrical or mechanical device while undergoing an MR procedure, it is important that compatibility with the MR system be demonstrated by: Clearance by the FDA Manufacturer declaration Prior testing A. True B. False

A (True)

In a GE pulse sequence, the rephasing lobe of the bipolar gradient only affects the magnetic moments that are dephased by the dephasing lobe of the gradient. A. True B. False

A (True)

In coronal scans of the chest, sat bands may be placed left and right of the FOV to reduce flow from the subclavian vessels. A. True B. False

A (True)

In emergency situations, a physician can order a procedure under implied consent if the benefits outweigh the risks, in reference to an unconscious patient, for example. A. True B. False

A (True)

In terms the of phase encoding, the magnetic moments at isocenter never undergo a change of phase because their frequencies are unaltered. A. True B. False

A (True)

In the event that a patient develops severe bronchospasms after the injection of contrast, Epinephrine would probably be administered by the radiologist or nurse. A. True B. False

A (True)

In the human body, CSF has the highest PD. A. True B. False

A (True)

In the steady state, there is a coexistence of both longitudinal and transverse magnetization. A. True B. False

A (True)

Increasing ETL reduces the number of available slices. A. True B. False

A (True)

Increasing the NSA is not necessarily the best way to increase SNR. A. True B. False

A (True)

Increasing the frequency matrix has the same effect as decreasing the rBw. A. True B. False

A (True)

Iron, nickel, cobalt, and gadolinium are the only four naturally occurring elements that are ferromagnetic at a normal ambient temperature. A. True B. False

A (True)

K-space is a storage device. A. True B. False

A (True)

Large coils increase the likelihood of aliasing bc tissue outside the FOV is more likely to produce signal. A. True B. False

A (True)

Longer TEs mean that less slices are available per TR period due to the fact that the system must wait longer before the signal can be collected. A. True B. False

A (True)

Longitudinal magnetization (or Net Magnetization Vector) is defined as the excess number of hydrogen protons aligned with the static magnetic field. A. True B. False

A (True)

Masks should always be worn with a patient that has TB, and the patient should also be wearing a mask. A. True B. False

A (True)

Maximum field strength in a resistive magnet is less than 0.2T or 0.3T, due to the fact that any increase in magnetic field would require an increase in current. This would increase the resistance in the windings which would raise the temp that would destroy the electromagnet. A. True B. False

A (True)

Natural products with high manganese concentration such as blueberry and green tea can also be used for T1 increasing contrast enhancement. A. True B. False

A (True)

Newer MR scanners contain digital receiver technology, reducing the inherent noise created by analog-to-digital signal conversion techniques. A. True B. False

A (True)

Noise stays the same (constant), signal can be increased or decreased. A. True B. False

A (True)

Objects exhibiting ferromagnetism have half filled electron shells. A. True B. False

A (True)

Patients in need of MRI IV gadolinium contrast should first have their glomerular filtration rate (GFR) checked if they: Are over the age of 60 Have a history of hypertension Have a history of diabetes Have a history of renal disease A. True B. False

A (True)

Peripheral triggering is not as accurate as EKG triggering. A. True B. False

A (True)

RF heating is more of a concern in fast spin echo sequences due to the multiple echo train lengths, leading to potential increases in tissue heating. A. True B. False

A (True)

RF pulses are still able to rephase even if their magnitude is less that 180 degrees. A. True B. False

A (True)

RF spoiling ensures that residual transverse magnetization is not sampled. This is achieved by altering the phase angle of each RF pulse every TR and locking this to the receiver coil. A. True B. False

A (True)

Reducing the phase encoding matrix yields higher SNR, shorter scan times, but decreased spatial resolution due to the increased pixel size. A. True B. False

A (True)

Reducing the phase encoding matrix yields higher SNR, shorter scan times, but decreased spatial resolution due to the increased pixel size. A. True B. False

A (True)

Regions of the body that do not quickly dissipate thermal absorption from SAR during MR procedures are the eyes and testicles. A. True B. False

A (True)

Respiratory triggering can lead to mixed contrast since the pt's breathing rate is what controls the TR. A. True B. False

A (True)

Reverse echo Ge sequences have largely been replaced by FSE pulse sequences. A. True B. False

A (True)

Risk factors of MR exposure with regards to SAR include all of the following: Obesity Hypertension Cardiovascular disease Elderly Sedatives/Diuretics A. True B. False

A (True)

SNR (signal-to-noise ratio) increases by the square root (√) of the % increase. A. True B. False

A (True)

Since the sella turcica forms a bony caudal border for the pituitary gland, a pituitary tumor can extend only upward in the superior direction. A. True B. False

A (True)

Square pixels always provide better spatial resolution than rectangular pixels as the image is equally resolved along both frequency and phase axis. A. True B. False

A (True)

Symptoms of a patient in cardiac arrest might include pallor and weakness, or not having a pulse. A. True B. False

A (True)

T1/PD weighted images will have higher SNR than T2 weighted images. A. True B. False

A (True)

T2 decay is caused by one spin transferring energy to another spin rather than to the lattice. A. True B. False

A (True)

TR does not control T1 contrast in an IR sequence because it is always long. A. True B. False

A (True)

The FOV is measured in phase and frequency dimensions, therefore reducing the FOV in half will reduce the phase AND frequency dimensions EACH by 2, for a total reduction of a factor of 4. A. True B. False

A (True)

The Larmor frequency is proportional to B0, and there T1 recovery takes longer as B0 is increased because there are fewer molecules moving at relaxation-causing frequencies. A. True B. False

A (True)

The direction of flow is probably the most important factor in determining the degree to which ESP penetrates into the slice stack. A. True B. False

A (True)

The duration of the frequency encoding gradient is called the sampling time, sampling window, or acquisition window. A. True B. False

A (True)

The further away from the center of k-space (effective TE), less desirable contrast will be found. A. True B. False

A (True)

The major bifurcation of the abdominal aorta is the right and left common iliac arteries. A. True B. False

A (True)

The objective of black blood imaging is to completely nullify the signal from flowing blood. A. True B. False

A (True)

The phase-encoding gradient can be switched on at any time in a pulse sequence, but it is usually applied as soon as the possible after the RF excitation pulse has been switched off. A. True B. False

A (True)

The right common carotid artery does not originate directly off the aorta. A. True B. False

A (True)

The sampling interval between a data point in a line of k-space is much shorter than the sampling interval between a data point in each column. A. True B. False

A (True)

The sampling window is how long the system has to acquire the data. It is the time during which the frequency-encoding gradient is turned on. A. True B. False

A (True)

To saturate either water or fat, the precessional difference between the magnetic moments of both types of nuclei must be sufficiently large so that they can be isolated from each other. Fat or water saturation is therefore most effectively achieved at higher field strengths. A. True B. False

A (True)

Tort may be defined as a personal injury; or as "a civil action other than a breach of contract.". A. True B. False

A (True)

Water molecules are spaced apart and have a tumbling rate that does not match the Larmor frequency. This means they are not efficient at exchanging energy. A. True B. False

A (True)

When moving blood enters a magnetic field, an effect on the ECG seen as a "T wave swelling" or spike occurs, also known as the magnetohydrodynamic effect, or also known as magnet-hydrodynamic effect or magnet-hemodynamic effect. A. True B. False

A (True)

When performing CE MRAs of the pituitary glad, it is important to scan rapidly following the gadolinium contrast injection because tumors appear as low signal intensity compared to the enhanced pituitary gland. A. True B. False

A (True)

When the stimulated echo and the FID are used to create a GE, T1, PD, and T2* weighting are achievable. A. True B. False

A (True)

With HIPAA, when a covered entity discloses any PHI, it must make a reasonable effort to disclose only the minimum necessary information required to achieve its purpose. A. True B. False

A (True)

·Longer TR results in more time to individually excite, rephrase, phase and frequency encode slices; if the TR is short there is less time to do this, so fewer slices are possible. A. True B. False

A (True)

The T1 recovery curve is an exponential curve that goes ____ with time. A. Up B. Down

A (Up)

Longitudinal magnetization (or Net Magnetization Vector) is defined as the excess number of hydrogen protons aligned ________ the static magnetic field. A. With B. Against

A (With)

Sequential acquisitions would be used for images that require breath-hold techniques. A. True B. False

A(True)

In ADC imaging, areas of injury will show up __________ on an ADC map compared to healthy tissue. A. Brighter B. Darker

B (Darker)

A short TR and long TE will __________ the SNR. A. Increase B. Decrease

B (Decrease)

A small FOV will ________ the SNR. A. Increase B. Decrease

B (Decrease)

A wide rBw will _________ the SNR. A. Increase B. Decrease

B (Decrease)

Decreasing the sampling time will ___________ the minimum TE. A. Increase B. Decrease

B (Decrease)

Diamagnetic substances slightly ___________ the applied magnetic field. A. Increase B. Decrease

B (Decrease)

If a frequency matrix of 256 is used while the rBw increases from 16 kHz to 32 kHz the sampling time will _____________. A. Increase B. Decrease

B (Decrease)

Increasing parallel imaging factors can _________ susceptibility artifacts around air tissue interfaces, such as temporal bone/auditory canal regions. A. Increase B. Decrease

B (Decrease)

Reducing the number of lines filled in k-space will produce an image with a _________ in spatial resolution. A. Increase B. Decrease

B (Decrease)

An aneurysm of the aortic arch root would be found in the ____________ portion of the thoracic aorta. A. Ascending B. Descending

A (Ascending)

The ______ scan plane best visualizes both dorsal and ventral nerve roots (blue arrows). The A. Axial B. Sagittal C. Coronal

A (Axial)

The ________ slice orientation is the best imaging plane to view the median nerve (a nerve of the upper limb, branching off the brachial plexus down to the wrist, the only nerve passing through the carpal tunnel). A. Axial B. Sagittal C. Coronal

A (Axial)

During dynamic enhanced imaging for vasculature or visceral structures, contrast is administered and k-space is filled with __________ to ensure that the contrast enhancement is well visualized. A. Centric B. Linear C. Reverse centric D. Reverse linear

A (Centric)

To produce echoes with a large signal amplitude, the magnetic moments of hydrogen nuclei must be _____________. A. Coherent B. Incoherent

A (Coherent)

Reducing the rBw will ___________ the number of slices per TR period. A. Increase B. Decrease

B (Decrease)

Thin slices will _________ the SNR. A. Increase B. Decrease

B (Decrease)

_______ FAs cause more saturation and therefore ______ ESP. A. Increase B. Decrease

B (Decrease)

As the velocity of flow decrease, TOF phenomenon _____________. A. Increases B. Decreases

B (Decreases)

ESP ___________ as the spins move further into the imaging volume. A. Increase B. Decrease

B (Decreases)

If the sampling frequency increases, then the sampling interval _____________. A. Increases B. Decreases

B (Decreases)

In rectangular FOV the size of the incremental step between each line of K-space is increased, and therefore ______________ the size of the phase FOV relative to the frequency and a rectangular or asymmetric FOV results. A. Increases B. Decreases

B (Decreases)

Increases in distance from magnet isocenter create __________ in Gauss, proportional to field strength. A. Increases B. Decreases

B (Decreases)

Increasing the rBw __________ the sampling time. A. Increases B. Decreases

B (Decreases)

Nuclei that are flowing in the same direction as slice excitation (co-current flow) are more likely to receive repeated RF excitation pulses as they move from one slice to the next. They therefore become saturated quickly, so ESP _____________ rapidly. A. Increases B. Decreases

B (Decreases)

Anti-aliasing is achieved by _______________ the incremental step between each line of K-space. This in turn increases the scan time, as more lines are filled. Data is over-sampled, so aliasing is less likely. A. Increasing B. Decreasing

B (Decreasing)

Spatial resolution increases by keeping the matrix the same and _________the FOV. A. Increasing B. Decreasing

B (Decreasing)

By selecting partial (fractional) echo it is possible to switch the frequency encoding gradient on a the normal time but have the peak of the echo occur sooner rather than centered in the middle of the acquisition window. This means that only the peak and the __________ part of the echo are sampled. A. Rephasing B. Dephasing

B (Dephasing - Due to the right left symmetry of K space, the system can extrapolate both sides contain data and over signal is not lost.)

The T2 recovery curve is an exponential curve that goes ____ with time. A. Up B. Down

B (Down)

To increase the voxel volume, which parameters would be adjusted? A. FOV, slice gap and matrix B. FOV, slice thickness and matrix C. Matrix, slice thickness and slice gap D. Slice thickness and interslice gap

B (FOV, slice thickness and matrix)

Sedated patients can sometimes be monitored with a pulse oximeter. A. True B. False

B (False - They should ALWAYS be monitored with Spo2)

Parallel imaging can be used in the presence of metal implants. A. True B. False

B (False - This is due to the fact that parallel imaging requires a GE calibration scan.)

Each data point in k-space contains information for some of the slice. A. True B. False

B (False - it contains infor for the ENTIRE slice.)

An incoherent GE contains info from the FID and the stimulated echo. A. True B. False

B (False - that describes a Coherent GE.)

A TR of 1200 ms is enough to minimize T1 contrast in a T2 weighted image. A. True B. False

B (False)

Once a sterile object touches a non-sterile object, it can still be considered non-sterile. A. True B. False

B (False)

Pathology has a high water content and is therefore best demonstrated on T1 images. A. True B. False

B (False)

The patient is not considered the primary contributor of noise in an MRI image. A. True B. False

B (False)

The shorter the TE, the more time given for intravoxel dephasing, resulting in signal loss from within the vessel. Larger voxels lead to an increase in inhomogeneities within the voxel, increasing intravoxel dephasing and reducing signal intensity. A. True B. False

B (False. Longer TEs lead to intravoxel dephasing)

The process that digitizes the MR signals is known as: A. Hahn's echo B. Fourier transform C. Gyromagnetic reconstruction D. Moire effect E. Faraday's law

B (Fourier transform)

The imaging technique that employs a very rapid pulse sequence while the patient is at rest or performing a task is: A. Perfusion B. Functional MRI C. MR Spectroscopy D. Diffusion Tensor Imaging E. Cardiac Viability

B (Functional MRI)

With a 50% Rectangular FOV, the phase matrix (recFOV direction) must be exactly _______ the frequency matrix in order to yield square pixels. A. Double B. Half C. 1/4th D. Triple

B (Half)

Cortical bone Avascular necrosis Infarction Infection Tumors Sclerosis Cysts Calcifcations All appear ____________ on T1 weighted images. A. Hyperintense B. Hypointense

B (Hyperintense)

On T1 weighted images of the spine, the CSF (cerebrospinal fluid) appears: A. Isointense to the spinal cord B. Hypointense to the spinal cord C. Hyperintense to the spinal cord D. None of the above

B (Hypointense to the spinal cord)

Signal misrepresentations that do not correspond to the spatial location of the specific tissue imaged. A. Artifact B. FID C. Dead pixel D. Anisotropic voxel

A (Artifact)

T1 and T2 times are both __________ of B0 strength. A. Dependent B. Independent

A (Dependent)

SNR is ___________ proportional to the FA. A. Directly B. Inversely

A (Directly - Assuming it's a 90 degree pulse. Anything less than 90 degrees becomes governed by the Ernst Angle.)

SNR is _________ proportional to the voxel volume. A. Directly B. Inversely

A (Directly)

SNR is ___________ proportional to PD of the area of interest. A. Directly B. Inversely

A (Directly)

SNR is ___________ proportional to the TR. A. Directly B. Inversely

A (Directly)

SNR is ___________ proportional to the field strength of the magnet. A. Directly B. Inversely

A (Directly)

Slew rate is ___________ proportional to echo spacing. A. Directly B. Inversely

A (Directly)

The time increase is ___________ proportional to an increase in NEX. A. Directly B. Inversely

A (Directly)

CSF suppression is performed with which type of technique? A. FLAIR B. STIR C. SPGR D. FISP

A (FLAIR)

The shorter the rise time, the _________ the gradients and therefore echo spacing. A. Faster B. Slower

A (Faster)

A low ADC corresponds to _______ signal intensity (restricted diffusion) A. High B. Low

A (High)

A low VENC would require a _____ gradient amplitude. A. High B. Low

A (High)

ESP will be more pronounced when there is _____ velocity flow. A. High B. Low

A (High)

In fast sequencing the gradients will have ________ slew rate. A. High B. Low

A (High)

Low ADC corresponds to _______ SI. A. High B. Low

A (High)

The Larmor frequency of hydrogen in water is _________ than hydrogen in fat. A. Higher B. Lower

A (Higher)

On a T2 weighted image of the brain, the white matter will appear ______________ when compared to the gray matter. A. Hyperintense B. Hypointense

B (Hypointense)

TOF phenomena result in a signal void from flowing nuclei and vessels are ________________. A. Hyperintense B. Hypointense

B (Hypointense)

The corpus callosum will appear _____________ on a Tw weighed image of the brain because it composed of white matter. A. Hyperintense B. Hypointense

B (Hypointense)

SNR is ___________ proportional to the size of the coil used. A. Directly B. Inversely

B (Inversely)

The FOV is determined by the difference between each data point in k-space in either direction. It is __________ proportional to the size of the FOV in that direction. A. Directly B. Inversely

B (Inversely)

The incremental step between each line of K-space is _____________ proportional to the FOV in the phase direction as a percentage of the FOV in the frequency direction. A. Directly B. Inversely

B (Inversely)

A T2 image will have ______ SNR compared to a T1 or PD image? A. More B. Less

B (Less - There is less trans mag available to be rephrased to produce an echo)

Reducing the flip angle yields images with ______ T1 information. A. More B. Less

B (Less)

A high ADC corresponds to _____ signal intensity. A. High B. Low

B (Low)

A high VENC would require a _____ gradient amplitude. A. High B. Low

B (Low)

Shallow phase encoding slopes produce ____ spatial frequencies. A. High B. Low

B (Low)

Fat precesses at _______ frequency compared to water. A. Higher B. Lower

B (Lower)

The extent to which a material or tissue becomes magnetized in an external magnetic field is called: A. Magnetic inversion B. Magnetic susceptibility C. Contrast to noise ratio D. Signal to noise ratio E. Time tau

B (Magnetic susceptibility)

The MRI system component that produces the magnetization of proton spins (alignment) is known as the: A. Shim system B. Main magnet C. Gradient system D. Radiofrequency system

B (Main magnet)

The purpose of shimming the magnet is to: A. Correct for gradient slopes B. Make the B0 field as homogenous as possible C. Make the B1 field as homogenous as possible D. Make the scan time as short as possible E. Reduce the footprint of the magnetic fringe field

B (Make the B0 field as homogenous as possible)

If the combination of FA and TR does NOT causes saturation of the vectors (they recover most or all of their longitudinal magnetization during the TR period) then T1 contrast is _______________. A. Maximized B. Minimized

B (Minimized)

At thermal equilibrium, the magnetic moments of hydrogen are ________________________. A. In phase B. Out of phase

B (Out of phase)

Which MRA technique produces the most background tissue suppression? A. TOF B. PC C. CE

B (PC)

A technique utilized to reduce the MRI scan time which requires the use of an array coil is: A. Half Fourier B. Parallel imaging C. 1/2 NEX D. Rectangular FOV E. Partial / Fractional echo

B (Parallel imaging)

In cardiac imaging, a four chamber view is acquired where the slices are selected _________ to the inter-ventricular septum. A. Parallel B. Perpendicular

B (Perpendicular)

___ asks the question, "Are we operating the devices or equipment correctly?" A. QC B. QA

B (QA)

All of the following would aid in reducing scan time EXCEPT: A. Increasing parallel imaging factor B. Reduction in ETL C. Reduction in NEX D. Utilizing the coarsest matrix possible E. Enabling half-fourier option F. Reducing TR

B (Reduction in ETL)

The __________ scan plane best demonstrates the degree of spinal stenosis. A. Axial B. Sagittal C. Coronal

B (Sagittal)

To achieve a large pixel, the highest or lowest step in the ladder is selected using a ___________ phase-encoding gradient. A. Steep B. Shallow

B (Shallow)

A _____ TR may cause inflowing spins to receive multiple RF pulses as they pass through the slice. This causes a degree of saturation and therefore decreases the ESP. A. Long B. Short

B (Short)

Fat has a _______ T1 relaxation time and a ________ T2 relaxation time. A. Long; long B. Short; short C. Short; long D. Long; short

B (Short; short)

What effect would using a steep slice select slope and/or narrow bandwidth have on slice thickness? A. Slices will be thick B. Slices will be thin C. Partial volume averaging will increase D. Aliasing artifact will occur E. B and C

B (Slices will be thin)

During a post-surgical MRI of the lumbar spine, the evaluation of post-operative surgical regions and/or the possibility of scar tissue can be best accomplished by the sagittal slice plane; T1 weighted post gadolinium images. Disc enhances more _________ than post-operative scar. A. Rapidly B. Slowly

B (Slowly)

3D TOF (time of flight) MRA is typically used to visualize ______ vessels, and utilizes thinner slices, but yields less suppression of background tissues than 2D TOF. A. Large B. Small

B (Small)

When imaging the wrist in MRI, in order to achieve high spatial resolution, a ________ FOV would be used, in conjunction with a dedicated wrist or local surface coil. A. Large B. Small

B (Small)

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as: A. Tesla B. Ohm C. Volts D. Gauss E. Relaxation

D (Gauss)

What is the sampling time for a 256 frequency matrix and 16 kHz rBw?

16 ms

Fat has a T1 time of _____ ms.

200

What is the chemical shift at 1.5T?

220 Hz

CSF has a T2 time of ____ ms.

300

If the highest frequency in the echo is 16 kHz above the center frequency, then to accurately sample the signal, the rBw would need to be ___ kHz.

5.2 T/m = ______ G/cm

520 (5.2 x 100)

Maximum signal amplitude is created with a ___ degree FA.

Normal body temperature is _____._º F (37º C).

98.6

In DWI, abnormal tissue that has a low ADC has a _____ signal intensity than normal tissue that has a high ADC.

High

In areas of free diffusion, the ADC is _____ because the extracellular space is small.

High

In human tissues, fat and water have similar parity, therefore they both return _______ signal in the steady state.

High

When the direction and velocity of flow are accelerating, it is defined as _______ -order motion.

Second

Fat Hemangioma Intraosseous lipoma Radiation change Degeneration Fatty deposition Methemoglobin Paramagnetic contrast agents and slow flowing blood All appear ________________ on T1 weighted images. A. Hyperintense B. Hypointense

A (Hyperintense)

The __________ horn of the lateral ventricle lies adjacent to the head of the caudate nucleus. A. Anterior B. Posterior

A (Anterior)

If the third ventricle is dilated, but the fourth ventricle is not, there would then be pathology associated with: A. Aqueduct of Sylvius B. Insular cortex C. Basal ganglia D. Corpus callosum E. Internal capsule

A (Aqueduct of Sylvius)

Heart valves would be considered acceptable for an MRI scan at ______ T.

1.5

100 G/cm = what?

1/ T/m

1 millisecond =_____/____ of a second.

1/1000

Which of the following field strengths would require the shortest TI time to suppress the signal from fat when performing a STIR sequence in an MRI of the ankle? A. 0.5T B. 1.0T C. 1.5T D. 3.0T

A (0.5T)

The pixel size of the images which result from a 3D acquisition using a 260mm FOV, a 320 x 320 matrix, 32 slices and a volume of 64 mm is: A. 0.81 x 0.81 mm B. 0.88 x 0.88 mm C. 1.12 x 1.12 mm D. 1.18 x 1.18 mm E. 1.28 x 1.28 mm

A (0.81 x 0.81 mm)

What is the percentage of patients reported to have allergic reactions to gadolinium contrast agents? A. 1% B. 5% C. 10% D. 15% E. 20%

A (1%)

Halving FOV cuts SNR to ___% of the original value, due to the pixel size reduction by a factor of 4 (phase and frequency dimensions) A. 25 B. 50 C. 75 D. 100

A (25)

A technologist may be permitted to administer oxygen in an emergency situation. The most common rate used is: A. 2L/min B. 5L/min C. 10L/min D. 20L/min

A (2L/min)

Question #85: Calculate the available imaging time for a patient with a heart rate of 90 beats/min, trigger window 15% and trigger delay of 80ms. A. 487 ms B. 567 ms C. 667 ms D. 787 ms

A (487 ms)

Which of the following best describes an IR sequence? A. A 180° pulse followed by a 90°/180° combination B. A 90° pulse followed by a 180° pulse C. A train of gradient echoes D. A train of spin echoes

A (A 180° pulse followed by a 90°/180° combination)

____________ images are constructed from diffusion weighted images with multiple b-values, and correspond to the spatially distributed diffusion coefficients of the target tissues. A. ADC B. FID C. FOV D. SNR

A (ADC)

Equates to the signal height or strength; the larger this is, the larger the numbers of protons. A. Amplitude B. Frequency C. Phase D. Shim

A (Amplitude)

An ______________ voxel is a voxel with uneven measurements, with regards to the phase, frequency, and slice thickness dimensions. A. Anisotropic B. Isotropic

A (Anisotropic)

In time-of-flight (TOF) imaging targeted to the subclavian arteries, the two best imaging planes would be ________ and _________, as both planes image perpendicular to the vessels of interest.

Axial, sagittal

The smallest object that can be resolved in an image acquired with a 24cm FOV and a 272 x 272 matrix is _________ mm. A. 0.76mm B. 0.88mm C. 0.93mm D. 1.13mm E. 1.24mm

B (0.88)

Choose the correct slice thickness to create an isotropic voxel for the following: TR 2000, TE 90, Matrix 272 x 272, FOV 24cm. A. 0.76mm B. 0.88mm C. 0.93mm D. 1.13mm E. 1.24mm

B (0.88mm)

If a 192 phase resolution is required, the TR must then be repeated _______ times (for 1 NEX). A. 128 B. 192 C. 256 D. 512

B (192)

Question #129: In a fast spin echo sequence with a 25 cm FOV, 224 x 320 matrix, TR 2500, 100 TE, 3mm slice thickness, 12 ETL and 4 NEX, the scan time would be: A. 2 minutes 6 seconds B. 3 minutes 7 seconds C. 3 minutes 11 seconds D. 4 minutes 27 seconds E. 4 minutes 44 seconds

B (3 minutes 7 seconds)

The optimal technique to visualize the Circle of Willis would be a ___ Time of Flight, to achieve the most accurate depiction of the small vessels in the brain's arterial blood supply. A. 2D B. 3D

B (3D)

The optimal technique to visualize the circle of willis would be a ___Time of Flight, to achieve the most accurate depiction of the small vessels in the brain's arterial blood supply. A. 2D B. 3D

B (3D)

The optimal technique to visualize the circle of willis would be a ______ Time of Flight, to achieve the most accurate depiction of the small vessels in the brain's arterial blood supply. A. 2D B. 3D

B (3D)

A pediatric patient undergoing an MRI with conscious sedation should be given nothing by mouth (NPO) for __ hours before sedation. A. 2 B. 4 C. 6 D. 8

B (4)

Calculate the effective TR for a patient with a heart rate of 70 beats / min. A. 692 ms B. 857 ms C. 1024 ms D. 1223 ms

B (857 ms)

To produce a high quality reformatted image, the: A. Acquisition voxel should be anisotropic B. Acquisition voxel should be isotropic C. NEX >4 should be utilized D. Acquisition voxel should be rectangular

B (Acquisition voxel should be isotropic)

A term describing the containment of the static magnetic fringe field through the use of secondary coils attached around the MR scanner. A. Passive shielding B. Active shielding C. Passive shimming D. Active shimming

B (Active shielding)

Comprises a multiprocessor that is switched in sequence and in parallel while simultaneously performing a computing task. A. Detector element B. Array processor C. ADC D. Body coil

B (Array processor)

Question #70: Healthcare workers generally practice ___________, which states the "goal is to do no harm." A. Confidentiality B. Beneficence C. Res Ipsa Loquitor D. Stare decisis E. Negligence

B (Beneficence)

The common carotid artery bifurcates into the internal and external carotid artery at the level of the: A. C1-2 disc space B. C3-4 disc space C. C5-6 disc space D. C7-T1 disc space

B (C3-C4 disc space)

When parallel imaging techniques are utilized, a low resolution __________ is acquired prior to the acquisition. A. Geometric accuracy pulse B. Calibration scan C. Presaturation pulse D. Contrast test bolus

B (Calibration scan)

The optimal imaging plane for visualization of a TFCC tear is: A. Axial B. Coronal C. Transverse D. Sagittal E. None of the above

B (Coronal)

When imaging the female pelvis, the most optimal view for evaluation of the ovaries is the: A. Axial B. Coronal C. Sagittal D. None of the above

B (Coronal)

The _________ coils are used as active shielding in an MRI scanner and oppose B0 to contain the fringe field.

Bucking

The 2003 FDA revision on RF absorption limits the absorption to ______________ for the head. A. 2.0W/kg for 5 minutes B. 3.0W/kg for 5 minutes C. 3.0W/kg for 10 minutes D. 4.0W/kg for 10 minutes E. 4.0W/kg for 15 minutes

C (3.0W/kg for 10 minutes -The 2003 FDA revision on RF absorption limits the absorption to 3.0W/kg for 10 minutes for the HEAD.)

Which of the following combinations of flip angle (FA) and TR would produce a T2 weighted gradient echo? A. 45 TR; 30º flip angle B. 45 TR; 90º flip angle C. 450 TR; 30º flip angle D. 450 TR; 90º flip angle

C (450 TR; 30º flip angle)

A magic angle artifact occurs when a tendon or ligament is positioned approximately _____° to the direction of the main magnetic field, and a short TE value pulse sequence is utilized. A. 45 B. 50. C. 55 D. 69

C (55)

Which of the following best describes an EPI sequence? A. A 180° pulse followed by a 90°/180° combination B. A 90° pulse followed by a 180° pulse C. A train of gradient echoes D. A train of spin echoes

C (A train of gradient echoes)

Occurs when tissue outside the FOV is undersampled, causing a misregistration of anatomical location, in the phase encoding direction, but on the opposite side of the anatomical location, also known as wrap-around artifact. A. Chemical shift B. Gibbs truncation C. Aliasing artifact D. Zipper artifact

C (Aliasing artifact)

In a contrast enhanced MR angiography of the abdominal arteries, the IV gadolinium would enhance in which order? A. Superior mesenteric, inferior mesenteric, celiac, renal B. Inferior mesenteric, superior mesenteric, renal, celiac C. Celiac, superior mesenteric, inferior mesenteric, renal D. Celiac, superior mesenteric, renal, inferior mesenteric

C (Celiac, superior mesenteric, inferior mesenteric, renal)

The Ernst angle can be defined as the optimal ___________ that yields the ____________ signal for a particular spin in the least amount of time. A. TR; maximum B. TE; minimum C. Flip angle; maximum D. Flip angle; minimum E. NEX; maximum

C (Flip angle; maximum)

Short TAU inversion recovery (STIR) sequences are typically used for the evaluation of all the following EXCEPT: A. Compression fracture B. Fat suppression C. Fluid (CSF) D. Lesions within retro-orbital fat E. Musculoskeletal contusions

C (Fluid/CSF)

MRAs utilize what type of pulse sequence? A. SE B. TSE C. GE D. DWI

C (GE)

As the TR is increased, I. SNR is increased II. Available number of slices is increased III. T2 information is maximized A. I only B. II only C. I and II only D. I and III only E. I, II and III

C (I and II only)

The receiver bandwidth (rBW) affects: I. Signal-to-noise ratio (SNR) II. Slice thickness III. Chemical shift IV. Spatial resolution A. I only B. I and II only C. I and III only D. I, II, IV E. I, II, III and IV

C (I and III only)

Contrast in Diffusion Weighted Imaging (DWI) depends on: I. The degree to which molecular mobility is impaired (water restriction) II. The sensitivity of the sequence to Brownian motion III. T1 relaxation time IV. The direction of water diffusion V. T2 relaxation time A. I and II only B. I, II and III C. I, II and IV D. I, II, III and IV E. I, II, III, IV and V

C (I, II and IV)

Which of the following parameter adjustments help to improve SNR in an MR image? I. Increase TR II.Reduce Phase Matrix III. Reduce Pixel Size IV. Increase FOV V. Reduce rBW VI. Increase rBW VII. Increase NSA VIII. Decrease NSA IX. Increase ETL X. Decrease ETL A. I, III, IV and VII B. I, II, IV, VI, VII and IX C. I, II, IV, VI, VII and X D. I, II, IV, V, VII and X E. I, III, IV, V, VII and IX

C (I, II, IV, VI, VII and X)

Which of the following parameter adjustments reduce the overall SNR in an MR image? I. Decrease TR II.Reduce Phase Matrix III. Reduce Pixel Size IV. Decrease FOV V. Reduce rBW VI. Increase rBW VII. Increase NEX VIII. Decrease NEX IX. Increase ETL X. Decrease ETL A. I, III, IV and VII B. I, II, IV, VI, VII and IX C. I, III, IV, VI, VIII and IX D. I, II, IV, V, VII and X E. I, III, IV, V, VII and X

C (I, III, IV, VI, VIII and IX)

The structures that comprise the rotator cuff in the shoulder are: I. Deltoid muscle II. Subscapularis muscle and tendon III. Infraspinatus muscle and tendon IV. Teres minor muscle and tendon V. Supraspinatus muscle and tendon VI. Trapezius muscle and tendon A. I and II only B. I, III and V C. I, III, V and VI D. All of the above

C (I, III, V and VI)

Which of the following parameter adjustments will LENGTHEN scan time in an MR pulse sequence? I. Decrease TR II. Increase TR III. Increase ETL IV. Decrease ETL V. Decrease NEX VI. Increase NEX VII. Enable Half-fourier VIII. Increase parallel imaging factor IX. Decrease parallel imaging factor X. Enable anti-aliasing A. I, III, IV and VII B. I, II, III and IV C. II, IV, VI and IX D. I, II, IV, V, VII and X E. I, III, IV, V, VII and IX F. I, III, IV, VI, VIII and IX

C (II, IV, VI and IX)

Circularly polarized transmission or receiver coil with two orthogonal transmission and/or receive channels, also known as a quadrature coil. This yields better SNR than a linear coil.

CP coil

Considered to be the "Gold standard in MRI pulse sequences.

CSE

A more accurate method of detecting small intra-ocular ferrous foreign bodies is a ___ scan.

A major advantage of a 2D time of flight over a 3D time of flight sequence is the ability to: A. Determine the precise, accurate percentage of stenosis B. Better image retrograde flow C. Complete image acquisition in twice the time D. Image larger areas without saturation of flowing blood

D (Image larger areas without saturation of flowing blood)

A STIR sequence with a TI time of 160 ms will null signal from fat at what field strength? A. 0.5T B. 0.8T C. 1.0T D. 1.5T E. 3.0T

D (1.5T)

Calculate the dose of contrast (0.1mmol/kg) that should be administered to a patient weighing 176 lbs with normal kidney function in a routine MR examination. A. 6mL B. 8mL C. 12mL D. 16mL E. 18mL

D (16mL)

What would the scan time be in a 3D volume acquisition as follows: TR 24 ms, TE 7 ms, Flip Angle 15°, FOV 20cm, 2mm slice thickness, 76 slices, 176 x 256 matrix, 1 NEX? A. 2min 31sec B. 3min 21sec C. 3min 35sec D. 5min 21sec E. 5min 35sec

D (5min 21sec)

If the desire is to null the signal from a specific tissue using an inversion recovery sequence, the inversion time (TI) selected should be ______ of the T1 relaxation time of that tissue. A. 37% B. 43% C. 63% D. 69% E. 82%

D (69%)

The final result in a spectroscopy study is: A. A spectrum of specific detected metabolites B. MIPped images of vascular anatomy C. Calculated MPR images of a 3D data set D. A set of calculated images which indicate various flow characteristics

D (A set of calculated images which indicate various flow characteristics)

Which of the following best describes a FSE sequence? A. A 180° pulse followed by a 90°/180° combination B. A 90° pulse followed by a 180° pulse C. A train of gradient echoes D. A train of spin echoes

D (A train of spin echoes)

A term used to describe the adjustment of current within the shim coils on a per/patient or per/sequence basis, for the purposes of achieving uniform fat suppression or optimal prescan calibrations. A. Passive shielding B. Active shielding C. Passive shimming D. Active shimming

D (Active shimming)

The HEIGHT of a peak on an MR spectrum correlates to the _________ of a substance that was detected. A. Frequency B. T1 weighting C. T2 weighting D. Amount E. Susceptibility

D (Amount)

Single order gradient moment nulling does not compensate for: A. Constant velocity flow B. Accelerated flow C. Reverse flow D. B and C

D (B and C)

During movement or transfer of patients, a urinary collection bag should be placed: A. Below the level of the MR table B. At the foot of the MRI table C. On the stretcher between the patients legs D. Below the level of the urinary bladder

D (Below the level of the urinary bladder)

The first major branch of the abdominal aorta is the _______. A. Superior mesenteric artery B. Inferior mesenteric artery C. Renal artery D. Celiac artery E. Iliac artery

D (Celiac artery)

All of the following artifacts except ________ occur along the phase encoding axis. A. Aliasing B. Ghosting C. Wrap around D. Chemical shift

D (Chemical shift)

In what orientation would a tear of the collateral ligaments of the knee be best visualized? A. Sagittal B. Axial C. Transverse D. Coronal E. None of the above

D (Coronal)

Droplet contamination frequently occurs via: A. Sharing the MRI scanner control mouse B. Routine breathing C. Patting on the back D. Coughing

D (Coughing)

Reducing the TE yields images with what change in image contrast? A. Increased T1 information B. Decreased T1 information C. Increased T2 information D. Decreased T2 information E. None of the above

D (Decreased T2 information)

Hemangiomas in the liver are typically benign lesions, and are best visualized with: A. All phases of contrast enhancement B. First pass dynamic images C. Second pass dynamic images D. Delayed images

D (Delayed images - Hemangiomas in the liver are typically venous-fed, benign lesions, and are best visualized with delayed enhancement images. Liver cancers, on the other hand, are typically arterial-fed and are best seen on first pass dynamic images.)

In K-space, the FOV is calculated by ____________ the dimensions of k-space by the distance between each point. A. Adding B. Subtracting C. Multiplying D. Dividing

D (Dividing)

Collecting the low frequency (high amplitude signal) data points in k-space at the start of the scan (in a spiral fashion) is known as: A. Centric B. Linear C. Reverse centric D. Elliptic centric

D (Elliptic centric)

The medial and lateral rectus muscles are located in the: A. Ears B. Posterior pelvic region C. Proximal calves D. Eyes E. Superior shoulder regions F. Soft tissues of the neck

D (Eyes)

The readout gradient is usually turned on during the sampling or readout of the peak echo and also during which other process? A. Slice orientation selection B. Slice selection C. Phase encoding D. Frequency encoding E. Transmit bandwidth

D (Frequency encoding)

The ____________ of the current passing through the coil will determine the polarity of the gradient.

Direction

Whether a gradient adds or subtracts from the main magnetic field depends on the _________ of current passing through the gradient coils.

Direction

A technique utilizing the differences in resonant frequencies of fat and water separating the two tissues, acquiring each separately, then adding the two to yield a water-only image (fat suppression), and then subtracting the two to yield a fat-only image.

Dixon

The _______ ______ is defined as the time the gradients are on during a TR period, the "gradient working time."

Duty cycle

The time which the gradient system can be run at maximum power.

Duty cycle

Using the "shortest TR" affects what?

Duty cycle (Less time for gradients to do their job.)

Defined as the mode of operation in which one or more outputs reach a value that may cause physiological stress to subjects, which needs to be controlled by medical supervision.

First-level controlled operating mode

Algorithm for fast reconstruction of raw data into an MR image.

FFT (Fast Fourier Transform)

A time-based electrical signal that is detected in a nuclear magnetic resonance spectrometer, that is produced by induction from the motion of the magnetic moments of nuclei, that decays with time (T2*), that can be converted to a more conventional frequency-based signal using analysis by Fourier transforms.

FID

In an incoherent GE pulse sequence, only the _____ blank is sampled so ___ contrast dominates.

FID, T1

Incoherent GE pulse sequences have image contrast that is mainly influenced by the _____ which means that images are ___/___ weighted.

FID, T1/PD

Amplitude of the frequency encoding gradient determines how far to the left and right K space is traversed and this in turn determines the _______ in the frequency direction of the image

FOV

The base size of the slice to be acquired, measured in dimensions of phase (short axis of anatomy) and frequency (long axis).

FOV (Field of view)

The amplitude of the frequency-encoding gradient and incremental step between data points in each row of k-space (sampling interval) determines what?

FOV (Frequency)

The incremental step between data points in each column of k-space, Degree of phase change from one line to the next determines what?

FOV (Phase)

What equation is used to calculate pixel size?

FOV/matrix

What equation is used to calculate voxel size?

FOV/matrix (phase and freq) + slice thickness

RF heating is more of a concern in _____ sequences due to the multiple echo train lengths, leading to potential increases in tissue heating.

FSE

The external carotid artery supplies blood to the _________.

Face

A process of utilizing specific sequence parameters to null the signal from fat in MR sequences.

Fat suppression (STIR)

An image yielding only the signals from fat protons in an image and suppressing the signal from water; usually a "phase" of the Dixon technique.

Fat-only image

An MR technique used to suppress the signal from fat protons, yielding a "water-only" image, utilizing a chemically selective pre saturation pulse.

Fat-saturation

A crime that is punishable by a fine and prison time that can exceed one year in jail

Felony

The ____________ fields have been documented to cause muscle contractions, cardiac arrhythmias, mild cutaneous sensations and visual light flashes(Magnetophosphenes).

Gradient (Time varying magnetic fields)

In fat sat images, presaturation can sometimes appear nonuniform across the slice or imaging volume to due the _________.

Gradients

Due to the symmetry of the matrix to be sampled, a little more than half of the raw data is necessary to be acquired, reconstructing the remaining data to complete the image, greatly reducing scan time.

Half-fourier

In the steady state, in tissues where T1 and T2 contrast are similar, signal intensity is _______, and where they are dissimilar, signal intensity is ________.

High, Low

Uniformity of the main magnetic field; a magnetic field is considered homogenous when it has the same field strength across the entire field.

Homogeneity

What is the only nerve to pass through the carpal tunnel?

Median nerve

Perflubron, a type of perflorocarbon, has been used as a gastrointestinal MRI contrast agent for __________ imaging. This contrast agent works by reducing the amount of protons (as hydrogen) in a body cavity, thus causing it to appear dark in the images.

Pediatric

Lining the MR room with steel or other ferromagnetic plating, thus reducing the scope and distance of the fringe field.

Passive shielding

Shimming the magnetic field with metal pieces either within or on the outer surface of the magnet bore, for the purpose of a more homogenous magnetic field.

Passive shimming

Any disease producing agent, especially a virus, bacterium or other microorganism.

Pathogen

In pituitary ademonas, some tumors secrete more than one harmone, the most common combination being GH and _________.

Prolactin

After excitation the longitudinal magnetization returns toward equilibrium with a time constant T1 and the transverse magnetization decays toward zero with a time constant T2.

Relaxation time

Patients with poor ________ function are considered to be more at risk for NSF.

Renal

The process of returning out-of-phase magnetic moments to phase coherence, instigated by applying a 180º RF pulse (spin echo) or reversing a magnetic gradient (gradient echo)

Rephasing

________ ______ ________ is defined as "the thing speaks for itself", or, a doctrine or legal ruling that permits the presumption that a defendant was negligent even without direct evidence of how any defendant behaved.

Res Ipsa Loquitur

A magnet that can be turned on and off, and uses the principles of electromagnetism to generate a magnetic field

Resistive

Which type of MRI configuration can be switched off instantly?

Resistive

The exchange of energy between two systems at a specific frequency

Resonance

____________ __________ is Latin for "let the master answer" and is a legal doctrine which states that, in many circumstances, an employer is responsible for the actions of employees performed within the course of their employment.

Respondeat Superior

The conversion of analog signals to digital values through a specific measurement process

Sampling

_________ time is the time to sample the entire K-space line.

Sampling

The frequency direction of the image is determined by the _________ ____________.

Sampling window

Described as a change in phase over distance in a patient caused by a gradient.

Spatial frequency

The ability to define adjacent points in an image (detail).

Spatial resolution

Adhere to ____________ precautions for ALL patients at ALL times for safety and infection control best practices.

Standard

The vertebral arteries are major arteries of the neck and originate from the right and left ____________ arteries. They merge to form the single midline basilar artery.

Subclavian

A magnet whose field is generated by current in wires made of a superconducting material, and is cooled with cryogens. Typically high field systems with horizontal field orientation

Superconducting

If a transverse/axial slice plane has been selected, the ___ gradient is enabled to alter the magnetic field around the patient's body in a patient lying supine in the bore of the magnet.

In coronal and sagittal images, the long axis of the anatomy lies along the ____ axis

In Coronal and Sagittal images the long axis of the anatomy lies along the __-axis of the magnet and therefore, the __ Gradient performs the frequency encoding

Z, Z

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