Mri quiz I

The brain is a complex structure constructed with tissues of ___________ (axons of neurons) and _____________ (cell bodies of neurons).

white matter; gray matter

Areas which were injured during a stroke showed up "_________" on an ADC (apparent diffusion co-efficient) map compared to healthy tissue

"Darker"

When imaging a hemorrhagic infarct in the brain, which pulse sequence would demonstrate the magnetic susceptibility effects better?

Gradient echo

All of the following are recommendations in the reduction of metallic susceptibility artifacts EXCEPT:

Use a narrow receiver bandwidth

The Food and Drug Administration (FDA) set clinical use limits of ______ for the entire population and _______ for those over 1 month of age.

4 Tesla; 8 Tesla

Approximately ______Hertz (Hz) separate the precessional frequency of fat and water at 1 Tesla. ________on 1.5 Tesla, and _______on 3.0 Tesla

147, 220 Hz, and 440 Hz

In _____, Damadian and his team constructed the first super conducting NMR scanner and produced the first image of the human thorax, which took almost 5 hours to scan

1977

In the year ______, Schering's _________ IV Gadolinium contrast gets the first approval by the FDA

1988; Magnevist

What would the pixel shift be in a sequence acquired at 1.5Tesla (220 Hz) with a 224 matrix and a BW of 26.8 kHz?

26.8(bandwidth in kHz) x 1000 to convert into Hz = 2680026800 ÷ 224(matrix) = 120 Hz frequency difference per pixel220(chemical shift) ÷ 120 = 1.8, the fat image will be shifted 1.8 pixels along the frequency/readout axis relative to water

What does the T wave represent

Ventricular diastole (repolarization)

Which MRI pulse sequence is best suited for evaluation of aortic dissection?

A. Steady state free precession C. CE-MRA (Both)

________ occurs when tissue outside the Field of View is undersampled, causing a misregistration of anatomical location, in the phase direction, but on the opposite side of the anatomical location,

Aliasing artifact

Primarily stemming from active RF coil channels or elements outside the scanning field of view, ______________ artifacts can be corrected by simply de-selecting the element(s) outside the scanning range.

Annefact ribbon like artifacts can be corrected by simply de-selecting the element(s) outside the scanning range

Both coronary arteries arise from

Aortic Root. They originate from left side of heart at immediate beginning of (Aortic Root) of aorta, above aortic valve.

What does the P wave represent?

Atrial Systole Muscle contraction. depolarization

________ and _________ won the Nobel Prize in 1952 for their invention of equipment which could measure the magnetic resonance in solids and fluids.

Bloch and Purcell

In what anatomical region would you expect to see chemical misregistration the least?

Cerebellum

A _______injury indicated brain damage on the opposite side where the blunt trauma occurred

Contrecoup

cyclic, non-ionic gadolinium-based contrast agent

Gadavist® (gadobutrol) injection is to detect and visualize areas with disrupted blood brain barrier (BBB) and/or abnormal vascularity of the central nervous system. For MRI of the breast to assess the presence and extent of malignant breast disease.

Which artifact mimics a syrinx in the spine?

Gibbs truncation

Completely insensitive to inhomogeneities, __________ sequences utilize an in-phase and out-of-phase acquisition to generate reconstructions via image algebra computations. insensitive to B0 or B1 inhomogeneities making these sequences an excellent choice in the presence of metal or with the utilization of a large field of view

Dixon

cyclic, ionic gadolinium based contrast agent.

Dotarem® (Gadoterate meglumine) for use in MRI of the brain, spine and associated tissues of patients ages 2 years and older.

hepatobiliary gadolinium for intravenous use in T1-weighted (MRI)

EOVIST® (Gadoxetate Disodium) is for liver to detect and characterize lesions in adults with known or suspected focal liver disease.

___________ discovered the spin echo phenomenon for nuclear magnetic resonance measurements.

Erwin Hahn

______________ discovered that a charged particle, such as a proton, spinning around its own axis, has a magnetic field, known as magnetic momentum.

Felix Bloch

A FID crushing artifact can be eliminated with the use of:

Flow compensation technique Increased NEX (DO BOTH) fine-line artifacts give the appearance of Gibbs-like artifacts, but originate from an incompletely crushed FID signal from an RF refocusing pulse\ common in FSE / TSE sequences because of their pulse sequence design and their high SNR. Contributing factors leading to fine line artifacts are reduced refocusing pulses, increases in FOV, and decreases in slice thickness

______________ discovered that a current flowing through a wire could produce a magnetic field.

Hans Christian Oersted

Which area of the brain is typically affected in patients with a history of epilepsy?

Hippocampus

Spoiled gradient echo

In dynamically acquired MRI images of the abdomen, which are the preferred sequences Typically, gradient-echo based Dixon techniques are used for rapid abdominal / dynamic imaging; whereas fast spin echo based versions have clinical value in musculoskeletal and spine applications

arterial

In the ______________ phase, hypervascular tumors will enhance via the hepatic artery, when normal liver parenchyma does not yet enhance.

What sequence shows adrenal adenoma and fatty liver as a signal dropoff, occurring in the presence of increased fatty content?

In-phase T1 gradient echo

DWI susceptibility artifacts in or around strong air tissue interfaces can be minimized by

Increasing parallel imaging acceleration factor

If a brain exam is being performed and the request is made to evaluate cranial nerves VII and VIII due to the patient's symptoms of tinnitus, a protocol with thin cuts through the ____________ should be performed.

Internal auditory canals

_______________ developed equations describing how electric and magnetic fields are generated and altered by each other and by charges and currents.

James Clerk Maxwell

____________ developed the mathematical equation to analyze the heat transfer between solid bodies, later becoming the basis for the rapid processing of phase and frequency signals in MRI.

Joseph Fourier

____________ and _____________ won the 2003 Nobel Prize in medicine for their work in the 1970's developing MR imaging techniques and capabilities

Lauterbur; Mansfield

What confirm the existence of MTS

MRI findings of hippocampal atrophy combined with elevated T2 FLAIR signal and increased choline-to-NAA levels. It predominantly results in surgical intervention to halt the presence of intractable seizures

___________ is commonly associated with intractable temporal lobe epilepsy, in conjunction with EEG findings.

Mesial temporal sclerosis

Which intracranial artery passes through the sylvian fissure?

Middle cerebral

Hydrocephalus

Most commonly caused by an obstruction in the cerebral aqueduct or an interventricular foramen Overproduction of CSF, obstruction of CSF flow, or interference with CSF absorption can result in excess fluid in the cerebral ventricles and enlargement of the head. Dilating the ventricles.

The insular cortex is primarily responsible for:

Motor control; cognitive function

linear, ionic gadolinium-based contrast agent indicated for intravenous use

MultiHance® (Gadobenate dimeglumine): • For (CNS) to visualize lesions with abnormal blood-brain barrier or abnormal vascularity of the brain, spine, and associated tissues • magnetic resonance angiography (MRA) to evaluate adults with known or suspected renal or aorto-ilio-femoral occlusive vascular disease Also; ABLAVAR® (Gadofosveset trisodium) is for (MRA) to evaluate aortoiliac occlusive disease (AIOD) in adults with known or suspected peripheal vascular disease. Magnevist® (Gadopentetate Dimeglumine) visualization lesions and abnormal vascularity in: Central Nervous System: brain, spine and associated tissues Extracranial/Extraspinal Tissues: head and neck Body

highest relaxivity, translating into brighter signal intensity on T1 weighted images

Multihance and Gadavist

MR findings of a low volume corpus callosum and increased white matter lesions can be indicative of a diagnosis of:

Multiple sclerosis

____________ discovered and developed the first rotating magnetic field.

Nikola Tesla

linear, non-ionic gadolinium

OMNISCAN® (Gadodiamide) OptiMARK® (Gadoversetamide)

_________ techniques should be avoided in metal artifact reduction sequences, as they require a gradient-echo-based coil calibration sequence prior to implementation.

Parallel imaging

________ conceived the idea of echo planar imaging, which can rapidly scan the whole brain. He and his colleagues publish the first successful MRI of a living human body part - a finger

Peter Mansfield

Which gradient is the primary focal point of acceleration techniques, due to its direct correlation with MRI scan time?

Phase encoding gradient

cyclic, non-ionic gadolinium-based contrast agent

ProHance® (Gadoteridol) visualize lesions with abnormal vascularity in the brain (intracranial lesions), spine and associated tissues.

The ___________ to reduce chemical shift artifacts.

Receiver bandwidth should be increased

: In 1975, ___________ introduced 2D NMR using phase and frequency encoding, and the Fourier Transform

Richard Ernst

Which of the following is NOT a metabolite found in a 1H spectrum of normal brain tissue?

Succinylcholine

Which fissure divides the frontal and parietal lobes from the temporal lobes?

Sylvian fissure

To further enhance the reduction of metallic susceptibility artifacts

Use STIR sequences in place of Fat Suppression

Metal Artifact Reduction methods

Use TSE over Gradient Echo • Use STIR instead of Fat Suppression techniques • Utilize Wide rBW (receiver Bandwidth) • No parallel imaging or image uniformity correction • Thin slices • Small pixel size/large matrix • High TSE factor/ ETL • Add NEX/NSA to buy back signal, restore IQ

Which dural venous sinuses drain from the confluence of sinuses (by the internal occipital protuberance) to the mastoid portion of the temporal?

Transverse sinuses

To Reduce Chemical Shift Artifact

Use STIR in place of chemical saturation

Alimentary system

What is the name of the organ system comprised of the digestive tract, performing the functions of ingestion, digestion of food and the subsequent discharge of waste?

7: _________ coined the word "electricity" and was the first to realize that the Earth was a giant magnet.

William Gilbert

Dielectric effects

______________ are caused by local eddy currents due to the increased conductivity of body tissue, and are identified by areas of shading or signal loss.

Solid and vascularized lesions enhance whereas ________ and __________ lesions do not enhance.

cystic : necrotic Hypervascularized lesions enhance intensely and early, whereas hypovascularized tumors enhance less intensely and later

A decrease in the voxel volume yields:

decrease in partial volume averaging artifacts.

Halfscan

imaging option where slightly more than half of k-space is acquired (~60%), using conjugate symmetry to assume the remaining portion of kspace (shaded area), shortening scan time.

Gadolinium Relaxivity

is a term used to describe a contrast agent's signal intensity relative to temperature, tissue interacted with, mL administered and magnetic field strength. Of the available agents approved for CNS usage,

Function of the gradient magnetic field

is to create the image orientation and the spatial resolution (detail) used to distinguish adjacent or abnormal structures. Field created by the coordinate gradient coils has biological risks associated with it i.e magnetophosphenes, muscle contractions, cardiac arrhythmias, and peripheral nerve stimulation. The FDA has set a limit on gradient field interactions to a level at which the peripheral nerve stimulation becomes unbearable, and the patient stops the exam.

The ___________ is responsible for mixing masticated food with gastric juices and for emptying contents of the stomach into the duodenum.

pylorus

Fast spin

sequence requires the use of a train of RF pulse echoes used to fill lines of k-space, reducing the overall amount of phase encoding gradient switching steps. Although significantly faster, each additional 180° RF pulse in this sequence implements four times the SAR power compared to the initial 90° RF excitation pulse. Care must be taken to avoid thermal injury in patients with sequential use of these sequences, such as lumbar spine exams.