CT boards practice test (Mosby)
The Hounsfield value of a pixel is a directly related to which of the following?
(u) of HO
A CT scanner measure the linear attenuation coefficient of a voxel of tissue as 0.40. The linear attenuation coefficient of water for this scanner equals 0.20. The CT number assigned to the pixel representing this voxel of tissue equals:
+1000 HU
For MDCT, identified areas of calcium must demonstrate relative attenuation values greater than:
+130 HU
A CT system measure the average linear attenuation coefficient of a voxel of tissue to be 0.189. The linear attenuation coefficient of water for this scanner equals 0.181. The CT number assigned to the pixel representing this voxel of tissue equals:
+44 HU
A CT system measures the average linear attenuation coefficient of a voxel of tissue to be 0.189. The linear attenuation coefficient of water for this scanner equals 0.181. The CT number assigned to the pixel representing this voxel of tissue equals:
+44, CT number is calculated by subtracting the linear attenuation coefficient of water from the linear attenuation coefficient of the tissue in the voxel
Normal unenhanced hepatic parenchyma exhibits CT densities within the range of:
+45 to +65 HU
The average CT value for blood is approximately:
+45HU
The typical range for possible pixel values in a modern CT system is between:
-1024 HU and +3071 HU
Two adjacent pixels are measure to have a difference of 1 HU. This amounts to a tissue density difference of approximately:
0.1%
The image was produced with a 1.0mm aperture size and was displayed using a 512^2 matrix and 15cm DFOV. The voxel dimension for this image would be:
0.29mm X 0.29mm x 1.0mm
A CT image is reconstructed using a 512^2 matrix and a display field of view of 17cm. What is the linear dimension of each pixel?
0.33mm
A CT image reconstructed using a 512^2 matrix and a display field of view of 17 cm what is the linear dimension of each pixel?
0.33mm, DFOV of 17 is converted into 170mm then divided by 512mm for a pixel dimension of 0.33mm
CT scanner with limiting resolution of 15 lp/cm can resolve an object as small as:
0.3mm
What is the dimension of each pixel in the matric of an image with the following parameters? FOV = 25.6cm Matrix = 512mm x 512mm
0.5mm or 0.05cm
The normal range for the International Normalized Ratio (INR) for prothrombin time (PT) results is:
0.8-1.2
A CT scanner capable of producing an image that is a perfect reproduction of the actual anatomic section is said to have an MTF of:
1
Excretion half-time of intravenous iodinated contrast media in a patient with normal renal function is between:
1 and 2 hours
Common formula used to calculate dosage of IV contrast material in the pediatric patient is:
1 mL per lb body weight or 2 mL per kg
What scan parameters should be used for a 3D disarticulation study of the hip?
1 to 2mm section width and overlapping sections
Because of its excessive density, barium sulfate may be used in CT only in suspensions with concentrations of:
1-3% barium sulfate
Due to excessive density, barium sulfate may be used in CT only in suspensions with concentrations of:
1-3% barium sulfate
What set of section widths and intervals is best suited for a CT examination of the c-spine to rule out intervertebral disc herniation?
1.25mm x 1.25mm
An acquisition is made on a 4-slice MDCT system with a detector array of 16 1.25mm detector elements along the z-axis. With a selected beam width of 20mm, what beam pitch would result in the table moving 35.00mm for each rotation of the gantry?
1.75, table feed per rotation divided (35.00mm) by total collimation. Total collimation is equal to the total number of detectors (16) multiplied by the detector dimension (1.25mm)
Each 1.0% in contrast between adjacent objects amounts to a difference in pixel value of approximately:
10 HU
What section width would cause the greatest amount of partial volume averaging? a. 1 mm b. 3 mm c. 5 mm d. 10 mm
10 mm
Typical dose of the radiopharmaceutical F-18-fluorodeoxyglucose (FDG) for combined PET-CT exam is within what range?
10.0-15.0 mCi
The typical dose of the radiopharmaceutical F-18-fluorodeoxyglucose (FDG) for combined PET-CT examination is within the rang of:
10.0-15.0 millicuries (mCi)
A high-osmolar contrast material has an average osmolality of:
1000-2400 mOsm/kg water
Which of the following matrices would provide the greatest spatial resolution? a. 256x256 b. 320x320 c. 512x512 d. 1024x1024
1024x1024
What is a suitable range for contrast agent volume for a intrathecal injection during a postmyelogram CT examination of the lumbar spine in an adult patient?
12-14mL
What is a suitable range for contrast agent volume for an intrathecal injection during a postmyelogram CT exam of the lumbar spine in an adult patient?
12-14mL
What DFOV size are most CT images of the spine?
12-15cm
What display field of view size is commonly used on imaging of the spine?
12-15cm
What display field-of-view is typically used for images of the spine?
12-15cm
The average range for normal prothrombin (PT) time is approximately:
12-15secondsbrain
Normal range for adult respirations
12-20 breaths per minute
What is the normal range of respirations for an adult?
12-20 breaths per minute
During a CTA of the brain's circle of Willis, if an iodinated contrast agent is injected at a rate of 3-4mL/sec, an adequate delay for optimal vessel opacification would range:
12-20 seconds
Prior to resuming breastfeeding, it is recommended for mothers that have gone under IV contrast should pump and dump for how long?
12-24 hours
After initiation of rapid bolus administration of an iodinated contrast agent, the equilibrium phase of hepatic contrast enhancement occurs at approximately:
120-180 seconds
What is the normal platelet count range for adults?
140,000-440,000 mL of blood
The normal platelet count range for an adult is:
140,000-440,000/mL of blood
To reduce radiation exposure to the orbits during a CT examination of the brain, the gantry may be angled
15 degrees superior to the infraorbital-meatal line (IOML)
After initiation of rapid bolus administration of an iodinated contrast agent, the early arterial phase of hepatic contrast enhancement occurs at approximately:
15-20 seconds
After initiation of rapid bolus administration of an iodinated contrast, the early arterial phase of hepatic contrast enhancement occurs at approximately:
15-20 seconds
What is the maximum allowable blood glucose measurement for patients scheduled to undergo PET-CT exam?
150 mg/dL
For a patient whose thorax measures 40cm, which of the following DFOV should be chosen for a CT exam of the thoracic spine? 1. 15cm 2. 25cm 3. 32cm 4. 42cm
15cm
A solitary pulmonary nodule can be assumed benign when its average density is within which of the following ranges?
165-200 HU
What mathematical technique is used for the reconstruction of volumetric MDCT images?
180-degree interpolation (180LI)
What are the sizes of butterfly needles in decreasing order in terms of bore dimension?
19 gauge, 21 gauge, 23 gauge
HRCT of the chest incorporates which of the following protocols? 1. 10mm, standard 2. 10mm, bone 3. 3mm, standard 4. 1mm, bone
1mm sections, bone algorithm
The plasma half-life of intravenously administered iodinated contrast material is approximately:
2 hours
Water-soluble oral contrast agents used for CT scans of the abdomen and pelvis should contain how much iodine?
2-5%
An MDCT image is reconstructed using a 512^2 matrix and a DFOV of 44cm. If the detector collimation is set to a section width of 2.5mm, what is the volume of each voxel?
2.15mm^3
For general contrast enhanced MDCT of the chest, sufficient opacification of vascular structures can be obtained with injection rates of:
2.5-4.0mL/sec
Ischemic brain tissue is identified as an infarct core when cerebral blood volume (CBV) falls below:
2.5mL/100 g
Which of the following acquisitions may be characterized as overlapping? a. 2.5mm sections reconstructed every 1.25mm b. 5mm sections reconstructed every 7.5mm c. 3.75mm sections reconstructed every 3.75mm d. 20 second cine acquisition with 1.25mm sections
2.5mm sections reconstructed every 1.25mm
What is typical protocol for a CT study of the brain for a patient with a history of dizziness?
2.5mm x 2.5mm sections through the posterior fossa, 5mm x 5mm to vertex
normal range of respirations for a child is:
20-30 breaths per minute
What is the appropriate scan delay for a CTA exam with a contrast rate of at least 4mL/sec of the mesenteric vasclature would be in the range of:
20-30 seconds
During a coronary artery CTA, single-segment reconstrion of a 400-msec rotation scan result in a temporal resolution of:
200-msec, single segment (half scan recon) data from only half the gantry rotation is used
A 64-slice MSCT system employs an array of 64 detectors, each with a dimension of 0.625mm. What beam collimation is required to expose the middle 32 detectors of the array to transmitted x-radiation?
20mm (multiply the middle detectors [32] by the dimension of each detector [0.625])
What is the DFOV used for a 320^2 matrix image with a pixel dimension of 0.75mm x 0.75mm?
24cm
What is the display FOV used for a 320^2 matrix image with a pixel dimension of 0.75 mm x 0.75 mm?
24cm
A 512x512 matrix will consist of how many pixels?
262,144
In CT a solitary pulmonary nodule may be defined as a focal area of increased density in the lung that is smaller than:
3 cm
After initiation of rapid bolus administration of an iodinated contrast agent, the excretory phase of renal contrast enhancement occurs at approximately:
3-5mins
The approximate inherenet filtration of the CT x-ray amounts to an aluminum equivalent of:
3.0 mm
The approximate inherent filtration of the CT x-ray amounts to an aluminum equivalent of:
3.0mm
Prior to and after contact with each patient, a proper hand-washing technique requires that the technologist use warm soap and water with a circular rubbing motion for at least:
30 seconds
Maximum dose of intravenous iodinated contrast for a child should not exceed:
3mg/kg body weight
The normal range of cerebral blood volume (CBV) contained within 100g of brain tissue is:
4-5mL/100 g
A chest CT patient measure 38cm across. An appropriate DFOV for the display of this image would be:
40 cm
In a modern CT system, the total number of possible Hounsfield values that may be assigned to any one pixel is approximately
4096
In an image of the chest that is measured 38cm across, but is cutting off a portion )of the shoulder, what is the appropriate DFOV?
40cm (large enough to include the entire area of interest
What method of oral contrast agent administration would be suitable for the CT scan of the abdomen?
450mL 30 minutes prior to scanning with an additional 250mL given just before the study
During IV contrast administration for peripheral CTA exams, the bolus duration should be equal to the scan time minus:
5 seconds
During IV contrast agent administration for peripheral CTA examinations, the bolus duration should be equal to the scan time minus:
5 seconds
Average range for normal adult BUN levels is:
5-20 mg/dl
What set of reconstructed section widths and intervals would be best suited for a general survey CT study of the abdomen and pelvis in a patient with lymphoma?
5.0mmx5.0mm
normal range of cerebral blood flow (CBF) through 100 g of the brain's gray matter is:
50-60mL/100 g/min
Which of the following acquistions may be characterized as non contiguous? 1. 2.5mm sections recon every 1.25mm 2. 5mm sections recon every 7.5mm 3. 3.75mm sections recon every 3.75mm 4. 20 second cine acquistion with 1.25mm sections
5mm sections reconned every 7.5mm
After initiation of rapid bolus administration of contrast, the hepatic venous phase of enhancement occurs at approximately:
60-70 seconds
The human eye is capable of differentiating approximately how many shades of gray?
60-80
What is the normal pulse rate range for a child?
70-120bpm
What is the maximum number of line pairs per centimeter (lp/cm) the smooth algorithm can demonstrate?
8.1
Which of the following lab values may be used to assess the renal function of a patient prior to IV contrast administration? 1.BUN 2. creatitine 3. GFR
BUN, creatinine and GFR
The approximate CT density of the unenhanced spleen is:
Between +40 and +75HU
Where is the Data Acquisition System (DAS) located
Between the detector and the computer
What correctly illustrates the central volume principle of cerebral perfusion?
CBF=CBV/MTT
What is the formula for the central volume principle of cerebral perfusion?
CBF=CBV/MTT
What contrast agents may be used for the purpose of colon insufflation during a CT colonography exam? 1. CO 2. room air 3. normal saline
CO and room air
For trauma indications, CT exams of the pelvis and hips may include which of the following advanced applications? 1. CT enteroclysis 2. CT angiography 3. CT cystography
CT angiography and CT cystography
An IV contrast enhanced specialized CT evaluation of the small bowel after the oral administration of a low-density (0.1%) barium sulfate solution is termed:
CT enterography
A stereotactic unit would be used for what specialized CT exam?
CT guided biopsy of the brain
What quality control test should be performed daily on a CT scanner?
CT number calibration and Examine noise levels (standard deviation) of a water phantom)
A patient is required to have the following exams: CT of the abdomen, GI series and a barium enema, what is the correct order for the scheduling of these exams?
CT of the abdomen, barium enema and then GI series
What is the correct scheduling order for a patient who needs a Abdomen CT, GI series and a barium enema?
CT of the abdomen, barium enema, GI series
Evaluation of the venous vascular structures of the brain is known as:
CT venography
The approximate radiation dose measured during a scan of a 100mm pencil ionization chamber is termed the:
CTDI
During CT perfusion studies, the quantity of blood in mL contrained within 100g of brain tissue is termed the:
Cerebral Blood Volume (CBV
The interaction between x-ray and matter that is responsible for the production of the scatter radiation absorbed by the patient and detector is:
Compton Effect
A patient is scheduled for an IV iodinated contrast-enhanced CT scan of the kidneys. Before injection, the involved medical personnel should examine recently lab values for: 1. CBC 2. Creatinine 3. PT
Creatinine
A patient scheduled for an IV contrast enhanced CT scan of the kidneys. Before injecting what lab values should be checked?
Creatinine
Dysphagia:
Difficulty swallowing
Which muscle surrounds the spine at the level of the kidneys?
Erector spinae muscle
What is NOT an iterative method of CT image reconstruction? 1. point-by-point correction 2. Fourier transform 3. simultaneous reconstruction 4. ray-by-ray correction
Fourier transform
Creatinine clearance, or the rate at which creatinine is filtered from the bloodstream, may be used to approximate
Glomerular filtration rate (GFR)
What are accurate methods that could be used to center a patient's hip in the gantry?
Have patient rotate the leg and palpate the greater trochanter or palpate the pubic bone
In 1979, the scientists _________ and ___________ shared the Nobel Prize for their research in computed tomography.
Hounsfield and Cormack
What type of contrast is used for a patient with air-fluid level present in the contrast filled bladder with the rectum not opacified?
IV contrast only
Which of the following types of contrast material may be used during CT evaluation of the pelvis? 1. IV iodinated contrast agent 2. low dense barium sulfate solution 3. oil-soluble contrast material
IV iodinated contrast agent and low dense barium sulfate solution
What technical considerations is necessary to differentiate hydronephrosis from a parapelvic cyst?
Iodinated IV contrast
The abdominal aorta divides into the left and right common illiac arteries at approximately the level of:
L4
Each iliac artery bifurcates in the internal and external iliac arteries at about the level of:
L5-S1
The calculation fo the average cumulative dose to each section within an acquisition of multiple sections is termed the:
MSAD
The quantity of radiation dose received by the patient from a series of CT scans is referred to as the:
MSAD
During CT angio, images may be reconstructed using only the greatest density encountered along each ray. This type of specialized CT image is called a:
Maximum Intensity Projections (MIPs)
During CT perfusion studies, the measured time (seconds) required for blood to pass through an area of brain tissue is termed the:
Mean transit time (MTT)
The spatial resolution of a CT scanner is often measured using the MTF of the system, what is the acronym for?
Modulation Transfer Function
The process of displaying CT images in a different orientation from the one used in the original reconstruction process:
Multiplanar reformation (MPR)
Quantitative computed tomography (QCT) is a specialized technique used most often for the diagnosis of:
Osteoporosis, it is used to measure the mineral content of bone
What mathematical functions may be used to quantify the spatial resolution of a CT scanner? 1. PSF 2. MTF 3. LSF
PSF, MTF and LSF
Which mathematical functions may be used to quantify the spatial resolution of a CT scanner? 1. Point Spread Function (PSF) 2. Modulation Transfer Function (MTF) 3. Line Spread Function (LSF)
PSF, MTF, and LSF
What laboratory values is used to measure the coagulation ability of a patient prior to an invasive CT study?
PTT and PT
How should a site be prepared with an antiseptic for an invasive procedure?
Paint the area with antiseptic in a circular motion, beginning at the center and working outward.
What are the calcifications within the pelvic veins called?
Phleboliths
What austrian mathematician proved in 1917 that it was possible to reconstruct a three-dimensional object from the infinite set of all of its projections?
Radon
What technical factor adjustment will result in a reduction in patient radiation dose?
Reduce mAs
Which of the following conditions or indications would not require the injection of iodinated contrast material for proper visualization during a CT exam of the brain? 1. S/P MVA 3 days ago;R/O subdural hematoma 2. headaches;R/O meningioma 3. loss of vision;R/O astrocytoma 4. lung cancer;R/O metastases
S/P MVA 3 days ago;R/O subdural hematoma
What term is commonly used to describe a CT scanner's ability to differentiate objects with similar linear attenuation coefficients?
Sensitivity and contrast resolution
Gated cardiac CT data acquisition occurs only during the portion of the ECG termed the:
T wave
The kidneys are located anatomically between which vertebrae?
T12 and L3
What statement most accurately describes the relationship between slice sensitivity profile (SSP) and dose profile?
The dose profile is always wider than the SSP
What is the junction called that connects the ureters to the bladder?
Uretrovesical junction
The act of the CT patient straining the abdominal muscles or "bearing down" to improve demonstration of an adominal wall hernia is referred to as:
Valsalva maneuver
During CT colonography examination, tagged fecal matter appears ______ on the image
White
Often seen in pediatric patients, a specific type of renal mass arising from immature kidney cells is referred to as:
Wilms tumor
pixel
a picture element
What is the primary advantage of prospective ECG gating?
a reduction in patient radiation dose
voxel may be defined as:
a volume element
A localizer (scanogram) from the diaphragm to the pubic symphysis could be used to program which of the following CT exams? 1. abdomen only 2. chest and abdomen 3. abdomen and pelvis
abdomen only or abdomen and pelvis
To calculate the linear attenuation coefficient with the Lambert-Beer law, what does x represent?
absorber thickness
Which of the following statements is true concerning CT scans of the abdomen for the differentiation of renal cysts? 1. acquisitions through the kidneys should be performed before and after administration of an IV contrast agent 2. ROI measurements of the cyst should be made to help determine its composition 3. the patient should refrain from urination for 2 hours before exam
acquisitions through the kidneys should be performed before and after administration of an IV contrast agent and ROI measurements of the cyst should be made to help determine its composition
The primary indication for CT perfusion of the brain:
acute stroke
What is the best method of reducing the risk of contrast-induced nephrotoxicity (CIN)?
adequate patient hydration
What manipulations involve the use of image data? 1. adjusting the width and level of a window setting 2. decreasing the DFOV 3. changing the algorithm selection 4. increasing the matrix size
adjusting the width and level of a window setting
Differentiation between the duodenum and head of the pancreas is best accomplished with: 1. an oral contrast agent administered 30-45 minutes prior to scanning 2. pre- and post- contrast images of the abdomen 3. placement of the patient in the right lateral decubitus position before scanning
administer oral contrast 30-45 minutes before scanning and placement of the patient in right lateral decub position before scanning
Patient demonstrates diffuse uticaria shortly after the IV administration of iodinated contrast media. Correct treatment includes:
administration of an antihistamine drug
What is another term for mastoids?
air cells
During HRCT of the lungs, image acquisition upon full expiration may be performed to improve demonstration of:
air trapping from COPD
Which of the following types of pathologic conditions cannot be diagnosed easily from a CT scan of the brain? 1. astrocytoma 2. traumatic hemorrhage 3. cerebral infarct 4. alzheimer's disease
alzheimer's disease
Axotemia
an excessive amound of nitrogenous materials in the blood and is a symtom of renal failure
Azotemia
an excessive amount of nitrogenous materials in the blood. Symptom of renal failure.
What should be included on a patient consent form for a CT scan incolving intravenous contrast media?
an explanation of the procedure with its accompanying risks and possible alternatives
As a solid-state detector measures transmitted radiation, it emits a proportional response in the form of:
analog signal
The role of computed tomography during combined PET-CT includes: 1. anatomic location of tumor activity 2. attenuation correction of emitted photons 3. reduction of overall patient dose
anatomic location of tumor activity and attenuation correction of emitted photons
How can you reduce dental filling artifacts?
angle gantry around fillings
What steps could be taken to reduce the dental artifact?
angle gantry around fillings
What is the only effective method of reducing streak artifact due to dental fillings?
angle the gantry around fillings
The detectors of a PET system absorb and measure what type of radiation?
annihilation photons
On axial CT images of the chest, the region between the ascending aorta and descending aorta just below the aortic arch is referred to as the:
aortic-pulmonary (AP) window
Contrast enhancement phases of the liver include which of the following? 1. corticomedullary 2. arterial 3. portal venous
arterial and portal venous
What phase of contrast enhancement optimally demonstrates the relationship between pancreatic neoplasm and the surrounding vasculature?
arterial phase
Errors during the measurement of transmitted radiation by the detectors can result in a form of noise on the image referred to as:
artifact
CT images of the abdomen should be acquired with the patient:
at full expiration
A pt has a severe vagal reaction to contrast material that includes bradycardia. Initial treatment may consist:
atropine
The multiple-scan average dose (MSAD) is used to describe the:
average dose to a single section within a scan of multiple sections
During prospectively ECG-gated cardiac CTA studies, the scanning acquisition mode may be described as:
axial "step and shoot"
Horizontal streaking artifact on axial CT scan is most likely due to:
beam hardening
Phantom measurement of the uniformity of a CT system is performed primarily to assess the negative effects of:
beam hardening
A suction unit used on a patient with a chest tube should always remain:
below the patient
Advantages of automatic CO insufflation for CT colonography includes:
better distention, lower risk of perforation and improved patient comfort
The medication Coumadin, warfarin, is often used to treat:
blood clots
The type of compensating filter used at the x-ray tube of a CT scanner is called a:
bow-tie filter
Which of the following vessels would not be used as a site for the injection of iodinated contrast? 1. cephalic vein 2. brachial artery 3. antecubital vein 4. basilic vein
brachial artery
What symptoms indicate a vagal reaction to IV contrast? 1. bradycardia 2. systolic pressure below 80 mm Hg 3. diastolic pressure above 90 mm Hg
bradycardia and systolic pressure below 80 mm Hg
Glioma is a term used to describe a group of primary tumors consisting of malignant glial cells. Where do gliomas occur?
brain
cupping artifacts most commonly occur in the:
brain
What are the tarsals?
calcaneus, talus, navicular, cuboid, medial cuneiform, intermediate cuneiform and lateral cuneiform
appendicolith
calcification or stone in the appendix
What are Phleboliths?
calcifications within pelvic veins outside urinary tract
The process of scanning a phantom device of known density to improve the accuracy of CT attenuation measurement is referred to as:
calibration
What is the name of the nerve bundle extending inferiorly to the spinal cord?
cauda equina
The hallmark CT finding for focal nodular hyperplasia (FNH) of the liver is:
central scar that remains hypodense after initial contrast agent administration
In a female patient, honadal shielding may be applied during which CT exams? 1. chest 2. abdomen 3. brain
chest, abdomen and brain
Cerebrospinal fluid (CSF) is produced in the:
choroid plexuses
patients whose posterior descending artery branches from the right coronary artery, and whose left posterior ventricular branches arise from the left circumflex artery, are said to be:
codominant
prostatic hypertrophy
common, nonmalignant enlargement of the prostate gland
What is the primary interaction between x-ray photons and tissue during computed tomography?
compton effect
hematocrit
concentration of red blood cells within the total volume of blood and can be used to evaluate the hydration status of a patient
Important characteristics of a quality control program in CT include: 1. consistent testing frequency 2. prompt corrective actions when necessary 3. accurate record-keeping
consistent testing frequency, prompt corrective actions when necessary and accurate record-keeping
What corresponds to the period of the cardiac cycle known as atrial systole?
contraction of the left and right atria
Which of the following corresponds to the period of the cardiac cycle known as ventricular systole?
contraction of the left and right ventricles
What condition absolutely prohibits a patient from undergoing a coronary CTA?
contraindication to iodinated contrast
What statements accurately describe the effects of administering an iodinated IV contrast agent during imaging of the brain? 1. contrast increases the attenuation values for normal grey matter 2. contrast improves the differentiation of subtle hemorrhage 3. contrast enhances neoplasms that have disrupted the blood-brain barrier
contrast increases the attenuation values for normal grey matter and contrast enhances neoplasms that have disrupted the blood-brain barrier
What term describes the ability of a CT scanner to differentiate objects with minimal differences in attenuation coefficients?
contrast resolution
Injury to the brain at a location opposite to the site of traumatic impact is referred to as:
contrecoup
At its distal end, the spinal cord tapers into:
conus medullaris
The primary indication for a non-contrast cardiac MDCT examination is:
coronary artery calcium quantification
30-40 seconds after the initiation of contrast agent administration, _______ phase demonstrates optimal enhancement of the renal cortex with maximum differentiation from the renal medulla:
corticomedullary
The period of peak enhancement of the renal cortex following rapid bolus injection of an iodinated contrast is termed:
corticomedullary phase
A patient scheduled for an IV contrast enhanced CT scan of the kidney. Prior to the injection, the involved medical personnel should examine recently measured lab values for:
creatinine
A test phantom containing water is scanned and five ROI measurements are performed. The subsequent density measurements are compared and demonstrate a max deviation of less than 2HU. This QA test was performed to evaluate:
cross-field uniformity
A dermoid tumor of the ovary may also be called
cystic teratoma
What is correct regarding the translate-rotate mode of CT data acquisition?
data is collected only during translation and it was used in first- and second-generation CT scanners
Which of the following would increase the noise apparent on a CT image? 1. increase in mAs 2. decrease in aperture size 3. increase in filtration 4. decrease in matrix size
decrease in aperture size
What can increase noise apparent on a CT image?
decrease in aperture size, reduces the amount of x-ray photons exposing the tissue.
Which of the following will serve to decrease the noise of a CT image?
decrease in matrix size
Which of the following technical adjustments would result in a decrease in patient dose? 1. decrease mAs 2. increase detector pitch 3. decrease kVp
decrease mAs and kVp and increase detector pitch
Automatic tube current modulation (ATCM) software is utilized by the CT system in an effort to:
decrease patient dose
Which of the following technical adjustments may be employed to improve the temporal resolution of an MDCT system? 1. decreased scan time 2. decreased section width 3. decreased DFOV
decreased scan time
A voxel's dimension may be decreased by which of the following?
decreasing the section width
Following a CTA of the chest for pulmonary embolism, an additional acquisition may be performed through the lower extremities to evaluate for:
deep vein thrombosis
spodylolysis
defect in par interarticularis commonly caused by osteophyte formation.
What is capable of causing an edge gradient artifact?
dense bone
The Stanford type B dissecting aneurysm affects which portion of the aorta?
descending thoracic
The standford type B dissecting aneurysm affects which potion of the aorta?
descending thoracic
What components of the CT system is the most common cause of ring artifacts on the reconstructed CT image?
detector
What technical factors exhibit an effect upon longitudinal spatial resolution? 1. detector collimation 2. detector pitch 3. interpolation algorithm
detector collimation, detector pitch and interpolation algorithm
The number, length and organization of the individual detector elements in an MSCT system are referred to as the:
detector configuration
A straight line appearing vertically on the scanogram (pilot) of a fourth-generation CT scanner is an artifact most likely caused by what?
detector malfunction
Which of the following technical factors exhibits an effect upon longitudinal spatial resolution? 1. detector pitch 2. interpolation algorithm 3. display field of view (DFOV)
detector pitch and interpolation algorithm
Portion of the cardiac cycle in which the heart muscle is in relaxation is termed:
diastole
The portion of the cardiac cycle in which the heart muscle is in relaxation is termed:
diastole
Cardiac CT images are typically acquired during which phase of the heart's cycle?
diastolic phase (period of relaxation)
What contrast media may be used during a CT exam of the chest? 1.diatrizoate meglumine 2. barium sulfate 3. iopamidol
diatrizoate meglumine, barium and iopamidol
During CT colonography, acquisitions are performed with the patient in at least two positions for the purpose of:
differentiating polyps from feces/fluid
dysphagia
difficulty swallowing
What are reasons why IV contrast is administered during CT evaluation of the pelvis? 1. distention and contrast enhancement of the bladder 2. visualization of the rectosigmoid junction 3. differentiation of blood vessels and pelvic lymph nodes
distention and contrast enhancement of the bladder and differentiation fo blood vessels and pelvic lymph nodes
The presence of outpocketings in the wall of the color is referred to as:
diverticulosis
How can pixel dimension be calculated?
dividing the DFOV by the matrix size and multiplying it by the length of the voxel.
What artifact manifests as a streaking effect at areas of extremely-high-density interfaces?
edge gradient
For a given CT acquisition, the calculated mAs applied to each reconstructed slice may be referred to as the:
effective mAs
The full width at half maximum (FWHM) of a slice sensitivity profile diagram indicates the:
effective section width
In what cranial nerve would an acoustic neuroma be found?
eighth
The quantitiy of blood pumped out of a ventricle every heartbeat is termed the:
ejection fraction
What type of CT scanner is best suited for the evaluation of coronary artery disease?
electron beam CT (EBCT)
What is the medical term for vomit?
emesis
The type of hemorrhage that occurs between the skull and outer layer of the dura in traumatic brain injury is referred to as:
epidural hematoma
CT scanning of the liver for tumor evaluation should not be performed during which phase of contrast enhancement?
equilibrium phase
What is modulation transfer function? (MTF)
examines the fidelity of the spatial densities and is derived from LSF and PSF
What is an accurate method of verifying patient identity?
examining the patient's wrist identification
What phase of contrast enhancement shows well-opacified ureters?
excretory
Infiltration of contrast agent outside of the blood vessel into the surrounding soft tissue is called:
extravasation
Examples of moderate adverse reactions to iodinated IV contrast are: 1. shock 2. faintness 3. severe vomiting
faintness and severe vomiting
What term accurately describes the type of x-ray beam used in a third-generation CT scanner?
fan beam
What abnormal findings will reduce the density of the liver? a. hyperdense cyst b. contrast-enhancing tumor c. fatty infiltrate d. calcified granuloma
fatty infiltrate
What technical characteristic of a CT system does NOT directly affect patient dose? 1. source-to-detector distance 2. filtration 3. detector efficiency 4. filament size
filament size
An abnormal connection between the intestine and an adjacent anatomic structure is called a:
fistula
Infection may occur indirectly through contact with contaminated objects known as:
fomites
What is the indent on the femoral head called?
fovea capitis
What range would be most suited for a scout image of the abdomen?
from above the diaphragm to the iliac crest
Axial CT image of the trunk should be viewed in what orientation?
from the feet towards the head with patient's left on the viewers right
During a CT exam of the abdomen including IV administration of an iodinated contrast agent which abnormal findings could appear hyperdense in comparison with surrounding tissue ?
gallstone
choledocholithiasis
gallstones in the bile ducts
The types of detectors used in computed tomography are: 1. gas ionization 2. stimulable phosphor 3. scintillation
gas ionization and scintillation
The lumens of needles used for the injection of contrast media vary in diameter. The unit used to describe this diameter is called:
gauge
The portion of the nephron responsible for filtrationg of unwanted materials from the blood plasma is called the:
glomerulus
Which of the following is not a category of isolation technique? 1. enteric precautions 2. gram-negative isolation 3. contrast precautions 4. strict isolation
gram-negative isolation
What unit is used to quantify absorbed dose?
grays (Gy)
The majority of pancreatic tumors occur in the pancreatic:
head
The liver has a dual blood supply and receives 25% of its blood from the:
hepatic artery
What is an example of a hypovascular hepatic mass?
hepatic cyst
Malignant neoplasms of the liver include: 1. focal nodular hyperplasia 2. cavernous hemangioma 3. hepatocellular carcinoma
hepatocellular carcinoma (HCC)
Iodine is commonly used in radiopaque contrast media because of it's
high atomic number
Areas of a CT image containing abrupt changes in tissue density are electronically represented by:
high spatial frequencies
The primary advantage of an isotropic MDCT data-set is:
high-quality multiplanar reformation
The type of MSCT detector array that contains midline narrow elements flanked by wider detectors is called a:
hybrid array
Abnormal accumulation of fluid around a testicle:
hydrocele
Portal venous phase imaging of the liver is used to optimally demonstrate?
hypovascular hepatic metastases
What technical change may increase the partial volume effect present on a spiral CT scan?
increase in pitch
What technical changes may increase the partial volume effect present on a spiral CT scan?
increase in pitch
What adjustment in technical factors will result in an increase in spatial resolution?
increase in sampling frequency
The purpose of intravenous contrast agent administration during a CT study is to: 1. increase the contrast between adjacent structures 2. increase the overall image density 3. increase beam attenuation of enhanced structures
increase the contrast between adjacent structures and increase beam attenuation of enhanced structures
What would increase the signal-to-noise ratio of a CT image?
increased aperture size
Advantages of automatic power injectors in comparison with the manual bolus method of intravenous contrast administration include: 1. increased tissue enhancement due to faster injection times 2. uniform administration of contrast agent over the entire length of the study 3. decreased incidence of adverse reaction to contrast
increased tissue enhancement and uniform administration of contrast through study
The viscosity of a contrast material may be decreased through:
increases in temperature
Which of the following technical adjustments would decrease the quantum noise of a CT image? 1. increase mAs 2. decrease section width 3. increase section width
increasing mAs and section width
What is the correct order for the stages of infection?
incubation, prodromal, active and convalescence
What is the correct order of the stages of infection?
incubation, prodromal, active, convalescence
Parenteral contrast administration refers to what?
intravenous administration
parenteral contrast administration refers to:
intravenous administration
The condition whereby a portion of the small intestine collapses or telescopes into itself is termed:
intussusception
Contrast materials that dissociate into charged particles when placed into solution are termed:
ionic
contrast materials that dissociate into charged particles when placed into a solution are termed:
ionic
Following an IV administration of contrast, a hepatic hamangioma may become _____________ and may no longer appear on the CT image
isodense
Which of the following statements regarding the pituitary gland is false? 1. It is sometimes referred to as the hypophysis cerebri 2. it is seated within the sella turcica 3. the infundibulum attaches it to the hypothalamus 4. it is responsible for producing epinephrine
it is NOT responsible for producing epinephrine
What is true regarding the pituitary gland?
it is sometimes referred to as the hypophysis cerebri, it is seated within the sella turcica and the infundibulum attaches it to the hypothalamus
What type of image reconstrucion was used in the first prototype CT scanner?
iterative technique
What type of image reconstruction was used in the first prototype CT scanner?
iterative technique
Which of the following factors has no measurable effect on spatial resolution? 1. focal spot size 2. kVp 3. detector sampling frequency 4. matrix
kVp
Which of the following organs are characterized as retroperitoneal in location? 1. pancreas 2. liver 3. kidneys
kidneys and pancreas
What describes the scout (localizer) projection used to prescribe axial CT acquisition of the brain?
lateral
Of the bones of the foot, which as tarsals? 1. third proximal phalanx 2. lateral cuneiform 3. first metatarsal
lateral cuneiform
The branches of the left coronary artery include the: 1. sinus node artery 2. left anterior descending artery 3. left circumflex artery
left anterior descending artery and the left circumflex artery
In patients who are left dominant, the posterior descending artery branches from the:
left circumflex artery
Why is it recommended that data acquisition for a CTA of the pulmonary arteries be performed in the caudocephalad direction?
less streaking artifact from dense contrast in the superior vena cava
severe reactions to intravenous iodinated contrast material occurs in approximately ______ of all patients
less than 1%
What window setting would optimal display CT colonography images?
level= -400, width= 1600
During a CT-guided needle biopsy, the insertion site is usually anesthetized with:
lidocaine
the duodenum is suspended from the diaphragm by the:
ligament of Treitz
The ability of an object to attenuate the x-ray beam is assigned a value known as:
linear attenuation coefficient
The most common indication for CT guided radiofrequency ablation (RFA) is in treatment of neoplasms involving the:
liver
The broadening of the slice sensitivity profile inherent to helical CT acquisition is said to negatively affect the:
longitudinal spatial resolution
another term for standard or soft tissue algorithm?
low spatial frequency
What is an advantage of automatic CO insufflation for CT colonography?
lower risk of perforation
The spatial resolution of a CT scanner is usually given in the unit of measure:
lp/cm
Intrathecal injection of iodinated contrast may be performed for which of the following exams? 1. brain 2. pituitary 3. lumbar spine 4. high-resolution chest
lumbar spine
What CT image archival media is capable of storing the greatest amount of information?
magnetic optical disk
What is the line spread function? (LSF)
measures the ability of a CT scanner to clearly image an edge or line
What is point spread function? (PSF)
measures the ability of a CT scanner to clearly image an edge or line for extremely small, point-like structures
Which of the following may be used to reduce metal streak artifacts on coronal-plane CT images of the orbits? 1. retrospective recons of targeted images with reduced DFOV 2. metallic artifact reduction (MAR) software to improve image quality 3. construction of coronal MPR images from acquired axial-plane images
metallic artifact reduction (MAR) software to improve image quality and construction of coronal MPR images from acquired axial-plane images
The plane that passes vertically through the midline of the body, dividing it into equal anterior and posterior portions, is referred to as the:
midcoronal
An Agatston score of 5 on an MDCT cardiac examination for coronary artery calcification is rated as:
minimal
An Agatston score of 250 on an MDCT cardiac exam for coronary artery calcification is rated as:
moderate
Which layer of the uterine wall brightly enhances after IV administration of a contrast agent?
myometrium
What are examples of mild adverse reactions to iodinated contrast?
nausea, warm/flushed sensation, uriticaria
A voxel whose attenuation coefficient is less than that water is assigned a pixel value with a ___________ CT number
negative
Unless contrast is contraindicated , which of the following conditions require the administration of IV contrast? 1. suspected neoplasm 2. arteriovenous malformation 3. acute hemorrhage
neoplasm and arteriovenous malformation (AVM)
What phase occurs between 70-90 seconds after contrast injection with enhancement between renal cortex and medulla reaching equilibrium, providing optimal sensitivity for parenchymal lesions?
nephrographic
What phase of rental contrast enhancement provides maximum sensitivity for parenchymal lesions?
nephrographic
Which phase of renal contrast enhancement provides maximum sensitivity for parenchymal lesions?
nephrographic
The computerized communication system used by a PACS to transmit data is referred to as a:
network
A CT image of a homogenous material contains variation in CT number from pixel to pixel. This image is said to have:
noise
CT image of a homogeneous material contains variations in CT number from pixel to pixel. This is said to have:
noise
What is the largest deterrent of a CT scanner's contrast resolution?
noise
The patient is not required to give informed consent for which of the following CT studies? 1. non-contrast brain to R/O subdural hematoma 2. CT guided abscess drainage 3. sterotactic biopsy of a cranial tumor 4. CTA chest for pulmonary embolism
non-contrast brain to R/O subdural hematoma
What is a correct difference between ionic and nonionic iodinated contrast media?
nonionic contrast media has a lower osmolality than ionic media
What is the difference between ionic and nonionic iodinated contrast media?
nonionic contrast media have a lower osmolality than ionic media
The soft center of each intervertebral disc is called the:
nucleus pulposes
CT imaging plane parallel to the metatarsals approximately 20-30 degrees caudal from the direct axial plane is called:
oblique axial plane
MPR images along the long axis of the optic nerve would be best described by what anatomic plane?
oblique sagittal
Multiplanar reformation images along the long axis of the optic nerve would be best described by which anatomic plane?
oblique sagittal
Differentiation between the duodenum and the head of the pancreas is best accomplished with:
oral contrast given 30-45minutes before scan and placing patient in right lateral decubitis position before scanning.
The propensity of a contrast agent to cause fluid to move from the extravascular space to the intravascular space is called:
osmolality
Which of the following is a malignant tumor of the skeletal system? 1. chondroblastoma 2. osteochondroma 3. enchondroma 4. osteosarcoma
osteosarcoma
What is NOT an improvement in CT chest imaging due to the development of MDCT?
overall reduction in patient radiation dose
What technical parameters would greatly improve the quality of CT studies requiring MPR images?
overlapping scans with narrow sections
CT-guided needle biopsies are most commonly performed on what anatomic area?
pancreas
which of the following organs is/are characterized as retro peritoneal in location? 1. pancreas 2. liver 3. kidneys
pancreas and kidneys
Axial CT sections of the lumbar spine for intervertebral disc evaluation should be reconstructed with the plane of imaging:
parallel to the plane of the intervertebral disc space
The degenerative pathologic process of the spine known as spondylolysis involves a defect in the:
pars interarticularis
When the mAs value utilized for a given CT acquisition is doubled, what occurs?
patient dose increases
What scan parameters is commonly used during a radiation therapy planning CT study of the prostate gland? 1. patient on a flat tabletop 2. dmall DFOV used to include only the prostate gland 3. CT scan performed with patient in exact position for radiation therapy
patient on a flat tabletop and CT scan performed with patient in exact position for radiation therapy.
Which of the following methods may be used to determine the appropriate injection delay for optimal vessel enhancement during a CTA exam of the brain? 1. measurement of the patient's pulse rate 2. performing bolus-timing sequence 3. utilizing bolus-tracking software
performing bolus-timing sequence and utilizing bolus-tracking software
components of the uterine wall include: 1. perimetrium 2. myometrium 3. endometrium
perimetrium, myometrium and endometrium
Where can the matrix size, algorithm type and section thickness be found on an image?
peripheral portion
What is the muscular contraction responsible for transporting material through the digestive tract called?
peristalsis
Coronal imaging through the paranasal sinuses is typically performed with the plane of imaging:
perpendicular to the hard palate
Which areas of the head commonly becomes calcified?
pineal gland and the choroid plexus
What is the formula to calculate the dimensions of a pixel?
pixel size = DFOV/matrix size
How are the dimensions of a voxel calculated?
pixel size and section width
The dimensions of a voxel may be calculated as the product of which of the following?
pixel size and section width
The oral administration of barium and iodinated contrast media prior to CT colonography serves the primary purpose of:
polyp tagging
What phase of IV contrast agent administration provides the best gastric and intestinal wall enhancement?
portal venous
The period of peak enhancement pf hepatic parenchyma following rapid bolus injection of iodinated contrast is termed:
portal venous phase
What reduces the scatter radiation reaching the detectors?
post-patient collimation and pre-detector collimation
After injecting IV contrast during a CT exam of the brain, what anatomic area would not enhance? 1. anterior communicating artery 2. choroid plexus 3. posterior horn of lateral ventricle 4. dura matter
posterior horn of lateral ventricle
Following the injection of IV contrast media during a CT exam of the brain, which of the following anatomic areas does not enhance? 1. anterior communicating artery 2. choroid plexus 3. posterior horn of lateral ventricle 4. dura matter
posterior horn of lateral ventricle
What describes the position of the seminal vesicles in the male pelvis?
posterior to the bladder and anterior to the rectum
The component of the DAS responsible for strengthening the signal emitted from a detector is termed the:
preamplifier
Where should the tourniquet be positioned during preparation of a patient for intravenous contrast administration?
proximal to the injection site
Patient with an elevated level of D dimer in the bloodstream may be at increased risk for what?
pulmonary embolism
The assessment of D dimer concentration is used to diagnose which of the following pathologic conditions? 1. dissecting aortic aneurysm 2. pulmonary embolism 3. deep vein thrombosis (DVT)
pulmonary embolism and DVT
What type of image noise can be most easily reduced by the CT tech?
quantum noise
What type of image noise can be most easily reduced by the CT technologist?
quantum noise
The portion of the primary beam interacting with a single detector is known as a:
ray
What is an advantage of nonionic contrast over ionic contrast?
reduced incidence of adverse reaction
What are advantages of spiral/helical CT over conventional CT scanning? 1. reduced scan time 2. reduction of misregistration artifacts 3. decreased patient radiation dose
reduced scan time and misregistration artifacts
What technical adjustment would result in a decrease int he signal-to-noise ratio (SNR)?
reducing the section width
What technical adjustments would result in a decrease in the signal-to-noise ratio(SNR)?
reducing the section width
Which of the following improvents in CT chest imaging is a direct result of the MDCT? 1. reduction in misregistration artifacts 2. increased exam speed 3. reduction in patient dose
reduction in misregistration artifacts and increased exam speed
What are factors of the period of the cardiac cycle known as complete cardiac diastole?
relaxation of left and right ventricles and atria and the T wave of the electrocardiogram (ECG)
Which refers to the period of the cardiac cycle known as complete cardiac diastole? 1. contraction of the left and right ventricles 2. relaxation of the heart muscle 3. the QRS complex of the electrocardiogram (ECG)
relaxation of the heart muscle
What refers to the period of the cardiac cycle known as complete cardiac diastole? 1. relaxation of the left and right ventricles 2. relaxation of the left and right atria 3. the T wave of the electrocardiogram (ECG)
relaxation of the left and right ventricles, relaxation of the left and right atria, and the T wave of the electrocardiogram (ECG)
Which of the following would require the IV injection of iodinated contrast for accurate differentiation during a CT study of the abdomen? 1. angiomyolipoma 2. renal stone 3. diverticulitis 4. renal cyst
renal cyst
Glomerular Filtration Rate (GFR) is a laboratory assessment test utilized to measure:
renal function
In patients who are right dominant, the posterior descending artery branches from the:
right coronary artery
What is not a component of the blood supply to the brain commonly referred to as the circle of Willis?
right middle cerebral artery
What imaging plane best demonstrates spondylolisthesis of the spine?
sagittal
What technical parameters is NOT a necessary component of a high resolution CT exam of the internal auditory canals(IAC)?
sagittal MIP images
What is the plane that passes vertically through the body, dividing it into left and right portions?
sagittal plane
Compression of the spinal cord or nerve roots from a herniated intervertebral disc may result in the referred limb pain commonly referred to as:
sciatica
The volume of a voxel may be calculated by multiplying the pixel dimension by the:
section width
What technical factor(s) play(s) a role in the production of an isotropic dataset? 1. section width 2. scan field-of-view (SFOV) 3. display field-of-view (DFOV)
section width and display field of view (DFOV)
Which technical factors plays a role in the production of an isotropic dataset? 1. section width 2. scan field-of-view 3. display field-of-view
section width and display field-of-view
CT images that have been reconstructed form a portion of the data acquisition process in the hopes of reducing patient motion artifacts are called:
segmented images
CT images that have been reconstructed from a portion of the data acquisition process in the hopes of reducing patient motion artifacts are called:
segmented images
What term(s) is/are used to describe a CT scanner's ability to differentiate objects with similar linear attenuation coefficients?
sensitivity and contrast resolution
A portion of a herniated intervertebral disc that has migrated from its normal position is called a
sequestered disc
What are the primary technical considerations for a CTA of the chest to rule out pulmonary embolism includes:
short acquisition in a single breath-hold from diaphragm to lung apex and bolus injection of iodinated contrast agent at 4-5mL/sec
What unit is used to quantify effective dose?
sieverts (Sv)
What are the iterative methods of CT image reconstruction?
simultaneous reconstruction, ray-by-ray correction and point-by-point correction
The tortuous S-shaped portion of the internal carotid artery as it enters the bony skull may be referred to as the carotid:
siphon
The degree of CT section broadening that occurs along the z-axis during volumetric data acquisition is represented graphically by the:
slice sensitivity profile (SSP)
Which technologic advances has led to the development of spiral/helical CT scanning?
slip-ring technology and high-efficiency x-ray tubes.
HRCT exams of the temporal bones and internal auditory canal should include which of the following technical parameters? 1. 5-7mm section width 2. small targeted DFOV 3. soft-tissue kernel
small targeted DFOV
Which of the following components of CT image quality may be controlled by the technologist? 1. spatial resolution 2. contrast resolution 3. noise
spatial resolution, contrast resolution and noise
CT acquisition of a water-filled phantom is performed utilizing a standardized set of technical factors. If a region-of-interest (ROI) measurement is made, the image noise corresponds to which data?
standard deviation
IV administration of iodinated contrast media requires strict adherence to:
standard precautions and aseptic technique
The Digital Imaging and Communications in Medicine (DICOM) protocol was developed to:
standardize the networking and storage of images
cholelithiasis
stones within the gallbladder
During combined PET-CT imaging, abnormal physiologic uptake of radiopharmaeutical can occur in patient muscle due to:
strenuous activity
Radiation protection of the CT patient should involve which of the following principles? 1. strict clinical indication 2. protocol optimization 3. shielding
strict clinical indication, protocol optimization and shielding
What type of isolation precautions is used to protect immunosuppressed patients from possible infection?
strict isolation
What condition or indication would not require the injection of iodinated contrast material for proper visualization of the brain?
subdural hematoma
What technical attributes enables MDCT systems to acquire motion-free images of the heart and surrounding vasculature?
superior temporal resolution
What patient position is best suited for CT evaluation of the chest?
supine
What is the proper patient position for a CT exam of the brain?
supine with chin down
What is dorsal recumbent?
supine with knees bent and hands above the head
What is the correct position of the patient relative to the gantry for a CT of the brain?
supine, head first
The technique that provides detail of outer portions of the 3D model while maintaining the typical CT detail of the lungs inside is called:
surface rendering
Which of the following is an acceptable form of immobilization during a CT? 1. suspended respiration 2. use of velcro straps 3. use of medical tape
suspended respiration and using velcro straps
The articulation between the distal tibia and fibula is called the:
syndesmosis
The articulation between the distal tibia and ficula is called the:
syndesmosis
As related to the cardiac cycle, the term _____________ refers to the contraction of heart muscle.
systole
Which of the following bones is found within the hindfoot? 1. talus 2. metatarsals 3. navicular 4. cuboid
talus
What techniques assists in visualizing the vagina during a CT study of the pelvis?
tampon insertion
What is the term used to describe the ability of a PACS to transmit data from the imaging facility to an off-site location?
teleradiology
The ability of CT system to reduce involuntary motion artifacts and provide CT images free of motion artifact is determined by what components of image quality?
temporal resolution
The ability of an MDCT system to freeze heart motion during a cardiac CT is described by its:
temporal resolution
spatial resolution
the ability of a CT scanner to image a small high-density object is controlled by the
viscosity
the ability of a fluid to flow
Pulmonary embolism
the blocking of a pulmonary artery by a thrombus that has migrated from a distal vein
Blooming
the exaggeration of displayed calcification within the coronary arteries during a cardiac MDCT study.
The term beam hardening is used to describe what physical phenomena?
the increase in average photon energy of a heterogenous x-ray beam
During post-contrast CT imaging of the abdomen, the degree of hepatic parenchymal enhancement depends on:
the iodine concentration of the contrast agent and the rate of contrast injection
What statement best describes why the image of the chest is displayed at a window whose level is -700 and width is 1500
the level is set at the average Hounsfield value for the tissue of interest within a range determined by the window width
The rights of the patient include which of the following? 1. the patient has the right to considerate and respectful care 2. the patient has the right to receive a copy of the diagnostic procedure performed 3. the patient has the right to refuse medical treatment
the patient has the right to considerate and respectful care and the right to refuse medical treatment
Cholelitiasis
the presence of stones within the gallbladder
Thermionic emission
the process by which electrons are produced at the cathode of a CT x-ray tube
When choosing a window to display a CT image, the width defines:
the range of CT numbers(pixels) to be displayed
What is the azimuth setting?
the relationship between the x-ray tube and detectors during scout or localizer production
HRCT exams of the temporal bones and IAC should include what technical parameters?
thin sections (1-2mm), small targeted DFOV, and use of high-resolution algorithm (kernel) for reconstruction
The technique that allows the user to select the range of pixel values used in a 3D CT reformation is termed:
thresholding
the _________ gland is located in the anterosuperior portion of the mediastinum and is often identified with CT during scanning of younger patients.
thymus
In multislice CT (MSCT), the beam pitch is equal to the table feed per rotation divided by the:
total collimation
The assignment of different generations to CT scanners is based on the configuration of the:
tube and detectors
When one is using a third-generation CT scanner, it is important that reference detectors positioned at the peripheral portions of the detector array be exposed to:
unattenuated radiation
When using a third-generation CT scanner, it is important that reference detectors positioned at the peripheral portions of the detector array be exposed to:
unattenuated radiation
The ability of a CT system to maintain consistent Hounsfield values across the entire image of a homogeneous object is termed:
uniformity
The portion of the male reproductive system responsible for storage of the majority of mature sperm is the:
vas deferens
The portion of the male reproductive system responsible for storage of the majority of mature sperm is:
vas deferens
What term describes a condition in which cerebral ischemia is caused by systemic hypertension?
vasovagal reaction
During a CT scan, each sample of ray sum measurements made by the data acquisition system (DAS) is called a:
view
CT number is a relative value that standardizes the attenuation value of a tissue by comparing it with the attenuation of:
water
What oral contrast agent offers the best visualization of the enhancing GI wall on post-IV contrast CT exam?
water
What oral contrast offers the best visulization of the enhancing GI wall on post-IV contrast CT exams?
water
What is the normal range of glomerular filtration rate (GFR) for women and men?
women: 60 + or - 10mL/min/m^2 men: 70 + or - 14mL/min/m^2
What is used in gas ionization CT detectors?
xenon
In an MSCT system the detector array is composed of multiple rows of inidividual detector elements along the:
z-axis
Increasing detector pitch during a spiral CT exam adversely affects the spatial resolution along which axis?
z-axis
Increasing the detector pitch during a spiral CT exam adversely affects the spatial resolution along the:
z-axis
What corresponds to the longitudinal dimension of the CT image voxel?
z-axis
The articulation between the inferior articular processes of one vertebra with the superior articular processes of the next is called:
zygapophyseal joint
