CT Registry Review Questions
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Question for Computed Tomography Registry
- 1.
- A.
IV contrast material is better visualized
- B.
Streak artifacts are reduced or eliminated.
- C.
The patient is more comfortable during scanning.
- D.
The patient receives a lower radiation dose
- 2.Which two strategies can reduce the effect of dental fillings in a sinus study?
- A.
High mA and shcrt scan time
- B.
Low kVp and high contrast, or bone alogrithm
- C.
Adjust the angle of the gantry and widen the window width
- D.
Small focal spot and small display field
- 3.Which of the following conditions may be visualized in a CT study of the brain?
- A.
Glioblastoma
- B.
Wilm's Tumor
- C.
Krukenberg Tumor
- D.
Plasmacytosis
- 4.Which of the following is affected by teh slice spacing in a CT study?
- A.
Spatial Resolution
- B.
Quantum Mottle
- C.
Radiation Dose to the Patient
- D.
Signal-to-Noise Ration
- 5.What is the name of the pinecon-shaped structure of the brain the can often be seen as calcified in CT images?
- A.
Choroid Plexus
- B.
Pineal Gland
- C.
Caudate Nucleus
- D.
Middle cerebral Artery
- 6.Third generation (rotate/rotate) scanners overcame which of the following limitations?
- A.
Detector singal drift sensitivity
- B.
Translation motion
- C.
Spurious signals from moving signal wires
- D.
Cost
- 7.What helical or spiral computed tomography term is defined as the table increment in distance per mm per 360 degrees gantry rotation divided by the section thickness in mm?
- A.
Rotation
- B.
Spiral
- C.
Helix
- D.
Pitch
- 8.What determines the section thickness?
- A.
Scan arc
- B.
Filtration algorithm
- C.
Incident beam collimation
- D.
Detector alignment
- 9.What effect would an array processor failure have on image processing?
- A.
Increase image display time
- B.
Halt analog to digital conversions
- C.
Lengthens detector data acquisition time
- D.
Decrease xray tube output
- 10.What change will occur in the number of detected photons if a section thickness is changed from 5 mm to 10mm?
- A.
Decrease 50%
- B.
Decrease 25%
- C.
Increase 50%
- D.
Increase 100%
- 11.Which of the following will magnify the image?
- A.
Increase field of view
- B.
Decreasing field of view
- C.
Increasing section thickness
- D.
Decreasing section thickness
- 12.Which of the following is convolution?
- A.
Filtered back projection
- B.
Fourier transform
- C.
Iterative filtration
- D.
3-d rendering
- 13.Which of the following determines the maximum number of shades of gray that can be displayed on the CT monitors?
- A.
Window level
- B.
Window width
- C.
Pixel size
- D.
Matrix size
- 14.Which of the following are benefits of narrower section thicknesses?
- A.
Reduced partial volume averaging and improved spatial resolution
- B.
Decreased scan time, and more anatomy covered
- 15.Which of the following is the term used to describe a voxel value that is the average of multiple tissue types contained within the voxel?
- A.
Linear attenuation coefficient
- B.
Partial volume averaging
- C.
Low contrast resolution
- D.
Edge gradient averaging
- 16.
- A.
Ct numbers above +300
- B.
Ct numbers between +150 and +300
- C.
Ct numbers between +150 and -150
- D.
Ct numbers below -150
- 17.Which fo the following is the central value in a range of gray shades used to display the image?
- A.
Window width
- B.
Window level
- C.
Region of interest
- D.
Dose index
- 18.What is the most common type of film used to recore CT exams?
- A.
Single emulsion
- B.
Double emulsion
- C.
Triple emulsion
- D.
Rare earth
- 19.Which of the following increase signal to noise ration?
- A.
Increased mAs
- B.
Wider section thickness
- C.
Increased detection efficiency
- 20.What is the appropriate compensation to avoid quantum noise when performing thin section computed tomography?
- A.
Increase mAs
- B.
Decrease field of view
- C.
Increase matrix size
- D.
Decrease scan speed
- 21.Which describes the relationship between section thickness and noise?
- A.
If section thickness increases, noise increases
- B.
If section thickness increases, noise decreases
- C.
If section thickness decreases, noise decreases
- D.
If section thickness decreases, noise remains unchanged
- 22.What term is used to describe as the ability to display an image of a large object that is only slightly different in density from its surroundings?
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Linearity
- D.
Clarity
- 23.Which of the following should be viewed with relatively wide window widths?
- A.
Lung and inner ear
- B.
Lung and brain
- C.
Inner ear and brain
- 24.How often should an average CT number water calibration test be performed?
- A.
Daily
- B.
Monthly
- C.
Yearly
- D.
Weekly
- 25.Which of the following accurately describes the relationship between patient dose and pitch?
- A.
If pitch increases, patient dose increases
- B.
If pitch increases, patient dose decreases
- C.
If pitch decreases, patient dose decreases
- D.
If pitch decreases, patient dose remains unchanged
- 26.Which of the following is defined as the ability to distinguish details in objects of different densities a small distance apart?
- A.
Contrast resolution
- B.
Cross field uniformity
- C.
Spatial resolution
- D.
Interpolation
- 27.What is the term that is used to describe contrast resolution?
- A.
High spatial detectibilty
- B.
Low spatial detectibilty
- C.
High contrast detectibilty
- D.
Low contrast detectibilty
- 28.What is the primary type of interaction that contributes to the subject contrast in CT images?
- A.
Pair production
- B.
Photoelectric effect
- C.
Compton scattering
- D.
Linear attenuation
- 29.What type of scan geometry is responsible for producing ring artifacts?
- A.
Translate-rotate
- B.
Rotate-rotate
- C.
Rotate only
- D.
Helical / spiral
- 30.
- A.
The computer overcorrects for beam hardening
- B.
The beam encounters metal in the body
- C.
The body hardens the beam thus lowering the attenuation numbers in the center
- D.
The body hardens the beam thus increasing the attenuation numbers in the center
- 31.Which of the following can be described as bands and streaks that appear across an area due to bone and soft tissue attenuation values in the same pixel?
- A.
Tube arcing artifacts
- B.
Beam hardening artifacts
- C.
Partial volume artifacts
- D.
Full volume artifacts
- 32.Which of the following is a streak artifact oriented tangentially to a flat surface having a high spatial frequency?
- A.
Low contrast artifact
- B.
Edge gradient artifact
- C.
Equipment induced artifact
- D.
Signal artifact
- 33.What filter selection would provide the best detail for imaging of the internal auditory canals?
- A.
Smooth
- B.
Sharp
- C.
Standard
- D.
Soft
- 34.What anatomical structure forms a roof over the posterior cranial fossa and is shaped like a tent?
- A.
Tentorium cerebelli
- B.
Falx cerebri
- C.
Pontine cistern
- D.
Pia mater
- 35.
- A.
- 36.Which of following results from a fracture in the temporal region of the skull with associated tearing of the middle meningeal artery?
- A.
Subdural hematoma
- B.
Epidural hematoma
- C.
Arteriovenous malformation
- D.
Subarchnoid hematoma
- 37.What canal allows communication between the third and fourth ventricles of the brain?
- A.
- 38.Where is contrast media introduced for a myelography exam of the spinal canal?
- A.
Subdural space
- B.
Epidural space
- C.
Subarachnoid space
- D.
Spinal cord
- 39.Which of the following would be visualized first when coronal images are obtained via multiplanar reformation from posterior to anterior?
- A.
- 40.Which of the following anatomical structures would be visualized first when obtaining sagittal sections from right to left?
- A.
C-loop of the duodenum
- B.
Tail of the pancreas
- C.
Gallbladder
- D.
Right kidney
- 41.What type of drug is Demerol?
- A.
Analgesic
- B.
Antipyretic
- C.
Antianxiety agent
- D.
Local anesthetic
- 42.Which of the following describes rapid, irregular, ineffective twitches of the ventricles?
- A.
Ventricular regurgitation
- B.
Ventricular palpitations
- C.
Ventricular arrythmia
- D.
Ventricular fibrillation
- 43.Which of the following is the more toxic cation that is incorporated into the organic ionic contrast media?
- A.
Sodium
- B.
Meglumine
- C.
Iodine
- D.
Calcium
- 44.What term is used to describe the computed tomography appearance of an intracerebral hemorrhage as a result of a higher CT number of the hemorrhage as compared to normal brain tissue?
- A.
Hyperdense
- B.
Isodense
- C.
Hypodense
- D.
Mass effect
- 45.Which of the following provides optimal liver lesion detection following the introduction of contras media?
- A.
Scanning prior to the equilibrium phase
- B.
Scanning during to the equilibrium phase
- C.
Scanning after to the equilibrium phase
- 46.Which of the following is the recommended percentage of barium in a barium sulfate suspension utilized in abdominal computed tomography?
- A.
1-3%
- B.
10-20%
- C.
30%
- D.
50%
- 47.Which of the following are used in scintillation CT detectors?
- A.
Gadolinium based ceramic
- B.
Bismuth germanate
- C.
Calcium fluoride
- 48.Which of the following will have an effect on image quality?
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Noise
- 49.What are the primary advantages of narrower section thicknesses?
- A.
Improved spatial resolution
- B.
Reduced partial volume averaging
- C.
Higher contrast
- 50.Which of the following geometric factors will have an effect on spatial resolution?
- A.
Focal spot size
- B.
Detector aperture width
- C.
Noise
- 51.What term describes an artifact that may appear on a low dynamic range detector system near the shoulders and hips because dense bone has too severely attenuated the xray beam?
- A.
Beam hardening
- B.
Photon starvation
- C.
Ring
- D.
Partial volume
- 52.Which of the following will help to reduce partial volume artifacts?
- A.
Scanning thinner sections
- B.
Scanning thicker sections
- C.
Scanning using a higher technique
- D.
Scanning using a lower technique
- 53.Which of the following terms defines the increase in the mean energy of a polychromatic beam as it passes through an object?
- A.
Partial volume effect
- B.
Beam hardening
- C.
Cross-field uniformity
- D.
Linearity
- 54.Contrast materials that dissociate into charged particles when placed into solution are termed
- A.
Positive
- B.
Non-ionic
- C.
Ionic
- D.
Negative
- 55.Which of the following is the correct order for the stages of infection?
- A.
Incubation, prodomal, active, convalescence
- B.
Convalescence, active, prodomal, incubation
- C.
Prodomal, incubation, convalescence, active
- D.
Incubation, convalescence, prodomal, active
- 56.The term used to descibe the ability of a fluid to flow is
- A.
Density
- B.
Viscosity
- C.
Osmolality
- D.
Specific gravity
- 57.A patient has a severe vagal reaction to iodinated contrast material that includes bradycardia. Initial treatment may include
- A.
Atropine
- B.
Diazapam
- C.
Rantidine hyrochloride (Zantac)
- D.
Albuterol sulfate (Proventil)
- 58.Which of the following interactions between xray and matter results in the largest amount of occupational exposure?
- A.
Characteristic effect
- B.
Compton effect
- C.
Bremsstrahlung effect
- D.
Photoelectric effect
- 59.The abdominal aorta bifurcates at the level of
- A.
T10
- B.
T12
- C.
L2
- D.
L4
- 60.After the injection of intravenous contrast material during a CT examination of the brain, which of the following anatomic areas does not enhance?
- A.
Anterior communicating artery
- B.
Choroid plexus
- C.
Posterior horn of the lateral ventricle
- D.
Dura mater
- 61.The mathematical technique that involves the estimation of an unknown value from values on either side of it its known as
- A.
Filtering
- B.
Interpolation
- C.
Convolution
- D.
Summation
- 62.When compared with conventional radiography, CT produces diagnostic images with improved
- A.
Low-contrast resolution
- B.
Spatial resolution
- C.
Minute detail
- D.
Patient dose reduction
- 63.Which of the following is not commonly used as a CT scintillation detector material?
- A.
Ceramic rare earth
- B.
Silver halide
- C.
Bismuth germinate
- D.
Cadmium tungstate
- 64.Which of the following is the primary interaction between xray photons and tissue during CT examinations?
- A.
Bremsstrahlung effect
- B.
Characteristic effect
- C.
Compton effect
- D.
Coherent scatter
- 65.Areas of a CT image that contain minimal changes in tissue density are electronically represented by
- A.
Positive CT numbers
- B.
High spatial frequencies
- C.
Negative CT numbers
- D.
Low spatial frequencies
- 66.Which of the following reconstruction methods is used by most modern CT scanners?
- A.
Back-projection
- B.
Iterative methods
- C.
Fourier tranform
- D.
Filtered back-projection
- 67.Which of the following increases the signal-to-noise ratio of a CT image?
- A.
Decreased aperature size
- B.
Decreased mAs
- C.
Increased filtration
- D.
Increased aperature size
- 68.Statistical noise appears as ___ on a CT image
- A.
Decreased contrast
- B.
Increased brightness
- C.
Concentric circles
- D.
Graininess
- 69.The term ___ describes the ability of a CT scanner to differentiate objects with minimal differences in attenuation coefficients
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Linearity
- D.
Modulation
- 70.Which of the following types of contrast material may be used during a CT examination of the chest?
- A.
Diatrizoate meglumine
- B.
Barium sulfate
- C.
Iopamidol
- D.
All the above
- 71.The kidneys are located in the retroperitoneum and are bound by a band of fibrous connective tissue called
- A.
Cooper's liagment
- B.
Fascia of Cooper
- C.
Linea alba
- D.
Gerota's fascia
- 72.Which of the following algorithm types provides the greatest soft-tissue detail during a CT study of the pelvis?
- A.
High spatial frequency
- B.
Detail
- C.
Edge
- D.
Low spatial frequency
- 73.First-generation CT scanners possess which of the following characteristics?
- A.
- 74.The average CT value for blood is approximately
- A.
-50 HU
- B.
0 HU
- C.
+45 HU
- D.
+100 HU
- 75.Before a CT image can be reconstructed by a computer, the transmission signal produced by the detectors must be converted into numeric information by a(n)
- A.
Kernel
- B.
Analog-to-digital converter
- C.
Array processor
- D.
Digital-to-analog converter
- 76.The dimensions of a voxel may be calculated as the product of which of the following?
- A.
Matrix size and pixel size
- B.
Pixel size and section width
- C.
DFOV and matrix size
- D.
DFOV and pixel size
- 77.Which of the following terms are commonly used to describe the ability of a CT scanner to differentiate objects with similar linear attenuation coefficients?
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Spatial resolution and sensitivity
- D.
Sensitivity and contrast resolution
- 78.Which of the following section widths would cause the greatest amount of partial volume averaging?
- A.
1mm
- B.
3mm
- C.
5mm
- D.
10mm
- 79.Which of the following has no measurable effect on spatial resolution?
- A.
Focal spot size
- B.
KVp
- C.
Detector sampling frequency
- D.
Matrix size
- 80.An image that is reconstructed a second time with some change in technical factor is termed _____.
- A.
Reiterated
- B.
Post-processed
- C.
Retrospective
- D.
Reformatted
- 81.During CT angiography, images may be reconstructed using only the greastest density encountered along each ray. This type of specialized CT image is called a(n)
- A.
3 demensional model
- B.
Volume-rendered model
- C.
MIP image
- D.
Surface-rendered image
- 82.The ability of a CT scanner to image a small high-density object is controlled by ___ of the scanner
- A.
Contrast resolution
- B.
Spatial resolution
- C.
Sensitivity
- D.
Contrast resolution and sensitivity
- 83.Which of the following technical changes may increase the partial volume effect present on a spiral CT scan?
- A.
Decrease the pitch
- B.
Decrease the aperature size
- C.
Increase in matrix size
- D.
Increase in pitch
- 84.The matrix size describes which of the following?
- A.
Aperture size used during data acquistion
- B.
Number of pixels used to display an image
- C.
Relationship between the field of view and algorithm
- 85.The type of filter used at the xray tube of a CT scanner is called a
- A.
Kernel
- B.
Water bath
- C.
Bow-tie filter
- D.
Wedge filter
- 86.Which of the following would increase the noise of a CT image?
- A.
Increased mAs
- B.
Decreased aperture size
- C.
Decreased filtration
- D.
Decreased matrix size
- 87.The interaction between xray and matter that is responsible for the production of the scatter radiation absorbed by the patient and detectors is
- A.
Compton interaction
- B.
Bremsstrahlung interaction
- C.
Photoelectric effect
- D.
Characteristic interaction
- 88.The major disadvantage of the back-projection method of image reconstruction is the appearance of the
- A.
Partial volume effect
- B.
Ring artifact
- C.
Gibbs phenomenon
- D.
Star artifact
- 89.The contast resolution of a CT scanner is not related to which of the following?
- A.
Focal spot size
- B.
Section width
- C.
Reconstruction algorithm
- D.
Signal-to-noise ratio
- 90.The intensity of the CT xray beam can be increased by
- A.
Increasing filtration
- B.
Decreasing collimation
- C.
Decreasing applied voltage
- D.
Increasing collimation
- 91.Which of the following is a solid-state device used to record the light flashes given off by a scintillation crystal?
- A.
Photomultiplier tube
- B.
Anode
- C.
Photodiode
- D.
Input phosphor
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