CT Scan MCQs With Answer Part 3
“Explore your knowledge with our comprehensive CT Scan MCQs With Answer Part 3. Test your understanding of computed tomography through a curated set of multiple-choice questions designed to enhance your expertise in medical imaging. Elevate your learning experience and reinforce key concepts with detailed explanations provided for each answer. Get ready to master CT Scan principles and stay ahead in your medical journey.”
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1. Air trapping within the trachea and bronchial tree may be optimally demonstrated with multiplanar volume reconstructions (MPVRs) of the thorax known as:
A. Maximum intensity projections (MIPs)
B. 3D volume renderings
C. Shaded-surface displays (SSDs)
D. Minimum intensity projections (min-IPs)
ANS:- D
2. Which of the following is NOT a portion of the small bowel?
A. Duodenum
B. Jejunum
C. Ileum
D. Cecum
ANS:- D
3. Which of the following is used as the IV-administered radiopharmaceutical during a PET-CT fusion examination?
A. Technetium Tc 99m
B. Iodine I 131
C. Fludeoxyglucose F 18 (FDG)
D. Strontium chloride Sr 89
ANS:- C
4. The specialized CT examination of the bladder in which an iodinated contrast agent is directly administered under gravity into the bladder via Foley catheter is termed:
A. CT IVP
B. CT urogram
C. CT enteroclysis
D. CT cystography
ANS:- D
5. Which of the following best describes the shape of the x-ray beam utilized in MDCT?
A. Pencil beam
B. Fan-shaped
C. Electron beam
D. Cone-shaped
ANS:- D
6. Collimation of the CT x-ray beam occurs:
1. At the x-ray tube, regulating slice thickness
2. Just beyond the patient, focusing off-axis transmitted radiation
3. Before the detectors, limiting the amount of scatter radiation absorbed
A. 1 only
B. 1 and 2 only
C. 1 and 3 only
D. 1, 2, and 3
ANS:- C
7. CT numbers are usually provided in the form of:
A. Hounsfield units
B. EMI numbers
C. Cormacks
D. m
ANS:- A
8. The mathematical technique allowing the reconstruction of motion-free images from helically acquired CT data is called:
A. Convolution
B. Radon transformation
C. Interpolation
D. Fourier reconstruction
ANS:- C
9. The full width at half maximum (FWHM) of a CT scanner is used to describe:
A. Spatial resolution
B. Contrast resolution
C. Noise
D. Calibration accuracy
ANS:- A
10. A first-generation CT scanner consists of an x-ray tube and two detectors that translate across the patient’s head while rotating in 1-degree increments for a total of:
A. 45 degrees
B. 90 degrees
C. 180 degrees
D. 360 degrees
ANS:- C
11. Which of the following abbreviations is used to identify a computerized network that stores, retrieves, communicates, and displays digital medical images?
A. WORM
B. PACS
C. DICOM
D. HIPAA
ANS:- B
12. The CT “window” controls the ____________ of the CT image as it appears to the viewer.
A. Density and detail
B. Spatial and contrast resolution
C. Contrast and brightness
D. Attenuation coefficient and Hounsfield value
ANS:- C
13. Voxels with equal dimensions along the x-, y-, and z-axes are referred to as:
A. Prospective
B. Isotropic
C. Retrospective
D. Anisotropic
ANS:- B
14. Which of the following artifacts is not affected by the CT technologist?
A. Motion
B. Partial volume
C. Edge gradient
D. Ring
ANS:- D
15. When one is viewing a multiplanar reformation (MPR) image, each pixel represents:
A. The maximum attentuation occurring within the voxel
B. The average attenuation occurring within the voxel
C. The minimum attenuation occurring within the voxel
D. All attenuation occurring within the voxel above a Set threshold value
ANS:- B
16. Statistical noise appears as __________ on a CT image.
A. Decreased contrast
B. Increased brightness
C. Concentric circles
D. Graininess
ANS:- D
17. An acquisition is made on a 64-slice MSCT system in which each detector element has a z-axis dimension of 0.625 mm. With a selected beam width of 40 mm and the beam pitch set at 1.50, how much will the table move with each rotation of the gantry?
A. 20 mm
B. 40 mm
C. 60 mm
D. 80 mm
ANS:- C
18. The component of the CT computer system responsible for the data processing of image reconstruction is the:
A. Pipeline memory
B. Array processor
C. Hard disk drive
D. RAM microprocessor
ANS:- B
19. For single-slice CT (SSCT) systems, which of the following statements regarding retrospective image reconstruction is FALSE?
A. The algorithm, matrix size, and DFOV may all be changed.
B. The slice thickness and SFOV may be changed.
C. Scan (raw) data must be available.
D. Retrospective image reconstruction may be used to adjust the center of the image.
ANS:- B
20. The loss of anatomic information between contiguous sections due to inconsistent patient breathing is called:
A. Cupping artifact
B. Misregistration
C. Overshoot artifact
D. Out-of-field artifact
ANS:- B
21. Before a CT image can be reconstructed by a computer, the transmission signal produced by the detectors must be converted into numerical information by a(n):
A. Kernel
B. Analog-to-digital converter (ADC)
C. Array processor
D. Digital-to-analog converter (DAC)
ANS:- B
22. A CT image is formed in part by projecting back all of the attenuation values recorded during data acquisition onto a:
A. Pixel
B. Voxel
C. Matrix
D. Reformat
ANS:- C
23. Which of the following archival media is capable of storing the largest number of CT images?
A. Floppy disk
B. Magnetic tape
C. VHS tape
D. Optical disk
ANS:- D
24. Areas of a CT image that contain abrupt changes in tissue density are electronically represented by which of the following?
A. Positive CT numbers
B. High spatial frequencies
C. Negative CT numbers
D. Low spatial frequencies
ANS:- B
25. Which of the following components of CT image quality are being evaluated in the figure?
1. Low-contrast detectability
2. Noise
3. Uniformity
A. 2 only
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
ANS:- D
26. The differences in Hounsfield value exhibited in the ROIs measured on this CT image of a waterfilled phantom are most likely due to the phenomenon referred to as:
A. Partial volume averaging
B. Noise
C. Beam hardening
D. Detector drift
ANS:- C
27. Which region of interest (ROI) on the figure demonstrates the greatest amount of image noise?
A. 1
B. 2
C. 3
D. impossible to determine from the information provided
ANS:- A
28. Which of the following terms is used to describe a set of rules for solving a mathematical problem?
A. Reconstruction
B. Algorithm
C. Function
D. Array
ANS:- B
29. Which of the following factors does not affect the dimensions of a voxel?
A. Slice thickness
B. Matrix size
C. Kernel
D. Display field of view
ANS:- B
30. The size of the CT image displayed on a computer monitor can be enlarged by increasing the:
1. DFOV
2. SFOV
3. Image magnification
A. 1 only
B. 3 only
C. 1 and 2 only
D. 1 and 3 only
ANS:- B
31. The average photon energy of the primary beam of a CT scanner operating at a tube potential of 120 kVp is approximately:
A. 50 keV
B. 70 keV
C. 100 keV
D. 120 keV
ANS:- B
32. MSCT systems typically employ which of the following detector geometries?
A. First-generation
B. Second-generation
C. Third-generation
D. Fourth -generation
ANS:- C
33. The acquisition of a series of CT images at a single anatomic location over a set period is referred to as:
A. Ultrafast CT
B. Cine CT
C. Conventional CT
D. Temporal CT
ANS:- B
34. The rate at which a quantity of x-radiation emitted from a CT tube passes through a unit area over a Unit of time is called the:
A. Effective mAs
B. Photon flux
C. Constant mAs
D. Photon fluence
ANS:- B
35. An average CT number value for bone is:
a. +100 HU
b. +500 HU
c. +1000 HU
d. +3000 HU
ANS:- C
36. A standard CT image reconstructed on a 5122 matrix has a digital size of approximately:
A. 0.5 MB
B. 3.0 MB
C. 5.0 MB
D. 10.0 MB
ANS:- A
37. The term used to describe the relationship between the linear attenuation coefficient of an object and the calculated CT numbers is:
A. Linearity
B. Mottle
C. Quantum noise
D. Spatial resolution
ANS:- A
38. Quality control measurements to test the accuracy of the CT scanner’s calibration should be performed:
A. Daily
B. Weekly
C. Monthly
D. Annually
ANS:- A
39. The 3D CT technique that includes all of the acquired voxel information in the reconstructed model with adjustments to its opacity is termed:
A. Surface rendering
B. Maximum intensity projection (MIP)
C. Curved multiplanar reformation
D. Volume rendering
ANS:- D
34. Where is the high-frequency generator often located in a modern CT scanner?
A. Inside the gantry
B. Just outside the scan room
C. Beneath the CT table
D. Inside the operator’s console
ANS:- A
35. The smallest unit of information used in the binary language of computers is the:
A. Bit
B. Chip
C. Base
D. Byte
ANS:- A
36. The continuous gantry rotation required by helical CT acquisition is made possible by the application of:
A. Electromagnetic bushings
B. Titanium bearings
C. Slip-rings
D. Oil-cooled couplings
ANS:- C
38. The process of applying a mathematical filter to remove blurring from the reconstructed CT image is termed:
A. Convolution
B. Interpolation
C. Iteration
D. Z-filtration
ANS:- A
39. Which of the following acquisitions may be characterized as contiguous?
A. 2.5-mm sections reconstructed every 1.25 mm
B. 5.0-mm sections reconstructed every 7.5 mm
C. 3.75-mm sections reconstructed every 3.75 mm
D. 20-second cine acquisition with 1.25-mm sections
ANS:- C
40. Pixels representing tissues with average attenuation coefficients greater than that of water have which of the following types of values?
A. Extremely small
B. Positive
C. Negative
D. Low contrast
ANS:- B
42. For a single-slice CT (SSCT) system, which of the following statements regarding pre-patient collimation is true?
1. An increase in pre-patient collimation increases patient radiation dose.
2. Pre-patient collimation is used to focus radiation through the section of interest.
3. Pre-patient collimation directly controls slice thickness.
A. 2 only
B. 3 only
C. 1 and 2 only
D. 2 and 3 only
ANS:- B
43. Digital CT images are networked and archived in accordance with a standardized computer protocol identified by which of the following abbreviations?
A. HIPAA
B. HTTP
C. TCP/IP
D. DICOM
ANS:- D
44. The contrast 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
ANS:- A
45. The artifact present on the lateral borders of the image in the figure most likely represents which of the following?
A. Edge gradient
B. Out-of-field artifact
C. Tube arcing
D. Beam hardening
ANS:- B
46. The image in the figure was produced using the following parameters: large (full) SFOV; maximum DFOV (48 cm); 200 mA, 120 kVp; soft tissue algorithm. Which of the following technical adjustments would serve to reduce the artifact present?
A. Switching to a detail or bone algorithm
B. Using a smaller SFOV
C. Increasing the mA to 240 and the kVp to 140
D. Centering the patient within the SFOV
ANS:- D
47. The average photon energy of the CT x-ray beam can be increased by:
A. Increasing mAs
B. Increasing filtration
C. Increasing collimation
D. All of the above
ANS:- B
48. 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
ANS:- C
49. Automatic tube current modulation (ATCM) software is used in current MDCT systems to control:
A. Patient radiation dose
B. Cardiac motion
C. Timing of the contrast agent bolus
D. Tissue perfusion assessment
ANS:- A
50. The type of MSCT detector array that contains multiple rows of detector elements, each of the same length, is called a(n):
A. Uniform matrix array
B. Adaptive array
C. Hybrid array
D. Stationary array
ANS:- A
51. A CT image is displayed in a window with a level of 0 and a width of 500. Which of the following statements is correct?
A. Pixels with values between 0 HU and 500 HU will appear white.
B. Pixels with values between 250 HU and þ250 HU will be assigned shades of gray.
C. Pixels with values greater than þ500 HU will be black.
D. Pixels with values less than 0 HU will appear white.
ANS:- B
52. Reformatted CT image planes that lie perpendicular to the original plane of acquisition may be described as:
A. Oblique
B. Orthogonal
C. Obtuse
D. Orthographic
ANS:- B
53. Segmenting the data acquisition process into separate components of smaller rotation angles may improve which of the following components of CT image quality?
A. Temporal resolution
B. Longitudinal spatial resolution
C. Contrast resolution
D. In-plane spatial resolution
ANS:- A
54. Which of the following image artifacts is unique to multislice CT (MSCT) systems?
A. Step artifact
B. Aliasing artifact
C. Out-of-field artifact
D. Cone beam artifact
ANS:- D
55. Which of the following is considered an analytic form of image reconstruction?
1. Iterative technique
2. Fourier reconstruction
3. Filtered back-projection
A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2, and 3
ANS:- C
56. A 16-slice MSCT system utilizes an adaptive array of 24 detectors, each ranging in size from 0.625 to 1.25 mm. What is the maximum number of sections the system can acquire with each rotation of the gantry?
A. 8
B. 16
C. 32
D. 64
ANS:- B
57. The measurement of transmitted radiation made by an individual detector is called a(n):
A. Attenuation coefficient
C. CT number
D. Ray sum
ANS:- D
58. The information included during the 3D reconstruction of a CT scan is controlled by the:
A. Algorithm
B. window setting
C. Threshold setting
D. Gray-scale map
ANS:- C
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