Image Production Flashcards
X-ray tubes in CT are most similar to the radiation source used within which modality?
A. Diagnostic Radiography
B. Positron emission tomography (PET)
C. Ultrasonography
D. Magnetic Resonance Imaging (MRI)
A. Diagnostic Radiography
If milliamperage (mA) is decreased by a factor of 2, how is the radiation dose to the patient changed if other factors remain unchanged?
A. Dose is increased by a factor of 2
B. Dose is decreased by a factor of 2
C. Dose remains unchanged
D. Dose is decreased by a factor of 22
B. Dose is decreased by a factor of 2
Which of the following statements correctly describes the flow of electrons through the x-ray tube?
A. Cathode to anode
B. Anode to cathode
C. Positive to negative
D. Target to a filament
A. Cathode to anode
An increase of which of the following exposure factors would increase the total number of x-ray photons exposing the detectors? (Select three)
A. Increased milliamperage (mA)
B. Increased kilovoltage peak (kVp)
C. Increased pitch
D. Increased filtration
E. Increased rotation time
A. Increased milliamperage (mA)
B. Increased kilovoltage peak (kVp)
E. Increased rotation time
Which technical change is expected to increase the penetrating ability of an x-ray beam?
A. Increased kVp
B. Increased mA
C. Increased rotation time
D. All of the above
A. Increased kVp
Which of the following effects can occur when mA is increased in CT? (Select three)
A. Increasing dose to the patient
B. Increasing image contrast
C. Increasing the intensity of the beam
D. Increasing the exposure to the detector elements
E. Increased spatial resolution
A. Increasing dose to the patient
C. Increasing the intensity of the beam
D. Increasing the exposure to the detector elements
If the rotation time of a scan is decreased, what other exposure parameter should be changed to maintain the image quality?
A. Increased mA
B. Increased kVp
C. Decrease scan length
D. Decrease mA
A. Increased mA
The specific process that accelerates electron in an x-ray tube is:
A. Evacuation of air in the envelope
B. Thermionic emission
C. Application of a voltage
D. Bremsstrahlung electron interactions
C. Application of a voltage
Compared to general radiography, CT x-ray tubes require:
A. Large heat capacity
B. Shorter exposure time
C. Less radiation output
D. Lower mA settings
A. Large heat capacity
Production of x-rays in a CT machine requires a: (select three)
A. Source of electrons
B. Means of rapid acceleration of electrons
C. Means of rapid deceleration of electrons
D. Source of radioactivity
A. Source of electrons
B. Means of rapid acceleration of electrons
C. Means of rapid deceleration of electrons
The signal produced by a CT detector is a(n):
A. Analog electrical signal
B. Processed image data
C. Raw digital data
D. Unprocessed binary data
A. Analog electrical signal
The width of the x-ray beam is controlled by:
A. kVp
B. Collimation
C. Matrix size
D. mA
B. Collimation
Physical components located inside the CT gantry typically include which two of the following? (Select two)
A. X-ray tube
B. Computer system
C. High-voltage generator
D. Archive sensors
A. X-ray tube
C. High-voltage generator
The main difference between image production in CT compared to image production in radiography:
A. X-ray photons are collected by detectors
B. An unprocessed digital signal is converted to image data
C. Projections are compiled into a 3D volume of data
D. The x-ray beam is partially attenuated by the patient
C. Projections are compiled into a 3D volume of data
A single “view” acquired during a CT scan is also called a:
A. Slice
B. Projection
C. Detector
D. Attenuation reading
B. Projection
A common kVp setting used in CT is:
A. 20 kVp
B. 120 kVp
C. 200 kVp
D. 20-500 kVp
B. 120 kVp
The phrase “8-slice scanner” refers to a CT imaging system that has:
A. 8 detectors
B. 8 detector rows
C. 8 mm x-ray beam
D. An 8 second rotation time
B. 8 detector rows
The principal advantage of thin detector rows is:
A. Faster scan time
B. Lower patient dose
C. Lower x-ray output
D. Higher spatial resolution
D. Higher spatial resolution
Increasing the mA and kVp of a CT scan will usually result in which two of the following? (Select two)
A. Increased patient dose
B. Increased processing time
C. Decreased image noise
D. Decreased spatial resolution
A. Increased patient dose
C. Decreased image noise
Which component of the CT imaging system is responsible for creating reconstructed image data?
A. Computer system
B. Data acquisition system
C. Detector array
D. Array processor
A. Computer system
CT angiography imaging of the heart is sometimes performed with the CT scanner in the volume acquisition mode. This means that the:
A. Patient couch moves only between x-ray exposures
B. Patient table is in constant motion
C. Scan data is acquired in one rotation of the x-ray tube
D. Scan data is collected in one large helical pattern
C. Scan data is acquired in one rotation of the x-ray tube
What number represents the x-axis?
1
A CT scanning protocol is set to use a pitch of 0.79. This will result in:
A. Overlap in the scan data
B. Missing views in the scan data
C. Overlap and missing views in the scan data
D. Scan data without overlap or missing views
A. Overlap in the scan data
Helical scanning mode is usually preferred over axial scanning mode for what three reasons? (Select three)
A. Decreased scan time
B. Improved IV contrast timing
C. Increased spatial resolution
D. Improved post-processing
E. Decreased patient dose
A. Decreased scan time
B. Improved IV contrast timing
D. Improved post-processing
Increasing the acquisition thickness of a CT scan means:
A. Combining detector rows together as one detector row
B. Increasing the displayed slice thickness
C. Combining reconstructed slices together to form thicker slices
D. Increasing the space between spirals in the helix
A. Combining detector rows together as one detector row
During helical scanning, if the table moves a greater distance than the width of the beam the pitch will be:
A. Greater than 1
B. Less than 1
C. Equal to 1
A. Greater than 1
What portion of the patient can be visualized through the process of retrospective reconstruction?
A. Only parts of the patient within the display field-of-view (DFOV)
B. Only parts of the patient within the scan field- of-view (SFOV)
C. Only parts of the patient outside the scan-of-view (SFOV)
D. Only parts of the patient within the scanner gantry
B. Only parts of the patient within the scan field- of-view (SFOV)
The sequential acquisition mode is described by which of the following statements?
A. The patient table moves only between x-ray exposures
B. The patient table is in constant motion
C. The scan data is acquired in one rotation of the x-ray tube
D. The scan data is collected in one large spiral pattern
A. The patient table moves only between x-ray exposures
Under what two circumstances would it be impossible to reconstruct the additional brain anatomy missing from the image below? (select two)
A. The missing anatomy is outside of the original display field-of-view (DFOV)
B. The original image data has been deleted from the CT computer system
C. The original scan data has been deleted from the CT computer system
D. The missing anatomy is outside of the original scan field-of-view (SFOV)
C. The original scan data has been deleted from the CT computer system
D. The missing anatomy is outside of the original scan field-of-view (SFOV)
What CT data acquisition mode collects a series of adjacent axial sections?
A. Axial scanning
B. Helical scanning
C. Volume scanning
A. Axial scanning
Shifting the center of a sagittal image requires changes to which two data coordinates? (Select two)
A, X-axis
B. Y-axis
C. Z-axis
B. Y-axis
C. Z-axis
Which of the following statements accurately describes the orientation of the x-axis in CT imaging? (Select two)
A. Extends horizontally across the scanner
B. Extends vertically across the scanner
C. Represents data coordinates in terms of right and left
D. Represents data coordinates in terms of anterior and posterior
A. Extends horizontally across the scanner
C. Represents data coordinates in terms of right and left
What portions of a patient receive radiation exposure during CT scanning?
A. Any portion of the patient within the display field-of-view
B. Any portion within the scan field-of-view but outside the display field-of-view
C. Any portion of the patient outside the scan field-of view
D. Any portion of the patient within the scanner gantry
D. Any portion of the patient within the scanner gantry
What CT scan data acquisition mode is demonstrated in this illustration?
A. Axial mode
B. Helical mode
C. Volume mode
B. Helical mode
What axis position has changed in this series of axial images?
A. X-axis
B. Y-axis
C. Z-axis
C. Z-axis
Pitch is defined as the ratio of the table movement to the:
A. Beam width
B. Acquisition thickness
C. Tube rotation time
D. Radiation output
A. Beam width
What CT scanning mode may induce patient motion artifact from several stops and starts of the gantry table during data acquisition?
A. Axial mode
B. Helical mode
C. Volume mode
A. Axial mode
Which two of the following statements regarding the scan field-of-view (SFOV) are true? (Select two)
A. The SFOV is larger than the DFOV
B. Data in the SFOV is sent to the radiologist
C. Data in the SFOV is saved on the CT computed system
D. The size of the SFOV is set by the technologist using the scout images
A. The SFOV is larger than the DFOV
C. Data in the SFOV is saved on the CT computed system
What axis position has changed in this series of sagittal images?
A. X-axis
B. Y-axis
C. Z-axis
A. X-axis
If the pitch is equal to 1.1, how far is the far is the patient table moving during each rotation of the tube?
A. 1.1 times the beam width
B. 1.1 divided by the number of data channels
C. 1.1 times the number of detector rows
D. 1.1 divided by the acquisition thickness
A. 1.1 times the beam width
What portion of the CT data collected during a scan is saved by the scanner but not reconstructed for viewing?
A. Any portion of the patient within the display field-of-view
B. Any portion within the scan field-of-view but outside the display field-of-view
C. Any portion of the patient outside the scan field-of view
D. Any portion of the patient within the scanner gantry
B. Any portion within the scan field-of-view but outside the display field-of-view
What CT scanning method requires a large detector array with numerous data collection channels?
A. Axial scanning
B. Helical scanning
C. Volume scanning
C. Volume scanning
If a routine helical scan of the chest is pre-programmed to use 16 detector rows and a pitch of 1.13, how will the resulting views comprise the scan data?
A. Duplicate views of the same positions in the scan data
B. Missing views in the scan data
C. Overlapping and missing views in the scan data
D. No overlap of missing views in the scan data
B. Missing views in the scan data
What number represents the y-axis?
A. 1
B. 2
C. 3
B. 2
When the pitch is less than one, how do the resulting views comprise the scan data?
A. Overlapping views in the scan data
B. Missing views in the scan data
C. Overlap and missing views in the scan data
D. No overlap or missing views in the scan data
A. Overlapping views in the scan data
During which acquisition mode is the patient table in constant motion?
A. Axial scanning
B. Helical scanning
C. Volume scanning
B. Helical scanning
After completing a CT of abdomen, you noticed that your images do not include the entire abdomen. Which of the following methods can to retrieve this information?
A. Prospective reconstruction
B. Retrospective reconstruction
C. Multiplanar reformation
D. This information cannot be retrieved
B. Retrospective reconstruction
When imaging a patient in CT, what portion of the patient is processed for viewing on the technologist’s computer monitor?
A. Any part within the DFOV
B. Any part within the SFOV but outside of the DFOV
C. Any part of the patient outside of the scan of the DFOV
D. Any part of the patient within the scanner gantry
A. Any part within the DFOV
How is anatomical data from the SFOV used during CT image production?
A. Data from the SFOV is used for multiplanar reformations
B. Data from the SFOV is used for volume rendering (VR)
C. Data from the SFOV is used for long-term image archival
D. Data from the SFOV is used for image reconstruction
D. Data from the SFOV is used for image reconstruction
What number is the Z-axis?
3
Which of the following statements accurately describes the orientation of the z-axis in CT imaging? (Select two)
A. Extends vertically across the scanner
B. Extends longitudinally through the scanner
C. Represents data coordinates in terms of anterior and posterior
D. Represents data coordinates in terms of superior and inferior
B. Extends longitudinally through the scanner
D. Represents data coordinates in terms of superior and inferior
Which of the following two statements concerning the SFOV are true? (Select two)
A. The SFOV is usually larger than the DFOV
B. Data in the SFOV is sent to the radiologist
C. Data in the SFOV is saved on the CT computed system
D. The size of the SFOV is set by the technologist using the scout images
A. The SFOV is usually larger than the DFOV
C. Data in the SFOV is saved on the CT computed system
During an axial scan, the total amount of anatomical coverage per tube rotation is dependent on which of the following two variables? (Select two)
A. Number of activated detector rows
B. Tube rotation time
C. Pitch
D. Thickness of activated detector rows
A. Number of activated detector rows
D. Thickness of activated detector rows
The localizer images are used by the technologist to assign which variable of a CT scan?
A. DFOV
B, SFOV
C. Acquisition thickness
D. Reconstruction thickness
A. DFOV
Acquiring x-axis measurement of a pathology is possible in which two imaging planes? (Select two)
A. Sagittal
B. Axial
C. Coronal
A. Sagittal
C. Coronal
A CT detector configuration is changed from 0.625 mm x 16 rows to 1.25 x 8 rows. The change may result in:
A. Decreased patient dose
B. Increased spatial resolution
C. Increased beam coverage
D. Increased scan time
A. Decreased patient dose
Consider two identical scanning protocols, except one protocol uses a pitch of 0.73 and the other uses a pitch of 0.87. The protocol using of 0.87 will result in which of the following protocols?
A. Decreased scan time
B. Increased spatial resolution
C. Decreased patient dose
D. Increased scan time
A. Decreased scan time
C. Decreased patient dose
What is the primary reason for decreasing the detector thickness for CT angiography examinations?
A. Decreased patient dose
B. Increased spatial resolution
C. Increased beam coverage
D. Decreased scan time
B. Increased spatial resolution
The helical acquisition mode is the most common technique used for imaging which three body sections? (select three)
A. Cranium
B. Chest
C. Abdomen
D. Extremities
B. Chest
C. Abdomen
D. Extremities
The inner rows of a non-uniform detector array have the advantage of:
A. Increased spatial resolution
B. Increased contrast resolution
C. Decreased patient dose requirement
D. Decreased image noise
A. Increased spatial resolution
What is the relationship between acquisition thickness and spatial resolution?
A. As acquisition thickness increases, spatial resolution decreases
B. As acquisition thickness increases, spatial resolution increases
C. As acquisition thickness increases, spatial resolution remains constant
D. As acquisition thickness increases, spatial resolution remains constant in the inner detector rows.
A. As acquisition thickness increases, spatial resolution decreases
Based on feedback from an American College of Radiology (ACR) site-visit, your imaging department needs to design a new low-dose CT protocol for patients who weigh less than 30 pounds. Which of these detector configurations would be most suited for this protocol?
A. 1 mm x 16 rows
B. 2 mm x 8 rows
C. 4 mm x 4 rows
D. 0.5 mm x 8 rows
C. 4 mm x 4 rows
Acquisition thickness refers to the:
A. Number of active detector rows
B. Thickness of active detector rows
C. Thickness of reconstructed slices
D. Number of data collection channels
B. Thickness of active detector rows
The visible difference between these two images might be explained by which of the following?
A. Different slice thickness
B. Different slice interval
C. Different window width
D. Different contrast volume
A. Different slice thickness
These three images were created by scanning the same spherical object using the same CT system. The difference in appearance is a result of using a different:
A. Reconstruction algorithm
B. Number of projections
C. Interpolation algorithm
D. Windowing technique
B. Number of projections
What two combinations of reconstruction parameters could be used to create detailed images of the bony trabeculae? (Select two)
A. Thin slices
B. Thick slices
C. Edge-enhancing algorithms
D. Smoothing algorithms
A. Thin slices
C. Edge-enhancing algorithms
Which of the following accurately describes where raw CT data is stored?
A. It is not stored
B. In the CT computer system
C. In the picture archiving and communication system (PACS)
D. In the radiologists reading station
B. In the CT computer system
The process of assigning a specific level of edge-enhancement to the CT image data is controlled by mathematical filters called: (select three)
A. Reconstruction algorithms
B. Reconstruction filters
C. Reconstruction kernels
D. Filter back-projection
A. Reconstruction algorithms
B. Reconstruction filters
C. Reconstruction kernels
The mathematical filtration of CT data to enhance the appearance of specific tissue types is called:
A. Interpolation
B. Filtration
C. Convolution
D. Back projection
C. Convolution
Thick reconstruction slices (greater than 3 mm) are not suitable for which of the following? (Select all that apply)
A. Multiplanar reformations
B. Angiographic imaging
C. Abdominal imaging
D. Thoracic imaging
A. Multiplanar reformations
B. Angiographic imaging
The process of reconstruction in the CT computer system creates:
A. Image data
B. Scan data
C. Unprocessed data
D. Reformatted data
A. Image data
After performing a thoracic spine scan for trauma, the radiologist requests images of the entire bony thorax. The raw data is still saved on the CT scanner. This will require:
A. Rescanning the patient
B. Retrospectively reconstructing images with a different DFOV
C. Retrospectively reconstructing images with a different algorithm
D. Retrospectively reconstructing images with a different SFOV
B. Retrospectively reconstructing images with a different DFOV
Which two of these algorithms are preferred for viewing bone? (Select two)
A. Edge-enhancing algorithms
B. Standard algorithms
C. Smoothing algorithms
D. Bone algorithms
A. Edge-enhancing algorithms
D. Bone algorithms
Which three of these scan parameters can be changed retrospectively? (Choose three)
A. Scan start and end locations
B. Slice thickness
C. SFOV
D. DFOV
A. Scan start and end locations
B. Slice thickness
D. DFOV
Estimating an unknown value in a series of known values is a mathematical process called:
A. Interpolation
B. Filtration
C. Convolution
D. Back-projection
A. Interpolation
In this scan of the temporal bones, the initial images series (left) was rejected by the radiologist. The technologist retrospectively reconstructed the image series (right), which was then accepted by the radiologist. Based on the appearance of these images, what is one possible reason the initial image series (left) was rejected?
A. Incorrect reconstruction algorithm
B. Incorrect window width
C. Incorrect window level
D. Incorrect gantry tilt
A. Incorrect reconstruction algorithm
By definition, the acquisition thickness is the same as the:
A. Detector row thickness
B. Reconstruction slice thickness
C. Reconstruction slice interval
D. Acquisition mode
A. Detector row thickness
Which of these image-processing techniques in CT are only used in helical scanning?
A. Interpolation
B. Filtration
C. Convolution
D. Back-projection
A. Interpolation
Which of these scenarios will result in gaps in reconstructed image information?
A. When the slice interval is equal to the slice thickness
B. When the slice interval is greater than the slice thickness
C. When the slice interval is less than the slice thickness
B. When the slice interval is greater than the slice thickness
During a routine CT scan of the pediatric chest, the radiologist requests that the technologist reconstruct the image data with 1.25 mm slices rather than 2.5 slices. One negative effect of this change will be:
A. Increased image noise
B. Increase spatial resolution
C. Decrease image data
D. Decreased scan time
A. Increased image noise
A region of interest (ROI) indicating an average hounsfield unit (HU) of +39 mostly likely corresponds to which of the follwing?
A. Fat
B. Water
C. Blood
D. Bone
C. Blood
These images are both coronal reformations of the same patient, but different image data sets were used to create each image. What is most likely explanation for the poor image quality in the image at the left?
A. Incorrect algorithm selection in the axial data set
B. Incorrect reconstruction slice thickness in the axial data set
C. Incorrect field-of-view in the axial data set
D. Incorrect windowing in the coronal data set
B. Incorrect reconstruction slice thickness in the axial data set
Compared to a 1.25 mm image data, 3.75 mm image data will demonstrate: (Select two)
A. Increased spatial resolution
B. Decreased image noise
C. Decreased contrast resolution
D. Fewer total slices
B. Decreased image noise
D. Fewer total slices
After performing an abdominal scan for trauma, the radiologist requests reconstructed images of the lumbar spine. The raw data is not saved on the CT scanner, so this will require:
A. Rescanning the patient
B. Retrospectively reconstructing images with a different display FOV
C. Retrospectively reconstructing images with a different algorithm
D. Retrospectively reconstructing images with a different scan FOV
A. Rescanning the patient
In the reconstructed image data, the distance from the start of one slice to the start of the next slice is defined as the:
A. Slice interval
B. Slice thickness
C. Beam width
D. Window width
A. Slice interval
If the reconstruction slice thickness is set to 3.0 mm, which of these statements is also true?
A. The image data is 3.0 mm thick
B. The image data is greater than 3.0 mm thick
C. The image data is less than 3.0 mm thick
D. The acquisition thickness is also 3.0 mm
A. The image data is 3.0 mm thick
What mathematical process prevents star-like artifacts from appearing on the CT images?
A. Interpolation algorithm
B. Reconstruction algorithm
C. Back-projection filter
D. Reconstruction kernel
C. Back-projection filter
Iterative reconstruction is an alternative to traditional reconstruction and helps to: (select two)
A. Reduce patient dose
B. Decrease scan time
C. Decrease required contrast volume
D. Increase image quality
A. Reduce patient dose
D. Increase image quality
Which two algorithms are most useful for viewing soft tissue changes around the cranium? (Select two)
A. Smoothing algorithms
B. Bone algorithms
C. Edge-enhancing algorithms
D. Standard algorithms
A. Smoothing algorithms
D. Standard algorithms
An ROI is placed over an abnormal lesion yeilds an average CT number of -52. This lesion may be composed of:
A. Fat
B. Water
C. Blood
D. Cerebral spinal fluid
A. Fat
Which of these CT protocols generally use thin slices?
A. Circle of Willis for arterial-venous malformation
B. Abdomen for ulcerativ-colitis
C. Chest for cancer evaluation
D. Head for hemorrhage
A. Circle of Willis for arterial-venous malformation
Using a larger reconstruction slice thickness results in which of the following? (select two)
A. Decreased image noise
B. Decreased contrast resolution
C. Decreased spatial resolution
D. Decreased partial volume averaging
A. Decreased image noise
C. Decreased spatial resolution
What anatomical section is typically displayed with a WW of 80 and a WL of 30?
A. Abdomen
B. Spine
C. Lungs
D. Brain
D. Brain
A CT myelogram calls for a 2100 WW and a 700 WL. What pixel values will be displayed as black?
A. CT numbers above 1750
B. CT numbers below -350
C. CT numbers above 2800
D. CT numbers below -1400
B. CT numbers below -350
The individual pixels in a CT image are not visible to the unaided eye because modern CT equipment uses:
A. Large matrices
B. Large data channels
C. Small scan fields
D. Small window levels
A. Large matrices
This image is displayed with a 2100 WW and 700 WL, Decreasing the window width will result in:
A. Increased brightness
B. Decreased brightness
C. Increased contrast
D. Decreased contrast
C. Increased contrast
How will increasing the window width of a digital image affect the overall appearance of the image?
A. Increased brightness
B. Decreased brightness
C. Increased contrast
D. Decreased contrast
D. Decreased contrast
This image of the spine was reconstructed with an edge enhancing algorithm. Based on the appearance of the image, improved visualization of the bone could be accomplished by changing the:
A. DFOV
B. Reconstruction algorithm
C. Window setting
D. Reconstruction thickness
C. Window setting
If using a 400 WW and 40 WL, the cerebral spinal fluid in the brain will appear as:
A. White
B. Gray
C. Black
B. Gray
What is the best way to correct the overall dark appearance of this image?
A. Increase the WW
B. Increase the WL
C. Decrease the WW
D. Decrease the WL
D. Decrease the WL
Consider a voxel that includes equal parts bone (+1000 HU) and air (-1000 HU). In the reconstructed image, the displayed pixel value will be approximately:
A. 0 HU
B. +1000 HU
C. -1000 HU
D. -2000 HU
A. 0 HU
A technologist modifies the image windowing from -100 WL to -700 WL. Following this change the image will demonstrate:
A. Increased brightness
B. Decreased brightness
C. Increased contrast
D. Decreased contrast
A. Increased brightness
Increasing the window level of a CT image will result in:
A. Increased brightness
B. Decreased brightness
C. Increases contrast
D. Decreased contrast
B. Decreased brightness
Which of these window settings would be appropriate for viewing the major organs of the abdomen?
A. 2500 WW and 60 WL
B. 400 WW and 40 WL
C. 1800 WW and -600 WL
D. 80 WW 30 WL
B. 400 WW and 40 WL
Consider this scenario: A new CT scanner in the radiology department has a matrix size of 1024 x 1024. What variable change can increase the matrix size?
A. Increase the DFOV
B. Increase the SFOV
C. Increase the acquisition thickness
D. None of these changes will affect the matrix
D. None of these changes will affect the matrix
The thickness of a voxel in CT is defined by which of these variables?
A. Acquisition thickness
B. Reconstruction thickness
C. Total beam collimation
D. Matrix dimensions
B. Reconstruction thickness
In CT imaging, window width controls the: (Select two)
A. Brightness of the display image
B. Contrast of the display image
C. Midpoint of the Hounsfield values in the displayed image
D. Range of the Hounsfield values in the displayed image
B. Contrast of the display image
D. Range of the Hounsfield values in the displayed image
Changing the thickness of a voxel may also change:
A. The tissue types included in the voxel
B. The matrix side of the digital image
C. The pixel size in the digital image
D. The window width of the digital image
A. The tissue types included in the voxel
In this sequence of images, what variable is changing?
A. Increasing WW
B. Increasing WL
C. Decreasing WW
D. Decreasing WL
B. Increasing WL
Consider an imaging protocol that calls for very high contrast images of the brain. Which of these settings will display an image with the highest contrast?
A. WW=550, WL=45
B. WW= 1500, WL=50
C. WW=300, WL=80
D. WW=40, WL=30
D. WW=40, WL=30
Which of these windowing techniques will result in the brightest overall image?
A. WW=450, WL=45
B. WW=1500, WL=40
C. WW=300, WL=100
D. WW=40, WL=-30
D. WW=40, WL=-30
Which of these scenarios will produce cervical spine images with the best spatial resolution?
A. 12 cm DFOV
B. 15 cm DFOV
C. 17 cm DFOV
D. 22 cm DFOV
A. 12 cm DFOV
A technologist completed a non-contrast scan of the heart for calcium scoring. If the technologist uses a WW of 300 and a WL of 30, how will dense calcifications in the heart be displayed?
A. White
B. Gray
C. Black
A. White
Which of these images was created using the larges matrix size?
Image A
A three-dimensional block of image data in CT is called a:
A. Voxel
B. Pixel
C. Slice
D. Projection
A. Voxel
Which of the following changes will increase the spatial resolution of a CT image?
A. Increased pixel size
B. Increased matrix size
C. Increased field-of-view
D. Increased reconstruction thickness
B. Increased matrix size
Which of these matrices will have the best spatial resolution?
A. 1024 x1024
B. 512 x 512
C. 256 x 256
D. 2048 x 2048
D. 2048 x 2048
Which of these variables can a technologist change to increase the spatial resolution of a CT image?
A. Increase the matrix size
B. Decrease the matrix size
C. Increase the DFOV
D. Decrease the DFOV
D. Decrease the DFOV
When using an 80 WW and 30 WL, what range of pixel intensities will be assigned a shade of gray?
A. 30 to 80
B. -50 to 110
C. -10 to 70
D. 50 to 110
C. -10 to 70
Consider the following scenario: A radiologist is requesting changes to the brightness and contrast of images used for a CT guided biopsy in the pelvis. Which of these windowing techniques will result in the darkest image with the highest contrast?
A. WW=450, WL=45
B. WW=1500, WL=40
C. WW=300, WL=30
D. WW=40, WL=100
D. WW=40, WL=100
In the context of a digital matrix, 1024 x 1024 refers to the:
A. Number of pixels in the matrix
B. Size of pixels in the matrix
C. Number of brightness levels displayed in the matrix
D. Physical measurement of the matrix
A. Number of pixels in the matrix
Patients with an Agatston grade greater than 400 have a severe risk of major adverse cardiac events. The Agatston grade for coronary calcification is acquired using which of these methods?
A. ROI ellipse
B. Histogram analysis
C. Ejection fraction
D. Calcium scoring
D. Calcium scoring
Ejection fraction analysis in CT is used for:
A. Real-time tracking of contrast enhancement
B. Measuring the size of a suspicious lesion
C. Evaluation of the efficiency of heart contractions
D. Defining the range of CT numbers in an ROI
C. Evaluation of the efficiency of heart contractions
If a radiologist needs to know the ratio of fluid to blood in a cerebral lesion, what quantitative tool can help to estimate this ratio?
A. ROI ellipse
B. Histogram analysis
C. Ejection fraction
D. Calcium scoring
B. Histogram analysis
Which of these 3D rendering techniques display only one tissue type?
A. Shaded surface display
B. Volume rendering
C. Maximum intensity projection
D. Minimum intensity projection
A. Shaded surface display
The best way to correct the noisy appearance of this reformation is to:
A. Create the reformations from thicker axial slices
B. Create the reformations with thicker sagittal slices
C. Create the reformations from thinner axial slices
D. Create the reformation with a larger slice interval
B. Create the reformations with thicker sagittal slices
Using edge-enhanced images for volume rendering is expected to result in:
A. Loss of contrast
B. Image noise
C. Poor spatial resolution
D. Partial volume averaging
B. Image noise
Which three of these measurements is usually acquired using a simple ROI tool? (Select three)
A. Average hounsfield unit (HU) unit
B. Milligray (mGy)
C. Standard deviation
D. Area (cm2)
E. Dose area product
A. Average hounsfield unit (HU) unit
C. Standard deviation
D. Area (cm2)
Based on the frequency of pixel values in the following graph, what is the predominate tissue type being measured?
A. Lung
B. Fat
C. Cerebral spinal fluid
D. Cortical bone
A. Lung
Which of the following statements correctly describes the creation of MPRs?
A. MPRs must be created from raw data
B. MPRs must be created in the same slice orientation as the image data
C. MPRs must be created with the same algorithm as the image data
D. MPRs must be created with the same algorithm as the image data
C. MPRs must be created with the same algorithm as the image data
Consider a voxel in a MPR that includes equal portions of water, fat, and bone. What hounsfield unit (HU) will be displayed on the pixel?
A. The average of all HU in the voxel
B. The HU for water
C. The HU for fat
D. The HU for bone
A. The average of all HU in the voxel
The process of converting axial images into coronal images requires a technique called:
A. Retrospective Reconstruction
B. Multiplanar Reformation
C. Filter back-projection
D. Convolution
B. Multiplanar Reformation
The following image is from a non-contrast scan of the heart. This data series may be used for:
A. Coronary angiography
B. Calcium scoring
C. Pulmonary angiography
D. Ejection fraction evaluation
B. Calcium scoring
What MPR technique is used to display images maximizing visibility of airways within the lungs?
A. Average intensity projection
B. Maximum intensity projection
C. Minimum intensity projection
D. Volume rendering
C. Minimum intensity projection
Which of the following MPR reformations are impossible to create?
A. 1.0 mm coronal reformation from 5.0 mm axial reconstructions
B. 5.0 mm sagittal reformation from 1.0 mm axial reconstructions
C. Bone reformation from bone algorithm reconstruction
D. Standard reformation from bone algorithm reconstruction
D. Standard reformation from bone algorithm reconstruction
Which of these methods is used to estimate a patient’s risk of coronary artery disease (CAD)?
A. ROI ellipse
B. Histogram analysis
C. Ejection fraction
D. Calcium scoring
D. Calcium scoring
What is the effect of using overlapping slices for volume rendered images?
A. Increased image noise
B. Decreased image noise
C. Increased smoothing in the images
D. Decreased tissue differentiation
C. Increased smoothing in the images
Which three of the following is considered a “post-processing” application of the CT image data? (Select three)
A. MPR
B. Retrospective reconstruction
C. 3D rendering
D. ROI measurements
E. Prospective reconstruction
A. MPR
C. 3D rendering
D. ROI measurements
Which of these axial data sets would be best suited for creating 5 mm coronal reformatted images through the abdomen?
A. 1.25 mm axial images
B. 2.5 mm axial images
C. 5 mm axial images
D. 10 mm axial images
A. 1.25 mm axial images
Which of these quantitative analysis methods in CT can be used to identify the maximum Hounsfield value in an area of concern?
A. ROI ellipse
B. Histogram analysis
C. Ejection fraction
D. Calcium scoring
B. Histogram analysis
If a multiplanar reformation is rendered as a maximum intensity projection, what CT number will be displayed for a voxel containing mostly air, lung, fluid and small amount of iodinated contrast?
A. The CT number for air
B. The CT number for lung
C. The CT number for contrast
D. The average CT number within the voxel
C. The CT number for contrast
Based on the transparency of surface tissues in this image, this was produced using what 3D imaging technique?
A. Shaded surface display
B. Volume rendering
C. Maximum intensity projection
D. Minimum intensity projection
B. Volume rendering
What might explain the difference appearance of these two coronal reformations of the chest?
A. The images were reformatted with different reconstruction algorithms
B. The images were reformatted from axial images with different slice thickness
C. The images were reformatted with different slice thickness
D. The images were reformatted with a different windowing technique
C. The images were reformatted with different slice thickness
A physician is requesting a 3D image showing several tissues with various levels of transparency. The appropriate rendering technique is:
A. Shaded surface display
B. Volume rendering
C. Maximum intensity projection
D. Minimum intensity projection
B. Volume rendering
Histogram analysis is useful for which of these applications?
A. Real-time tracking of contrast enhancement
B. Measuring the size of suspicious lesion
C. Evaluating the efficiency of heart contractions
D. Defining range of CT numbers in a region of interest (ROI)
D. Defining range of CT numbers in a region of interest (ROI)\
Which of these scans will have the best contrast resolution?
A. 600 mA, 0.3 second rotation time, 1 mm slices, bone algorithm
B. 500 mA, 0.4 second rotation time, 2 mm slices, standard algorithm
C. 400 mA, 0.5 second rotation time, 3 mm slices, bone algorithm
D. 300 mA, 1.0 second rotation time, 4 mm slices, standard algorithm
D. 300 mA, 1.0 second rotation time, 4 mm slices, standard algorithm
Which of these variable changes is most likely to improve the contrast resolution of the resulting images?
A. Decreased patient size
B. Decreased reconstruction slice thickness
C. Decreased acquisition thickness
D. Decreased mA
A. Decreased patient size
The following image represents a CT phantom used to evaluate which of these image quality factors?
A. Spatial resolution
B. Contrast resolution
C. Temporal resolution
D. Linearity
E. Uniformity
B. Contrast resolution
Motion artifact is a quality control issue related to:
A. Spatial resolution
B. Contrast resolution
C. Temporal resolution
D. Linearity
E. Uniformity
C. Temporal resolution
A CT of the cranium may call for 2.0 mm slices in the posterior fossa and 5.0 mm slices through the vertex. What change in image quality will be observed in the 5.0 mm slices?
A. Increased noise
B. Decreased noise
C. Increased spatial resolution
B. Decreased noise
Scanning a large patient without changing the exposure factors could result in increased:
A. Image noise
B. Contrast resolution
C. Spatial resolution
D. Exposure linearity
A. Image noise
Which of these variable changes may decrease the spatial resolution of the resulting CT images?
A. Increased rotation time
B. Increased reconstruction thickness
C. Increased edge-enhancement
D. Increased matrix size
B. Increased reconstruction thickness
Motion artifact in the heart can be minimized by using:
A. Thick reconstruction slices
B. Thinner detector rows
C. EKG gating
D. Decreased pitch
C. EKG gating
Temporal resolution is defined as the ability to:
A. Visualize small parts
B. Distinguish between parts with similar physical densities
C. Produce still images of objects in motion
D. Produce CT images without image noise
C. Produce still images of objects in motion
This image is an example of a phantom used for evaluating what aspect of a CT scanning system?
A. Spatial Resolution
B. Contrast resolution
C. Temporal resolution
D. Linearity
E. Uniformity
A. Spatial Resolution
Consider a CT scan used to evaluate the brain for metastatic disease. If the average CT number of the tumors differs only slightly from the surrounding brain matter, what characteristic of the scanner might cause limited visibility of the tumors?
A. Spatial resolution
B. Contrast resolution
C. Temporal resolution
D. Linearity
B. Contrast resolution
The CT phantom pictured below is used to evaluate:
A. Spatial resolution
B. Contrast resolution
C. CT number accuracy
D. Linearity
E. Uniformity
A. Spatial resolution
When an ROI is placed over a homogenous structure, which of these values represent the image noise?
A. HU average
B. HU Standard deviation
C. Total area
D. Circumference
B. HU Standard deviation
Excessive noise in a CT image may result in which two of the following? (Select two)
A. Decreased spatial resolution
B. Decreased contrast resolution
C. Decreased temporal resolution
A. Decreased spatial resolution
B. Decreased contrast resolution
When scanning a water phantom for quality control, you notice that a ROI in the center of the phantom read 0 Hu but an ROI on the edge of the phantom reads 4 HU. This is a problem with:
A. Accuracy
B. Linearity
C. Uniformity
D. Contrast resolution
E. Spatial resolution
C. Uniformity
What are the two major differences in image quality between the following images? (Select two)
A. Contrast resolution
B. Temporal resolution
C. Image noise
D. CT number accuracy
E. CT number uniformity
A. Contrast resolution
C. Image noise
Which of these scenarios will result in images with the best contrast resolution?
A. Soft tissue algorithm with 1 mm slices
B. Soft tissue algorithm with 2 mm slices
C. Bone algorithm with 1 mm slices
D. Bone algorithm with 2 mm slices
B. Soft tissue algorithm with 2 mm slices
What quality control test evaluates the ability of the CT scanner to produce the same CT number for the same material regardless of where the ROI is placed?
A. Accuracy
B. Linearity
C. Uniformity
D. Contrast resolution
E. Spatial resolution
C. Uniformity
The phantom pictured below contains only water. Based on the ROI readings, what issue should be reported to the medical physicist?
A. Unacceptable linearity
B. Unacceptable uniformity
C. Unacceptable spatial resolution
D. Unacceptable CT number accuracy
B. Unacceptable uniformity
Which of the following describes the ability of CT scanners to produce detailed images of small parts?
A. Spatial Resolution
B. Contrast Resolution
C. Temporal Resolution
D. Linearity
E. Uniformity
A. Spatial Resolution
Which of these variable changes will increase temporal resolution?
A. Increased pitch
B. Increased rotation time
C. Increased reconstruction thickness
D. Increase kilovoltage potential
A. Increased pitch
Which of these scans will have the best spatial resolution?
A. 600 mA, 1 second rotation time, 1 mm slices, bone algorithm
B. 500 mA 1.0 second rotation time, 2 mm slices, standard algorithm
C. 400 mA, 0.5 second rotation time, 3 mm slices, bone algorithm
D. 300 mA, 0.5 second rotation time, 4 mm slices, standard algorithm
A. 600 mA, 1 second rotation time, 1 mm slices, bone algorithm
The ability of the scanner to visually discriminate between objects with similar physical density is called:
A. Spatial Resolution
B. Contrast Resolution
C. Temporal Resolution
D. Linearity
E. Uniformity
B. Contrast Resolution
Of the following options, what reconstruction slice thickness will display images with the highest level of spatial resolution?
A. 0.625 mm
B. 1.25 mm
C. 5 mm
D. 3.75 mm
A. 0.625 mm
After performing a CT of the chest, an ROI placed in the air outside of the patient yields an average CT number of -1,223. This error represents a problem with:
A. Accuracy
B. Linearity
C. Uniformity
D. Contrast resolution
E. Spatial resolution
A. Accuracy
Spatial resolution is defined as the ability to:
A. Visualize small parts
B. Distinguish between parts with similar densities
C. Produce still images of objects in motion
D. Produce CT images without image noise
A. Visualize small parts
While imaging an infant, the rotation time may be decreased to prevent motion artifacts. A decrease in rotation time represents a change in:
A. Spatial resolution
B. Contrast resolution
C. Temporal resolution
D. Linearity
C. Temporal resolution
Of the following options, what reconstruction slice thickness will display images with the highest level of contrast resolution?
A. 0.625 mm
B. 1.25 mm
C. 5 mm
D. 3.75 mm
C. 5 mm
Which of these reconstruction algorithms are likely to produce the best spatial resolution?
A. Standard algorithm
B. Soft tissue algorithm
C. Brain algorithm
D. Bone algorithm
D. Bone algorithm
Centering the patient too high or too low in the gantry can result in an artifact called:
A. Beam hardening artifact
B. Motion artifact
C. Ring artifact
D. Partial volume averaging
E. Out-of-field artifact
E. Out-of-field artifact
When scanning a patient’s chest, the axial images demonstrate ring artifact. This might be prevented in the future by:
A. Using EKG gating
B. Placing the patient’s arms above their head
C. Providing breathing instructions
D. Correctly calibrating the detector array
D. Correctly calibrating the detector array
How does cone beam artifact affect the appearance of the CT image?
A. Shape distortion of anatomy
B. Vertical streaking
C. One or more bright rings
D. Bright areas on the edges of the images
A. Shape distortion of anatomy
This image demonstrates a processing error called:
A. Beam hardening artifact
B. Motion artifact
C. Ring artifact
D. Partial volume averaging
E. Out-of-field artifact
E. Out-of-field artifact
The use of thick reconstruction slices can result in an error called:
A. Beam hardening artifact
B. Motion artifact
C. Ring artifact
D. Partial volume averaging
E. Out-of-field artifact
D. Partial volume averaging
Positioning the patient comfortable on the CT table is important in order to prevent which type of image degradation?
A. Ring artifact
B. Beam hardening
C. Patient motion
D. Cone beam artifact
C. Patient motion
Out-of-field artifact might be prevented by:
A. Administering a beta blocker
B. Using EKG gating
C. Using a larger display field-of-view
D. Compressing the patient with straps
D. Compressing the patient with straps
In the following image, the misalignment of patient anatomy is a type of motion artifact called:
A. Misregistration
B. Miscalibration
C. Misdirection
D. Miscalculation
A. Misregistration
Dark streaks extending from the interface between the contrast and air in the GI tract is called:
A. Edge-gradient artifact
B. Cone beam artifact
C. Ring artifact
D. Partial volume averaging
A. Edge-gradient artifact
When imaging a patient’s paranasal sinuses, Which of the following procedures may help prevent beam-hardening artifact?
A. Angle the gantry to avoid dental implants
B. Decrease the kVp
C. Use straps to prevent patient motion
D. Clean the Mylar window prior to scanning
A. Angle the gantry to avoid dental implants
While acquiring the scout images for a bony pelvis CT, you notice the patient has a hip prosthesis. The axial images may have:
A. Beam hardening artifact
B. Motion artifact
C. Ring artifact
D. Partial volume averaging
E. Out-of-field artifact
A. Beam hardening artifact
Consider this scenario: The director of the radiology department is brought to the emergency department unconscious following a severe motor vehicle accident. After a CT head is performed, the radiology staff gathers around the PACS monitor to view the images. Is this a breach of the Health Insurance Portability and Accountability Act (HIPPA) law?
A. This a breach of HIPAA law
B. This is not a breach of HIPAA law
C. This is a breach of HIPAA law only if the staff discuss the images with non-radiology personnel
D. This is a breach of HIPAA law only if the staff provide the preliminary report to the family
A. This a breach of HIPAA law
A technologist leaves a radiology requisition in a public bathroom near the sink. Is this defined as a breach of HIPAA law?
A. This is a breach of HIPAA law
B. This is not a breach of HIPAA law
C. This is a breach of HIPAA law only if an investigation determines the technologist left the requisition in the bathroom with a malicious intent
D. This is a breach of HIPAA law only if requisition is viewed by a non-employee
A. This is a breach of HIPAA law
A Picture Archiving and Communication System (PACS) network consists of which three of the following? (Select three)
A. Archive server
B. Imaging modality
C. Electronic medical record
D. Display workstations
E. Hard-copy image library
A. Archive server
B. Imaging modality
D. Display workstations
Consider a PACS network in which imaging studies are distributed directly to specific reading station and to the PACS archive server. What are two main advantages of this distribution system? (Select two)
A. Prior studies are immediately accessible
B. Images are duplicated in the PACS archive server and at the reading workstation
C. Any exam can be open from any workstation
D. If the archiver server goes down, images can still be sent to specific reading stations
B. Images are duplicated in the PACS archive server and at the reading workstation
D. If the archiver server goes down, images can still be sent to specific reading stations
To avoid violation of the HIPAA law, paper medical records must be stored:
A. In airtight storage filing cabinets
B. In a publicly accessible locations
C. In locked rooms or file cabinets
D. In off-campus locations
C. In locked rooms or file cabinets
Which part of the PACS system houses all of the historic digital image data along with the current digital data being generated by the modalities?
A. Archive Server
B. Display workstations
C. Radiologist reading station
D. Administrative workstation
A. Archive Server
Results from an MRI scan are accidentally mailed to the wrong person. Is this a HIPAA violation?
A. This is a HIPAA violation
B. This is not a HIPAA violation
C, This is a HIPAA violation only if the patient is harmed by the accident
D. This is a HIPAA violation only if the person receiving the report knows the patient
A. This is a HIPAA violation
To avoid violation of federal law on patient data protections, access to EMRs should be protected with which three of the following? (Select three)
A. Complex passcode requirements
B. Anti-hacking software
C. Encryption
D. Three-step identity verification
A. Complex passcode requirements
B. Anti-hacking software
C. Encryption
According to the HIPAA law, protected health information includes which three of the following? (Select three)
A. Employment status and employer
B. Billing and payment for care received
C. Patient health conditions
D. Treatment received for health conditions
E. Highest level of education received
B. Billing and payment for care received
C. Patient health conditions
D. Treatment received for health conditions
Imaging and archiving systems in radiology communicate using a digital format called:
A. JPEG interchange format
B. Tagged image file format (TIFF)
C. Electronic Health Record (EHR)
D. Digital imaging and communication in medicine (DICOM)
D. Digital imaging and communication in medicine (DICOM)
Which of the following defines standards for radiology image formatting?
A. Picture Archiving and Communicating (PACS)
B. Electronic Health Record (EHR)
C. Internal Classification of Diseases, 10th Edition (ICD-10)
D. Digital Imaging and Communication in Medicine (DICOM)
D. Digital Imaging and Communication in Medicine (DICOM)
When diagnostic studies are viewed and interpreted directly through the PACS server, this presents what potential disadvantage?
A. If the PACS server goes down, all images are inaccessible
B. If the internet is slow, images take longer to process
C. Prior imaging studies are not easily accessible
D. Imaging studies are not accessible at all PACS reading stations?
A. If the PACS server goes down, all images are inaccessible
In a server-based PACS network, what are two main advantages of accessing the archive server through a dedicated PACS network? (Select two)
A. Images are duplicated in the PACS archive server and at the reading workstation
B. Prior studies are immediately accessible
C. Only one radiologist can access the study for interpretation
D. If the network goes down, the archive server is still accessible through the internet
B. Prior studies are immediately accessible
C. Only one radiologist can access the study for interpretation
Concerning personal health records, federal laws does NOT allow a patient to:
A. Remove their health records from a system database
B. Request a copy of their health records
C. Request corrections to their health records
D. Review who has seen their health records
A. Remove their health records from a system database
