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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 correct answers A
Compared to a 1.25 mm image data, 3.75 mm image data will demonstrate: correct answers
decreased spatial resolution, fewer total slices
The process of assigning a specific level of edge-enhancement to the CT image data is controlled
by mathematical filters called: correct answers Reconstruction algorithms, reconstruction filters,
and reconstruction kernels
In the reconstructed image data, the distance from the start of one slice to the start of the next
slice is defined as the: correct answers Slice interval
Using a larger reconstruction slice thickness results in which of the following?
1) Decreased image noise
2) Decreased spatial resolution
3) More total image slices correct answers 1 and 2
Which of these CT protocols generally use thin slices? correct answers Circle of willis for
arterial-venous malformation
which of the following accurately describes where the raw CT data is stored? correct answers In
the CT computer system
An ROI placed over an abnormal lesion yields an average CT number of -52. This lesion may be
composed of: correct answers Fat
Iterative reconstruction is an alternative to traditional reconstruction and helps to do which two if
the following? correct answers reduce patient dose and increase image quality
During a routine CT scan of a pediatric chest, the radiologist requests that the technologist
reconstruct the image data with 1.25 mm slices rather than 2.5 mm slices. One negative effect of
this change will be: correct answers Increased image noise
An ROI indicating an average hounsfield unit of +39 most likely corresponds to which of the
following? correct answers Blood
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 which of the
,following? correct answers Retrospectively reconstructing images with a different display field
of view
Which two of these algorithms are preferred for viewing bone? correct answers edge-enhancing
and bone
Which of these scenarios will result in gaps in the reconstructed image information? correct
answers When the slice interval is greater than the slice thickness
Estimating an unknown value in a series of known values is a mathematical process called:
correct answers interpolation
After performing an abdominal scan for trauma, the radiologist requests reconstructed images of
the lumbar spine. The raw data is not saved no the CT scanner, so this will require: correct
answers Rescanning the patient
Thick reconstruction slices (greater than 3 mm) are not suitable for which of the following?
correct answers
After performing an abdominal scan for trauma, the radiologist requests reconstructed images of
the lumbar spine. The raw data is not saved no the CT scanner, so this will require: correct
answers Rescanning the patient
Thick reconstruction slices (greater than 3 mm) are not suitable for which of the following?
correct answers Multiplanar reformations and angiographic imaging
What mathematical process prevents star-like artifacts from appearing on the CT images? correct
answers Back projection filter
Which of these image-processing techniques in CT are only used in helical scanning? correct
answers Interpolation
Thicker slices are suitable for which two of the following? correct answers abdominal and
thoracic imaging
By definition, the acquisition thickness is the same as the: correct answers detector row thickness
Which three of the following scan parameters can be changed retrospectively? correct answers
scan start and end locations
slice thickness
display field of view
A patient in the emergency department is suspected of having a blowout fracture of the right
maxillary sinus. Structural damage to the soft tissue of the eye will be best demonstrated with
which of these filters? correct answers smoothing
, The process of reconstruction in the CT computer system creates: correct answers Image data
The mathematical filtration of CT data to enhance the appearance of specific tissue types is
called: correct answers Convolution
which of the following effects can occur when mA is increased in CT? correct answers Increased
dose to the patient, increased beam intensity, and increased exposure to the detector elements
Which of the following statements correctly describes the flow of electrons through an x-ray
tube? correct answers Cathode to anode
An increase in which of the following exposure factors would increase the total number of x-ray
photons exposing the detectors? correct answers Increased mA, kVp, and rotation time
What technical change is expected to increase the penetrating ability of an x-ray beam? correct
answers Increased kVp
The specific process that accelerates electrons in an x-ray tube is: correct answers application of
a voltage
If the rotation time of a scan is decreased, what other exposure parameter should be changed to
maintain the image quality? correct answers Increase mA
x-ray tubes in CT are most similar to the radiation source used within which modality? correct
answers Diagnostic radiography
If mA is decreased by a factor of 2, how is the radiation dose to the patient changed if all other
factors remain unchanged? correct answers dose is decreased by a factor of 2
Compared to general radiography, CT x-ray tubes require which of the following? correct
answers Larger heat capacity
Production of x-rays in a CT machine requires a: correct answers source of electrons
means of rapid acceleration of electrons
means of rapid deceleration of electrons
Calculate the total beam width of a CT scan using 32 detector rows, 0.5 mm detectors, 100 mA
and 140 kVp: correct answers 16 mm
The phrase "8-slice scanner" refers to a CT imaging system that has: correct answers 8 detector
rows
Increasing the mA and kVp of a CT scan will usually result in which two of the following?
correct answers Increased patient dose
Decreased image noise
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 correct answers A
Compared to a 1.25 mm image data, 3.75 mm image data will demonstrate: correct answers
decreased spatial resolution, fewer total slices
The process of assigning a specific level of edge-enhancement to the CT image data is controlled
by mathematical filters called: correct answers Reconstruction algorithms, reconstruction filters,
and reconstruction kernels
In the reconstructed image data, the distance from the start of one slice to the start of the next
slice is defined as the: correct answers Slice interval
Using a larger reconstruction slice thickness results in which of the following?
1) Decreased image noise
2) Decreased spatial resolution
3) More total image slices correct answers 1 and 2
Which of these CT protocols generally use thin slices? correct answers Circle of willis for
arterial-venous malformation
which of the following accurately describes where the raw CT data is stored? correct answers In
the CT computer system
An ROI placed over an abnormal lesion yields an average CT number of -52. This lesion may be
composed of: correct answers Fat
Iterative reconstruction is an alternative to traditional reconstruction and helps to do which two if
the following? correct answers reduce patient dose and increase image quality
During a routine CT scan of a pediatric chest, the radiologist requests that the technologist
reconstruct the image data with 1.25 mm slices rather than 2.5 mm slices. One negative effect of
this change will be: correct answers Increased image noise
An ROI indicating an average hounsfield unit of +39 most likely corresponds to which of the
following? correct answers Blood
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 which of the
,following? correct answers Retrospectively reconstructing images with a different display field
of view
Which two of these algorithms are preferred for viewing bone? correct answers edge-enhancing
and bone
Which of these scenarios will result in gaps in the reconstructed image information? correct
answers When the slice interval is greater than the slice thickness
Estimating an unknown value in a series of known values is a mathematical process called:
correct answers interpolation
After performing an abdominal scan for trauma, the radiologist requests reconstructed images of
the lumbar spine. The raw data is not saved no the CT scanner, so this will require: correct
answers Rescanning the patient
Thick reconstruction slices (greater than 3 mm) are not suitable for which of the following?
correct answers
After performing an abdominal scan for trauma, the radiologist requests reconstructed images of
the lumbar spine. The raw data is not saved no the CT scanner, so this will require: correct
answers Rescanning the patient
Thick reconstruction slices (greater than 3 mm) are not suitable for which of the following?
correct answers Multiplanar reformations and angiographic imaging
What mathematical process prevents star-like artifacts from appearing on the CT images? correct
answers Back projection filter
Which of these image-processing techniques in CT are only used in helical scanning? correct
answers Interpolation
Thicker slices are suitable for which two of the following? correct answers abdominal and
thoracic imaging
By definition, the acquisition thickness is the same as the: correct answers detector row thickness
Which three of the following scan parameters can be changed retrospectively? correct answers
scan start and end locations
slice thickness
display field of view
A patient in the emergency department is suspected of having a blowout fracture of the right
maxillary sinus. Structural damage to the soft tissue of the eye will be best demonstrated with
which of these filters? correct answers smoothing
, The process of reconstruction in the CT computer system creates: correct answers Image data
The mathematical filtration of CT data to enhance the appearance of specific tissue types is
called: correct answers Convolution
which of the following effects can occur when mA is increased in CT? correct answers Increased
dose to the patient, increased beam intensity, and increased exposure to the detector elements
Which of the following statements correctly describes the flow of electrons through an x-ray
tube? correct answers Cathode to anode
An increase in which of the following exposure factors would increase the total number of x-ray
photons exposing the detectors? correct answers Increased mA, kVp, and rotation time
What technical change is expected to increase the penetrating ability of an x-ray beam? correct
answers Increased kVp
The specific process that accelerates electrons in an x-ray tube is: correct answers application of
a voltage
If the rotation time of a scan is decreased, what other exposure parameter should be changed to
maintain the image quality? correct answers Increase mA
x-ray tubes in CT are most similar to the radiation source used within which modality? correct
answers Diagnostic radiography
If mA is decreased by a factor of 2, how is the radiation dose to the patient changed if all other
factors remain unchanged? correct answers dose is decreased by a factor of 2
Compared to general radiography, CT x-ray tubes require which of the following? correct
answers Larger heat capacity
Production of x-rays in a CT machine requires a: correct answers source of electrons
means of rapid acceleration of electrons
means of rapid deceleration of electrons
Calculate the total beam width of a CT scan using 32 detector rows, 0.5 mm detectors, 100 mA
and 140 kVp: correct answers 16 mm
The phrase "8-slice scanner" refers to a CT imaging system that has: correct answers 8 detector
rows
Increasing the mA and kVp of a CT scan will usually result in which two of the following?
correct answers Increased patient dose
Decreased image noise
