Computed Tomography (CT) Questions with
Accurate Answers
A 20-cm water bath should be imaged weekly; the average value for water should
be within ± 10 HU of... correct answer zero.
A CT image is a transaxial or transverse image that is perpendicular to the long
axis of the... correct answer body.
A CT number of − 1000 corresponds to air, and a CT number of + 3000
corresponds to dense... correct answer bone.
A CT number of zero indicates... correct answer water.
A dedicated quality control (QC) program is essential for each CT imaging...
correct answer system.
A graph of the image contrast to object contrast at each spatial frequency results
in an MTF... correct answer curve.
A high spatial frequency represents... correct answer small objects.
A high-frequency generator is small because the high-voltage step-up transformer
is small, so it can be mounted on the rotating... correct answer gantry.
A large variation of pixel values represents high image... correct answer noise.
,A low spatial frequency represents... correct answer large objects.
A pitch of 0.5 : 1 results in overlapping images and higher patient radiation...
correct answer dose.
A pitch of 2 : 1 results in extended imaging and reduced patient radiation...
correct answer dose.
All CT imaging systems should be capable of resolving 5-mm objects at 0.5%...
correct answer contrast.
All multislice helical CT imaging systems operate on high-frequency... correct
answer power.
Although MTF and spatial frequency are used to describe CT spatial resolution, no
imaging system can do better than the size of a... correct answer pixel.
An MTF curve that extends farther to the right indicates better spatial resolution,
which means the imaging system is better able to reproduce very small... correct
answer objects.
An MTF curve that is higher at low spatial frequencies indicates better contrast...
correct answer resolution
Anatomy that does not lie totally within a slice thickness may not be resolved, an
artifact called partial volume... correct answer averaging.
, At any time that a water bath is imaged, the pixel values should be constant in all
regions of the reconstructed... correct answer image.
At the end of this translation, the source detector assembly returns to its starting
position, and the entire assembly rotates and begins a second... correct answer
translation.
Composite brushes made of conductive material (e.g., silver graphite alloy) are
used as a sliding... correct answer contact.
Computed tomography excels as an imaging modality because of its superior
contrast... correct answer resolution.
Computed tomography imaging systems must be calibrated frequently so that
water is consistently represented by CT number zero and other tissues by the
appropriate CT... correct answer numbers.
Computer processing of these projections involves effective superimposition of
each projection to reconstruct an image of the anatomical structures within that...
correct answer slice.
Constant spatial resolution ensures proper performance of the detector array,
reconstruction electronics, and the mechanical... correct answer components.
Contrast resolution is superior in CT principally because of x-ray beam... correct
answer collimation.
Contrast resolution should be assessed... correct answer semiannually.
Accurate Answers
A 20-cm water bath should be imaged weekly; the average value for water should
be within ± 10 HU of... correct answer zero.
A CT image is a transaxial or transverse image that is perpendicular to the long
axis of the... correct answer body.
A CT number of − 1000 corresponds to air, and a CT number of + 3000
corresponds to dense... correct answer bone.
A CT number of zero indicates... correct answer water.
A dedicated quality control (QC) program is essential for each CT imaging...
correct answer system.
A graph of the image contrast to object contrast at each spatial frequency results
in an MTF... correct answer curve.
A high spatial frequency represents... correct answer small objects.
A high-frequency generator is small because the high-voltage step-up transformer
is small, so it can be mounted on the rotating... correct answer gantry.
A large variation of pixel values represents high image... correct answer noise.
,A low spatial frequency represents... correct answer large objects.
A pitch of 0.5 : 1 results in overlapping images and higher patient radiation...
correct answer dose.
A pitch of 2 : 1 results in extended imaging and reduced patient radiation...
correct answer dose.
All CT imaging systems should be capable of resolving 5-mm objects at 0.5%...
correct answer contrast.
All multislice helical CT imaging systems operate on high-frequency... correct
answer power.
Although MTF and spatial frequency are used to describe CT spatial resolution, no
imaging system can do better than the size of a... correct answer pixel.
An MTF curve that extends farther to the right indicates better spatial resolution,
which means the imaging system is better able to reproduce very small... correct
answer objects.
An MTF curve that is higher at low spatial frequencies indicates better contrast...
correct answer resolution
Anatomy that does not lie totally within a slice thickness may not be resolved, an
artifact called partial volume... correct answer averaging.
, At any time that a water bath is imaged, the pixel values should be constant in all
regions of the reconstructed... correct answer image.
At the end of this translation, the source detector assembly returns to its starting
position, and the entire assembly rotates and begins a second... correct answer
translation.
Composite brushes made of conductive material (e.g., silver graphite alloy) are
used as a sliding... correct answer contact.
Computed tomography excels as an imaging modality because of its superior
contrast... correct answer resolution.
Computed tomography imaging systems must be calibrated frequently so that
water is consistently represented by CT number zero and other tissues by the
appropriate CT... correct answer numbers.
Computer processing of these projections involves effective superimposition of
each projection to reconstruct an image of the anatomical structures within that...
correct answer slice.
Constant spatial resolution ensures proper performance of the detector array,
reconstruction electronics, and the mechanical... correct answer components.
Contrast resolution is superior in CT principally because of x-ray beam... correct
answer collimation.
Contrast resolution should be assessed... correct answer semiannually.
