Computed Tomography Test CT Image Quality and Reconstruction 2

Question 1

What is the primary advantage of iterative reconstruction over filtered back projection (FBP) in CT?

Accepted Answer

Significant noise reduction at equivalent or lower dose

Answer

Faster reconstruction time

Answer

Better spatial resolution at high kVp

Answer

Elimination of metal artifacts

Question 2

Which window level and window width settings are appropriate for evaluating brain parenchyma on CT?

Accepted Answer

Level 35 HU, Width 80 HU

Answer

Level 400 HU, Width 2000 HU

Answer

Level −600 HU, Width 1500 HU

Answer

Level 60 HU, Width 350 HU

Question 3

Ring artifacts in CT are most commonly caused by which problem?

Accepted Answer

Defective or mis-calibrated detector elements

Answer

Patient motion

Answer

High kVp settings

Answer

Incorrect FOV selection

Question 4

What is the relationship between CT slice thickness and the partial volume artifact?

Accepted Answer

Thinner slices reduce partial volume artifact

Answer

Thicker slices reduce partial volume artifact

Answer

Slice thickness has no effect on partial volume

Answer

Thinner slices increase partial volume artifact

Question 5

What does multiplanar reformation (MPR) allow clinicians to do with CT data?

Accepted Answer

View reconstructed images in coronal, sagittal, and oblique planes from axial data

Answer

Increase spatial resolution after acquisition

Answer

Remove contrast enhancement from images

Answer

Generate 3D models for printing

Question 6

The concept of isotropic voxels in modern multi-detector CT (MDCT) means that voxels are:

Accepted Answer

Equal in all three dimensions (x, y, z)

Answer

Larger in the z-axis than x-y plane

Answer

Round rather than square

Answer

Variable depending on reconstruction kernel