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

Iterative reconstruction repeatedly refines the image estimate against raw data, reducing noise substantially, which allows lower dose acquisition without sacrificing image quality.

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

Brain window settings (level ~35 HU, width ~80 HU) optimize contrast between gray matter, white matter, and CSF within the narrow HU range of brain tissue.

Question 3

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

Accepted Answer

Defective or mis-calibrated detector elements

Answer

A single malfunctioning detector channel consistently produces incorrect readings at the same projection angle, creating a characteristic ring or arc artifact in the reconstructed image.

Question 4

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

Accepted Answer

Thinner slices reduce partial volume artifact

Answer

Thinner CT slices reduce the volume of each voxel, decreasing the chance that multiple tissue types are averaged together within a single voxel.

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

MPR uses isotropic or near-isotropic volumetric CT data to generate reconstructions in any desired imaging plane without additional scanning.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test CT Image Quality and Reconstruction 2