ARRT ARRT CT Artifacts and Troubleshooting

Question 1

What type of artifact appears as bright or dark streaks radiating from high-density objects like metal implants in CT images?

Accepted Answer

Beam hardening artifact

Answer

Beam hardening artifacts appear as streaks or dark bands radiating from dense metallic objects because lower-energy photons are preferentially absorbed.

Question 2

A ring or band artifact centered on the image is most likely caused by a malfunction of which CT component?

Accepted Answer

A single detector element

Answer

Ring artifacts result from a miscalibrated or malfunctioning detector element producing a circular artifact at a fixed radius from the isocenter.

Question 3

Which artifact is caused by patient movement during CT data acquisition and appears as blurring or ghosting on the reconstructed image?

Accepted Answer

Motion artifact

Answer

Motion artifacts result from patient movement during scanning, causing inconsistent data at each projection angle and manifesting as blurring or streaking.

Question 4

The 'cupping artifact' in CT, where the center of a uniform object appears less dense than its periphery, is a manifestation of which phenomenon?

Accepted Answer

Beam hardening

Answer

Cupping artifact is a form of beam hardening where the edges of the object appear brighter because the beam hardens less traveling a shorter path length.

Question 5

Partial volume averaging artifacts in CT are best reduced by which acquisition parameter adjustment?

Accepted Answer

Using a thinner slice thickness

Answer

Thinner slices reduce partial volume averaging by ensuring each voxel contains tissue from a smaller volume, improving accuracy of CT numbers.

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

ARRT ARRT CT Artifacts and Troubleshooting