ARRT CT Artifacts and Troubleshooting Flashcards

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

Answer: Beam hardening artifact

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

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

Answer: A single detector element

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

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

Answer: Motion artifact

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

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

Answer: Beam hardening

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.

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

Answer: Using a thinner slice thickness

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

Aliasing artifacts in CT, which appear as fine streaks or Moiré patterns, are caused by which factor?

Answer: Insufficient detector sampling

Aliasing artifacts occur when the object being imaged contains spatial frequencies higher than the detector sampling rate can capture, per the Nyquist theorem.