ARRT CT Artifacts and Troubleshooting Flashcards

Which technique is most commonly used to reduce metal artifact in CT imaging of patients with hip prostheses?

Answer: Metal artifact reduction (MAR) software

Metal artifact reduction (MAR) algorithms replace corrupted projection data near metal with interpolated data, significantly reducing streaking artifacts.

A starburst pattern of streaks emanating from the edge of the patient's shoulders during a neck CT is most likely caused by:

Answer: Beam hardening from bone and soft tissue interfaces

Dense cortical bone at the shoulder causes beam hardening, producing characteristic streak artifacts that radiate into adjacent soft tissues.

Quantum (photon) noise in CT images is most visible under which conditions?

Answer: Low mAs or large patient size

Quantum noise increases when fewer photons reach the detectors, which occurs with low mAs settings or when X-rays are attenuated by a large patient.

The windmill artifact seen in helical CT is most commonly associated with which acquisition parameter?

Answer: High pitch values

Windmill artifacts appear as alternating dark and bright streaks rotating around structures and are caused by the under-sampling that occurs at high pitch values.

Which of the following best describes an out-of-field artifact in CT?

Answer: Streaking caused by anatomy extending beyond the scan FOV

Out-of-field artifacts occur when part of the patient's anatomy lies outside the calibrated scan FOV, causing truncation of projection data and bright peripheral streaks.

A horizontal band of decreased attenuation passing through the posterior fossa on a head CT is a classic example of which artifact?

Answer: Beam hardening between the petrous bones

The dense petrous temporal bones cause preferential absorption of lower-energy photons, producing a dark band across the posterior fossa known as a beam hardening artifact.