ARRT CT Artifacts and Troubleshooting Flashcards

To troubleshoot a CT image showing significant noise (grainy appearance), the technologist should first consider adjusting which parameter?

Answer: Increasing mAs

Increasing mAs raises the number of X-ray photons, directly reducing quantum noise and improving signal-to-noise ratio.

Which reconstruction kernel (filter) should be chosen to minimize noise when imaging soft tissue structures in the abdomen?

Answer: Smooth or standard soft tissue kernel

Soft tissue kernels apply low-pass filtering that smooths the image and reduces noise, which is appropriate for abdominal soft tissue evaluation.

A patient with a cardiac pacemaker presents for chest CT. Which artifact should the technologist anticipate?

Answer: Metallic streak artifact from the pacemaker leads and generator

Pacemaker generators and leads are highly attenuating metallic objects that produce characteristic beam hardening streak artifacts on chest CT.

Respiratory motion artifacts on chest CT can best be minimized by:

Answer: Using breath-hold technique during acquisition

Instructing the patient to suspend respiration during CT acquisition eliminates breathing motion, preventing blurring and step artifacts in the chest.

Which of the following is the correct action if a detector ring artifact is identified during a quality control check of the CT scanner?

Answer: Recalibrate the detector and notify the medical physicist

A ring artifact indicates a detector calibration issue that must be corrected by recalibration or service; the medical physicist should be notified per QC protocols.

Cardiac motion artifacts on coronary CT angiography are primarily reduced by which technique?

Answer: ECG gating to synchronize data acquisition with the cardiac cycle

ECG gating synchronizes CT data acquisition to the relatively motion-free phases of the cardiac cycle (typically mid-diastole), reducing coronary motion artifact.