Pulsation-related motion artifact of the external iliac artery mimicking localized dissection: An unexpected finding.

Contrast-enhanced CT is widely used for the evaluation of acute aortic dissection, but non-ECG-gated studies may still be affected by motion artifacts that mimic true vascular pathology. We report a woman in her forties who presented with right back pain. Non-ECG-gated contrast-enhanced CT demonstrated a discontinuous linear finding in the right external iliac artery, suggestive of a localized dissection. Follow-up CT performed 3 weeks later showed a similar appearance. Cine MRI subsequently revealed marked pulsatile motion of the right external iliac artery with approximately 6-mm displacement, resulting in compression and deformation of the adjacent external iliac vein. These findings confirmed that the CT abnormality represented a pulsation-induced motion artifact rather than true dissection. Although advances in CT technology have reduced motion artifacts, they may still occur in vessels with substantial pulsatile mobility. When such artifacts are suspected, complementary imaging-such as ultrasound, cine MRI, or ECG-gated CT-can facilitate accurate diagnosis and prevent unnecessary intervention.