Three‐Dimensional Contrast‐Enhanced Magnetic Resonance Angiography of Carotid Artery after Stenting

Abstract

ABSTRACT Purpose. This study presents 3‐dimensional, contrast‐enhanced, magnetic resonance (MR) angiographic appearances of the carotid artery after stenting. Methods. The authors reviewed contrast‐enhanced MR angiograms of 18 carotid arteries in 13 patients. These arteries were not stenotic or occluded in the stented segment, as shown on carotid angio‐grams (11 patients) or carotid Doppler images (2 patients) obtained later. Results. Five patients had 1 stent in each of their bilateral carotid arteries. One patient with 1 stent in 1 artery underwent the examination twice with different MR coils. Different artifact patterns were found in 19 carotid‐stent examinations. Type 1a involved short segments of false narrowing or false focal occlusion at both ends of the stent (n = 12); the carotid artery in the stented segment between the ends was normal. Types 2a and 2b occurred along the stented segment of the artery between the 2 ends of the stent. Type 2a was milder, with segmental faint signal intensity or luminal stenosis in the entire length of the stented segment (n = 5). Type 2b was total loss of luminal signal intensity over the whole length of the stented segment (n = 2). Last, type 1b was a band of hyperintensity at the ends of type 2a or 2b artifacts. Types 1a and 1b were due to susceptibility effect, and types 2a and 2b were from radio‐frequency shielding effect. Both of these effects were identified in MR angiogram of nitinol stents and stainless steel stents. Conclusion. Awareness of these artifacts is essential to prevent misdiagnosis.