Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography of Carotid Artery after Stenting |
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Authors: | Michael M H Teng MD Fong Tsai MD Adrian Jy-Kang Liou MS Jiing-Feng Lirng MD Feng-Chi Chang MD Chao-Bao Luo MD Hui-Cheng Cheng MD |
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Institution: | Department of Radiology, Veterans General Hospital-Taipei and School of Medicine, National Yang Ming University, Taipei, 11217, Taiwan. mhteng@vghtpe.gov.tw |
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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. |
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Keywords: | 3D contrast-enhanced MRA MR-DSA interventional neuroradiology carotid stent MR artifacts |
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