Carotid artery stenosis, occlusion, and pseudo-occlusion: First-pass, gadolinium-enhanced, three-dimensional MR angiography - Preliminary study

PURPOSE: To determine the accuracy of gadolinium-enhanced three-dimensional magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis. MATERIALS AND METHODS: A prospective blinded comparison of first-pass MR angiography with conventional digital subtraction angiography (DSA) was performed in 21 patients suspected of having carotid artery stenosis. MR angiography was performed on a 1.5-T magnet with gradient overdrive equipment, with a coronal radio-frequency-spoiled, three-dimensional, fast low-angle shot sequence after intravenous injection of contrast material. The guidelines of the North America Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection images and conventional angiograms. RESULTS: Grading of stenoses at MR angiography agreed with that at DSA in 92% of the 44 carotid arteries. In the 18 carotid arteries with severe stenosis (70%-99%), agreement was 94%. All internal carotid occlusions (n=7) or pseudo-occlusions (n=3) were accurately detected with MR angiography. CONCLUSION: The accuracy of gadolinium-enhanced MR angiography in characterizing the degree of carotid stenosis was high. Findings with MR angiography were accurate for differentiating between occlusion and pseudo-occlusion.