OBJECTIVE: We compared peripheral vascular MR angiography done with a standard transmit-receive head coil with conventional arteriography for identifying and evaluating runoff vessels below the knee. MATERIALS AND METHODS: We examined 55 legs in 31 symptomatic patients with both conventional contrast angiography and gradient-echo two-dimensional time-of-flight MR angiography. Both legs of patients were placed in a standard transmit-receive head coil for MR angiography and were imaged simultaneously. For evaluation of stenoses, images of vessels were divided into 10 segments, and each segment was graded on a four-point scale. RESULTS: In the 393 native vascular segments evaluated, the sensitivity of MR angiography in identifying normal vessels was 95% and the specificity was 98%. In detecting segmental occlusion, MR angiography was 98% sensitive and 97% specific. Sensitivity and specificity for stenoses greater than 75% were 98% and 96%, respectively, and for stenoses greater than 50%, they were 98% and 95%, respectively. Interpretative discrepancies were found in 35 vessel segments in 18 legs; none was of clinical relevance. Of all vessel segments shown as occluded by conventional angiography, 1% appeared patent on MR angiograms. No vessel segments shown as normal on MR angiograms were found to be occluded on conventional angiograms. CONCLUSION: When performed simultaneously on both legs of symptomatic patients, 2D time-of-flight MR angiography with a standard transmit-receive head coil provides a time-efficient and highly sensitive and specific means of evaluating below-knee runoff.
OBJECTIVE: We compared peripheral vascular MR angiography done with a standard transmit-receive head coil with conventional arteriography for identifying and evaluating runoff vessels below the knee. MATERIALS AND METHODS: We examined 55 legs in 31 symptomatic patients with both conventional contrast angiography and gradient-echo two-dimensional time-of-flight MR angiography. Both legs of patients were placed in a standard transmit-receive head coil for MR angiography and were imaged simultaneously. For evaluation of stenoses, images of vessels were divided into 10 segments, and each segment was graded on a four-point scale. RESULTS: In the 393 native vascular segments evaluated, the sensitivity of MR angiography in identifying normal vessels was 95% and the specificity was 98%. In detecting segmental occlusion, MR angiography was 98% sensitive and 97% specific. Sensitivity and specificity for stenoses greater than 75% were 98% and 96%, respectively, and for stenoses greater than 50%, they were 98% and 95%, respectively. Interpretative discrepancies were found in 35 vessel segments in 18 legs; none was of clinical relevance. Of all vessel segments shown as occluded by conventional angiography, 1% appeared patent on MR angiograms. No vessel segments shown as normal on MR angiograms were found to be occluded on conventional angiograms. CONCLUSION: When performed simultaneously on both legs of symptomatic patients, 2D time-of-flight MR angiography with a standard transmit-receive head coil provides a time-efficient and highly sensitive and specific means of evaluating below-knee runoff.