Magnetic Resonance Imaging of Angiographically Occult Runoff Vessels in Peripheral Arterial Occlusive Disease

Bypass grafting to arteries of the lower leg has become standard surgical management of advanced peripheral vascular disease. Its success depends on identifying suitable distal vessels. Preoperative preparation includes imaging of the arteries of the lower leg, usually by conventional contrast arteriography. An alternative procedure, magnetic resonance (MR) angiography, has been successfully employed in patients with various cardiovascular diseases, but its possible value in patients with peripheral vascular disease has received little attention. We used both conventional and MR angiography in preoperative studies of the lower-leg vessels of 23 patients (25 legs) with peripheral arteriosclerosis and arterial insufficiency, and developed independent therapeutic plans based on the information provided by each technique. When the plans differed, the interventional procedure judged more likely to save the limb was performed. The findings of conventional and MR angiography were verified by intraoperative arteriography, postinterventional arteriography, or direct operative exploration. MR angiography detected all vessels identified by conventional angiography, whereas conventional arteriography failed to detect 22 percent of the runoff vessels identified by MR angiography. The detection by MR angiography of vessels not identified by conventional angiography altered the surgical management of the disorders of four patients (17 percent) and guided successful bypass procedures. MR angiography is a noninvasive technique with greater sensitivity than conventional contrast arteriography for detecting distal runoff vessels in patients with peripheral arterial occlusive disease., With improvements in the techniques of vascular surgery, bypass grafting to very small distal vessels to save a limb has become possible. Grafts to the arteries of the foot are now standard vascular surgical practice. As the options for salvaging limbs have expanded, the need for detailed imaging of the distal lower extremities has increased. Since the introduction of safe iodinated contrast materials in the 1950s, contrast arteriography has served as the standard diagnostic technique for evaluating peripheral arterial disease. However, conventional contrast arteriography fails to demonstrate distal vessels suitable for reconstructive surgery in up to 70 percent of patients with severe disease^1-4. In addition, conventional angiography is not without risk. Although the vast majority…