Atherosclerotic occlusive disease of the lower extremity: prospective evaluation with two-dimensional time-of-flight MR angiography.

A prospective, blinded comparison of two-dimensional time-of-flight (TOF) magnetic resonance (MR) angiography and conventional arteriography was performed in 25 patients who underwent routine arteriography for symptomatic atherosclerotic occlusive disease of the lower extremity. MR angiography was performed from the distal abdominal aorta through the popliteal trifurcation. The native arterial tree was divided into nine segments; each segment was assessed for patency (defined as stenosis < 50% of arterial diameter), moderate stenosis (50%-69%), severe stenosis (70%-99%), or occlusion (100%). In all 206 segments examined, the sensitivity of MR angiography in diagnosis of occlusion was 100%; the specificity, 98%. All long occlusions were correctly classified. In specific categories of occlusive disease, the sensitivity and specificity were as follows: in all segments with 70% or greater stenosis, including occlusions, 90% and 97%; in all segments with 50% or greater stenosis, including occlusions, 92% and 88%; in femoropopliteal segments with 50% or greater stenosis, 92% and 93%; and in iliac segments, 93% and 83%. Long occlusions were distinguished from short occlusions and stenoses; hence, MR angiography enabled identification of patients with lesions suitable for angioplasty.