Cardiac-gated MR angiography of the entire lower extremity: a prospective comparison with conventional angiography

The purpose of this study was to prospectively evaluate cardiac-gated two-dimensional (2D) time-of-flight MR angiography in patients with peripheral arterial occlusive disease (PAOD).

Twenty-three patients with PAOD were studied using cardiac-gated 2D time-of-flight MR angiography in the body coil from each patients' aortic bifurcation to the pedal arches. Blinded comparison with conventional angiograms was used to determine sensitivity, specificity, and positive and negative predictive values of this MR angiography technique. Kappa statistics were used to compare treatment plans of these patients studied with MR angiography and with conventional angiography.

In the aortoiliac region, MR angiography had a correlation coefficient of .89 for all degrees of narrowing. For hemodynamically significant lesions, MR angiography had an 89% sensitivity, 98% specificity, 84% positive predictive value, and 99% negative predictive value. In the femoral region, MR angiography had a correlation coefficient of .91 for all degrees of narrowing. For hemodynamically significant lesions, MR angiography had an 89% sensitivity, 98% specificity, 93% positive predictive value, and 97% negative predictive value. In the popliteal region, MR angiography had a correlation coefficient of .93 for all degrees of narrowing. For hemodynamically significant lesions, MR angiography had an 89% sensitivity, 98% specificity, 94% positive predictive value, and 95% negative predictive value. In the tibioperoneal and foot regions, MR angiography had a correlation coefficient of 88% for all degrees of narrowing. For hemodynamically significant lesions, MR angiography had an 86% sensitivity, 93% specificity, 89% positive predictive value, and 91% negative predictive value. When the treatment planning data were classified into one of four outcomes (no intervention, surgery, percutaneous angioplasty, or further diagnostic study), MR angiography and conventional angiography had excellent agreement, with a Cohen's kappa value of .78.

Cardiac-gated 2D time-of-flight MR angiography that uses the body coil provides a useful examination for PAOD with reasonable resolution. This imaging technique is potentially more time-efficient than techniques using extremity coils.