Dynamic contrast-enhanced subtraction MR angiography of the lower extremities: initial evaluation with a multisection two-dimensional time-of-flight sequence.

Abstract

To determine the clinical feasibility of a contrast material--enhanced two-dimensional (2D) magnetic resonance (MR) angiographic sequence in lower extremity arteries. Four healthy volunteers and 12 patients underwent dynamic contrast-enhanced MR angiography; all patients also underwent conventional angiography. A 2D multisection gradient-echo sequence with image subtraction was used for all MR imaging examinations. Oblique-coronal contrast-enhanced MR angiography was completed in less than 4 minutes, with a 256 x 512 matrix. The arterial contrast enhancement ratio was 2.0 +/- 0.8 (standard deviation), and the pre- and post-contrast contrast-to-noise ratios were 2.1 +/- 13.8 and 46.2 +/- 18.7, respectively. The sensitivity for MR angiography was 100% and specificity was 69% for distinction of vessels with greater than 50% stenoses from normal or mildly stenotic vessels. Dynamic contrast-enhanced 2D MR angiography is capable of increasing intraarterial signal intensity and depicting small vessel anatomy of the lower extremities over a large field of view in a short imaging time.