FLOW-INDEPENDENT ANGIOGRAPHY FOR PERIPHERAL VASCULAR-DISEASE - INITIAL IN-VIVO RESULTS

Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than now effects, wa s evaluated for application in peripheral vascular disease (PVD). Firs t, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to asse ss clinical utility, All control images corresponded to the expected l eg arterial anatomy with little interference from deep veins (one of f ive) and muscle (zero of five). Superficial venous signal was less wel l suppressed in comparison to deep veins (four of five). Images of sym ptomatic patients were less consistent with difficulty suppressing mus cle and deep venous signal in some cases and edema when present, We th en compared T2 values for muscle (T2(m), tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, pop liteal, and saphenous veins) in controls (n = 8) and symptomatic patie nts with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients, Patients with ischemic rest pain ha d significantly higher T2(m) compared with controls (T2(m) = 39.3 +/- 2.1 (1 standard error of the mean [SEM]) versus 30.9 +/- .4, P < .01), For all measurements, other than saphenous vein, variances were great er in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signa ls from muscle, veins, and edema is required, One promising approach i nvolves shifting from projection images to three-dimensional acquisiti ons for improved tissue suppression.