MAGNETIC-RESONANCE-IMAGING DETECTION OF VASCULAR OCCLUSION OF A PEDICLED MUSCLE FLAP

Contrast-enhanced magnetic resonance imaging (MRI) can be a highly sen sitive monitor of tissue blood perfusion. This technique has been used to assess blood flow through liver, kidney, and certain tumors, but h as not been widely applied to the study of skeletal muscle circulation . In our study, we used a novel scanning software to obtain contrast-e nhanced T2-weighted gradient echo MRI images of pedicled quadriceps m uscle flaps in rabbits in order to study images of arterial, venous, a nd arterio-venous occlusion. We administered an intravenous bolus of g adoteridol contrast agent al the initiation of scanning, which produce s a decrease in T2-signal and improves the sensitivity of measuring b lood perfusion. Within 30 seconds of MRI scanning, control flaps with intact pedicles exhibited a rapid decrease in T2-signal intensity, in dicating adequate perfusion of blood through muscle tissue; however, o ccluded pedicled flaps showed no significant change in signal intensit y, indicating lack of blood perfusion. Differences in signal intensiti es as measured by MRI between occluded and control flaps were statisti cally significant (P < 0.05). Selective vascular occlusion of either a rtery alone, or both artery and vein were detected within 15 minutes, whereas selective venous occlusion could be detected after 2 hours. We conclude that MRI has the ability to assess skeletal muscle perfusion , and is capable of noninvasively evaluating a cross-section of tissue in both superficial and buried flaps. MRI, therefore, may have the po tential for evaluating perfusion in muscle flaps (including buried fla ps), and other disorders of muscle circulation such as compartment syn drome. (C) 1997 Wiley-Liss, Inc.