Functional MRI in Peripheral Arterial Disease: Arterial Peak Flow versus Ankle-Brachial Index

OBJECTIVES The purpose of this study was to compare the success rate of successful arterial peak flow (APF) and ankle-brachial index (ABI) measurements in patients with suspected or known peripheral arterial disease (PAD). MATERIALS AND METHODS 183 patients with varying degrees of PAD were included. All subjects underwent ABI measurements and MR imaging of the popliteal artery to determine APF. Proportions of patients with successful APF and ABI measurements were compared and the discriminative capability was evaluated. RESULTS APF was successfully measured in 91% of the patients, whereas the ABI could be determined in 71% of the patients (p<0.01). Success rates of APF and ABI were significantly higher in patients with intermittent claudication (95% and 80%, respectively) than in patients with critical ischemia (87% and 62%, respectively). CONCLUSIONS Compared to the assessment of PAD severity with ABI, the success rate of MRI-based APF measurements in patients with a clinical indication for MRA is 20% higher, with similar discriminatory capacity for disease severity. Therefore, APF is an especially convenient and valuable measure to assess severity in PAD patients scheduled to undergo MR angiography to obtain additional functional information concerning the vascular status.