Blood Oxygenation Level–Dependent Magnetic Resonance Imaging of the Skeletal Muscle in Patients With Peripheral Arterial Occlusive Disease

Abstract

Background— Blood oxygenation level–dependent (BOLD) magnetic resonance imaging (MRI) has been used to measure T2* changes in skeletal muscle tissue of healthy volunteers. The BOLD effect is assumed to primarily reflect changes in blood oxygenation at the tissue level. We compared the calf muscle BOLD response of patients with peripheral arterial occlusive disease (PAOD) to that of an age-matched non-PAOD group during postischemic reactive hyperemia. Methods and Results— PAOD patients (n=17) with symptoms of intermittent calf claudication and an age-matched non-PAOD group (n=11) underwent T2*-weighted single-shot multiecho planar imaging on a whole-body magnetic resonance scanner at 1.5 T. Muscle BOLD MRI of the calf was performed during reactive hyperemia provoked by a cuff-compression paradigm. T2* maps were generated with an automated fitting procedure. Maximal T2* change (ΔT2* max ) and time to peak to reach ΔT2* max for gastrocnemius, soleus, tibial anterior, and peroneal muscle were evaluated. Compared with the non-PAOD group, patients revealed significantly lower ΔT2* max -values, with a mean of 7.3±5.3% versus 13.1±5.6% ( P <0.001), and significantly delayed time-to-peak values, with a mean of 109.3±79.3 versus 32.2±13.3 seconds ( P <0.001). Conclusions— T2* time courses of the muscle BOLD MRI signal during postocclusive reactive hyperemia revealed statistically significant differences in the key parameters (ΔT2* max ; time to peak) in PAOD patients compared with age-matched non-PAOD controls.