Oxygen-15-water PET assessment of muscular blood flow in peripheral vascular disease

To assess quantitatively regional nutritive muscular blood flow in patients with peripheral vascular disease (PVD), we evaluated the utility of PET with 15O-water.

Eight healthy volunteers and 16 patients with angiographically proven PVD were studied. Regional blood flow of the calf was measured with 15O-water PET during rest, after intra-arterial infusion of prostaglandin E1 and during ergometry. The studies were quantified using a one tissue compartment model.

Normalized mean tracer uptake from 15-60 sec correlated closely (r = 0.98) with absolute blood flow. Scan times longer than 90 sec were required to determine blood flow reliably. The flow values were overestimated by 2% if arterial blood volume was neglected or if the input function delay was corrected globally for parametric imaging. Mean blood flow of calf muscles at rest did not differ significantly between patients (0.017 +/- 0.006 ml/min/ml) and control subjects (0.018 +/- 0.010 ml/min/ml). In PVD patients, blood flow increased by 100% after intra-arterial infusion of PGE1 in the respective leg. In the control subjects, average flow increased by a factor of six during exercise. The increase was more pronounced in the extensor muscles (0.182 +/- 0.031 ml/min/ml) than in flexor muscles (0.121 +/- 0.045 ml/min/ml). Due to the specific type of ergometry, superficial flexors exhibited higher flow values than the profound ones.

PET with 15O-water enables reliable determination of regional nutritive skeletal muscle blood flow for research and clinical applications in patients with PVD.