ASL demonstrates higher and more homogenous calf muscle perfusion with post-occlusion hyperemia than with exercise

Background Pulsed arterial spin labeling (PASL) is a non-contrast MRI technique capable of quantifying calf muscle perfusion with comparable accuracy to contrast enhancedMRI perfusion in normal subjects and peripheral arterial disease (PAD) patients. Peak perfusion can be achieved with exercise or during post-occlusion hyperemia. However, exercise stress may underestimate peak perfusion because of submaximal effort and/or heterogeneous flow. We hypothesized that post-occlusion hyperemia would yield higher peak calf muscle flow compared to peak exercise calf muscle flow measured with PASL.