Dual Quantification of Skeletal Muscle Perfusion and Metabolism in a Porcine Model of Peripheral Artery Disease Using Multiparametric 18F-FDG PET Imaging.

Abstract

Background: A standard imaging strategy for quantifying skeletal muscle perfusion in peripheral artery disease (PAD) does not exist, and the widespread use of PET imaging for this purpose has traditionally been limited by the need for onsite production of short half-life perfusion radioisotopes. Therefore, this study investigated the feasibility of multiparametric PET imaging with commercially available fluorine-18 (¹⁸F)-fluorodeoxyglucose (FDG) for the quantification of skeletal muscle perfusion and metabolism in a porcine model of PAD.

Methods: Eight Yorkshire pigs underwent 60-min dynamic ¹⁸F-FDG PET imaging under resting conditions immediately following unilateral surgical ligation of the femoral artery and 2 weeks after arterial occlusion. Calf muscle perfusion was computed using 1-compartment modeling of the first 2.5 min of PET data acquisition, and the metabolic rate of glucose (MRGlu) was computed using 3-compartment modeling of the entire 60-min dataset. Two weeks after arterial occlusion, the gastrocnemius muscle was harvested to compare microvascular density between ischemic and control hindlimbs.

Results: Calf perfusion and MRGlu were significantly reduced following peripheral artery occlusion and recovered to control levels 2 weeks later. Recovery of perfusion and metabolism in calf skeletal muscle coincided with a significant increase in calf muscle capillary density 2 weeks after arterial occlusion.

Conclusions: This study demonstrates the novel use of dynamic, multiparametric ¹⁸F-FDG PET/CT imaging for quantifying ischemia-induced alterations in skeletal muscle perfusion and metabolism, providing a unique comprehensive approach for evaluating PAD pathophysiology and creating opportunities for monitoring treatment responses to emerging therapeutics.