Abstract 325: Non-Invasive Volumetric Assessment of Angiosome Perfusion in Diabetic Patients With Critical Limb Ischemia and Non-Healing Ulcers Using Radiotracer Imaging

Introduction: Impaired lower extremity perfusion is a hallmark of peripheral vascular disease (PVD) and is particularly problematic in diabetic patients, who suffer from high rates of PVD, ulceration, and lower extremity amputation. The ability to non-invasively detect deficits in microvascular perfusion within vascular territories, or angiosomes, of the feet may provide information related to tissue viability, assist with classification of diabetic wounds, and guide future therapeutic interventions. In this study, we sought to quantify volumetric microvascular perfusion within specific angiosomes containing non-healing foot ulcers in diabetic patients with critical limb ischemia. Methods: Twenty-eight diabetic patients (mean age, 68 ± 13 yrs) with non-healing ulcers underwent SPECT/CT imaging of the feet following a resting injection of 99m Tc-tetrofosmin (dose, 550.6 ± 37 Mbq). CT images were segmented into five angiosomes and used for quantifying relative radiotracer uptake (Fig. 1A), expressed as standardized uptake values (SUVs). SUVs were assessed for each patient in the angiosome containing the non-healing ulcers, which were rated using the Wagner Grade Classification. Results: SPECT/CT imaging allowed for visualization of resting perfusion deficits in ulcer sites (Fig. 1B) and quantitative image analysis revealed variability in angiosome perfusion based on Wagner Grade of ulcers. Angiosomes containing Wagner Grade IV ulcers exhibited significantly lower SUVs when compared to SUVs of angiosomes containing Wagner Grade I, II, and III ulcers (Fig. 1C). Conclusions: SPECT/CT imaging provides a useful non-invasive tool for evaluating a wide clinical spectrum of ulcers within associated angiosomes of the foot and can be performed without requiring pharmacological or exercise stress. Future application of SPECT/CT imaging may provide additional value for detection and targeting of ischemic tissue for therapeutic interventions.