Abstract 297: SPECT/CT Imaging of Regional Foot Perfusion Provides a Quantitative Index for Evaluation of Targeted Revascularization in the Diabetic Foot

Abstract

Introduction: No standard quantitative imaging approach exists to evaluate volumetric changes in tissue perfusion in the lower extremities following medical treatment. In this study, we develop and apply a three-dimensional model of the foot for evaluation of regional changes in perfusion following revascularization in diabetic patients with non-healing foot ulcers. We hypothesize that SPECT/CT imaging will permit quantification of regional improvements in tissue perfusion in territories of the foot that contain non-healing ulcers, allowing for quantitative evaluation of revascularization procedures. Methods: Resting 99m Tc-tetrofosmin (dose 554.0 ± 26.6 MBq) SPECT/CT was performed on diabetic patients (n=5; 64 ± 15 yrs) before and 1-3 days after lower extremity angioplasty and/or stenting. The CT attenuation scans were used to define five regions of interest (ROIs) in the foot and for quantification of relative changes in regional perfusion with 99m Tc-tetrofosmin SPECT (Fig. 1A). Radiotracer uptake for each ROI was normalized to injected dose and ROI volume, and expressed as a percent change from baseline value. Results: SPECT/CT imaging demonstrated quantitative improvements in regional tissue perfusion in ROIs containing non-healing ulcers for 4 out of 5 patients following revascularization (Fig. 1B). The single patient demonstrating a negative response (11.7% decrease in perfusion) underwent eventual amputation. Conclusions: Early changes in tissue perfusion following revascularization can be non-invasively evaluated in specific vascular territories of the foot using SPECT/CT imaging and may be associated with wound healing and limb salvage outcomes.