Oximetric angiosome imaging in diabetic feet

Area of Science:

• Medical Imaging
• Diabetology
• Vascular Biology

Background:

• Diabetic foot ulcers are a significant complication of diabetes, often linked to impaired skeletal muscle oxygenation.
• Assessing localized oxygenation in foot muscles is crucial for understanding and treating diabetic foot complications.
• Current methods for evaluating tissue oxygenation may not adequately capture regional variations in diabetic patients.

Purpose of the Study:

• To develop and validate a noncontrast oximetric angiosome imaging approach for assessing skeletal muscle oxygenation in the feet of individuals with diabetes.
• To compare the novel oximetric angiosome model with the traditional angiosome model in evaluating oxygen extraction fraction distribution.

Main Methods:

• Feasibility study involving four healthy subjects and five subjects with diabetes using a 3T clinical MRI scanner.
• Foot oximetry was performed at rest and during isometric toe-flexion exercise.
• Oxygen extraction fraction (OEF) was measured using a susceptibility-based MRI method, and the oximetric angiosome model was applied.

Main Results:

• During toe-flexion exercise, the traditional angiosome model showed an increased OEF in healthy subjects but a decreased OEF in diabetic subjects.
• The novel oximetric angiosome model revealed a greater percent difference in OEF (0.7-1.0 range) between rest and exercise in healthy subjects compared to diabetic subjects (8% vs. 4%, P=0.02).

Conclusions:

• The study demonstrates the feasibility of measuring skeletal muscle oxygen extraction fraction in the foot during exercise using MRI.
• The foot oximetric angiosome model, by assessing OEF across all foot muscle regions, may be more suitable than the traditional angiosome model for detecting local ischemia in diabetic feet.