Evaluation of Tibial Nerve Microcirculation in Diabetes Mellitus at Superresolution US.

Abstract

Background Dysfunction of the peripheral nerve microcirculation is crucial in the onset and progression of diabetic neuropathy. Purpose To evaluate the feasibility of superresolution US for quantifying tibial nerve microvasculature in diabetic adults with and without peripheral neuropathy, and in control participants. Materials and Methods In this prospective single-center study, consecutive participants were enrolled between June 2024 and October 2024 and divided into three groups: group I, diabetic peripheral neuropathy with ulcers; group II, type 2 diabetes without peripheral neuropathy; and group III, the control group. All participants underwent conventional US in the tibial nerves followed by superresolution US with intravenous microbubble injection. Regions of interest were delineated manually along the tibial nerve. Quantitative parameters, including interfascicular and intrafascicular vessel ratio, complexity, density, velocity, perfusion index, and single-vessel curvature were compared using one-way analysis of variance (parametric) and Dunn-corrected Kruskal-Wallis (nonparametric) tests. Results A total of 100 participants were enrolled, including 30 participants in group I (mean age, 67 years ± 10 [SD]; 23 men), 35 in group II (mean age, 61 years ± 11; 20 men), and 35 in group III (mean age, 54 years ± 14; 15 men). Superresolution US showed group I had higher vessel ratio (23% vs 10% vs 6%), complexity level (1.3 vs 1.2 vs 1.1), maximum density (25 vs 20 vs 12), mean velocity (12.6 vs 8.7 vs 8.4 mm/sec), perfusion index (4.5 vs 1.4 vs 0.9), and curvature (1.19 vs 1.09 vs 1.05) compared with groups II and III, respectively (all <i>P</i> < .05). Microvascular tortuosity was observed in 83% (25 of 30), 43% (15 of 35), and 14% (five of 35) of groups I, II, and III, respectively (<i>P</i> < .001). Conclusion Superresolution US provided a 10-μm scale resolution view of tibial nerve microvascular structure, helping to identify microvascular alterations in participants with diabetic peripheral neuropathy with ulcers. © RSNA, 2026 <i>Supplemental material is available for this article.</i>