Diagnostic performance of two-dimensional shear wave elastography for evaluating tibial nerve stiffness in patients with diabetic peripheral neuropathy

Abstract

Objectives: To evaluate the stiffness of the tibial nerve with two-dimensional shear wave elastography (2D-SWE) and to determine whether 2D-SWE can be used to diagnose diabetic peripheral neuropathy (DPN).

Methods: The study included 70 consecutive diabetic patients with DPN or without DPN and 20 healthy volunteers. The tibial nerve stiffness measured with 2D-SWE was studied. The differences in stiffness values among patients with DPN, patients with clinically defined DPN, patients without DPN, and healthy volunteers based on clinical features and electrodiagnostic tests were evaluated with the Mann-Whitney U test and the Kruskal-Wallis test. Inter- and intraobserver variability was evaluated, and a receiver operator characteristic curve analysis was performed.

Results: The tibial nerve stiffness based on mean (E_Mean), minimum (E_Min), and maximum (E_Max) shear elasticity indices was significantly higher in patients with DPN and clinically defined DPN than that in patients without DPN and control subjects (p < 0.05). The area under the curve (AUC) for the SWE measurements of E_Mean, E_Min, and E_Max was 0.846, 0.867, and 0.821, respectively. An E_Min cutoff value of 45.7 kPa had a sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 74.0%, 87.6%, 6.0, and 0.3, respectively. The inter- and intraobserver agreements were excellent for the SWE measurements.

Conclusions: Tibial nerve stiffness is significantly higher in diabetic patients with DPN and clinically defined DPN. The E_Mean and E_Min have a good accuracy for identifying DPN. Minor degree of peripheral nerve lesions appear to might exist in patients with clinically defined DPN, not detectable by electrophysiology. 2D-SWE has a potential use for cases with clinically defined DPN and can be detected with 2D-SWE.

Key points: • 2D-SWE elastography is a noninvasive method that can be used to evaluate precise nerve stiffness for diagnosing DPN. • Minor degree of neurologic lesion might exist early in patients with clinically defined DPN and can be detected by 2D-SWE. • E _Min and E _Mean of SWE elasticity indices have better diagnostic accuracies than E _Max for identifying DPN.

Keywords: Diabetic neuropathies; Elasticity imaging techniques; Tibial nerve.