Quantitative ultrasound characterization of intensity-dependent changes in muscle tissue during percutaneous electrolysis

Abstract

Background/Objectives: Percutaneous electrolysis is a physiotherapeutic technique based on the application of galvanic current to induce structural and biochemical changes in musculoskeletal tissues. Although widely used in tendinopathies, its application in muscle tissue, particularly regarding optimal dosage, remains poorly understood. This study aimed to evaluate the dose-dependent effects of galvanic current on cadaveric muscle tissue (medial gastrocnemius) using quantitative ultrasound analysis, and to identify objective biomarkers to guide dosage. Methods: An experimental model was employed, applying galvanic current at varying intensities (0–10.0 mA) to 29 samples of cadaveric medial gastrocnemius. Quantitative ultrasound parameters were measured, including geometric and textural features. Correlation analyses and simple and multiple linear regressions were performed to assess the relationship between current intensity and ultrasound variables. Additionally, dose segmentation into three groups (low: 0–1.0 mA, medium: 1.0–4.0 mA, high: >4.0 mA) allowed for comparative statistical analysis using Kruskal–Wallis and post hoc Mann–Whitney U tests. Results: Significant dose–response relationships were observed in key ultrasound parameters, including A_Number, A_Area, A_Perimeter, and A_Contrast (p < 0.001). Regression analysis revealed that a combination of A_Area, A_Number, and A_Perimeter accounted for 66.7% of the variance in applied dose (R2 = 0.667, p < 0.001), leading to the creation of the predictive variable Muscle_Electrolysis_Dose. Comparative analysis confirmed significant differences between low-, medium-, and high-dose groups, particularly between lower and higher doses. Conclusions: Quantitative ultrasound effectively detects structural changes in muscle tissue following percutaneous electrolysis. The results support the development of objective, image-based criteria for optimizing galvanic current dosage, enhancing the precision and personalization of treatment.