New application of multimodal ultrasound imaging for identification of myofascial trigger points in the trapezius muscle.

BACKGROUND: The study aimed to quantify the characteristics of trapezius myofascial trigger points (MTrPs) using shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) and explore the application value of the new ultrasound techniques in identifying MTrPs. METHODS: Forty patients participated in this study. MTrPs in the trapezius muscle were determined by palpation, and SWE and CEUS were used to quantify the focal and adjacent areas. The elastic modulus values and CEUS parameters between the focal area of MTrPs and adjacent areas were evaluated and compared. Pathological biopsy was performed according to the above two methods, and the pathological tissues were observed by Masson staining, immunohistochemistry and electron microscope. RESULTS: The elastic modulus values were significantly higher for the focal area of MTrPs compared to those for adjacent areas (P<0.05). There were statistically significant differences in MTrP parameters, including peak intensity, mean transit time, and area between the focal and adjacent areas (P<0.05). Masson staining showed that there were inflammatory cell infiltration dominated by lymphocytes in the vascular wall. Electron microscopy showed a large number of fibroblast proliferation, lamellar collagen proliferation and lysosomal deposition; immunohistochemical results: the expression of CD3+, CD4+, CD8+, CD68+, mhc-1+, dys+, CD8 was more than that of CD20 (F=4.385, P=0.036). CONCLUSIONS: Combined use of SWE and CEUS provides a new detection approach for quantitative identification of MTrPs in the trapezius muscle, which has high application value and is a method worthy of wider use in clinical practice.