title: Characterization of Myofascial Trigger Points Utilizing an Automated Shear Wave Elastography Approach
Creators: name: Rios, Cristian (Chris)
Publisher: name: George Mason University
Year: 2024
Subjects: subject: Ultrasound
subject: Trigger Points
subject: Shear wave elastography
subject: Automated SWE
subject: Myofascial Pain

description: MPS is a leading and challenging musculoskeletal chronic pain problem, typically localized, that is well recognized but lacks a clear definition across the board. The lack of a clear definition results from limited epidemiology, pathophysiology, and diagnosis information regarding MPS. A key characteristic of MPS is having myofascial trigger points (MTrPs), defined as a palpable nodule within a taut band of a skeletal muscle and linked to patient-specific pain symptoms. Advances in ultrasound and shear wave elastography technologies to characterize MTrPs have shown merit to localize, determine hypoechogenicity properties, anisotropy properties of tissue, variance in blood flow distribution, map tissue stiffness properties, understanding the impact on surrounding tissue, provide targeted and local treatment, and the role of fascia within MTrPs. Based on previous research advances, our group focused on using SWE to characterize the tissue anisotropy of MTrPs from different population groups to extract potential biomarkers for detecting and characterizing MTrPs. However, to address the current limitations of SWE and data acquisition, our group investigated the merit of using an automated SWE method for improving reproducibility and minimizing variance on extracted data. In this research, we conducted three pilot studies in the following areas: (1) the reproducibility and variance observed utilizing three SWE devices, each from different manufacturers using a manual SWE method, (2) understanding the reproducibility and variance utilizing an automated SWE method of different muscle groups, and (3) using an automated SWE method to characterize MTrPs on the upper trapezius muscle group from a small sample group. Muscle groups evaluated during these pilot studies included trapezius and vastus lateralis. The results of this study showed that the reproducibility within a single US-SWE device has a moderate to high amount of CV and moderate to low ICC on images analyzed. Moreover, the reproducibility across multiple SWE devices when evaluating the same muscle group shows a statistically significant SWS distribution across devices. This highlights the impact of US-SWE devices estimating SWS differently and providing different profiles within a given muscle group. The results of the MTrPs pilot study demonstrated that using the shear anisotropy ratio (SAR) as an extracted feature for distinguishing between different population groups has potential merit. However, SAR is affected by the variance observed from a given SWE device, the estimation of shear wave speed by a SWE device, and the data acquisition methodology. This research highlights the value of using an automated SWE method, the limitations and implications of existing SWE devices, and potential features, like SAR, having the merit of being biomarkers for characterizing and detecting MTrPs.