Myofascial pain syndrome is a common musculoskeletal pain disorder characterized by the presence of myofascial trigger points (MTrPs). The diagnosis of myofascial pain syndrome is currently made on clinical grounds. Numerous diagnostic criteria are used to identify myofascial pain syndrome, including the localization of MTrPs. Identifying the presence of MTrPs currently requires the physician to palpate the symptomatic region. Because the interrater reliability of the palpation technique has been found to be poor, numerous groups have been interested in finding objective imaging measures to localize the MTrP. This comprehensive review focuses on summarizing ultrasound imaging techniques that have shown promise in visually localizing the trigger point. The authors’ literature search identified three sonographic approaches that have been used in MTrP localization: conventional gray-scale imaging, Doppler imaging, and elastographic ultrasound imaging. This review article explains the basic physics behind the imaging methods and summarizes the characteristics of the MTrP as identified by the ultrasonic techniques.
From the Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Toronto, Toronto, Ontario, Canada (DAK); and Department of Medical Physics and Applied Radiation Sciences (AHE, MDN), School of Biomedical Engineering (MDN), and Department of Electrical and Computer Engineering (MDN), McMaster University, Hamilton, Ontario, Canada.
All correspondence and requests for reprints should be addressed to: Dinesh A. Kumbhare, MSc, MD, FRCPC, DABPMR, Toronto Rehabilitation Institute, University of Toronto, 550 University Ave, Toronto, ON, Canada M5G 2A2.
Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.