Detection of myofascial trigger points in the masseter muscle using ultrasonography in patients with myogenous temporomandibular disorder

Objective We aimed to investigate the diagnostic efficacy of ultrasonography (US) using gray scale B-mode and ultrasound elastography (UE) in detecting myofascial trigger points (MTPs) in the masseter muscles of patients with myogenous temporomandibular disorder (TMD). Study Design A diagnostic cross-sectional study of patients with MTPs in the masseter muscles using US was conducted. The diagnostic results from the US examinations were compared with the clinical examination reference standard to determine the diagnostic efficacy of US. MTPs were detected as spherically shaped or band-like hypoechoic localized areas with reduced vibration amplitude (stiffer) under grayscale and UE modes of US. Results In total, 116 sites from 29 patients (3 males, 26 females) with a mean age of 39.4 years were examined. US exhibited sensitivity of 94.6% (95% CI: 85.1% to 98.9%) and specificity of 90.0% (95% CI: 79.5% to 96.2%) in detecting MTPs when compared to the clinical examination. Diagnostic accuracy ranged from 80% to 90.5% when assuming 3 levels of myogenous TMD prevalence. Conclusion Ultrasonography with gray scale and UE modes exhibited diagnostic accuracy comparable to the standard clinical examination carried out by a trained specialist. It can be a reliable technique in the detection and localization of MTPs for the diagnosis of myogenous TMD and localization of MTPs for therapeutic purposes.