Ultrasound appears to be a reliable technique for the diagnosis of piriformis syndrome

Introduction: Piriformis muscle syndrome (PS) is a disorder encompassing a constellation of symptoms, including buttock and hip pain. In this study we aimed to assess the value of ultrasound (US) in the diagnosis of PS. Methods: Thirty‐three clinically diagnosed PS patients and 26 healthy volunteers underwent a clinical PS scoring examination and US and MRI assessment of the bilateral piriformis muscles. The areas under the receiver operating characteristic curves (AUROCs) of the US parameters (i.e., increased thickness [iTh] and increased cross‐sectional area [iCSA]) for piriformis muscle were evaluated. Results: On US and MRI, the thickness and CSA were increased in PS patients. The AUROCs for the iTh and iCSA for discriminating stage 0 (healthy volunteers) from stage 1 through stage 3 (PS patients) were 0.88 and 0.95, respectively. Discussion: US may be a reliable technique for the clinical diagnosis of PS. Muscle Nerve 59:411–416, 2019