Validity of skeletal muscle ultrasound as a screening tool in the assessment of patients with suspected limb-girdle muscular dystrophy

Abstract

This cross-sectional study measured the sensitivity and specificity of muscle ultrasound (MUS) in the assessment of patients with suspected limb-girdle muscular dystrophy (LGMD). Sixty patients with suspected LGMD from the Neuromuscular Unit, Myology Clinic, Ain Shams University Hospital, Cairo, Egypt, and a series of healthy subjects were included. The patients underwent real-time B-mode ultrasonography performed using a General Electric ultrasound machine (GE Logiq P7) and a General Electric 7.5 MHz linear array ultrasound probe (USA). All images were obtained and scored by a single examiner, and muscle echo intensity was visually graded semiquantitatively using Heckmatt’s scale. The examiner was blinded to the clinical evaluations and patients’ investigations. Statistical analysis using receiver operating characteristic (ROC) curve analysis revealed that the total upper-limb (UL) Heckmatt’s US score at a cutoff point >1 predicted patients with dystrophy, with good (88%) accuracy and with sensitivity and specificity of 100% and 75%, respectively (p < 0.01). Moreover, the total lower-limbs (LL) Heckmatt’s US score at a cutoff point >1 predicted patients with dystrophy, with excellent (91%) accuracy and with sensitivity and specificity of 100% and 75%, respectively (p < 0.01). Finally, the total Heckmatt’s US score at a cutoff point >2 predicted patients with dystrophy, with good (89%) accuracy and with sensitivity and specificity of 100% and 75%, respectively (p < 0.01). Thus, MUS can be considered a valid screening tool in the assessment of patients with suspected LGMD.