Ultrasound pattern of anterolateral leg muscles in facioscapulohumeral muscular dystrophy

Background/Aims of Study: To evaluate the degree of tibialis anterior (TA) and peroneus longus (PL) muscle involvement in facioscapulohumeral muscular dystrophy (FSHD) patients using ultrasound. Methods: We performed qualitative and quantitative assessments of muscle echogenicity, using Heckmatt's rating scale and gray scale analysis, respectively, in eight patients (five males, mean age 36.9 +/- 8.4 years) with genetically confirmed FSHD 1. Results: Both methods demonstrated a distinct pattern of preferential TA involvement and PL sparing in all FSHD patients, irrespective of the degree of muscle involvement. More specifically, echogenicity was higher in TA compared to PL according to Heckmatt score in the patient group (TA 3.43 +/- 0.49/PL 1.43 +/- 0.49, p < .001). In the gray-scale histogram, ranging from 0 (black) to 255 (white), the mean measurements of TA were significantly increased in patients compared to healthy (71.60 +/- 10.28 vs. 53.70 +/- 10.05, p = .012) and significantly higher than PL measurements in the patient group, but not in healthy subjects (p-values .012 and .779, respectively). A strong correlation between TA hyperechogenicity and muscle weakness was demonstrated in patients with mild-to-moderate weakness, but not in patients with severe weakness (r = -.949 and r = .644, respectively). Conclusions: This study shows a consistent US pattern of proximal anterolateral leg muscle involvement in FSHD, in agreement with findings of MRI studies and suggests that anterolateral leg muscle US may be a practical, fast and low-cost alternative to MRI.

Automated summary

The study revealed a distinct pattern of muscle involvement in FSHD patients, with preferential tibialis anterior involvement and peroneus longus sparing. Ultrasound was shown to be a practical alternative to MRI for assessing muscle involvement, with a strong correlation between high echogenicity and muscle weakness in mild-to-moderate cases.