The magnetic resonance imaging spectrum of facioscapulohumeral muscular dystrophy.

BACKGROUND

Facioscapulohumeral muscular dystrophy (FSHD) is associated with a repeat contraction in the D4Z4 gene locus on chromosome 4q35. We used a one-step quantitative magnetic resonance imaging (MRI) method to evaluate muscle, edema, and fat in patients spanning the range of severity.

METHODS

Fifteen patients with FSHD were compared with 10 healthy subjects using non-negative linear least-squares fitting of 32-echo relaxation data (T2). The results were compared with a biexponential approach for characterizing muscle/fat ratio and T2 relaxation measurements from fat-suppressed inversion recovery.

RESULTS

Increased T2 signal consistent with edema was common in FSHD subjects, a pattern not present in healthy controls. A varied pattern of edema and fatty replacement in muscles was shown.

CONCLUSIONS

As a discrete biomarker, edema may be useful for following the clinical course of FSHD. Future work toward optimizing measurement is discussed.