Quantitative muscle ultrasound versus quantitative magnetic resonance imaging in facioscapulohumeral dystrophy

INTRODUCTION: Ultrasound and magnetic resonance imaging (MRI) are non-invasive methods that can be performed repeatedly and without discomfort. In the assessment of neuromuscular disorders it is unknown if they provide complementary information. In this study we tested this for patients with facioscapulohumeral muscular dystrophy (FSHD). METHODS: We performed quantitative muscle ultrasound (QMUS) and quantitative MRI (QMRI) of the legs in 5 men with FSHD. RESULTS: The correlation between QMUS-determined z-scores and QMRI-determined muscle fraction and T1 signal intensity (SI) was very high. QMUS had a wider dynamic range than QMRI, whereas QMRI could detect inhomogeneous distribution of pathology over the length of the muscles. CONCLUSIONS: Both QMUS and QMRI are well suited for imaging muscular dystrophy. The wider dynamic range of QMUS can be advantageous in the follow-up of advanced disease stages, whereas QMRI seems preferable in pathologies such as FSHD that affect deep muscle layers and show inhomogeneous abnormality distributions.