MRI/MRS evaluation of a female carrier of Duchenne muscular dystrophy

The purpose of this study was to evaluate skeletal muscle composition of lower extremity muscles in a manifesting female carrier of Duchenne muscular dystrophy (MFCDMD) using magnetic resonance imaging (MRI) and spectroscopy (MRS). MRI/MRS was performed on the lower extremities and heart of a MFCDMD (47 years, 51 kg) on four occasions within 21 months and in a control subject. Heterogeneity and asymmetry among muscles in the MFCDMD was observed in lipid fraction and mean transverse relaxation time (T2) of lower extremity muscles with some muscles presenting as unaffected (e.g., rectus femoris) and others showing substantial deterioration and lipid infiltration (e.g., vasti muscles). There was an association of abnormal MRI findings and strength and motor function. Over the 21 months a small decrease in CSAmax and increase in lipid fraction and T2 was observed in the MFCDMD in some muscles. In summary, this MFCDMD revealed significant imaging evidence of pathologic heterogeneity among muscles. Furthermore, this study shows the feasibility of combining various quantitative MRI and MRS approaches to monitor skeletal muscle involvement.