Imaging methods reveal unexpected patchy lesions in late onset distal myopathy.

Computed tomography (CT), ultrasonography (US) and low field magnetic resonance imaging (MRI) of muscles were performed in 13 patients of a large family with two clinically separate phenotypes of muscular dystrophy. Five patients had severe proximal muscle weakness and wasting like in limb-girdle muscular dystrophy. Imaging methods showed loss of muscle structure and replacement with adipose tissue especially in proximal muscles. Eight patients had distal myopathy of late onset with weakness and wasting of anterior tibial muscles. Imaging methods confirmed fatty degeneration of tibial muscles and, moreover, revealed unexpected large patchy lesions in several other clinically unaffected muscles. Our results indicate that some myopathies which are clinically localized, may actually have a more widespread patchy involvement as revealed by non-invasive imaging methods. In this family CT and MRI were more informative concerning lesions and distribution than US.