[Results of muscular x-ray computed tomography in 145 cases of neuromuscular disease]

CT Scan examination in 145 cases of neuromuscular diseases yielded the following results: Diagnosis between myogenic and neurogenic process is inconstant and cannot be considered as absolute. In myogenic diseases the X ray density of muscle is early decreased with a preservation of muscle outline. In neurogenic diseases muscle volume is early decreased. Coexistence of atrophic and hypertrophic muscles indicates primarily muscle disease. Some patterns of involvement appear to be frequent. In Duchenne's dystrophy a contrast exists between atrophic "empty" or hypertrophic muscles during the ambulatory period and "ghostly" muscles during the terminal period. In facio-scapulo-humeral muscular dystrophy, tibialis anterior and hamstring muscles have often a decreased density and psoas muscles are normal or hypertrophic. In myotonic dystrophy a hypodense perifemoral crescent is frequently observed. Diagnosis between limb-girdle myopathy ("empty" muscles with preserved limits, hypertrophic muscles, hypodense gastrocnemius medialis muscles) and chronic spinal amyotrophy (irregular and atrophic muscles without selective involvement and hypertrophic muscles) is tentatively proposed but is not considered to be clear-cut. Muscle involvement has an asymmetric distribution in amyotrophic lateral sclerosis and is rather symmetric in peripheral neuropathies.