Computed tomography of the skeletal muscles in neuromuscular diseases

Computed tomographic (CT) scans of the shoulder girdle, upper arm, waist, pelvic girdle, thigh, and lower leg were obtained in a total of 21 patients with neuromuscular diseases, including 10 with Duchenne muscle dystrophy (DMD), 3 with Fukushima type congenital muscular dystrophy (FCMD), 3 with Werdnig-Hoffmann's disease (WH), 3 with autosomal recessive muscular dystrophy in childhood (childhood MC), one with nemaline myopathy (NM), and one with myositis ossificans circumscripta (MOC). Age-dependent changes in CT findings were examined in the 10 DMD patients ranging in age from 3 to 15 years. Each muscle of the shoulder girdle and upper arm was seen as a low density area on CT in patients 9 years of age when the arms are difficult to elevate. Changes in the m. quadriceps femoris occurring in all the patients were visible earlist on CT, followed by those in the m. gluteus maximus, m. gastrocnemius, and m. soleus. CT scans of the thigh was thus considered most useful in diagnosing DMD. CT scans of the lower leg showed low density areas in the m. gastrocnemius and m. soleus in both WH and FCMD patients, while a low density area seen in the m. gluteus maximum on CT was restricted to FCMD patients. This suggests the potential of CT in the differentiation of WH from FCMD. In patients with childhood ARMD, there were various CT findings including normal and extremely low density areas. CT findings in NM patients were similar to those in DMD patients. High density areas were seen along the fascia of the trunk in MOC patients. (Namekawa, K.)