Carrier detection in Duchenne muscular dystrophy using computed tomography

In Duchenne dystrophy computed tomography of muscles shows total or partial replacement of normal muscle by low density tissue, presumably representing fat. It was hypothesised that female carriers would have increased fat deposition, and hence lower density readings in certain muscle groups when compared with controls. Three C.T. scans, two through the thigh and one through the calf, were obtained on 9 obligate carriers, 12 "possible" carriers, and 10 controls. A total of 15 density readings in different muscle groups were obtained for each subject. The results, analysing the mean densities in Hounsfield units, show that the obligate carriers have statistically significant lower density readings than controls. The 9 obligate carriers and 10 controls were correctly allocated using discriminant function analysis of muscle density readings. An attempt to assign the "possible" carriers was made. The use of C.T. scanning in addition to creatine kinase (C. K.) estimations will significantly improve accuracy of genetic counselling and has the advantage of being non-invasive.