In GNE myopathy, standard MRI shows the progression of fatty infiltration into the muscles of the lower limbs, which relatively spares the quadriceps. The quantitative MRI (qIRM) allows to refine the observation. It detects more subtle muscle changes early on and makes it possible to measure the affected areas, the percentages of fat, water …
The ClinBio-GNE study [NCT02196909] is a three-year natural history study conducted at the Institute of Myology in ten people with GNE myopathy. This French study aims to determine which parameters of qIRM would be sensitive enough to detect minimal changes in the muscle. It is based on the study of the evolution of clinical signs, functional scores (in particular Myogrip, Myopinch, MoviPlate, Brooke scale, 6MWT) and qIRM measurements in the legs, thighs, forearms and hands. The results were compared with those of 29 healthy subjects of the same age and gender.
Quantitative MRI detects muscle changes even over a year. The first results of this study showed 
that:
- qIRM measurements detect signs of change even over a relatively short period of a year;
the more the fatty infiltration of the muscles increases, the more the contractile muscle part decreases: - there is also a strong correlation between these indices and the functional scores.
The same team continued their work and demonstrated that disease activity indices (in qMRI and NMR spectroscopy) could be predictive of muscle progression of the disease.
The authors suggest that these measurements (measurement of water in T2 sequence and phosphorus 31 NMR spectroscopy) could serve as biomarkers of the evolution of GNE myopathy.
