Quantitative MRI (qMRI) is a promising tool in the assessment of disease involvement in muscular dystrophies. Specifically, fat fraction and quantitative measures of intramuscular edema are of particular interest, as it is possible to use them to quantify fat replacement and muscle free water, that have mainly been evaluated qualitatively so far. Such features may playas outcome measures for clinical trials. The purpose of this study is to evaluate qMRI as an outcome marker of follow-up in the longitudinal assessment of FSHD, transversally and longitudinally.

A cohort of 30 subjects with diagnosis of FSHD was evaluatedwith a 3 Tesla MRI protocol including a 6-point GRE sequence and a TSE T2 multi-echo sequence with EPG fitting (17 echo times). Sequences are centered on the thigh and lower leg muscles. The Fatty Riot algorithm was used offline for the calculation of fat/water fraction maps from the GRE multi-echo acquisition (see Smiths DS et al. Proceedings of 21st ISMRM 2013) . For the multi-echo T2 sequence, extended phase graph signal simulation for a...

30 subjects have been scanned at baseline, and 16 at 6-month follow-ups, whereas data analysis has been concluded for 14 of those subjects at baseline and 11 at 6-month follow-up. Current preliminary data showed that fat fraction of tibialis anterior (TA), hamstring muscles and also adductor magnus (AM) muscleshadpositive correlation with CSS and negative correlation with 6MWT and dynamometric measures. wT2 for the same muscle groups also showed a positive correlation with CSS and a negative correlation with 6MWT and dynamometric measures. Longitudinally, wT2 values...

FF and waterT2 showed a good correlation with clinical measures in FSHD in more extensively involved muscles (hamstring and anterior muscles of the leg). Longitudinally waterT2 decreased mainly in the same muscle groups. No change in FF at 6mo was shown. Imaging findings seems to closely follow the pathophysiology of the disease, as in time the inflammatory features tend to preceed dystrophic features. As quantitative data represent clinico-metric properties and track the severity of involvement, they stand out as a promising biomarker of disease in...

A. Pichiecchio; Pavia/IT -consultant fee for G enzyme; M. Paoletti; Pavia/IT - nothing to disclose F. Solazzo; Pavia/IT - nothing to disclose N. Bergsland; Buffalo/US - nothing to disclose E. Ballante; Pavia/IT - nothing to disclose X. Deligianni; Basel/CH - nothing to disclose F. Santini; Basel/CH - nothing to disclose S. Bastianello; Pavia/IT - nothing to disclose E. Ricci; Rome/IT - nothing to disclose

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