Ericky C A Araujo1,2, N Azzabou1,2, A Vignaud3, G Guillot4, P G Carlier1,2. 1. NMR Laboratory, Institute of Myology, Pitié-Salpêtrière University Hospital, Paris, France. 2. CEA/DRF/I2BM/MIRCen, Fontenay aux Roses, France. 3. CEA/DRF/I2BM/NeuroSpin/UNIRS, Gif Sur Yvette, France. 4. IR4M UMR8081, CNRS, University of Paris-Sud, University of Paris-Saclay, Orsay, France.
Abstract
PURPOSE: To introduce an ultrashort echo time (UTE) based method for quantitative mapping of short-T2 signals in skeletal muscle (SKM) in the presence of fat, with the aim of monitoring SKM fibrosis. METHODS: From a set of at least five UTE images of the same slice, a long- T2* map, a fat-fraction map, and a map of short-T2 -signal fraction are extracted. The method was validated by numerical simulations and in vitro studies on collagen solutions. Finaly, the method was applied to image the short-T2 signals in the leg of eight healthy volunteers. RESULTS: The imaged short-T2 -signal fractions in the collagen solutions correlated with their respective collagen concentrations ( R=0.999, P=0.009). Short-T2 tissues such as cortical bone and fasciae were highlighted in the resulting short-T2 fraction maps. A significant fraction of short-T2 signal was systematically observed in the skeletal muscle of all of the subjects (4.5±1.2%). CONCLUSION: The proposed method allows the quantitative imaging of short-T2 components in tissues containing fat. By also having the fat-fraction and T2* maps as outcomes, long-T2 suppression is accomplished without requiring modifications to the basic UTE sequence. Although the hypersignal observed in the fasciae suggests that the short-T2 signal observed in SKM might arise from interstitial connective tissue, further investigation is necessary to confirm this statement. Magn Reson Med 78:997-1008, 2017.
PURPOSE: To introduce an ultrashort echo time (UTE) based method for quantitative mapping of short-T2 signals in skeletal muscle (SKM) in the presence of fat, with the aim of monitoring SKM fibrosis. METHODS: From a set of at least five UTE images of the same slice, a long- T2* map, a fat-fraction map, and a map of short-T2 -signal fraction are extracted. The method was validated by numerical simulations and in vitro studies on collagen solutions. Finaly, the method was applied to image the short-T2 signals in the leg of eight healthy volunteers. RESULTS: The imaged short-T2 -signal fractions in the collagen solutions correlated with their respective collagen concentrations ( R=0.999, P=0.009). Short-T2 tissues such as cortical bone and fasciae were highlighted in the resulting short-T2 fraction maps. A significant fraction of short-T2 signal was systematically observed in the skeletal muscle of all of the subjects (4.5±1.2%). CONCLUSION: The proposed method allows the quantitative imaging of short-T2 components in tissues containing fat. By also having the fat-fraction and T2* maps as outcomes, long-T2 suppression is accomplished without requiring modifications to the basic UTE sequence. Although the hypersignal observed in the fasciae suggests that the short-T2 signal observed in SKM might arise from interstitial connective tissue, further investigation is necessary to confirm this statement. Magn Reson Med 78:997-1008, 2017.
Authors: Aurea B Martins-Bach; Damien Bachasson; Ericky C A Araujo; Lucas Soustelle; Paulo Loureiro de Sousa; Yves Fromes; Pierre G Carlier Journal: Sci Rep Date: 2021-01-11 Impact factor: 4.379