Elevated phosphodiester and T₂ levels can be measured in the absence of fat infiltration in Duchenne muscular dystrophy patients

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• 作者：M.T. Hooijmans ; E.H. Niks ; J. Burakiewicz ; J.J.G.M. Verschuuren ; A.G. Webb and H.E. Kan
• 刊名：NMR in Biomedicine
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：30
• 期：1
• 全文大小：503K
• ISSN：1099-1492

文摘

Quantitative MRI and MRS are increasingly important as non-invasive outcome measures in therapy development for Duchenne muscular dystrophy (DMD). Many studies have focussed on individual measures such as fat fraction and metabolite levels in relation to age and functionality, but much less attention has been given to how these indices relate to each other. Here, we assessed spatially resolved metabolic changes in leg muscles of DMD patients, and classified muscles according to the degree of fat replacement compared with healthy controls. Quantitative MRI (three-point Dixon and multi-spin echo without fat suppression and a tri-exponential fit) and 2D–CSI ³¹P MRS scans were obtained from 18 DMD patients and 12 healthy controls using a 3 T and a 7 T MR scanner. Metabolite levels, T₂ values and fat fraction were individually assessed for five lower leg muscles. In muscles with extensive fat replacement, phosphodiester over adenosine triphosphate (PDE/ATP), inorganic phosphate over phosphocreatine, intracellular tissue pH and T₂ were significantly increased compared with healthy controls. In contrast, in muscles without extensive fat replacement, only PDE/ATP and T₂ values were significantly elevated. Overall, our results show that PDE levels and T₂ values increase prior to the occurrence of fat replacement and remain elevated in later stages of the disease. This suggests that these individual measures could not only function as early markers for muscle damage but also reflect potentially reversible pathology in the more advanced stages.