Multivoxel proton magnetic resonance spectroscopy in facioscapulohumeral muscular dystrophy

Abstract

Introduction: Facioscapulohumeral muscular dystrophy (FSHD) is a hereditary disorder that causes progressive muscle wasting. This study evaluates the use of proton magnetic resonance spectroscopy (1 H MRS) as a biomarker of muscle strength and function in FSHD.

Methods: Thirty-six individuals with FSHD and 15 healthy controls underwent multivoxel 1 H MRS of a cross-section of the mid-thigh. Concentrations of creatine, intramyocellular and extramyocellular lipids, and trimethylamine (TMA)-containing compounds in skeletal muscle were calculated. Metabolite concentrations for individuals with FSHD were compared with those of controls. The relationship between metabolite concentrations and muscle strength was also examined.

Results: The TMA/creatine (Cr) ratio in individuals with FSHD was reduced compared with controls. The TMA/Cr ratio in the hamstrings also showed a moderate linear correlation with muscle strength.

Discussion: 1 H MRS offers a potential method of detecting early muscle pathology in FSHD prior to the development of fat infiltration. Muscle Nerve 57: 958-963, 2018.

Keywords: biomarkers; facioscapulohumeral muscular dystrophy; magnetic resonance spectroscopy; metabolite quantification; skeletal muscle; trimethylamine.

Conflict of interest statement

Disclosure of Conflicts of Interest:

None of the authors has any conflict of interest to disclose.

© 2017 Wiley Periodicals, Inc.

Figures

Figure 1

Representative spectrum from a single voxel in a 54 year-old female with FSHD. Peaks from trimethylamines (TMA), creatine, extra- (EMCL) and intra-myocellular lipid (IMCL) are identified. The red line is the spectrum fitted by LCModel. Inset T1-weighted MRI shows MRS voxel location.

Figure 2

Histogram representing the distribution of log[TMA/Cr] ratio in all voxels from controls (transparent bars) and subjects with FSHD (blue bars). The log[TMA/Cr] ratio is statistically significantly lower in the FSHD population compared to controls.

Figure 3

Metabolite concentrations with respect to muscle strength and function. Fitted regression lines showing the association between hamstrings strength (a) and 10-meter walk time (b) as a function of the mean log[TMA/Cr] ratio of the hamstring muscles in individuals with FSHD.