Muscle-fat MRI: 1.5 Tesla and 3.0 Tesla versus histology.

Introduction: We evaluated muscle/fat fraction (MFF) accuracy and reliability measured with an MR imaging technique at 1.5 Tesla (T) and 3.0T scanner strengths, using biopsy as reference. Methods: MRI was performed on muscle samples from pig and rabbit species (n = 8) at 1.5T and 3.0T. A chemical shift based 2-point Dixon method was used, collecting in-phase and out-of-phase data for fat/water of muscle samples. Values were compared with MFFs calculated from histology. Results: No significant difference was found between 1.5T and 3.0T (P values = 0.41–0.96), or between histology and imaging (P = 0.83) for any muscle tested. Conclusions: Results suggest that a 2-point Dixon fat/water separation MRI technique may provide reliable quantification of MFFs at varying field strengths across different animal species, and consistency was established with biopsy. The results set a foundation for larger scale investigation of quantifying muscle fat in neuromuscular disorders. Muscle Nerve 50:170–176, 2014