MRI Quantitative Evaluation of Muscle Fatty Infiltration

Magnetic resonance imaging (MRI) is the gold-standard technique for evaluating muscle fatty infiltration and muscle atrophy due to its high contrast resolution. It can differentiate muscular from adipose tissue accurately. MRI can also quantify the adipose content within muscle bellies with several sequences such as T₁-mapping, T₂-mapping, spectroscopy, Dixon, intra-voxel incoherent motion, and diffusion tensor imaging. The main fields of interest in musculoskeletal radiology for a quantitative MRI evaluation of muscular fatty infiltration include neuro-muscular disorders such as myopathies, and dystrophies. Sarcopenia is another important field in which the evaluation of the degree of muscular fat infiltration or muscular hypotrophy is required for a correct diagnosis. This review highlights several MRI techniques and sequences focusing on quantitative methods of assessing adipose tissue and muscle atrophy.