Accelerated Five-Dimensional Echo-Planar Correlated Spectroscopic Imaging to assess Lipids and Metabolite differences between Type-2 Diabetic and Healthy Calf Muscle

Synopsis Obesity-related diseases such as Type 2 Diabetes have become increasingly widespread. This condition can be characterized in part by changes in the fat composition of muscle, specifically in the relative concentrations of extra-myocellular (EMCL) and intra-myocellular (IMCL) lipids. Although 1D MRS techniques have been applied to assess skeletal muscle metabolite composition, they are hindered by lipid contamination from EMCL and spectral overlap which can complicate quantitation and differentiation from IMCL. 2D MRS improves spectral dispersion, allowing clear separation of both EMCL and IMCL and determination of the unsaturation index of muscle lipids. In this study, we apply a 5D (3D spatial + 2 spectral) echo-planer correlated spectroscopic imaging (EP-COSI) technique to assess the lipid and metabolic differences within the calf muscle among three groups of subjects – diabetic, age-matched healthy, and young healthy controls.