MRI thigh measurements predict whole‐body skeletal muscle mass in patients with type 2 diabetes: a comparison with DXA

Sarcopenia is an age‐related loss of skeletal muscle mass (SMM) and function, associated with falls, frailty, and functional decline. It is more prevalent and often accelerated in people with Type 2 diabetes (T2D), especially when co‐existing with obesity (sarcopenic obesity). Accurate whole‐body SMM measurement, feasible using dual‐energy X‐ray absorptiometry (DXA) or magnetic resonance imaging (MRI), has utility both in clinical practice and in epidemiological and mechanistic research, considering the dual mechanical and metabolic function of skeletal muscle. Compared with MRI, DXA may underestimate age‐related muscle mass by up to 30%, and so direct comparison of DXA/MRI‐derived SMM measurements may be invalid in patients with obesity and T2D, who have potentially even more pronounced sarcopenia/sarcopenic obesity. We aimed to validate single‐slice or multiple‐slice measures of SMM, using MRI, with whole‐body SMM measures derived from DXA scans of appendicular lean soft tissue, specifically in patients with obesity and T2D.