Enhanced Precision of the OXPHOS Measurement with integrated CrCEST MRI and Down Field Proton MR Spectroscopy

Creatine recovery time constant (τCr) of exercised muscle is strongly coupled to net mitochondrial oxidative phosphorylation. However, local in vivo pH drop plays the role of a potential confounder, leading to significantly slower creatine recovery. Even under the same prescribed exercised regime, the extent of acidification and hence its impact on τCr would be variable across participant. To the best of our knowledge, this is the first study where downfield 1H-MR spectroscopy and 3D creatine chemical exchange saturation transfer are extensively used to prescribe mild exercise regime in terms of maximal voluntary contraction of participants while avoiding any acidification.