A Comparative Study of CrCEST and PCrCEST for Mapping of Oxidative Phosphorylation in Exercised Muscle

Motivation: This study compares the sensitivity and specificity of two CEST-based methods for assessing oxidative phosphorylation (OXPHOS) in participants' skeletal muscle and also shows that creatine in muscle is a fast-exchanging species. Goal(s): We compare the sensitivity and specificity of creatine CEST and phosphocreatine CEST for exercised calf muscle. Approach: We acquired z-spectra at multiple saturation parameters to compare creatine CEST and phosphocreatine CEST at 3.0T and 7.0T. We also acquired creatine CEST and phosphocreatine CEST from exercised calf muscle. Results: Our findings indicate that creatine rapidly exchanges in skeletal muscle. Additionally, creatine CEST demonstrates higher sensitivity and specificity than phosphocreatine CEST. Impact: OXPHOS deficiency in skeletal muscle is associated with primary mitochondrial disorders, muscle injury, cardiovascular disease, and diabetes mellitus. This study compares the sensitivity and specificity of two CEST-based methods for assessing OXPHOS.