Fig. 4.

Phosphorus-31 magnetic resonance spectroscopy. Representative spectra from a patient carrying the m.3243A>G mutation (left) and a matched control subject (right) at baseline (upper panels) and following completion of 16 week exercise training (lower panels) showing a difference in PCr concentration that is unaffected by exercise. Spectra obtained from patient 3 (A) at baseline with PCr/ATP ratio 1.1, and (B) following exercise training with PCr/ATP 1.2 are displayed alongside spectra from the matched control participant (C) at baseline with PCr/ATP 2.0, and (D) following exercise training with PCr/ATP 1.9. Spectra are presented as acquired before correction for heart rate, flip angle and blood content. PCr = phosphocreatine; ATP = adenosine triphosphate; ppm = parts per million.