31P MRS at 7T Shows a Relation Between the Alkaline Ph Compartment Content Compared to Phosphocreatine Recovery Kinetics At 1.5T

Joep van Oorschot¹, Hermien Kan², Andrew Webb², Klaas Nicolay¹, Jeroen Jeneson¹

Non-invasive assessment of mitochondrial content in skeletal muscle, during rest, using 31P spectroscopy would be a major improvement over conventional methods, including kinetics of phosphocreatine (PCr) recovery from exercise. Previous research at 7T attributed a peak at 5.2 ppm to the Pi pool inside the mitochondrial matrix (Pi2). In this study we obtained further evidence for this hypothesis, by showing a correlation between Pi2 intensity assessed at 7T to the PCr recovery rate as assessed during in-magnet exercise at 1.5T. Studies were done in both endurance trained athletes and normally active subjects.