Measurement and Correction for the Magnetic Susceptibility Effects of Fat in Venous Oximetry: Application in the Quantification of Muscle Oxygen Consumption (VO2) with Plantar Flexion Exercise

The magnetic field shift within cylindrical blood vessels can be used to estimate venous oxygen saturation, based on the magnetic susceptibility of deoxyhemoglobin. However, conduit veins in the periphery are often surrounded by fat, which has a larger magnetic susceptibility than water and the venous blood pool. It is shown that the magnetic susceptibility effects of fat can confound estimation of venous oxygen saturation. A new method to correct for these effects is described with application for plantar flexion exercise, for the measurement of muscle oxygen extraction, blood flow and calculation of oxygen consumption (VO₂).