Figure 3.

Blood flow heterogeneity in the quadriceps femoris muscle during a fatigue task Voxel-by-voxel map of relative blood flow with a region of interest shown in the exercising quadriceps femoris muscle of one subject. To calculate blood flow heterogeneity, the s.d. of blood flow values for each pixel within each muscle were divided by the mean blood flow for each quadriceps femoris muscle and multiplied by 100. Note the small voxels that show the blood flow level in small pieces of muscle and which are used for perfusion heterogeneity calculations.