Fig 4. Percentage difference between corrected and uncorrected relative cerebral blood volume (rCBV) for each of the 43 gliomas separated by grade. For all 3 grades, there were several cases in which correction made no difference (shown in white), probably because of a combination of low vascular permeability (possibly from steroids) and the Gd preload. Most of the high-grade tumors, however, had >10% difference, with 6 cases differing by at least a factor of 2.