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Fig 3. A, rCBV estimates corrected for contrast agent extravasation correlate significantly with glioma grade by using a Spearman rank correlation, whereas uncorrected relative cerebral blood volume (rCBV) does not. The disparity is due primarily to artificially low uncorrected blood-volume estimates in high-grade tumors that arises from the competing T1 effects of Gd leaking through disrupted blood-brain barrier.
B, Despite significant correlation, there exists moderate corrected rCBV variability within each grade and intergrade overlap. This supports the notion that glioma grading remains controversial and that multiple parameters, including vascular permeability and vessel size distribution, will probably be required in aggregate for accurate prognostication.
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