Perfusion MR imaging in gliomas: Comparison with histologic tumor grade

Objective: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. Materials and Methods: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enh anced T2*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were c alculated and compared between glioblastomas, anaplastjc gliomas and low-gr ade gliomas. Results: Mean rCBV ratios were 4.90 degrees +/- 1.01 for glioblastomas, 3.9 7 degrees +/- 0.56 for anaplastic gliomas and 1.75 degrees +/- 1.51 for low -grade gliomas, and were thus significantly different; p < .05 between glio blastomas and anaplastic gliomas, p < .05 between anaplastic gliomas and lo w-grade gliomas, p < .01 between glioblastomas and low-grade gliomas, The r CBV ratio cutoff value which permitted discrimination between high-grade (g lioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and th e sensitivity and specificity of this value were 100% and 75%, respectively . Conclusion: Perfusion MR imaging is a useful and reliable technique for est imating the histologic grade of gliomas.