Comparison of relative cerebral blood volume and proton spectroscopy in patients with treated gliomas

BACKGROUND AND PURPOSE: Elevated relative regional cerebral blood volume (r CBV) reflects the increased microvascularity that is associated with brain tumors. The purpose of this study was to investigate the potential role of rCBV in the determination of recurrent/residual disease in patients with tr eated gliomas. METHODS: Thirty-one rCBV studies were performed in 19 patients with treated gliomas. All patients also had proton MR spectroscopy and conventional MR imaging. Regions of abnormality were identified on conventional MR images b y two neuroradiologists and compared with rCBV and MR spectroscopic data. M etabolites and rCBV were quantified and compared in abnormal regions, RESULTS: In high-grade tumors, rCBV values were proportional to choline in regions of tumor and nonviable tissue. Although the presence of residual/re current disease was often ambiguous on conventional MR images, the rCBV map s indicated regions of elevated vascularity in all low-grade tumors and in 12 of 17 grade IV lesions. Regions of elevated and low rCBV corresponded we ll with spectra, indicating tumor and nonviable tissue, respectively. CONCLUSION: This study suggests that rCBV maps and MR spectroscopy are comp lementary techniques that may improve the detection of residual/recurrent t umor in patients with treated gliomas. Compared with the spectra, the rCBV maps may better reflect the heterogeneity of the tumor regions because of t heir higher resolution, The multiple markers of MR spectroscopy enable bett er discrimination between normal and abnormal tissue than do the rCBV maps.