Relationships between choline magnetic resonance spectroscopy, apparent diffusion coefficient and quantitative histopathology in human glioma

This study sought to correlate quantitative presurgical proton magnetic res onance spectroscopic imaging (H-1- MRSI) and diffusion imaging (DI) results with quantitative histopathological features of resected glioma tissue. Th e primary hypotheses were (1) glioma choline signal correlates with cell de nsity, (2) glioma apparent diffusion coefficient (ADC) correlates inversely with cell density, (3) glioma choline signal correlates with cell prolifer ative index. Eighteen adult glioma patients were preoperatively imaged with H-1-MRSI and DI as part of clinically-indicated MRI evaluations. Cell dens ity and proliferative index readings were made on surgical specimens obtain ed at surgery performed within 12 days of the radiologic scans. The resecte d tissue location was identified by comparing preoperative and postoperativ e MRI. The tumor to contralateral normalized choline signal ratio (nCho) an d the ADC from resected tumor regions were measured from the preoperative i maging data. Counts of nuclei per high power field in 5-10 fields provided a quantitative measure of cell density. MIB-1 immunohistochemistry provided an index of the proportion of proliferating cells. There was a statistical ly significant inverse linear correlation between glioma ADC and cell densi ty. There was also a statistically significant linear correlation between t he glioma nCho and the cell density. The nCho measure did not significantly correlate with proliferative index. The results indicate that both ADC and spectroscopic choline measures are related to glioma cell density. Therefo re they may prove useful for differentiating dense cellular neoplastic lesi ons from those that contain large proportions of acellular necrotic space.