MULTIMODALITY CORRELATIVE STUDY OF CANINE BRAIN-TUMORS - PROTON MAGNETIC-RESONANCE SPECTROSCOPY - POSITRON EMISSION TOMOGRAPHY, AND HISTOLOGY

RATIONALE AND OBJECTIVES. Structural/functional relationships in an in duced canine brain tumor were studied using proton-magnetic resonance spectroscopy (H-1-MRS), positron emission tomography (PET), and histol ogy. METHODS. Proton-MRS and PET data of implanted canine brain tumors were correlated with quantitative analysis of the tissue composition within the MRS and PET regions of interest (ROIs). Linear regression a nalysis was employed to correlate the H-1-MRS and PET data with the pe rcent tumor and the percent total lesion (comprising tumor plus associ ated pathology ie, edema, cysts, hemorrhage, inflammation) within the ROI. RESULTS. Using H-1-MRS, N-acetyl aspartate concentrations were in directly correlated with the amount of tumor (P = .058), as well as th e amount of tumor plus associated pathology (P = .032) within the ROI. Total creatine concentrations were indirectly correlated with the amo unt of tumor and the amount of tumor plus associated pathology within the ROI (P < .05). Lactate concentrations were directly correlated wit h the amount of tumor (P = .053) and the amount of tumor plus associat ed pathology (P = .058) within the ROI. Using PET, Oxygen metabolic ra tes were indirectly correlated with the amount of tumor and with the a mount of tumor plus associated pathology within the ROI (P < .05). Glu cose metabolic rates were directly correlated with both the amount of tumor and with the amount of tumor plus associated pathology at P < .0 5. Proton-MRS measured concentrations of choline and PET measured valu es for blood flow, and oxygen extraction showed correlations with the amount of tumor and with the amount of tumor plus associated pathology at P greater than or equal to .080. CONCLUSIONS. The PET and MRS data were complementary with respect to suggesting anaerobic glucose metab olism for the tumor. Unlike other tumors, no increase in choline was n oted in the canine tumor.