NMR relaxation times from serial stereotactic biopsies in human brain tumors

Tissue samples were obtained by serial stereotactic biopsies in 32 patients with glial brain tumors localized by CT. On each sample, several tissue parameters, such as water content, specific gravity of the dry and wet tissue, electrical impedance, histopathological and cytological examinations, as well as nuclear magnetic resonance (NMR) relaxation times T1 and T2 were measured and correlated. Comparisons were made between both normal and tumorous tissues and between the various types of neoplasms. Differences of the measured parameters between tumors and normal brain tissue and their intercorrelations are analyzed and discussed. Comparison of the NMR results with the corresponding densitometric data from CT images suggests that NMR may add useful information in brain tumor imaging. The authors propose an index of malignancy for gliomas dependent on relaxation time T1 and proton density measured by NMR imaging.