Microgravimetric analysis of human brain tissue: correlation with computerized tomography scanning.

Microgravimetric technique was used to measure the water content of tumors and adjacent brain. Multiple 1-cu mm samples were obtained from 17 patients with neurosurgical lesions. The site of each sample was located on the appropriate computerized tomography (CT) slice, and the water content correlated with the CT attenuation coefficient. The water content of peritumor white matter in 11 patients with glioblastomas was 5% to 8% H2O/gm tissue greater than the water content of white matter measured in three normal control individuals. These areas corresponded to low CT attenuation coefficients (8 to 15 EMI units). There was no statistically significant differences between the water content of tumors and adjacent white matter, even though the CT attenuation coefficient of the tumor was often at higher value. Low CT attenuation coefficient areas surrounding meningioma, metastasis, and lymphoma always correlated with elevated water content. The greatest water content (84.7% H2O/gm tissue) was found in the white matter surrounding an arteriovenous malformation. There was no correlation between the CT attenuation coefficient of this tissue and the water content in the arteriovenous malformation. This study shows that areas of low CT attenuation coefficient may correlate with measurements of the water content of tissue, but that increased water content may exist without demonstrable changes in the CT attenuation coefficient.