[Evaluation of peritumoral edema by proton T1 values with special remarks on time courses following intracranial surgery].

Proton NMR is said to be sensitive to change in tissue water content. Much more attention has been paid to clinical NMR technique for evaluating pathophysiological states including intracranial edema dynamics. This paper describes the follow up data in NMR imaging and spin-lattice relaxation time (T1) measurement in peritumoral brain tissues. Special attention was directed to the time course of focal T1 values before and after surgery. Twenty-one patients with brain tumor, including 6 meningiomas, 7 gliomas and 8 metastatic tumors, were subjected to the present studies in the term from March 1983 to September 1985. Age distribution of this series ranged from 39 to 74 years (average: 58.2). Fonar QED 80-alpha system was applied for NMR examinations of dual modes (static magnetic field: 433 gauss), i.e. image display by steady state free precession (SSFP) and in vivo T1 measurement by field focussing technique. Standard T1 values for healthy brain were 290 +/- 41 ms and 230 +/- 34 ms (mean +/- SD) in cerebral gray and white matter, respectively. Both T1 values in tumors and in peritumoral tissues before craniotomy were obviously prolonged as compared to standard T1 of corresponding site. However, it remained difficult to discriminate statistically these histological differences by preoperative T1 values. Time course of peritumoral T1 was characteristic in accordance with the sorts of brain tumor. T1 values in the brain parenchyma around meningioma were shortened after operation in the earlier stage up to 1 month, showing relatively rapid normalization in T1.(ABSTRACT TRUNCATED AT 250 WORDS)