[Regional cerebral blood flow in senile patients with meningiomas (author's transl)]

We investigated the regional cerebral blood flow of 4 meningioma patients who were all of ages over 60 years old. The average age of the patients was 68 years. Cerebral blood flow was determined by the 133Xe clearance method of Lassen and Ingvar. By extra-cranial recording of the radioactivity from the freely diffusible inert gas 133Xe, which dissolved in saline, was injected into the internal carotid artery, a clearance curve was obtained from the cerebral hemisphere. This curve could be resolved into two monoexponential clearance functions that corresponed to the flow in the grey and white matter. Graphical analysis of the original curve allowed the estimation of the relative weight of these two tissue components as well as of the mean cerebral blood flow. In three patients, regional cerebral blood flow was measured both pre- and post-operatively and these values were compared. Focal rCBF disturbances could be detected in agreement with the tumor location as verified directly or by other diagnostic procedures. That is, a relative hyperemia was detected at the areas corresponding to the tumor site. Mean fg (the flow in the grey matter) of four patients was 77.3 +/- 14.0 ml/100 g/min on the tumor areas, 48.1 +/- 6.6 ml/100 g/min on the peritumoral regions, 63.1+/- 4.1 ml/100 g/min on the non-tumoral regions. CBFr (average cerebral blood flow) of non-tumoral areas in the four patient was 36.6 +/- 2.4 ml/100 g/min and that of the peri-tumoral area, 33.1 +/- 7.9 ml/100g/min. These figures are moderately smaller than that of the normal one. A comparison between the neurological features and regional flow values noted in patients who had a removal of menigiomas indicated that the flow values of non-tumoral area increased markedly a month after operation, instead of only slight or no improvement in neurological features. Although our cases with rCBF studies are still too few to warrant conclusions, it seems that post-operative follow-up of mean cerebral blood flow changes might be rather greater help in the assessment of prognosis after operation of meningiomas than fg (the flow in the grey matter).