Normal pressure hydrocephalus. (Part I). Pre- and post-operative r-CBF

Abstract

Pre- and post-operative r-CBF was examined with the 133Xe inhalation method in 11 patients of normal pressure hydrocephalus (NPH). In the effective shunt group consisting of 8 patients, the preoperative mean hemispheric CBF was slightly lower than normal, while depression of the r-CBF in the frontal and parietal lobes was considerable. However, in the non-effective shunt group consisting of 3 patients, the preoperative mean hemispheric CBF was significantly lower than normal, and the r-CBF in the frontal, parietal and temporal lobes was consistantly low. In the effective shunt group, about a 10% increase in the postoperative mean hemispheric CBF was noticed and the increased r-CBF was more prominent in the frontal and parietal lobes. However, the postoperative CBF did not increase in the noneffective shunt group. Improvement of symptoms did not always parallel the postoperatively increased mean hemispheric CBF. The possibility of predicting shunt effectiveness from the features of preoperative r-CBF study in NPH, the mechanism of the postoperative change in CBF, and the necessity of pathogenetic diagnosis of NPH for the evaluation of pre and post-operative CBF study were discussed.