Postsurgical Disappearance of Dementia without Increased Cerebral Blood Flow in Hydrocephalic Patients

Abstract

Cerebral blood flow (CBF) was measured by the 133-Xe inhalation method in four hydrocephalic patients without signs of increased intracranial pressure. Dementia decreased markedly after shunting procedures in two patients and after removal of posterior fossa tumors in the other two patients. The preoperative average hemispheric CBF was subnormal in three patients; it did not increase when dementia disappeared, within 7 to 21 days postoperatively, in any of the four patients. The cerebral circulation time, measured by dynamic computed tomography in three patients, was prolonged before operation and returned to normal after operation reflecting improvement in the microcirculation of the affected tissue. The results of this study demonstrate that disappearance of dementia following surgical intervention in hydrocephalic patients, possibly including those with normal-pressure hydrocephalus, is not always accompanied or preceded by increased CBF as measured by the conventional method. © 1987, The Japan Neurosurgical Society. All rights reserved.