[The changes of regional cerebral blood flow and oxygen metabolism following ventricular puncture]

In seven patients who underwent ventricular puncture as a procedure for either continuous ventricular drainage or ventriculoperitoneal shunt between April 1983 and December 1988, the changes between pre- and postoperative regional cerebral blood flow (rCFB) and the regional cerebral metabolic rate of oxygen (rCMRO2) around the regions along the tract of puncture were evaluated. In each patients, rCBF and rCMRO2 were measured using Positron Emission Tomography (PET) by the steady state method. The regions of interest (ROIs) with diameters of 2cm were set as follows: The gray matter (PSG) and white matter (PSW) along the tract of the puncture, the same regions on the opposite side (OSG and OSW) and the bilateral motor cortex (PSM and OSM) as control. All changes, as well as lateralities at each region were studied. In 4 of 7 patients long term follow up PET studies (mean = 657 days after the procedure) were performed. After the procedure values of rCBF significantly increased in OSG and OSW (p < 0.05) and tended to increase in PSG and PSW. But compared with OSG and OSW, the degree of increase in PSG and PSW were suppressed. In the motor cortex evident changes were not recognized. Lateralities between PSG and OSG and those between PSW and OSW tended to increase after procedure. In long term follow up studies the values further increased in all regions including PSG and PSW and lateralities tended to decrease, but suppression of improvement around the puncture site was prolonged. The changes of rCMRO2 had the same tendency but it was not significant. The rCBF and rCMRO2 generally increased following the procedure accompanying ventricular puncture. Perhaps this was because of adjustment of increased intracranial pressure or cerebrospinal fluid circulation. But the degree of improvement around the puncture site was suppressed. Minor brain injury caused by the procedure was considered to be the cause of reduction of improvement of cerebral blood flow and cerebral oxygen metabolism.