Oxygen metabolism changes in patients with idiopathic normal pressure hydrocephalus before and after shunting operation.

OBJECTIVE

The present study revealed the changes in cerebral oxygen metabolism before and after ventriculo-peritoneal shunt (VPS) using (15)O positron emission tomography ((15)O-PET).

METHODS

Eight patients with idiopathic normal pressure hydrocephalus (i-NPH) underwent VPS. A (15)O-PET study was undertaken before and approximately 3 months after VPS. In five patients, the symptoms improved based on the classification by Krauss et al. [Neurosurgery 1996;39:292] (good responders) after VPS. In three patients, the symptoms improved subjectively following VPS (poor responders). The changes in oxygen metabolism before and after VPS were analyzed.

RESULTS

The postoperative regional cerebral metabolic rate of oxygen (rCMRO(2)) of the good responders increased significantly. The postoperative regional oxygen extraction fraction (rOEF) is reduced in the poor responders.

CONCLUSION

The improvement of rCMRO(2) correlated with the response to VPS. Significant changes in rOEF might predict poor response to VPS.