HIGH-ENERGY PHOSPHATE-METABOLISM IN A NEONATAL MODEL OF HYDROCEPHALUSBEFORE AND AFTER SHUNTING

The authors studied the effects of hydrocephalus on the high-energy ph osphate metabolism of the brain and the impact of ventriculoperitoneal (VP) shunting on these changes in an experimental model of hydrocepha lus. High-energy phosphate metabolism was analyzed using in vivo magne tic resonance (MR) imaging and P-31 MR spectroscopy. Hydrocephalus was produced in 34 1-week-old kittens by cisternal injection of 0.05 mi o f a 25% kaolin solution. Sixteen litter mates were used as controls. A VP shunt with a distal slit valve was implanted in 17 of the 34 hydro cephalic animals 10 days after induction of hydrocephalus. Both MR ima ging and P-31 MR spectroscopy were obtained 1 and 3 weeks after either kaolin or distilled water injection. Untreated hydrocephalic animals had marked dilatation of the lateral ventricles and periventricular ed ema. Magnetic resonance spectroscopy showed a significant decrease in the energy index ratio of phosphocreatine (PCR): inorganic phosphate ( PI) and an increase in the PI:adenosine triphosphate (ATP) ratio. Ther e was a direct correlation between the decrease in the energy index an d ventricular size. Compared with preoperative scans, shunted animals showed no periventricular edema, and the ventricles decreased in size. Also, PCR:PI and PI:ATP ratios were within the levels of controls. Th is study suggests that neonatal hydrocephalus results in a mild hypoxi c/ischemic insult that is treatable by VP shunting.