Cerebral Hemodynamics in Hydrocephalus During Infancy: Experimental and Clinical Studies

Summary

We carried out a series of experimental and clinical studies in an attempt to clarify the cerebral hemodynamics of hydrocephalus during infancy. Experimental hydrocephalus was induced in SD-JCL rats by the transplacental administration of N-methyl N-nitrosourea (MNU). Postnatal change of cerebral blood flow (CBF) was assessed by the hydrogen clearance method. Angioarchitecture was studied by India ink injection and the resin cast method. Clinically, in 30 infants, the threshold of the cerebral perfusion pressure (CPP) related to the intracranial pressure situation was assessed by computerized analysis. In 34 infants with hydrocephalus, the distribution pattern of CBF was assessed with N-isopropyl-p-[123-I]iodoamphetamine single photon emission computed tomography (CT) before and after shunting. In MNU-induced hydrocephalic rats, during the first postnatal week, CBF was progressively reduced to 27.5% of the control value then later up to 65% of the control values were regained, Angioarchitecture showed the relative increase of precapillary anastomotic channels with a reduction of capillaries. Clinically, the age-related threshold level of CPP which tightened the intracranial cavity was shown. Although in neonatal hydrocephalus, frontally dominant reduction of CBF was more evident that in the controls, after 4 months of age this pattern was detected only in those with rapidly progressive hydrocephalus. These results indicate the critical role of the microcircualtion in the impaired cerebral hemodynamics of hydrocephalus during infancy.