The value of estimating pressure-volume index in childhood macrocephaly. The relationship between pressure-volume index and the volumes of intracranial structures.

In this study on cerebrospinal fluid (CSF) dynamics in childhood macrocephaly, we investigated the relationship between the pressure volume index (PVI) and the volume of various brain structures. The most important variables of CSF dynamics are the outflow resistance (Ro) and the PVI. We applied a constant CSF infusion rate to measure the PVI. The volumes of intracranial structures were calculated by means of computed tomography. Our study revealed no significant correlation between PVI and CSF volume or between PVI and the intracranial volume, as suggested by earlier studies. We did, however, find a significant correlation between PVI and ventricle volume. These results indicate that in order to estimate PVI for clinical purposes, the ventricle volume rather than CSF volume or head circumference should be used.