Association between ventricular volume measures and pulsatile and static intracranial pressure scores in non-communicating hydrocephalus

Abstract

Background: In non-communicating hydrocephalus (HC), enlarged cerebral ventricles are often thought to reflect increased intracranial pressure (ICP) or increased pulsatile ICP. The present study was undertaken to explore the association between ventricular volume measures and pulsatile or static ICP scores in patients with non-communicating HC. Since linear measures of ventricular size have the most widespread use, we also examined how linear and volume measures of ventricular size compare.

Methods: The patient material includes all patients with non-communicating HC that underwent continuous over-night ICP monitoring during the period 2002-2011. The scores of pulsatile and static ICP were determined from the continuous ICP signals stored on the hospital server. Ventricular volume was determined both as linear measures of sectional CT or MR images and as 3D volume of all ventricles. We also determined the ventricular volume index as a relationship between ventricular volume and intracranial volume.

Results: Eighty-five patients were included in the study; they were dichotomized into those that previously had not received endoscopic third ventriculostomy (ETV; n=52; Group 1), and those that had previously underwent ETV (n=33; Group 2). None was previously shunted. We found no significant correlations between the ICP scores and the ventricular volume indices in neither of the patient groups. In Group 1, however, the mean ICP wave amplitude was significantly higher than in Group 2. There was a strong positive correlation between volume and linear measures of ventricular size. We found neither any association between age and ventricular volume; nor any association between ventricular volume and duration of symptoms.

Conclusions: In this cohort of patients with non-communicating HC, we found no evidence of a proportional correlation between ventricular volume and pulsatile or static ICP. However, the findings suggest that symptomatic and untreated non-communication HC is still associated with reduced intracranial compliance.

Keywords: Hydrocephalus pathogenesis; Non-communicating hydrocephalus; Pulsatile ICP; Static ICP; Ventricular growth; Ventricular volume.