Quantitative CT ventriculography for Assessment and Monitoring of Hydrocephalus: a Pilot Study and Description of Method in Subarachnoid Hemorrhage (SAH)

Abstract Background There is no facile quantitative method for monitoring hydrocephalus (HCP). Objective We propose quantitative CT ventriculography (qCTV) as a novel computer vision tool for empirically assessing HCP in patients with subarachnoid hemorrhage (SAH). Methods Twenty patients with SAH who were evaluated for ventriculoperitoneal shunt (VPS) placement were selected for inclusion. Ten patients with normal CT head (CTH) were analyzed as negative controls. CTH scans were segmented both manually and automatically (qCTV) to generate measures of ventricular volume. Results Median manually calculated ventricular volume was 36.1cm 3 (IQR 30-115cm 3 ), which was similar to a median qCTV measured volume of 37.5cm 3 (IQR 32-118cm 3 ) (p=0.796). Patients undergoing VPS placement demonstrated an increase in ventricular volume on qCTV from 21cm 3 to 40cm 3 on Day T-2, and 51cm 3 by Day 0, a change of 144%. This contrasts with patients who did not require shunting whose ventricular volumes decreased from 16cm 3 to 14cm 3 on Day T-2, and 13cm 3 by Day 0, with an average overall decrease in volume of 19% (p=0.001). Average change in ventricular volume predicted which patients would require VPS placement, successfully identifying 7/10 patients (p=0.004). Using an optimized cutoff of change in ventricular volume of 2.5cm 3 identified all patients who went on to require VPS placement (10/10, p=0.011). Conclusions qCTV is a reliable means of quantifying ventricular volume and hydrocephalus. This technique offers a new tool for monitoring neurosurgical patients for hydrocephalus, and may be beneficial for use in future research studies as well as the routine care of patients with hydrocephalus.