Evaluation of the Evan's and Bicaudate Index for Rural Population in Central India using Computed Tomography

Evans index (EI) and Bicaudate index (BCI) are practical markers of ventricular volume and are helpful radiological markers in the diagnosis of normal pressure hydrocephalus. Worldwide, variation exists in normative studies for both these indices. Most of the studies conducted for EI and BCI are based on the Western population data. No study has been performed on the rural population of Central India. The purpose of this study is to develop normative data on EI and BCI that can be extrapolated for future reference.

This was a retrospective study conducted from December 2018 to May 2019 in MGIMS Hospital, Sevagram, Maharashtra, India, which is a rural hospital in Central India. All patients with either a head injury or neurological complaints although with normal computed tomography (CT) brain were included in the study. Patients with diagnosed neurological disorder, clinical features suggesting hydrocephalus, or intracranial pathology on CT brain were excluded from the study. Five hundred and eleven patients were selected for this study, and EI and BCI was calculated for them.

The mean value of EI and BCI in our study was 0.2707 and 0.1121, respectively. Both indices showed a statistically significant difference between males and females. The value of both indices increased with age.

Although our study is in agreement with the cutoff value of EI to diagnose dilated lateral ventricles as 0.3 for age <70 years, cutoff value of EI for the older population should be reconsidered to 0.34.