Normative Evaluation of Evans Index and Bicaudate Index in a Tertiary Care Centre of Uttarakhand: A Cross-Sectional MRI Study

Abstract Background: Evans index (EI) and bicaudate index (BCI) are two simplified linear indices that are widely used to assess brain ventricle measurement to diagnose hydrocephalus. The establishment of normal values of these indices plays a significant role in making early diagnosis of brain ventricle enlargement and analysing patterns of age- and sex-related changes. This study was done to establish baseline values of EI and BCI in adults attending a tertiary health care center and to evaluate their variation with age and sex. Methodology: A total of 84 patients, comprising 42 males and 42 females aged 16–75 years, were enrolled in this cross-sectional study, who underwent magnetic resonance imaging (MRI) brain for various indications and were found to be normal for age and gender. EI and BCI were measured on magnetic resonance images by using DICOM viewer 2024. Data were analyzed on SSP-22 for sex- and age-wise variation and correlation between indices. Results: Mean EI was 0.25 ± 0.017 in males and 0.24 ± 0.021 in females ( P = 0.045). Mean BCI was 0.11 ± 0.014 in males and 0.09 ± 0.020 in females ( P < 0.001). Both indices showed a progressive increase with age. A notable positive correlation was observed between the EI and BCI ( R = 0.461, P < 0.001), most prominent in males in the age group 16–25 years. Conclusions: EI and BCI both increase with age and are markedly higher in males. Their strong correlation, particularly in young adult males, demonstrates their synergistic role in evaluating age-related and potentially pathological brain ventricle changes.