Evans index among adult Ghanaians on normal head computerized tomography scan

Abstract

Introduction: Normal-Pressure Hydrocephalus (NPH) is a neurological condition which is made up of a clinical triad of gait disturbance, dementia and urinary incontinence and can be reversed by ventricular shunting. Currently, some guidelines suggest the use of Evans' index (EI) for diagnosis of hydrocephalus radiologically. Most of the studies are based on the Western population data. None of these studies have been performed in the Ghanaian population setting yet. The aim of this study was to quantitatively establish normal borderline value for Evans Index in the Ghanaian adult population with respect to age and sex. Methods: This study was retrospectively conducted on normal enhanced head CT scan images of 266 males and 241 females. EI was calculated as the linear ratio of Maximum Anterior Horn Width (MAHW) of the frontal horns of the lateral ventricles at the level of foramina of Monroe and the Maximum Intracranial Diameter (MICD) of the inner skull. Student T-test, ANOVA and Pearson's correlation were used to analyze the data. A test for a relationship was performed with a scatter plot and a linear regression was performed based on age, sex and different EI of ventricular size. Results: The mean and median value of EI was 0.24 AE 0.02. There was no statistically significant difference in the EI values between males and females, (p-value ¼ 0.61). A steady increase in EI with age was observed. There was a strong correlation coefficient r ¼ 0.89 of EI and age, which suggested a strong linear relationship between EI and Age. The overall linear relationship model was EI ¼ 0.1879 þ 0.0011*Age. Conclusions: The mean EI of 0.24 AE 0.02 in our study agrees with adapted international guidelines cut-off value for normal adult patients of (<0.30) and can be a useful tool in determining ventricular enlargement particularly in resource limited settings.

Mean Evan's Index among Patients with Normal Computed Tomography Scan visiting Radiology Department in a Tertiary Care Centre of Nepal: A Descriptive Cross-sectional Study

“…3 However the study in Ghanaians, Nigerians and South Indian population did not show any statistical difference. [6][7][8] The mean values for both sexes are within the normal cutoff of 0.3 for Evan's index in our study.…”

In search of subcortical and cortical morphologic alterations of a normal brain through aging: an investigation by computed tomography scan

“…Several studies have referred to the positive relationship between aging and ventricular indices changes [3][4][5][11][12][13]. Currà et al [4] investigated three ventricular indices in more than 3,000 brain scans, and reported earlier ventricular enlargement in males than females, and also demonstrated sig- Since the literature review suggests the significance of ventricular symmetry [14,15], it was also investigated in our study.…”

“…Several studies have referred to the positive relationship between aging and ventricular indices changes [ 3 - 5 , 11 - 13 ]. Currà et al [ 4 ] investigated three ventricular indices in more than 3,000 brain scans, and reported earlier ventricular enlargement in males than females, and also demonstrated significant changes in Evans, bitemporal, and parieto-occipital indices at the ages of 79, 83, and 87 years, respectively.…”