Computerized Tomographic Study of Normal Evans Index in Adults at University of Gondar Comprehensive Specialized Hospital, North West Ethiopia, Gondar 2019

Introduction: Evans indexis one of the most important parameter in diagnosis of hydrocephalus, follow up cases of ventriculoperitoneal shunt, dementia and numerous other pathologies. In this situation, having a standard reference value of the Evan's index will be supportive in a wide extent of clinical pathologies. The main objective of this study was to establish normal values for Evans index in a population of North West Ethiopia as there is no study found in Ethiopian medical literature. Methods: Computerized tomographic brain scans of 169 normal subjects were reviewed. Evan's index was measured as the direct proportion of the most extensive frontal horn tips diameter of the cerebral lateral ventricles to the most extensive internal distance across the cranium. Results: In this study, 123(72.78) of the patients were males and 46 (27.22%) were females; their ages ranged from 18 to 79 years with a mean age of 40 years. The mean value for Evans index for the studied population was 0.262 ± 0.03. The Evan's index increased with age and it was slightly higher among males. The difference in Evans value in males and females was not statistically significant. People over 60 years old had the highest Evans values in both genders. Conclusion: This study found the ranges of normal value for Evans index in north west Ethiopian population. It agrees with the diagnostic cut-off value of > 0.3 for hydrocephalus.