Type of Article:  Original Research

Volume 8; Issue 1.1 (January 2020)

Page No.: 7212-7216

DOI: https://dx.doi.org/10.16965/ijar.2019.341


Lohani M 1, Sehgal G *2, Pasricha N 3, Stapak E 4, Mishra SK 5.

1 Assistant Professor, Department of Anatomy, Prasad Institute of Medical Sciences, Lucknow, India.

*2 Associate Professor, Department of Anatomy, King George’s Medical University, U.P., Lucknow, India.

3 Associate Professor, Department of Anatomy, Dr Ram Manohar Lohia Institute of Medical   Sciences, Lucknow, India.

4 Assistant Professor, Department of Anatomy, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India.

5 Consultant & Head, Department of Anaesthesia, Charak Hospital &Research Centre, Dubagga, Lucknow, India.

Corresponding Author: Dr. Garima Sehgal, Associate Professor, Department of Anatomy, King George’s Medical university, U.P., Lucknow- 226003, India. Mobile: 9044513758   E-Mail: drgarimabhasin@gmail.com


Background: As the humans age, there is decrease in size of brain tissue, increase in cerebrospinal fluid volume and enlargement of ventricles. Brain ventricles can be studied by taking linear, planimetric or volumetric measurements. Linear ratios of width of ventricles to the width of skull or brain are considered to be an easy and reproducible measurement for assessment of ventricles. Evans’ index is one such linear ratio; it is the ratio of maximum width of frontal horns and maximum transverse internal diameter of skull in the same plane.

Purpose of study: The purpose of our study was to obtain a baseline data of reference values of Evans index, in healthy north Indian population.

Materials and Methods: This study was jointly conducted by Department of Anatomy and Department of Radiodiagnosis, King George’s Medical University, U.P, Lucknow. Axial CT scans of head region reported radiologically normal, belonging to 100 individuals of different age groups were retrospectively collected and thoroughly analyzed using Radiant DICOM Viewer Software. Study subjects were categorized into V groups as per age: 18-30years, 31-40years, 41-50years, 51-60years and above 60years. Evans’ index was calculated.

Results: Among study subjects, Evans’index ranged from 0.167 to 0.29 with a mean value of 0.23±0.02. No significant association was observed between age and mean Evans’ Index (p>0.05). Mean Evans’ index was equal for male and female and was not found to change with age.

Conclusion: Study provided values for normal range of Evans’ index and proposes age dependent values of the same for healthy adult males and females. The data could be utilized in routine radiological practice and by others where required.

Key words: Evans’index, Ventricles, CT scan, Linear ratio, Brain.


  1. Jack Jr CR, Shiung MM, Weigand SD, O’Brien PC, Gunter JL, Boeve BF.Brain atrophy rates predict subsequent clinical conversion in normal elderly and amnestic  MCI, Neurology 2005;65(8):1227-1231.
  2. LeMay M. Radiologic Changes of the Aging Brain and Skull. AJNR 1984;5:269-275.
  3. Sherman JL, Citrin CM, Gangarosa RE, Bowen BJ. The MR appearance of CSF flow in patients with ventriculomegaly. AJR Am. J. Roentgenol 1987;148(1):193-199.
  4. Evans WA, Jr. An encephalographic ratio for estimating the size of the cerebral ventricles: Further experience with serial observations. Am J Dis Child. 1942;64:820–30.
  5. Synek V, Reuben JR, Du Boulay GH. Comparing Evans’ index and computerized axial tomography in assessing relationship of ventricular size to brain size. Neurology 1976;26(3):231-233.
  6. Relkin N, Marmarou A, Kline P, Bergsneider M, Black PM. Diagnosing idiopathic normal pressure hydrocephalus. Neurosurgery 2005;57(3 suppl):S4-S16.
  7. Hahn FJY, Rim K. Frontal ventricular dimensions on normal computed tomography. AJR 1976;126:492-496.
  8. De Carli C, Kaye JA, Horwitz B, Rapoport SI. Critical analysis of the use of computer-assisted transverse axial tomography to study human brain in aging and dementia of Alzheimer type. Neurology 1990;40(6):872-883.
  9. Gawler J, DuBoulay GH, Bull JHD, Marshall J. Computerized tomography: comparison with pneumoencephalography and ventriculography. J Neurol Neurosurg Psychiatry 1976; 39: 203-11.
  10. Gyldensted C. Measurements of the normal ventricular system and hemispheric sulci of 100 adults with computed tomography. Neuroradiology 1977;14:183-192.
  11. Jacoby RJ, Levy R, Dawson JM. Computed Tomography in the elderly: The normal population. BJPsych 1980;136:249-255.
  12. D’Souza DMC, Natekar PE. Validity of criteria for estimating the ventriculo-hemispheric ratio of the brain by Computerised Tomography. J Anat Soc India 2010;59(1):6-11.
  13. Karakas P, Koc Z, Koc F, Gulhal Bozkir M. Morphometric MRI evaluation of corpus callosum and ventricles in normal adults. Neurol Res 2011;33(10):1044-9.
  14. Patnaik P, Singh V, Singh S, Singh D. Lateral ventricle ratios correlated to diameters of cerebrum-A study on CT scans of head. J Anat Sciences 2014 ;22(2):5-11.
  15. Reddy VU, Hegde KV, Agrawal A, Pathapati RM, Arumulla M. Normative values for Evan’s index on CT scan for apparently healthy individuals. J Anat Soc India 2015;64:137-140.
  16. Hamidu AU, Olarinoye-Akorede SA, Ekott DS, Danborno B, Mahmud MR, Balogun MS. Computerized tomographic study of normal Evans index in adult Nigerians. J Neurosci Rural Pract 2015;6(1):55-8.
  17. Missori P, Rughetti A, Peschillo S, Gualdi G, Di Biasi C, Nofroni I et al. In normal ageing ventricular system never attains pathological values of Evans’ Index. Oncotarget 2016;7(11):11860-11863.
  18. Brix MK, Westman E, Simmons A, Ringstad GA, Eide PK, Wagner-Larsen K et al. Evans’ index revisited. New cut-off levels for use in radiological assessment of ventricular enlargement in the elderly. Eu J Radiol 2017;95:28-32.

Cite this article: Lohani M, Sehgal G, Pasricha N, Stapak E, Mishra SK. EVANS’ INDEX IN HEALTHY NORTH INDIAN POPULATION: A COMPUTED TOMOGRAPHIC STUDY. Int J Anat Res 2020;8(1.1):7212-7216. DOI: 10.16965/ijar.2019.341