Morphometric Analysis of Age and Genderrelated Variations of Corpus Callosum by using Magnetic Resonance Imaging: A Cross-sectional Study

Introduction: The Corpus Callosum (CC) is the largest commissural bundle connecting the two cerebral hemispheres which is involved in learning, memory, thinking, three-dimensional visual ability, executive functions as well as behavioural patterns. Exact morphometric dimensions are a prerequisite before surgical interventions and stereotactic approaches to the foramen of Munro and also in cases of callosectomy for intractable epilepsy as inconsistencies exist regarding gender and age related changes of CC. Also, most published studies are from the western world and very few studies are from South-east Asia and India.

Aim: To study the morphometry of CC and possible age, gender related variations using Magnetic Resonance Imaging (MRI) in the North Indian population.

Materials and Methods: An observational, cross-sectional study was done in Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India from January 2019 to October 2019. A total of 200 head MRI scans, using PACS (Picture Archiving and Communication System) System Viewer software were evaluated. In all the scans, length, height, minimum and maximum thickness of CC were studied. The data were statistically analysed using STATA Software for age and gender-related differences. Student’s t-test, one-way Analysis of Variance (ANOVA), linear regression and Pearson correlation coefficient were applied.

Results: The study showed decrease in thickness of body, rostrum and splenium with age, linked to generalised degeneration of cortical neurons or atrophy of white matter with advancing age. Also, there was increase in length with age, possibly due to age mediated structural dilatation in lateral ventricles. Statistically significant sexual dimorphism was observed as a larger CC length in males (74.24±4.26 mm) than females (72.67±4.16 mm) (p-value<0.001) and larger brain length in males (171.75±5.51 mm) as compared to females (163.70±5.75 mm) (p-value<0.001). Males also showed greater splenial thickness (10.15±1.79 mm) in comparison to females (9.68±1.51 mm) (p-value<0.001) which may represent the importance of distribution of fibres of visual cortex in males due to larger occipital lobe.

Conclusion: The present study documented morphometry of normal CC in different gender and age groups and observed sexual dimorphism, especially greater CC length and splenial thickness in males than females. With age increase in the length and decrease in thickness of CC was seen.