Normative MRI Morphometry of the Adult Corpus Callosum: Age- and Sex-Specific Variations in 250 Individuals

Background: Corpus callosum dimensions vary with age, sex, brain size, and population characteristics. Population-specific magnetic resonance imaging reference values are therefore important for differentiating normal anatomical variation from pathological alterations. The objective is to establish normative MRI-based morphometric values of the corpus callosum in adults and evaluate their relationships with age, sex, and forebrain volume. Material and Methods: This cross-sectional observational study included 250 adults aged 18–80 years with normal brain MRI findings. Corpus callosum length, height, midsagittal area, genu thickness, body thickness, splenium thickness, and corpus callosum index were measured on true midsagittal T1-weighted images. Forebrain volume was estimated using a modified ellipsoid formula. Participants were stratified according to age and sex, and sex-specific normograms were developed. Results: The study included 111 males and 139 females, with a mean age of 49.0 ± 17.9 years. Mean corpus callosum length, height, and midsagittal area were 70.93 ± 1.20 mm, 24.04 ± 1.10 mm, and 586.9 ± 25.0 mm², respectively. Regional thickness followed the pattern genu > splenium > body. Corpus callosum area demonstrated a strong positive correlation with forebrain volume (r = 0.873). Callosal length remained relatively stable across adulthood, whereas height, area, and regional thickness progressively decreased with advancing age. Sex-related differences were limited. Conclusion: The study provides normative MRI-based reference values and age- and sex-specific normograms for adult corpus callosum morphometry. These data may aid the radiological assessment of callosal atrophy in neurodegenerative, demyelinating, developmental, and other neurological disorders.

Keywords: Corpus callosum; magnetic resonance imaging; morphometry; normative data; ageing; sex differences; forebrain volume.