An MRI-Based Normative Morphometric Atlas of the Corpus Callosum and Ventricular System in a Northwestern Nigerian Population: A Descriptive Cross-sectional Study

Background: Accurate morphometric definition of the corpus callosum (CC) and ventricular system is important for clinical neuroradiology and neuroanatomic research. Northwestern Nigeria lacks population-specific normative MRI data for adults, limiting accurate anatomical interpretation and diagnostic accuracy. Objective: To determine the MRI-based morphometric dimensions of the corpus callosum and ventricular system among neurologically normal adults in Northwestern Nigeria. Methods: A retrospective cross-sectional study of 422 MRI scans of adults (18 to 80 years) from Usmanu Danfodiyo University Teaching Hospital, Sokoto. Using sagittal T1-weighted and axial T2-weighted sequences, CC (rostrum, genu, body, and splenium) and ventricular subregions (lateral, third, and fourth ventricles; frontal and posterior horns) were identified. Measurements followed standardised protocols. Sex-stratified descriptive statistics and percentile-based reference ranges (2.5th-97.5th) were assessed. Results: The anteroposterior length of the CC was approximately 68.1 mm to 81.3 mm, and other sub-regions of the callosal region exhibited low dispersion, implying that there is a stable midline morphology. An increased range of variance was observed in the ventricular dimensions, with a mean lateral ventricular width of 8.01 ± 0.799 mm, a third ventricular width of 4.19 ± 0.869 mm, and a frontal horn width of 33.32 ± 0.264 mm. A normative percentile range of all the CC and ventricular measurements was established. Conclusion: This study presents the first comprehensive MRI-based normative morphometric atlas of the corpus callosum and ventricular system for adults in northwestern Nigeria. Such reference data promote anatomical understanding and aid accurate neuroradiological analysis in clinical practice.