Corpus Callosum

Corpus Callosum

The corpus callosum is the largest white matter structure in the brain and serves as the primary connection between the left and right cerebral hemispheres. By facilitating communication between corresponding cortical regions, it plays a crucial role in the integration of sensory, motor, and cognitive information. The corpus callosum contributes to a wide range of higher-order functions, including attention, processing speed, language, learning, memory, and executive functioning. Recent studies have suggested that radiation-induced injury to the corpus callosum may be associated with declines in attention, information processing speed, and other cognitive functions. As a result, there is growing interest in evaluating radiation dose to this structure and its potential relationship with neurocognitive outcomes following brain irradiation.

Co-registration with a T1-weighted MRI is recommended to facilitate accurate identification of the structure. The corpus callosum is most easily visualized on the sagittal plane, where it appears as a characteristic C-shaped white matter bundle. It measures approximately 10 cm in length and typically 5–10 mm in thickness. Anatomically, it can be divided into the rostrum, genu, body, and splenium.

Key anatomical landmarks include:

• Superior border: the interhemispheric fissure (falx cerebri) and the cingulum.
• Inferior border: the septum pellucidum and fornix medially, and the lateral ventricles laterally.
• Anterior border: curves anteriorly in front of the septum pellucidum and continues towards the lamina terminalis.
• Posterior border: terminates superior to the vein of Galen region.
• Lateral borders: defined at the level of the lateral borders of the lateral ventricles.

Because the corpus callosum extends across the midline and closely neighbours several important limbic and ventricular structures, careful review in the sagittal, coronal, and axial planes is recommended to ensure accurate delineation of its full extent.

The accompanying video demonstrates a step-by-step approach for identifying and contouring the corpus callosum using anatomical landmarks on MRI. This educational resource is intended to support consistent, accurate, and reproducible delineation for clinical and research applications.

Please site as follows:

Hofstede, D., Di Perri, D., Roelofs, E., Postma, A., Troost, E., & Eekers, D. EPTN International Neurological Contouring Atlas (INCA) instruction videos. CancerData, 2022. doi:10.17195/candat.2022.02.1