Splenial Lesions of the Corpus Callosum: Disease Spectrum and MRI Findings

The corpus callosum (CC) is the largest white matter structure in the brain, consisting of more than 200-250 million axons that provide a large connection mainly between homologous cerebral cortical areas in mirror image sites. The posterior end of the CC is the thickest part, which is called the splenium. Various diseases including congenital to acquired lesions including congenital anomalies, traumatic lesions, ischemic diseases, tumors, metabolic, toxic, degenerative, and demyelinating diseases, can involve the splenium of the CC and their clinical symptoms and signs are also variable. Therefore, knowledge of the disease entities and the imaging findings of lesions involving the splenium is valuable in clinical practice. MR imaging is useful for the detection and differential diagnosis of splenial lesions of the CC. In this study, we classify the disease entities and describe imaging findings of lesions involving the splenium of the CC based on our experiences and a review of the literature.