Acquired lesions of the corpus callosum: MR imaging
In this pictorial review, we illustrate acquired diseases or conditions of the corpus callosum that may be found by magnetic resonance (MR) imaging of the brain, including infarction, bleeding, diffuse axonal injury, multiple sclerosis, acute disseminated encephalomyelitis, Marchiafava-Bignami disease, glioblastoma, gliomatosis cerebri, lymphoma, metastasis, germinoma, infections, metabolic diseases, transient splenial lesion, dilated Virchow-Robin spaces, wallerian degeneration after hemispheric damage and focal splenial gliosis. MR imaging is useful for the detection and differential diagnosis of corpus callosal lesions. Due to the anatomical shape and location of the corpus callosum, both coronal and sagittal fluid-attenuated inversion recovery images are most useful for visualizing lesions of this structure.
KeywordsCorpus callosumAcquired lesionMagnetic resonance imaging
The corpus callosum is a large white matter tract connecting the two cerebral hemispheres. Thus, numerous connecting fibers pass through the corpus callosum. Recently developed diffusion tensor imaging is useful for the identification of these fiber tracts . The fibers comprising the corpus callosum are more dense than those of the periventricular or deep white matter. The corpus callosum can be involved in many acquired diseases and conditions. Patients with a callosal lesion usually have severe clinical symptoms. Thus, the differential diagnosis of these lesions by means of magnetic resonance (MR) imaging is clinically important.
The purpose of this pictorial review is to describe the various types of acquired lesions that can appear in the corpus callosum on MR images. To our knowledge, there are few previous reports on this topic [2, 3]. We reviewed images obtained from many patients with acquired corpus callosal lesions diagnosed by MR imaging. These images included conventional spin-echo T1-weighted, spin-echo or fast spin-echo T2-weighted and fast fluid-attenuated inversion recovery (FLAIR) images obtained by various 1.5– or 1.0–T scanners. In some patients, proton-density (PD)-weighted, T2*-weighted or diffusion-weighted images were also obtained. Axial images were usually obtained, and coronal or sagittal images were obtained occasionally.
Acute disseminated encephalomyelitis
Transient splenial lesion
Dilated Virchow-Robin spaces
Wallerian degeneration after hemispheric damage
Focal splenial gliosis
Acquired corpus callosal lesions include vascular, traumatic, demyelinating, neoplastic and miscellaneous lesions. MR imaging is useful for the detection and differential diagnosis of corpus callosal lesions. Because these lesions are located close to the lateral ventricle, FLAIR images are most useful in their detection. Due to the anatomical shape and location of the corpus callosum, either coronal or sagittal images should be added in the evaluation of corpus callosal lesions.