Abstract
Corpus callosum (CC) is the largest brain commissure interconnecting the left and right cerebral hemisphere. It consists of fibers projecting mainly to homotopical cortical regions and is well visualized on the conventional MR scans.
The main types of callosal abnormalities are congenital defects, signal changes and atrophy, where the first two are rarely unnoticed and unreported - contrary to atrophy, which is frequently attributed to the old age only. Aside from age-related involution, callosal atrophy may be caused by a broad spectrum of pathological conditions damaging either white or gray matter.
Demyelinating conditions lead to CC atrophy by primary damage of white matter. Loss of cortical neurons and subsequent wallerian degeneration lead to loss of axons projecting through CC and its secondary atrophy.
Because fibers in CC are topographically arranged, loss of neurons in certain cortical regions corresponds to loss of fibers (and thus loss of volume) in certain segments of CC, resulting in regional callosal atrophy. The aim of this article is to provide a broader view on the atrophy of corpus callosum, present its differential diagnosis and potential practical use.