Trauma to the corpus callosum: MR features.

The frequency, distribution, and appearance of corpus callosum injuries were evaluated with MR and CT in a prospective study of 78 patients with acute (n = 63) and chronic (n = 15) head injuries. Traumatic lesions of the corpus callosum were detected in 47% of patients. MR was significantly (p less than .001) more sensitive than CT in the detection of callosal injuries. MR and CT visualized 100% and 27%, respectively, of the traumatic callosal lesions that were detected in the study population. The majority of lesions were located in the splenium but a few were also found in the body and genu. Patients with callosal injuries had a significantly higher incidence of primary brainstem injury (p less than .02) as well as a greater number of subcortical gray-matter (p less than .05) and diffuse axonal "shear" (p less than .001) lesions. In addition, patients with callosal injuries had a significantly higher incidence of traumatic lesions of the septum pellucidum (p less than .007) and fornix (p less than .001). Intraventricular hemorrhage occurred significantly more often (p less than .002) in patients with callosal injuries, especially if traumatic lesions of the fornix or septum pellucidum were also present. Patients with callosal injuries had significantly lower initial Glasgow Coma Scale scores (mean, 6.6) than those without injuries (mean, 10.7) (p less than .001). Injury to the corpus callosum occurs much more often with nonfatal head injuries than had been believed previously.