Degeneration of cingulum and fornix in a patient with traumatic brain injury: diffuse tensor tractography study.

Abstract

The cingulum and fornix are important structures for memory function. Using follow-up diffusion tensor tractography in a patient with traumatic brain injury we found degeneration of the cingulum and fornix. An 18-year-old male who had had a traffic accident underwent conservative management for diffuse axonal injury. Brain magnetic resonance imaging showed an encephalomalactic lesion in the posterior portion of the corpus callosum. The patient had severe cognitive problems at 3 months after onset. However, while his intelligence had improved, his memory impairment had been aggravated at 14 months from onset. On the first diffusion tensor tractographies, the integrity of both corticospinal tracts, right cingulum, and left fornix were preserved; however, compared with controls, there were disruptions in both ends of the left cingulum and right fornical crus. On the second diffusion tensor tractographies, both the cingulum and fornix showed severe degeneration, although the integrities of both corticospinal tracts were well preserved. We conclude that patients with memory impairment following traumatic brain injury should be evaluated using diffusion tensor imaging. In addition, follow-up diffusion tensor imaging may be necessary in patients with sustained memory impairment.