Neuroimaging in Mild TBI

Alexander (1995) provided an excellent overview of mild traumatic brain injury (TBI) wherein he discussed pathophysiology, natural history, and clinical management of this disorder. In his review of mild TBI, Alexander stated that “by common clinical agreement, neuroimaging studies are negative, but this defining characteristic may be more complex than just positive or negative findings on CT” (p. 1253). Accordingly, traditional neuroimaging in mild TBI usually does not demonstrate major abnormalities or structural defects; however, some abnormalities may be present, and new neuroimaging techniques or refinements of existing techniques have the potential to reveal subtle abnormalities associated with mild TBI. Because of potential complications associated with any TBI, the majority of mild TBI cases do receive standard neuroimaging at some point in the course of their clinical work-up. This chapter briefly reviews the status of neuroimaging in mild TBI. However, before neuroimaging of mild TBI is presented, the typical acute and chronic imaging findings in more severe injury are presented for comparison. This chapter only discusses neuroimaging findings from computerized tomography (CT), magnetic resonance (MR) imaging, and cerebral perfusion studies. These are currently the neuroimaging methods in use for clinical investigations for the effects of cerebral trauma. For details concerning imaging methods and clinical interpretation the reader is referred to Bigler (1996a, 1996b), Gean (1994), and Osborn (1994).