Diffusion tensor imaging in mild traumatic brain injury litigation.

A growing body of literature addresses the application of diffusion tensor imaging (DTI) to traumatic brain injury (TBI). Most TBIs are of mild severity, and their diagnosis and prognosis are often challenging. These challenges may be exacerbated in medicolegal contexts, where plaintiffs seek to present objective evidence that supports a clinical diagnosis of mild (m)TBI. Because DTI permits quantification of white matter integrity and because TBI frequently involves white matter injury, DTI represents a conceptually appealing method of demonstrating white matter pathology attributable to mTBI. However, alterations in white matter integrity are not specific to TBI, and their presence does not necessarily confirm a diagnosis of mTBI. Guided by rules of evidence shaped by Daubert v. Merrell Dow Pharmaceuticals, Inc., we reviewed and analyzed the literature describing DTI findings in mTBI and related neuropsychiatric disorders. Based on this review, we suggest that expert testimony regarding DTI findings will seldom be appropriate in legal proceedings focused on mTBI.