Michael Lipton MD, PhD, Presenter: Nothing to Disclose

Erik Leonard Gellella MD, Abstract Co-Author: Nothing to Disclose

Tamar Gold BA, Abstract Co-Author: Nothing to Disclose

Keivan Shifteh MD, Abstract Co-Author: Nothing to Disclose

Calvin Lo MD, Abstract Co-Author: Nothing to Disclose

Babak Ardekani PhD, Abstract Co-Author: Nothing to Disclose

Craig A. Branch PhD, Abstract Co-Author: Nothing to Disclose

Jacqueline Anne Bello MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Following mild traumatic brain injury (mTBI), most patients recover, but as many as 15-30% develop persistent cognitive and behavioral deficits. Two features of mTBI impede early diagnosis: (1) imaging is typically normal and (2) clinical deficits may not manifest initially. It is thought that mTBI lesions evolve over weeks to months due to a response to the initial injury including cellular events such as excitotoxicity and inflammation. The full extent of lesions may not manifest at the time of injury, even on pathological analysis. We previously reported evidence of acute white matter abnormalities in mTBI using diffusion tensor imaging (DTI). The present study shows that acute mTBI lesions evolve during follow-up, supporting the concept that injury can be detected, though not fully manifest, initially.

5 patients (ages 18-50) were studied 2 weeks and 3 months following mTBI (GCS 13-15, LOC < 30 minutes, no clinical deficit, normal CT scan). Voxel-wise partial correlation analysis (p<0.001) of DTI images (3.0 T, 32 directions, b=1000) was used to compare patient FA at each time point to a matched control group. Next, a within subjects design was used to assess change in patient FA over 3 months of follow-up.

No evidence of hemorrhage or signal abnormality was present on conventional MRI images. Initially and at 3 months, multiple foci of decreased FA were present in the patient group. Deep and superficial white matter was predominantly affected as well as corpus callosum, brainstem and cerebellum. Within subjects measures demonstrated two subsets of lesions: one group showed increase in FA over time, consistent with improvement of initial injury. Importantly, a second subset of lesions showed decline in FA over time. These results support the concept of mild TBI as a dynamic, evolving pathologic process.

DTI identifies the evolution of initially detected white matter abnormalities upon 3 months follow-up, underscoring the dynamic nature of mTBI.

The findings have major clinical implications: they may identify a therapeutic window when imaging can direct treatment prior to the development of irreversible pathology and clinical deficits.

Lipton, M, Gellella, E, Gold, T, Shifteh, K, Lo, C, Ardekani, B, Branch, C, Bello, J, et al, , et al, , Evolution of Diffusion Tensor Imaging (DTI) Findings after Mild Traumatic Brain Injury (mTBI): Implications for Treatment of a Major Public Health Problem.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5006740.html