Analyze hippocampus, amygdala, and thalamus volumes in patients who have had TBI at least 6 months prior and are undergoing neurologic evaluations.

Traditional CT and structural MR imaging is commonly unrevealing in patients with chronic complaints after TBI, particularly in those who did not experience prolonged coma.  Previous studies in patients with moderate to severe diffuse axonal injury have shown that the hippocampus, amygdala, and thalamus commonly show atrophy post-TBI. Neuroquant® (CorTechs Labs, San Diego, CA) is an automated analytical pipeline suitable for routine clinical use which has been widely utilized for quantitative volumetric assessments in neurodegenerative conditions, including Alzheimer’s disease and multiple sclerosis.   

58 TBI patients evaluated at a specialty TBI Clinic were studied. All had MR imaging conducted more than six months after their index TBI. 3D T1 MRI scans were processed through Neuroquant® to obtain volumetric measurements and normative percentiles for 25 regions of interest. Hippocampus, amygdala, and thalamus normative percentiles were then used to assess regional atrophy. Volumetric results were correlated with functional outcomes and symptoms self-reports.

Atrophic regions were defined as those at or below the 5^th percentile for age and gender.  Of the 58 subjects, 19 (33%) demonstrated atrophy in at least one of the three structures analyzed (RR 1.7, p = 0.0025).  8 (14%) showed atrophy in a single region, while 11 (19%) showed atrophy in 2 or more regions.  Patients with at least one atrophic brain region experienced some degree of post-traumatic disability.

Quantitative analysis of regional brain volumes can be used to identify structures that exhibit atrophy after TBI.  Analysis pipelines such as Neuroquant® may be useful for the evaluation of chronic TBI in clinical settings.