Evidence of increased brain amyloid in severe TBI survivors at 1, 12, and 24 months after injury: report of 2 cases

Traumatic brain injury (TBI) is a major risk factor for Alzheimer’s disease. With respect to amyloid deposition, there are no published serial data regarding the deposition rate of amyloid throughout the brain after TBI. The authors conducted serial 18F-AV-45 (florbetapir F18) positron emission tomography (PET) imaging in 2 patients with severe TBI at 1, 12, and 24 months after injury. A total of 12 brain regions were surveyed for changes in amyloid levels. Case 1 involved a 50-year-old man who experienced a severe TBI. Compared with the 1-month time point, of the 12 brain regions that were surveyed, a decrease in amyloid (as indicated by standard uptake value ratios) was only observed in the hippocampus (−16%, left; −12%, right) and caudate nucleus (−18%, left; −18%, right), suggesting that initial amyloid accumulation in the brain was cleared between time points 1 and 12 months after injury. Compared to the scan at 1 year, a greater increase in amyloid (+15%) was observed in the right hippocampus at the...