FDDNP-PET Tau Brain Protein Binding Patterns in Military Personnel with Suspected Chronic Traumatic Encephalopathy1

Abstract

Background: Our group has shown that in vivo tau brain binding patterns from FDDNP-PET scans in retired professional football players with suspected chronic traumatic encephalopathy differ from those of tau and amyloid aggregate binding observed in Alzheimer's disease (AD) patients and cognitively-intact controls.

Objective: To compare these findings with those from military personnel with histories of mild traumatic brain injury(mTBI).

Methods: FDDNP-PET brain scans were compared among 7 military personnel and 15 retired players with mTBI histories and cognitive and/or mood symptoms, 24 AD patients, and 28 cognitively-intact controls. Nonparametric ANCOVAs with Tukey-Kramer adjusted post-hoc comparisons were used to test for significant differences in regional FDDNP binding among subject groups.

Results: FDDNP brain binding was higher in military personnel compared to controls in the amygdala, midbrain, thalamus, pons, frontal and anterior and posterior cingulate regions (p < 0.01-0.0001). Binding patterns in the military personnel were similar to those of the players except for the amygdala and striatum (binding higher in players; p = 0.02-0.003). Compared with the AD group, the military personnel showed higher binding in the midbrain (p = 0.0008) and pons (p = 0.002) and lower binding in the medial temporal, lateral temporal, and parietal regions (all p = 0.02).

Conclusion: This first study of in vivo tau and amyloid brain signals in military personnel with histories of mTBI shows binding patterns similar to those of retired football players and distinct from the binding patterns in AD and normal aging, suggesting the potential value of FDDNP-PET for early detection and treatment monitoring in varied at-risk populations.

Keywords: Alzheimer’s disease; FDDNP-PET; brain tau and amyloid; chronic traumatic encephalopathy; mild traumatic brain injury; military personnel; retired professional football players.

Figures

Fig. 1.

Examples of FDDNP-PET DVR transaxial, coronal, and sagittal images of a cognitively healthy individual, Alzheimer’s disease patient, football player, and a military subject. The Alzheimer’s disease patient shows higher DVR signals in parietal, temporal and frontal regions compared to the healthy individual, who may have neuropathology deposition given the age of the subject (80 years) [11]. The football player and military subject show higher amygdala, midbrain, and other subcortical binding compared with the healthy individual and Alzheimer’s disease patient. The healthy individual showed some mild cortical binding typical of other healthy individuals age 70 and older (or darker shades in greyscale) [10]. Warmer colors (or darker shades in greyscale) indicate higher FDDNP binding.

Fig. 2.

FDDNP DVR parametric images of the brains of two war veterans with histories of multiple blast concussions (mTBIs) during their war zone deployment. The upper row shows a 48-year-old man (veteran 24010) and the lower row a 36-year-old man (veteran 24011). Left four images in each row show transaxial brain images from top of the brain to the bottom. The right image shows a coronal cut through the midbrain. (This figure was originally published in Barrio et al., 2015 [16].)