Stability of hippocampal subfield volumes after trauma and relationship to development of PTSD symptoms

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2021-08, Vol.236, p.118076-118076, Article 118076
• Main Authors: Weis, C.N., Webb, E.K., Huggins, A.A., Kallenbach, M., Miskovich, T.A., Fitzgerald, J.M., Bennett, K.P., Krukowski, J.L., deRoon-Cassini, T.A., Larson, C.L.
• Format: Article
• Language: English
• Subjects: Adult; Automation; Biomarkers; Cross-Sectional Studies; Emergency medical care; Female; FreeSurfer; Hippocampal subfields; Hippocampus; Hippocampus - diagnostic imaging; Hippocampus - pathology; Humans; Injuries; Longitudinal Studies; Magnetic Resonance Imaging; Male; Memory; Middle Aged; Morphology; Neuroimaging; Post traumatic stress disorder; PTSD; Reproducibility of Results; Segmentation; Severity of Illness Index; Stress Disorders, Post-Traumatic - diagnostic imaging; Stress Disorders, Post-Traumatic - pathology; Stress Disorders, Post-Traumatic - physiopathology; Test-retest reliability; Trauma; Wounds and Injuries - complications; Young Adult
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2021.118076

•Hippocampal subfields were automatically segmented with FreeSurfer.•Reliability of subfield measurements was assessed using three timepoints.•FreeSurfer preprocessing pipeline had excellent reliability.•Hippocampal subfields were not related to prospective PTSD symptoms. The hippocampus plays a central role in post-traumatic stress disorder (PTSD) pathogenesis, and the majority of neuroimaging research on PTSD has studied the hippocampus in its entirety. Although extensive literature demonstrates changes in hippocampal volume are associated with PTSD, fewer studies have probed the relationship between symptoms and the hippocampus’ functionally and structurally distinct subfields. We utilized data from a longitudinal study examining post-trauma outcomes to determine whether hippocampal subfield volumes change post-trauma and whether specific subfields are significantly associated with, or prospectively related to, PTSD symptom severity. As a secondary aim, we leveraged our unique study design sample to also investigate reliability of hippocampal subfield volumes using both cross-sectional and longitudinal pipelines available in FreeSurfer v6.0. Two-hundred and fifteen traumatically injured individuals were recruited from an urban Emergency Department. Two-weeks post-injury, participants underwent two consecutive days of neuroimaging (time 1: T1, and time 2: T2) with magnetic resonance imaging (MRI) and completed self-report assessments. Six-months later (time 3: T3), participants underwent an additional scan and were administered a structured interview assessing PTSD symptoms. First, we calculated reliability of hippocampal measurements at T1 and T2 (automatically segmented with FreeSurfer v6.0). We then examined the prospective (T1 subfields) and cross-sectional (T3 subfields) relationship between volumes and PTSD. Finally, we tested whether change in subfield volumes between T1 and T3 explained PTSD symptom variability. After controlling for sex, age, and total brain volume, none of the subfield volumes (T1) were prospectively related to T3 PTSD symptoms nor were subfield volumes (T3) associated with current PTSD symptoms (T3). Tl – T2 reliability of all hippocampal subfields ranged from good to excellent (intraclass correlation coefficient (ICC) values > 0.83), with poorer reliability in the hippocampal fissure. Our study was a novel examination of the prospective relationship between hippocampal subfield volumes in relation to PTSD in a large trauma-ex