Multimodal PET, Diffusion Tensor Imaging, and Volumetric MRI Findings in Orbitofrontal Cortex Dysfunction: A Quantitative Single-Case Analysis.

Fetal alcohol spectrum disorder (FASD) is a neurodevelopmental condition associated with executive dysfunction and impaired impulse control. When compounded by traumatic brain injury (TBI) and adverse childhood experiences (ACEs), FASD may substantially elevate the risk of violent behavior. This case study examines a 35-year-old violent offender with confirmed FASD, multiple TBIs, and a high ACE score, using multimodal neuroimaging to explore the neurobiological underpinnings of his behavioral pathology. A multimodal approach using 18F-fluorodeoxyglucose (FDG)-PET, diffusion tensor imaging (DTI), and volumetric MRI was employed, with results compared against healthy controls obtained from the Functional Biomedical Informatics Research Network (FBIRN) data repository (n = 16 for PET; n = 42 for DTI/MRI). FDG-PET revealed reduced neocortex-to-cerebellum ratios consistent with FASD, alongside hypermetabolism in the cerebellum, posterior cingulate, and superior temporal gyrus, suggesting limbic irritability. DTI demonstrated reduced fractional anisotropy in major white-matter tracts implicated in executive function, while volumetric MRI revealed enlargement of the right putamen and increased relative volumes in the hippocampus and amygdala. Findings suggest that FASD-related abnormalities, compounded by head trauma and early adversity, may contribute to violent behavior. This case underscores the forensic value of integrating PET, DTI, and MRI to inform neuropsychiatric evaluation and risk assessment in high-risk offenders.