Probabilistic mapping and automated segmentation of human brainstem white matter bundles.
Probabilistic mapping and automated segmentation of human brainstem white matter bundles.
Where did the research take place?
The study site has not been established. Author addresses may differ from where the research occurred.
Tours, FR · Author affiliation
Imaging Brain and Neuropsychiatry iBraiN U1253, Université de Tours, INSERM, Tours 37032, France.Location evidence
London, GB · Author affiliation
Hawkes Institute, University College London, London WC1V 6LJ, United Kingdom.Location evidence
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Original abstract
Brainstem white matter (WM) bundles are essential conduits for neural signals that modulate homeostasis and consciousness. Their architecture forms the anatomic basis for brainstem connectomics, subcortical circuit models, and deep brain navigation tools. However, their small size and complex morphology, compared to cerebral WM, makes mapping and segmentation challenging in neuroimaging. As a result, fundamental questions about brainstem modulation of human homeostasis and consciousness remain unanswered. We leverage diffusion MRI tractography to create BrainStem Bundle Tool (BSBT), which automatically segments eight WM bundles in the rostral brainstem. BSBT performs segmentation on a custom probabilistic fiber map using a convolutional neural network architecture tailored to detect small anatomic structures. We demonstrate BSBT's robustness across diffusion MRI acquisition protocols with in vivo scans of healthy subjects and ex vivo scans of human brain specimens with corresponding histology. BSBT also detected distinct brainstem bundle alterations in patients with Alzheimer's disease, Parkinson's disease, multiple sclerosis, and traumatic brain injury through tract-based analysis and classification tasks. Finally, we provide proof-of-principle evidence for the prognostic utility of BSBT in a longitudinal analysis of traumatic coma recovery. BSBT creates opportunities for scalable mapping of brainstem WM bundles and investigation of their role in a broad spectrum of neurological disorders.