3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain

M.J. Hoch; M.T. Bruno; A. Faustin; N. Cruz; A.Y. Mogilner; L. Crandall; T. Wisniewski; O. Devinsky; T.M. Shepherd

doi:10.3174/ajnr.A6088

Abstract

BACKGROUND AND PURPOSE: The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging.

MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point.

RESULTS: We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°–37°), transverse dimension (range, 2–6.7 mm), and most inferior border (range, 4–7 mm below the intercommissural plane).

CONCLUSIONS: Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.

ABBREVIATIONS:

DBS: deep brain stimulation
DRT: dentatorubrothalamic tract
PLIC: posterior limb of the internal capsule
STN: subthalamic nucleus
SUDC: sudden unexplained death of childhood
Vim: thalamic ventrointermedius nucleus
ZI: zona incerta

Footnotes

Disclosures: Laura Crandall—RELATED: Grant: SUDC Foundation and Finding a Cure for Epilepsy and Seizures*; Support for Travel to Meetings for the Study or Other Purposes: SUDC Foundation, Comments: travel reimbursement only for meetings attended on behalf of the Foundation; Other: Lange Shaw Donor-Advisor Fund, Comments: Funds support my effort in the study*; UNRELATED: Board Membership: SUDC Foundation, Comments: volunteer position; Travel/Accommodations/Meeting Expenses Unrelated to Activities Listed: SUDC Foundation, Comments: travel reimbursement only for meetings attended on behalf of the Foundation. Thomas Wisniewski—RELATED: Grant: National Institute on Aging, National Institutes of Health grant No. AG08051.* Orrin Devinsky—UNRELATED: Board Membership: SUDC Foundation, Comments: research grants to New York University Langone Health*; Other: National Institute of Neurological Disorders and Stroke, Comments: research support for Sudden unexpected death in epilepsy (SUDEP) research. Timothy M. Shepherd—RELATED: Grant: SUDC Foundation, Taylor McKeen Shelton Foundation, Finding a Cure for Epilepsy and Seizures fund, National Institutes of Health–National Institute on Aging AG048622.* Alon Y. Mogilner—UNRELATED: Consultancy: Medtronic, St. Jude, Brainlab, Boston Scientific, Alpha Omega, Comments: consulting for issues related to deep brain stimulation; Stock/Stock Options: ElectroCORE, Comments: Stock warrants were not exercised. *Money paid to institution.
This study was funded by the SUDC Foundation, the Taylor McKeen Shelton Foundation, and the Finding a Cure for Epilepsy and Seizures fund. T.M.S. received research support from the National Institute of Aging (grant AG048622). T.W. and A.F. received research support from the National Institute of Aging (grant AG008051). This work was supported, in part, by the Center for Advanced Imaging Innovation and Research, a National Institutes of Health–National Institute of Biomedical Imaging and Bioengineering Biomedical Technology Resource Center (Grant P41EB017183).