title: Language pathway tracking: comparing nTMS-based DTI fiber tracking with a cubic ROIs-based protocol.
abstract: OBJECTIVE Diffusion tensor imaging (DTI) fiber tracking (FT) has been widely used in glioma surgery in recent years. It can provide helpful information about subcortical structures, especially in patients with eloquent space-occupying lesions. This study compared the newly developed navigated transcranial magnetic stimulation (nTMS)-based DTI FT of language pathways with the most reproducible protocol for language pathway tractography, using cubic regions of interest (ROIs) for the arcuate fascicle. METHODS Thirty-seven patients with left-sided perisylvian lesions underwent language mapping by repetitive nTMS. DTI FT was performed using the cubic ROIs-based protocol and the authors' nTMS-based DTI FT approach. The same minimal fiber length and fractional anisotropy were chosen (50 mm and 0.2, respectively). Both protocols were performed with standard clinical tractography software. RESULTS Both methods visualized language-related fiber tracts (i.e., corticonuclear tract, arcuate fascicle, uncinate fascicle, superior longitudinal fascicle, inferior longitudinal fascicle, arcuate fibers, commissural fibers, corticothalamic fibers, and frontooccipital fascicle) in all 37 patients. Using the cubic ROIs-based protocol, 39.9% of these language-related fiber tracts were detected in the examined patients, as opposed to 76.0% when performing nTMS-based DTI FT. For specifically tracking the arcuate fascicle, however, the cubic ROIs-based approach showed better results (97.3% vs 75.7% with nTMS-based DTI FT). CONCLUSIONS The cubic ROIs-based protocol was designed for arcuate fascicle tractography, and this study shows that it is still useful for this intention. However, superior results were obtained using the nTMS-based DTI FT for visualization of other language-related fiber tracts.
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Chiara
authors.initials: C
authors.lastname: Negwer
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Nico
authors.initials: N
authors.lastname: Sollmann
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ille
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Theresa
authors.initials: T
authors.lastname: Hauck
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Maurer
authors.affiliation: Section of Neuroradiology, Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Germany.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Kirschke
authors.affiliation: Department of Neurosurgery.
authors.forename: Florian
authors.initials: F
authors.lastname: Ringel
authors.affiliation: Department of Neurosurgery.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurosurgery.|TUM-Neuroimaging Center, and.
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Krieg
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002985:Clinical Protocols; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007802:Language; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D011300:Preoperative Care; D011446:Prospective Studies; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: AF = arcuate fascicle; ArF = arcuate fibers; CST = corticospinal tract; DCS = direct cortical stimulation; DTI = diffusion tensor imaging; FA = fractional anisotropy; FT = fiber tracking; MFL = minimum fiber length; RMT = resting motor threshold; ROI = region of interest; SLF = superior longitudinal fascicle; TMS = transcranial magnetic stimulation; UF = uncinate fascicle; cortical mapping; fMRI = functional MRI; fiber tracking; language; nTMS = navigated transcranial magnetic stimulation; navigated transcranial magnetic stimulation; rTMS = repetitive navigated transcranial magnetic stimulation; space-occupying lesions; subcortical; surgical technique