Visualization of subcortical language pathways by diffusion tensor imaging fiber tracking based on rTMS language mapping.
Diffusion tensor imaging fiber tracking (DTI FT) is used to visualize subcortical fiber tracts. Yet, there is no standard at hand to visualize language-involved subcortical fibers reliably. Thus, this study investigates the feasibility of using language-related cortical areas identified via repetitive navigated transcranial magnetic stimulation (rTMS) to seed DTI FT of subcortical language tracts. From 2011 to 2014, 37 patients with left-hemispheric perisylvian lesions were examined. Language-positive rTMS stimulation spots were integrated in the deterministic tractography software (BrainLAB, iPlanNet 3.0) as objects and used as seed regions for DTI FT. Tractography was then performed in each patient with 77 different combinations of fiber lengths (40 - 100 mm) and fractional anisotropy (FA; 0.01 - 0.5). The rTMS-based DTI FT identified all commonly known subcortical language tracts, such as the corticonuclear tract, arcuate fascicle, uncinate fascicle, superior longitudinal fascicle, inferior longitudinal fascicle, arcuate fibers, commissural fibers, corticothalamic fibers, and the fronto-occipital fascicle. In 32 patients (86.5 %), each above-named tract could be visualized, while at least 6 out of these 9 tracts were identified in each patient. A fiber length of 100 mm and an FA of 0.1 or 0.15 provided optimal visualization by revealing 125 and 61 individually tracked fibers per visualized language tract and 90 % and 73 % of all language-related tracts, respectively. This study proves the feasibility of rTMS-based DTI FT for subcortical language tracts, provides suitable settings, and shows its easy and standardizable application for the visualization of every language tract in 86.5 % of patients.
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Munich, Germany.
Chiara
C
Negwer
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Munich, Germany.
Sebastian
S
Ille
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Munich, Germany.
Theresa
T
Hauck
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Munich, Germany.
Nico
N
Sollmann
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM-Neuroimaging Center, Munich, Germany.
Stefanie
S
Maurer
Department of Radiology, Section of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
Jan S
JS
Kirschke
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
Florian
F
Ringel
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
Bernhard
B
Meyer
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Sandro.Krieg@tum.de.|TUM-Neuroimaging Center, Munich, Germany. Sandro.Krieg@tum.de.
Sandro M
SM
Krieg
D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007802:Language; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D057234:Preoperative Period; D011446:Prospective Studies; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D066127:White Matter / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D055815:Young Adult
Cortical mapping; Fiber tracking; Language; Subcortical; Transcranial magnetic stimulation