Loss of subcortical language pathways correlates with surgery-related aphasia in brain tumor patients: an investigation via rTMS-based DTI fiber tracking.

Loss of subcortical language pathways correlates with surgery-related aphasia in brain tumor patients: an investigation via rTMS-based DTI fiber tracking.

World Neurosurg. 2018 Jan 05;:

Authors: Negwer C, Beurskens E, Sollmann N, Maurer S, Ille S, Giglhuber K, Kirschke JS, Ringel F, Meyer B, Krieg SM

Abstract
BACKGROUND: Within language function research there is a shift of focus from cortical specialization to a more hodotopical view including subcortical fiber tracts in functional and oncological considerations. Diffusion tensor imaging fiber tracking (DTI FT) is well established to visualize subcortical fiber tracts. Recently a new technique was developed using cortical regions mapped via repetitive navigated transcranial magnetic stimulation (rTMS) as seed regions. This study investigates if rTMS-based DTI FT for language pathways is also feasible postoperatively and whether pre- vs. postoperative fiber changes correlate with changes and severity of the patients' aphasia grades.
METHODS: rTMS-based DTI FT was performed pre- and postoperatively in 24 patients with left-hemispheric perisylvian tumors. Language pathways were analyzed individually pre- and postoperatively with five different settings of minimum fiber length and fractional anisotropy. Transient aphasia was defined as any new or worse language impairment due to surgery that resolved within the regular 3-month follow-up interval. Since postoperative aphasia does not allow rTMS language mapping, preoperative rTMS data were used throughout.
RESULTS: Patients with transient aphasia postoperatively had a significant reduction in fiber count compared to patients without deficit (321.5 ± 242.8 fibers vs. 518.0 ± 435.2 fibers, p=0.01). Furthermore, in this patient group, the arcuate fascicle was lost postoperatively twice as often compared to patients with no deficit after surgery (52% vs. 26%; p<0.01).
CONCLUSION: This study shows that rTMS-based DTI FT is feasible for postoperative examination of language pathways. Moreover, changes in pre- vs. postoperative fibers correlate well with the grade of aphasia.

PMID: 29309976 [PubMed - as supplied by publisher]

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