Medical Student Baylor College of Medicine Houston, Texas, United States
Disclosure(s):
Matthew Muir: No financial relationships to disclose
Introduction: The proper role of non-invasive brain mapping modalities for presurgical planning each remains elusive due to the lack of robust, multi-modal data sets. Here we investigate the clinical relevance of multi-modal, cortical and subcortical, structural and functional preoperative language mapping data in a cohort of patients with language eloquent gliomas.
Methods: This retrospective study included 62 patients who underwent preoperative fMRI and TMS language mapping. We used anatomy, TMS points, and fMRI BOLD signal for different tractography cortical seeding paradigms with various FA thresholds. Persistent aphasia was recorded when the 4-6 week follow up showed significant decline compared to the preoperative baseline using the Western Aphasia Battery. We evalauated the association between the resection versus preservation of various preoperative imaging variables with persistent aphasia.
Results: The resection of TMS points, fMRI BOLD signal, and Broca's and/or Wernicke's Area were not associated with persistant aphasia. The preoperative BOLD signal laterality index (ipsilateral BOLD/contralateral BOLD) was positively correlated with aphasic deficit (r=.41, p < .001). The resection of the anatomically seeded arcuate fasciculus was not associated with deficits at any of the four tested thresholds. Finally, we found that TMS seeded tractography at 50% and 75% FA thresholds were significantly correlated with persistent worsened aphasia (r=.37, p=.003; r=.66, p < .001; respectively). For TMS tractography at 75%, the sensitivity was .85, the specificity was .93, the positive predictive value was .6, and the negative predictve value was.98.
Conclusion : Resection of cortex identified by fMRI BOLD signal as well as the resection of subcortex identified by anatomical tractography had no association with language outcomes. The BOLD laterality index was positively correlated with persistent aphasia. TMS seeded tractography at the 75% FA threshold was significantly associated with aphasic surgical deficits with the highest predictive value. This study challenges current practices and provides foundation for a data-driven approach to presurgical imaging.
