Ki Yun Park¹, John J. Lee¹, Donna Dierker¹, Laura M. Marple¹, Carl D. Hacker², Jarod L. Roland³, Daniel S. Marcus¹, Mikhail Milchenko¹, Michelle M. Miller-Thomas¹, Tammie L. Benzinger¹, Joshua S. Shimony¹*, Abraham Z. Snyder¹, Eric C. Leuthardt²

¹ Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America

² Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri, United States of America

³ Department of Neurosurgery, University of California San Francisco, San Francisco, California, United States of America

• shimonyj@wustl.edu

Abstract

Background

Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre-operative functional mapping for patients with brain tumors, especially tumors located near eloquent cortex. Currently, this practice predominantly involves task-based fMRI (T-fMRI). Resting state fMRI (RS-fMRI) offers an alternative with several methodological advantages. Here, we compare group-level analyses of RS-fMRI vs. T-fMRI as methods for language localization.

Purpose

To contrast RS-fMRI vs. T-fMRI as techniques for localization of language function.

Methods

We analyzed data obtained in 35 patients who had both T-fMRI and RS-fMRI scans during the course of pre-surgical evaluation. The RS-fMRI data were analyzed using a previously trained resting-state network classifier. The T-fMRI data were analyzed using conventional techniques. Group-level results obtained by both methods were evaluated in terms of two outcome measures: (1) inter-subject variability of response magnitude and (2) sensitivity/specificity analysis of response topography, taking as ground truth previously reported maps of the language system based on intraoperative cortical mapping as well as meta-analytic maps of language task fMRI responses.

Results

Both fMRI methods localized major components of the language system (areas of Broca and Wernicke) although not with equal inter-subject consistency. Word-stem completion T-fMRI strongly activated Broca’s area but also several task-general areas not specific to language. RS-fMRI provided a more specific representation of the language system.