title: Usage of fMRI for pre-surgical planning in brain tumor and vascular lesion patients: task and statistical threshold effects on language lateralization.
abstract: OBJECTIVE
  Functional magnetic resonance imaging (fMRI) is a non-invasive pre-surgical tool used to assess localization and lateralization of language function in brain tumor and vascular lesion patients in order to guide neurosurgeons as they devise a surgical approach to treat these lesions. We investigated the effect of varying the statistical thresholds as well as the type of language tasks on functional activation patterns and language lateralization. We hypothesized that language lateralization indices (LIs) would be threshold- and task-dependent.
  
  
  METHODS
  Imaging data were collected from brain tumor patients (n = 67, average age 48 years) and vascular lesion patients (n = 25, average age 43 years) who received pre-operative fMRI scanning. Both patient groups performed expressive (antonym and/or letter-word generation) and receptive (tumor patients performed text-reading; vascular lesion patients performed text-listening) language tasks. A control group (n = 25, average age 45 years) performed the letter-word generation task.
  
  
  RESULTS
  Brain tumor patients showed left-lateralization during the antonym-word generation and text-reading tasks at high threshold values and bilateral activation during the letter-word generation task, irrespective of the threshold values. Vascular lesion patients showed left-lateralization during the antonym and letter-word generation, and text-listening tasks at high threshold values.
  
  
  CONCLUSIONS
  Our results suggest that the type of task and the applied statistical threshold influence LI and that the threshold effects on LI may be task-specific. Thus identifying critical functional regions and computing LIs should be conducted on an individual subject basis, using a continuum of threshold values with different tasks to provide the most accurate information for surgical planning to minimize post-operative language deficits.
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Tanvi N
authors: TN
authors: Nadkarni
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Matthew J
authors: MJ
authors: Andreoli
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Veena A
authors: VA
authors: Nair
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Peng
authors: P
authors: Yin
authors: Medical Scientist Training Program, University of Wisconsin - Madison, USA.
authors: Brittany M
authors: BM
authors: Young
authors: Medical Scientist Training Program, University of Wisconsin - Madison, USA.
authors: Bornali
authors: B
authors: Kundu
authors: School of Medicine and Public Health, University of Wisconsin - Madison, USA.
authors: Joshua
authors: J
authors: Pankratz
authors: School of Medicine and Public Health, University of Wisconsin - Madison, USA.
authors: Andrew
authors: A
authors: Radtke
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Ryan
authors: R
authors: Holdsworth
authors: School of Medicine and Public Health, University of Wisconsin - Madison, USA ; Department of Neurological Surgery, University of Wisconsin - Madison, USA.
authors: John S
authors: JS
authors: Kuo
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Aaron S
authors: AS
authors: Field
authors: School of Medicine and Public Health, University of Wisconsin - Madison, USA ; Department of Neurological Surgery, University of Wisconsin - Madison, USA.
authors: Mustafa K
authors: MK
authors: Baskaya
authors: Department of Radiology, University of Wisconsin - Madison, USA ; Department of Medical Physics, University of Wisconsin - Madison, USA.
authors: Chad H
authors: CH
authors: Moritz
authors: Department of Radiology, University of Wisconsin - Madison, USA ; Department of Medical Physics, University of Wisconsin - Madison, USA ; Department of Biomedical Engineering, University of Wisconsin - Madison, USA.
authors: M Elizabeth
authors: ME
authors: Meyerand
authors: Department of Radiology, University of Wisconsin - Madison, USA.
authors: Vivek
authors: V
authors: Prabhakaran
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000601:surgery*; D002561:Cerebrovascular Disorders / Q000601:surgery*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*
keywords: AWG, antonym-word generation; LI, lateralization index; LWG, letter-word generation; Lateralization index (LI); Surgical planning; Task-specific; Thresholding; fMRI