Assessment of the language laterality index in patients with brain tumor using functional MR imaging: Effects of thresholding, task selection, and prior surgery Journal Article
| Authors: | Ruff, I. M.; Petrovich Brennan, N. M.; Peck, K. K. ; Hou, B. L.; Tabar, V.; Brennan, C. W.; Holodny, A. I. |
| Article Title: | Assessment of the language laterality index in patients with brain tumor using functional MR imaging: Effects of thresholding, task selection, and prior surgery |
| Abstract: | BACKGROUND AND PURPOSE: Functional MR imaging (fMRI) is used to determine preoperatively the laterality of cortical language representation along with the relationship of language areas to adjacent brain tumors. The purpose of this study was to determine whether changing the statistical threshold for different language tasks influences the language laterality index (LI) for a group of controls, patients with tumor without prior surgery, and patients with tumor and prior surgery. MATERIALS AND METHODS: Seven controls, 9 patients with tumor without prior surgery, and 4 patients with tumor and prior surgery performed verb-generation, phonemic fluency, and semantic fluency language tasks during fMRI. Interhemispheric activation differences between the left and right Broca regions of interest were determined by calculating language Lis. Lis were compared within each group, between groups, and between language tasks. Intraoperative electrocortical mapping or the presence of aphasia during postoperative neurology examinations or both were used as ground truth. RESULTS: The language LI varied as a result of statistical thresholding, presence of tumor, prior surgery, and language task. Although patients and controls followed a similar shape in the LI curve, there was no optimal P value for determining the LI. Three patients demonstrated a shift in the LI between hemispheres as a function of statistical threshold. Verb generation was the least variable task both between tasks and across groups. CONCLUSION: For preoperative patients with tumor, the LI should be examined across a spectrum of P values and a range of tasks to ensure reliability. Our data suggest that the LI may be threshold- and task-dependent, particularly in the presence of adjacent tumor. |
| Keywords: | clinical article; controlled study; functional assessment; preoperative care; neuroimaging; brain tumor; brain neoplasms; magnetic resonance imaging; preoperative evaluation; image analysis; risk assessment; reliability; language; functional magnetic resonance imaging; hemispheric dominance; brain mapping; cerebral cortex; functional laterality; task performance; calculation; mathematical analysis; nuclear magnetic resonance scanner; semantics; diagonal band of broca; phoneme; differential threshold |
| Journal Title: | American Journal of Neuroradiology |
| Volume: | 29 |
| Issue: | 3 |
| ISSN: | 0195-6108 |
| Publisher: | American Society of Neuroradiology |
| Date Published: | 2008-03-01 |
| Start Page: | 528 |
| End Page: | 535 |
| Language: | English |
| DOI: | 10.3174/ajnr.A0841 |
| PUBMED: | 18184849 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 17" - "Export Date: 17 November 2011" - "CODEN: AAJND" - "Source: Scopus" |
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