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Usage of fMRI for pre-surgical planning in brain tumor and vascular lesion patients: task and statistical threshold effects on language lateralization.

Nadkarni TN, Andreoli MJ, Nair VA, Yin P, Young BM, Kundu B, Pankratz J, Radtke A, Holdsworth R, Kuo JS, Field AS, Baskaya MK, Moritz CH, Meyerand ME, Prabhakaran V - Neuroimage Clin (2014)

Bottom Line: We investigated the effect of varying the statistical thresholds as well as the type of language tasks on functional activation patterns and language lateralization.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Wisconsin - Madison, USA.

ABSTRACT

Background and purpose: 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.

Materials and 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.

Conclusion: 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.

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Average hemispheric LIs (left) and group activation (right) for letter-word generation task in the control, tumor, and vascular lesion patient groups. Left: the average LIs for tumor patients (n = 42), vascular lesion patients (n = 10), and controls (n = 25), from the letter-word generation task, are shown at different threshold values for the hemispheric mask. Tumor patients show bilateral dominance regardless of t-value. Tumor patient LIs are significantly different from control LIs at each threshold (ps < 0.0125, Table 5). Vascular lesion patients show bilateral dominance at t < 2.0 and left lateralization at t < 4.0. Vascular lesion patient LIs are significantly different from control LIs at at t < 2.0 (p < 0.0125, Table 5). The control group maintains left lateralization despite variable threshold effects. Right: images display the group activation maps at low threshold values (ts < 2.0) and at higher threshold values (ts < 4.0). The control subjects (A) show average left language lateralization, the vascular lesion patients (B) show average bilateral and left-lateral dominance, and the tumor patients (C) show average bilateral dominance during the letter word generation task.
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f0010: Average hemispheric LIs (left) and group activation (right) for letter-word generation task in the control, tumor, and vascular lesion patient groups. Left: the average LIs for tumor patients (n = 42), vascular lesion patients (n = 10), and controls (n = 25), from the letter-word generation task, are shown at different threshold values for the hemispheric mask. Tumor patients show bilateral dominance regardless of t-value. Tumor patient LIs are significantly different from control LIs at each threshold (ps < 0.0125, Table 5). Vascular lesion patients show bilateral dominance at t < 2.0 and left lateralization at t < 4.0. Vascular lesion patient LIs are significantly different from control LIs at at t < 2.0 (p < 0.0125, Table 5). The control group maintains left lateralization despite variable threshold effects. Right: images display the group activation maps at low threshold values (ts < 2.0) and at higher threshold values (ts < 4.0). The control subjects (A) show average left language lateralization, the vascular lesion patients (B) show average bilateral and left-lateral dominance, and the tumor patients (C) show average bilateral dominance during the letter word generation task.

Mentions: The predominant activation pattern we observed in brain tumor and vascular lesion patients indicated that as the threshold was increased from a low to a high threshold, the average LI became more left-lateralized, except for the brain tumor patient group performing the LWG task (Figs. 1 and 2). The control group showed left-lateralization in the inferior, middle, and superior frontal gyri across all threshold values during the LWG task. In contrast, the brain tumor patient group showed bilateral activity in the inferior, middle, and superior frontal gyri, and supramarginal and inferior parietal gyri across all threshold values. The vascular lesion patient group showed bilateral activity in the inferior, middle, and medial frontal gyri, inferior parietal gyri, and superior temporal gyri at a low threshold value (t < 2.0), but showed robust left hemispheric activity in the inferior and middle frontal gyri at high threshold values (ts < 3.5) (Fig. 2). There was significantly more bilateral activity in the tumor patient group compared to the control group across all t-values. The vascular lesion patient group showed a significantly bilateral LI only at t < 2.0 compared to the control group (Fig. 2 and Table 5).


Usage of fMRI for pre-surgical planning in brain tumor and vascular lesion patients: task and statistical threshold effects on language lateralization.

Nadkarni TN, Andreoli MJ, Nair VA, Yin P, Young BM, Kundu B, Pankratz J, Radtke A, Holdsworth R, Kuo JS, Field AS, Baskaya MK, Moritz CH, Meyerand ME, Prabhakaran V - Neuroimage Clin (2014)

Average hemispheric LIs (left) and group activation (right) for letter-word generation task in the control, tumor, and vascular lesion patient groups. Left: the average LIs for tumor patients (n = 42), vascular lesion patients (n = 10), and controls (n = 25), from the letter-word generation task, are shown at different threshold values for the hemispheric mask. Tumor patients show bilateral dominance regardless of t-value. Tumor patient LIs are significantly different from control LIs at each threshold (ps < 0.0125, Table 5). Vascular lesion patients show bilateral dominance at t < 2.0 and left lateralization at t < 4.0. Vascular lesion patient LIs are significantly different from control LIs at at t < 2.0 (p < 0.0125, Table 5). The control group maintains left lateralization despite variable threshold effects. Right: images display the group activation maps at low threshold values (ts < 2.0) and at higher threshold values (ts < 4.0). The control subjects (A) show average left language lateralization, the vascular lesion patients (B) show average bilateral and left-lateral dominance, and the tumor patients (C) show average bilateral dominance during the letter word generation task.
© Copyright Policy - CC BY
Related In: Results  -  Collection

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f0010: Average hemispheric LIs (left) and group activation (right) for letter-word generation task in the control, tumor, and vascular lesion patient groups. Left: the average LIs for tumor patients (n = 42), vascular lesion patients (n = 10), and controls (n = 25), from the letter-word generation task, are shown at different threshold values for the hemispheric mask. Tumor patients show bilateral dominance regardless of t-value. Tumor patient LIs are significantly different from control LIs at each threshold (ps < 0.0125, Table 5). Vascular lesion patients show bilateral dominance at t < 2.0 and left lateralization at t < 4.0. Vascular lesion patient LIs are significantly different from control LIs at at t < 2.0 (p < 0.0125, Table 5). The control group maintains left lateralization despite variable threshold effects. Right: images display the group activation maps at low threshold values (ts < 2.0) and at higher threshold values (ts < 4.0). The control subjects (A) show average left language lateralization, the vascular lesion patients (B) show average bilateral and left-lateral dominance, and the tumor patients (C) show average bilateral dominance during the letter word generation task.
Mentions: The predominant activation pattern we observed in brain tumor and vascular lesion patients indicated that as the threshold was increased from a low to a high threshold, the average LI became more left-lateralized, except for the brain tumor patient group performing the LWG task (Figs. 1 and 2). The control group showed left-lateralization in the inferior, middle, and superior frontal gyri across all threshold values during the LWG task. In contrast, the brain tumor patient group showed bilateral activity in the inferior, middle, and superior frontal gyri, and supramarginal and inferior parietal gyri across all threshold values. The vascular lesion patient group showed bilateral activity in the inferior, middle, and medial frontal gyri, inferior parietal gyri, and superior temporal gyri at a low threshold value (t < 2.0), but showed robust left hemispheric activity in the inferior and middle frontal gyri at high threshold values (ts < 3.5) (Fig. 2). There was significantly more bilateral activity in the tumor patient group compared to the control group across all t-values. The vascular lesion patient group showed a significantly bilateral LI only at t < 2.0 compared to the control group (Fig. 2 and Table 5).

Bottom Line: We investigated the effect of varying the statistical thresholds as well as the type of language tasks on functional activation patterns and language lateralization.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Wisconsin - Madison, USA.

ABSTRACT

Background and purpose: 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.

Materials and 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.

Conclusion: 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.

Show MeSH
Related in: MedlinePlus