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Diagnostic benefits of presurgical fMRI in patients with brain tumours in the primary sensorimotor cortex.

Wengenroth M, Blatow M, Guenther J, Akbar M, Tronnier VM, Stippich C - Eur Radiol (2011)

Bottom Line: FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome.Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery.The additional imaging time seems justified.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroradiology, University of Heidelberg Medical School, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. martina.wengenroth@med.uni-heidelberg.de

ABSTRACT

Objectives: Reliable imaging of eloquent tumour-adjacent brain areas is necessary for planning function-preserving neurosurgery. This study evaluates the potential diagnostic benefits of presurgical functional magnetic resonance imaging (fMRI) in comparison to a detailed analysis of morphological MRI data.

Methods: Standardised preoperative functional and structural neuroimaging was performed on 77 patients with rolandic mass lesions at 1.5 Tesla. The central region of both hemispheres was allocated using six morphological and three functional landmarks.

Results: fMRI enabled localisation of the motor hand area in 76/77 patients, which was significantly superior to analysis of structural MRI (confident localisation of motor hand area in 66/77 patients; p < 0.002). FMRI provided additional diagnostic information in 96% (tongue representation) and 97% (foot representation) of patients. FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome.

Conclusion: Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery. The additional imaging time seems justified. FMRI has the potential to reduce postoperative morbidity and therefore hospitalisation time.

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Related in: MedlinePlus

Functional landmarks of the central region (51-year-old female patient with cerebral metastasis of lung adenocarcinoma and impaired fine motor skills of the left hand). Axial (left), coronal (middle) and sagittal (right) sections depict motor areas for foot (top), hand (middle) and tongue (bottom). With morphological criteria alone, localisation of the central region was not feasible due to tumour-associated distortions. Functional landmarks however illustrate how the perifocal oedema but not the contrast-enhancing metastasis itself reaches eloquent areas of the postcentral gyrus. Anterior (A), posterior (P), left (L), right (R)
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Fig2: Functional landmarks of the central region (51-year-old female patient with cerebral metastasis of lung adenocarcinoma and impaired fine motor skills of the left hand). Axial (left), coronal (middle) and sagittal (right) sections depict motor areas for foot (top), hand (middle) and tongue (bottom). With morphological criteria alone, localisation of the central region was not feasible due to tumour-associated distortions. Functional landmarks however illustrate how the perifocal oedema but not the contrast-enhancing metastasis itself reaches eloquent areas of the postcentral gyrus. Anterior (A), posterior (P), left (L), right (R)

Mentions: All fMRI investigations were performed with standardised block-designed BOLD technique employing a T2*-weighted single-shot, blipped gradient echo Echo-Planar-Imaging sequence (GE-EPI, TR/TE = 4,000/80 ms, FOV = 256 × 256 mm2, image matrix = 128 × 128 voxels, flip angle = 90°, 22 contiguous axial images, slice thickness 5 mm, inter-slice gap 1 mm). Each single measurement consisted of 1 offset, 4 baseline and 3 stimulation intervals of 20 s each; totalling approximately 7 min. additional imaging time for complete somatotopic mapping. During the experiments subjects performed self-paced tongue up and down movements with closed lips, complex finger tapping with sequential finger-to-thumb opposition as well as repetitive toe flexion–extension (without any movements in the ankles) of the side contralateral to the respective lesion [31, 32]. In the case of tumour-associated paralysis whereby complex finger opposition was not accomplishable, repetitive fist clenching was performed alternatively. Processing and analysis of functional MRI data were carried out with BrainVoyager® (BrainInnovation, Maastricht, Netherlands; http://www.brainvoyager.com), including motion correction, spatial and temporal smoothing and voxel-wise calculation of BOLD activation using linear cross-correlations. Data processing was fully standardised and automated except for semi-automated structural-functional image superposition. BOLD signal characteristics were computed, e.g. correlation of the measured BOLD signal to the applied haemodynamic reference function (hrf) = r and the relative BOLD signal change = ΔS(%). Individual functional data were analyzed using a standardized evaluation routine with a dynamic statistical threshold [30–33]: A minimum cluster size of 36 mm3 was preset as the standard for data evaluation to achieve a precise determination of the anatomical correlates of the different functional activations and also to eliminate very small clusters in the activation maps. At first, a very high statistical threshold value for the correlation (r) between the measured BOLD-signals and the hrf was selected, so that no functional activation was displayed (empty map). This threshold was then continually reduced (dynamic threshold). As a result, the activation with the highest correlation to the hrf that exceeded the cluster size of 36 mm3 was displayed foremost. By further reducing the threshold, activations in other functional areas with a lower correlation between the measured BOLD-signals and the hrf were displayed in hierarchical order. This procedure was continued until activations were identified in all regions of interests (ROI). A minimum threshold of r = 0.4 with p < 0.05 (Bonferroni corrected) was established as very conservative limit in order to ensure that BOLD-signals were clearly distinguishable from background noise. If no BOLD-activation was displayed in a ROI within this lower limit, this was evaluated as "no activation." Likewise, BOLD signals with a relative change of ΔS > 5% were considered bias and not included in the evaluation, as such high-level activations are likely to originate from draining veins [32]. In keeping with our previous studies activations with the highest correlation to the hrf were considered precentral and therefore used as functional landmarks, namely (Fig. 2):Fig. 2


Diagnostic benefits of presurgical fMRI in patients with brain tumours in the primary sensorimotor cortex.

Wengenroth M, Blatow M, Guenther J, Akbar M, Tronnier VM, Stippich C - Eur Radiol (2011)

Functional landmarks of the central region (51-year-old female patient with cerebral metastasis of lung adenocarcinoma and impaired fine motor skills of the left hand). Axial (left), coronal (middle) and sagittal (right) sections depict motor areas for foot (top), hand (middle) and tongue (bottom). With morphological criteria alone, localisation of the central region was not feasible due to tumour-associated distortions. Functional landmarks however illustrate how the perifocal oedema but not the contrast-enhancing metastasis itself reaches eloquent areas of the postcentral gyrus. Anterior (A), posterior (P), left (L), right (R)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3101350&req=5

Fig2: Functional landmarks of the central region (51-year-old female patient with cerebral metastasis of lung adenocarcinoma and impaired fine motor skills of the left hand). Axial (left), coronal (middle) and sagittal (right) sections depict motor areas for foot (top), hand (middle) and tongue (bottom). With morphological criteria alone, localisation of the central region was not feasible due to tumour-associated distortions. Functional landmarks however illustrate how the perifocal oedema but not the contrast-enhancing metastasis itself reaches eloquent areas of the postcentral gyrus. Anterior (A), posterior (P), left (L), right (R)
Mentions: All fMRI investigations were performed with standardised block-designed BOLD technique employing a T2*-weighted single-shot, blipped gradient echo Echo-Planar-Imaging sequence (GE-EPI, TR/TE = 4,000/80 ms, FOV = 256 × 256 mm2, image matrix = 128 × 128 voxels, flip angle = 90°, 22 contiguous axial images, slice thickness 5 mm, inter-slice gap 1 mm). Each single measurement consisted of 1 offset, 4 baseline and 3 stimulation intervals of 20 s each; totalling approximately 7 min. additional imaging time for complete somatotopic mapping. During the experiments subjects performed self-paced tongue up and down movements with closed lips, complex finger tapping with sequential finger-to-thumb opposition as well as repetitive toe flexion–extension (without any movements in the ankles) of the side contralateral to the respective lesion [31, 32]. In the case of tumour-associated paralysis whereby complex finger opposition was not accomplishable, repetitive fist clenching was performed alternatively. Processing and analysis of functional MRI data were carried out with BrainVoyager® (BrainInnovation, Maastricht, Netherlands; http://www.brainvoyager.com), including motion correction, spatial and temporal smoothing and voxel-wise calculation of BOLD activation using linear cross-correlations. Data processing was fully standardised and automated except for semi-automated structural-functional image superposition. BOLD signal characteristics were computed, e.g. correlation of the measured BOLD signal to the applied haemodynamic reference function (hrf) = r and the relative BOLD signal change = ΔS(%). Individual functional data were analyzed using a standardized evaluation routine with a dynamic statistical threshold [30–33]: A minimum cluster size of 36 mm3 was preset as the standard for data evaluation to achieve a precise determination of the anatomical correlates of the different functional activations and also to eliminate very small clusters in the activation maps. At first, a very high statistical threshold value for the correlation (r) between the measured BOLD-signals and the hrf was selected, so that no functional activation was displayed (empty map). This threshold was then continually reduced (dynamic threshold). As a result, the activation with the highest correlation to the hrf that exceeded the cluster size of 36 mm3 was displayed foremost. By further reducing the threshold, activations in other functional areas with a lower correlation between the measured BOLD-signals and the hrf were displayed in hierarchical order. This procedure was continued until activations were identified in all regions of interests (ROI). A minimum threshold of r = 0.4 with p < 0.05 (Bonferroni corrected) was established as very conservative limit in order to ensure that BOLD-signals were clearly distinguishable from background noise. If no BOLD-activation was displayed in a ROI within this lower limit, this was evaluated as "no activation." Likewise, BOLD signals with a relative change of ΔS > 5% were considered bias and not included in the evaluation, as such high-level activations are likely to originate from draining veins [32]. In keeping with our previous studies activations with the highest correlation to the hrf were considered precentral and therefore used as functional landmarks, namely (Fig. 2):Fig. 2

Bottom Line: FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome.Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery.The additional imaging time seems justified.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroradiology, University of Heidelberg Medical School, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. martina.wengenroth@med.uni-heidelberg.de

ABSTRACT

Objectives: Reliable imaging of eloquent tumour-adjacent brain areas is necessary for planning function-preserving neurosurgery. This study evaluates the potential diagnostic benefits of presurgical functional magnetic resonance imaging (fMRI) in comparison to a detailed analysis of morphological MRI data.

Methods: Standardised preoperative functional and structural neuroimaging was performed on 77 patients with rolandic mass lesions at 1.5 Tesla. The central region of both hemispheres was allocated using six morphological and three functional landmarks.

Results: fMRI enabled localisation of the motor hand area in 76/77 patients, which was significantly superior to analysis of structural MRI (confident localisation of motor hand area in 66/77 patients; p < 0.002). FMRI provided additional diagnostic information in 96% (tongue representation) and 97% (foot representation) of patients. FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome.

Conclusion: Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery. The additional imaging time seems justified. FMRI has the potential to reduce postoperative morbidity and therefore hospitalisation time.

Show MeSH
Related in: MedlinePlus