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Assessing Region of Interest Schemes for the Corticospinal Tract in Patients With Brain Tumors

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ABSTRACT

Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) techniques are widely used for identifying the corticospinal tract (CST) white matter pathways as part of presurgical planning. However, mass effects in patients with brain tumors tend to cause anatomical distortions and compensatory functional reorganization of the cortex, which may lead to inaccurate mapping of white matter tracts. To overcome these problems, we compared different region-of-interest (ROI) selection schemes to track CST fibers in patients with brain tumors. Our study investigated the CSTs of 16 patients with intracranial tumors. The patients were classified into 3 subgroups according to the spatial relationships of the lesion and the primary motor cortex (PMC)/internal capsule. Specifically, we investigated the key factors that cause distorted tractography in patients with tumors. We compared 3 CST tractography methods that used different ROI selection schemes. The results indicate that CST fiber tracking methods based only on anatomical ROIs could possibly lead to distortions near the PMC region and may be unable to effectively localize the PMC. In contrast, the dual ROI method, which uses ROIs that have been selected from both blood oxygen level-dependent functional MRI (BOLD-fMRI) activation and anatomical landmarks, enabled the tracking of fibers to the motor cortex. The results demonstrate that the dual ROI method can localize the entire CST fiber pathway and can accurately describe the spatial relationships of CST fibers relative to the tumor. These results illustrate the reliability of using fMRI-guided DTT in patients with tumors. The combination of fMRI and anatomical information enhances the identification of tracts of interest in brains with anatomical deformations, which provides neurosurgeons with a more accurate approach for visualizing and localizing white matter fiber tracts in patients with brain tumors. This approach enhances surgical performance and perserves brain function.

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The CST fiber tracking results for patient 2, who was diagnosed with transitional meningioma in the right frontal cortex that did not affect the primary motor cortex or the right internal capsule. (A) The lesion and motor-activated area are displayed on a T1-weighted image. (B) The CST fiber tracking results based on different ROI definitions. Yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. fMRI activation is observed in the primary and supplementary motor cortex. Similar fiber tracking results are presented for the fMRI-guided DT approach (ROI2) and the dual ROI approach (ROI1 + ROI2). (C) The 3D visualization of the CST fiber tracking results based on different ROI definitions. CST = corticospinal tract, fMRI = functional MRI, ROI = region-of-interest.
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Figure 4: The CST fiber tracking results for patient 2, who was diagnosed with transitional meningioma in the right frontal cortex that did not affect the primary motor cortex or the right internal capsule. (A) The lesion and motor-activated area are displayed on a T1-weighted image. (B) The CST fiber tracking results based on different ROI definitions. Yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. fMRI activation is observed in the primary and supplementary motor cortex. Similar fiber tracking results are presented for the fMRI-guided DT approach (ROI2) and the dual ROI approach (ROI1 + ROI2). (C) The 3D visualization of the CST fiber tracking results based on different ROI definitions. CST = corticospinal tract, fMRI = functional MRI, ROI = region-of-interest.

Mentions: Group III patients (patients 2, 5, 8, 9, 14) had lesions that were not in the PMC or the internal capsule. Figure 4 shows the CST fiber tracking results for patient 2. Patient 2 had a confirmed pathological diagnosis of transitional meningioma. In this case, the lesion was located in the right frontoparietal lobe and did not affect the motor cortex or the right internal capsule. Figure 4A shows the lesion and the motor activated area on a T1-weighted image. Figure 4B and Figure 4C show the CST fiber tracking results based on different ROIs; yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. Supplementary Figure S3 shows all of the CST results for Group III patients (patients 2, 5, 8, 9, 14), all of whom had a tumor that was distal to the PMC and the internal capsule.


Assessing Region of Interest Schemes for the Corticospinal Tract in Patients With Brain Tumors
The CST fiber tracking results for patient 2, who was diagnosed with transitional meningioma in the right frontal cortex that did not affect the primary motor cortex or the right internal capsule. (A) The lesion and motor-activated area are displayed on a T1-weighted image. (B) The CST fiber tracking results based on different ROI definitions. Yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. fMRI activation is observed in the primary and supplementary motor cortex. Similar fiber tracking results are presented for the fMRI-guided DT approach (ROI2) and the dual ROI approach (ROI1 + ROI2). (C) The 3D visualization of the CST fiber tracking results based on different ROI definitions. CST = corticospinal tract, fMRI = functional MRI, ROI = region-of-interest.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 4: The CST fiber tracking results for patient 2, who was diagnosed with transitional meningioma in the right frontal cortex that did not affect the primary motor cortex or the right internal capsule. (A) The lesion and motor-activated area are displayed on a T1-weighted image. (B) The CST fiber tracking results based on different ROI definitions. Yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. fMRI activation is observed in the primary and supplementary motor cortex. Similar fiber tracking results are presented for the fMRI-guided DT approach (ROI2) and the dual ROI approach (ROI1 + ROI2). (C) The 3D visualization of the CST fiber tracking results based on different ROI definitions. CST = corticospinal tract, fMRI = functional MRI, ROI = region-of-interest.
Mentions: Group III patients (patients 2, 5, 8, 9, 14) had lesions that were not in the PMC or the internal capsule. Figure 4 shows the CST fiber tracking results for patient 2. Patient 2 had a confirmed pathological diagnosis of transitional meningioma. In this case, the lesion was located in the right frontoparietal lobe and did not affect the motor cortex or the right internal capsule. Figure 4A shows the lesion and the motor activated area on a T1-weighted image. Figure 4B and Figure 4C show the CST fiber tracking results based on different ROIs; yellow, green, and purple represent the CST fiber tracking results obtained using ROI1, ROI2, and ROI1 + ROI2, respectively. Supplementary Figure S3 shows all of the CST results for Group III patients (patients 2, 5, 8, 9, 14), all of whom had a tumor that was distal to the PMC and the internal capsule.

View Article: PubMed Central - PubMed

ABSTRACT

Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) techniques are widely used for identifying the corticospinal tract (CST) white matter pathways as part of presurgical planning. However, mass effects in patients with brain tumors tend to cause anatomical distortions and compensatory functional reorganization of the cortex, which may lead to inaccurate mapping of white matter tracts. To overcome these problems, we compared different region-of-interest (ROI) selection schemes to track CST fibers in patients with brain tumors. Our study investigated the CSTs of 16 patients with intracranial tumors. The patients were classified into 3 subgroups according to the spatial relationships of the lesion and the primary motor cortex (PMC)/internal capsule. Specifically, we investigated the key factors that cause distorted tractography in patients with tumors. We compared 3 CST tractography methods that used different ROI selection schemes. The results indicate that CST fiber tracking methods based only on anatomical ROIs could possibly lead to distortions near the PMC region and may be unable to effectively localize the PMC. In contrast, the dual ROI method, which uses ROIs that have been selected from both blood oxygen level-dependent functional MRI (BOLD-fMRI) activation and anatomical landmarks, enabled the tracking of fibers to the motor cortex. The results demonstrate that the dual ROI method can localize the entire CST fiber pathway and can accurately describe the spatial relationships of CST fibers relative to the tumor. These results illustrate the reliability of using fMRI-guided DTT in patients with tumors. The combination of fMRI and anatomical information enhances the identification of tracts of interest in brains with anatomical deformations, which provides neurosurgeons with a more accurate approach for visualizing and localizing white matter fiber tracts in patients with brain tumors. This approach enhances surgical performance and perserves brain function.

No MeSH data available.


Related in: MedlinePlus