Intraoperative Visualization of Fiber Tracking Based Reconstruction of Language Pathways in Glioma Surgery

Abstract BACKGROUND: For neuroepithelial tumors, the surgical goal is maximum resection with preservation of neurological function. This is contributed to by intraoperative magnetic resonance imaging (iMRI) combined with multimodal navigation. OBJECTIVE: We evaluated the contribution of diffusion tensor imaging (DTI)-based fiber tracking of language pathways with 2 different algorithms (tensor deflection, connectivity analysis [CA]) integrated in the navigation on the surgical outcome. METHODS: We evaluated 32 patients with neuroepithelial tumors who underwent surgery with DTI-based fiber tracking of language pathways integrated in neuronavigation. The tensor deflection algorithm was routinely used and its results intraoperatively displayed in all cases. The CA algorithm was furthermore evaluated in 23 cases. Volumetric assessment was performed in pre- and intraoperative MR images. To evaluate the benefit of fiber tractography, language deficits were evaluated pre- and postoperatively and compared with the volumetric analysis. RESULTS: Final gross-total resection was performed in 40.6% of patients. Absolute tumor volume was reduced from 55.33 ± 63.77 cm3 to 20.61 ± 21.67 cm3 in first iMRI resection control, to finally 11.56 ± 21.92 cm3 (P < .01). Fiber tracking of the 2 algorithms showed a deviation of the displayed 3D objects by <5 mm. In long-term follow-up only 1 patient (3.1%) had a persistent language deficit. CONCLUSION: Intraoperative visualization of language-related cortical areas and the connecting pathways with DTI-based fiber tracking can be successfully performed and integrated in the navigation system. In a setting of intraoperative high-field MRI this contributes to maximum tumor resection with low postoperative morbidity.

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Language pathway tracking: comparing nTMS-based DTI fiber tracking with a cubic ROIs-based protocol

Journal of Neurosurgery ◽

10.3171/2016.2.jns152382 ◽

2017 ◽

Vol 126 (3) ◽

pp. 1006-1014 ◽

Cited By ~ 19

Author(s):

Chiara Negwer ◽

Nico Sollmann ◽

Sebastian Ille ◽

Theresa Hauck ◽

Stefanie Maurer ◽

...

Keyword(s):

Diffusion Tensor ◽

Fiber Tracking ◽

Subcortical Structures ◽

Language Mapping ◽

Glioma Surgery ◽

Fiber Tracts ◽

Uncinate Fascicle ◽

Dti Fiber Tracking ◽

Language Pathways ◽

Diffusion Tensor Imaging Dti

OBJECTIVE Diffusion tensor imaging (DTI) fiber tracking (FT) has been widely used in glioma surgery in recent years. It can provide helpful information about subcortical structures, especially in patients with eloquent space-occupying lesions. This study compared the newly developed navigated transcranial magnetic stimulation (nTMS)-based DTI FT of language pathways with the most reproducible protocol for language pathway tractography, using cubic regions of interest (ROIs) for the arcuate fascicle. METHODS Thirty-seven patients with left-sided perisylvian lesions underwent language mapping by repetitive nTMS. DTI FT was performed using the cubic ROIs–based protocol and the authors' nTMS-based DTI FT approach. The same minimal fiber length and fractional anisotropy were chosen (50 mm and 0.2, respectively). Both protocols were performed with standard clinical tractography software. RESULTS Both methods visualized language-related fiber tracts (i.e., corticonuclear tract, arcuate fascicle, uncinate fascicle, superior longitudinal fascicle, inferior longitudinal fascicle, arcuate fibers, commissural fibers, corticothalamic fibers, and frontooccipital fascicle) in all 37 patients. Using the cubic ROIs-based protocol, 39.9% of these language-related fiber tracts were detected in the examined patients, as opposed to 76.0% when performing nTMS-based DTI FT. For specifically tracking the arcuate fascicle, however, the cubic ROIs-based approach showed better results (97.3% vs 75.7% with nTMS-based DTI FT). CONCLUSIONS The cubic ROIs-based protocol was designed for arcuate fascicle tractography, and this study shows that it is still useful for this intention. However, superior results were obtained using the nTMS-based DTI FT for visualization of other language-related fiber tracts.

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Tracking the Corticospinal Tract in Patients With High-Grade Glioma: Clinical Evaluation of Multi-Level Fiber Tracking and Comparison to Conventional Deterministic Approaches

Frontiers in Oncology ◽

10.3389/fonc.2021.761169 ◽

2021 ◽

Vol 11 ◽

Author(s):

Andrey Zhylka ◽

Nico Sollmann ◽

Florian Kofler ◽

Ahmed Radwan ◽

Alberto De Luca ◽

...

Keyword(s):

Diffusion Mri ◽

Corticospinal Tract ◽

Diffusion Tensor ◽

Tumor Resection ◽

High Grade Glioma ◽

Fiber Tracking ◽

High Grade ◽

Fiber Tractography ◽

Radial Extent ◽

Multi Level

While the diagnosis of high-grade glioma (HGG) is still associated with a considerably poor prognosis, neurosurgical tumor resection provides an opportunity for prolonged survival and improved quality of life for affected patients. However, successful tumor resection is dependent on a proper surgical planning to avoid surgery-induced functional deficits whilst achieving a maximum extent of resection (EOR). With diffusion magnetic resonance imaging (MRI) providing insight into individual white matter neuroanatomy, the challenge remains to disentangle that information as correctly and as completely as possible. In particular, due to the lack of sensitivity and accuracy, the clinical value of widely used diffusion tensor imaging (DTI)-based tractography is increasingly questioned. We evaluated whether the recently developed multi-level fiber tracking (MLFT) technique can improve tractography of the corticospinal tract (CST) in patients with motor-eloquent HGGs. Forty patients with therapy-naïve HGGs (mean age: 62.6 ± 13.4 years, 57.5% males) and preoperative diffusion MRI [repetition time (TR)/echo time (TE): 5000/78 ms, voxel size: 2x2x2 mm3, one volume at b=0 s/mm2, 32 volumes at b=1000 s/mm2] underwent reconstruction of the CST of the tumor-affected and unaffected hemispheres using MLFT in addition to deterministic DTI-based and deterministic constrained spherical deconvolution (CSD)-based fiber tractography. The brain stem was used as a seeding region, with a motor cortex mask serving as a target region for MLFT and a region of interest (ROI) for the other two algorithms. Application of the MLFT method substantially improved bundle reconstruction, leading to CST bundles with higher radial extent compared to the two other algorithms (delineation of CST fanning with a wider range; median radial extent for tumor-affected vs. unaffected hemisphere – DTI: 19.46° vs. 18.99°, p=0.8931; CSD: 30.54° vs. 27.63°, p=0.0546; MLFT: 81.17° vs. 74.59°, p=0.0134). In addition, reconstructions by MLFT and CSD-based tractography nearly completely included respective bundles derived from DTI-based tractography, which was however favorable for MLFT compared to CSD-based tractography (median coverage of the DTI-based CST for affected vs. unaffected hemispheres – CSD: 68.16% vs. 77.59%, p=0.0075; MLFT: 93.09% vs. 95.49%; p=0.0046). Thus, a more complete picture of the CST in patients with motor-eloquent HGGs might be achieved based on routinely acquired diffusion MRI data using MLFT.

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Enhanced Fiber Tractography Using Edema Correction: Application and Evaluation in High-Grade Gliomas

Neurosurgery ◽

10.1093/neuros/nyab129 ◽

2021 ◽

Author(s):

Fraser Henderson Jr ◽

Drew Parker ◽

Anupa A Vijayakumari ◽

Mark Elliott ◽

Timothy Lucas ◽

...

Keyword(s):

Magnetic Resonance ◽

Diffusion Tensor ◽

Free Water ◽

High Grade Glioma ◽

Fiber Tracking ◽

High Grade ◽

Peritumoral Edema ◽

Fiber Tractography ◽

Motor Pathways

Abstract BACKGROUND A limitation of diffusion tensor imaging (DTI)-based tractography is peritumoral edema that confounds traditional diffusion-based magnetic resonance metrics. OBJECTIVE To augment fiber-tracking through peritumoral regions by performing novel edema correction on clinically feasible DTI acquisitions and assess the accuracy of the fiber-tracks using intraoperative stimulation mapping (ISM), task-based functional magnetic resonance imaging (fMRI) activation maps, and postoperative follow-up as reference standards. METHODS Edema correction, using our bi-compartment free water modeling algorithm (FERNET), was performed on clinically acquired DTI data from a cohort of 10 patients presenting with suspected high-grade glioma and peritumoral edema in proximity to and/or infiltrating language or motor pathways. Deterministic fiber-tracking was then performed on the corrected and uncorrected DTI to identify tracts pertaining to the eloquent region involved (language or motor). Tracking results were compared visually and quantitatively using mean fiber count, voxel count, and mean fiber length. The tracts through the edematous region were verified based on overlay with the corresponding motor or language task-based fMRI activation maps and intraoperative ISM points, as well as at time points after surgery when peritumoral edema had subsided. RESULTS Volume and number of fibers increased with application of edema correction; concordantly, mean fractional anisotropy decreased. Overlay with functional activation maps and ISM-verified eloquence of the increased fibers. Comparison with postsurgical follow-up scans with lower edema further confirmed the accuracy of the tracts. CONCLUSION This method of edema correction can be applied to standard clinical DTI to improve visualization of motor and language tracts in patients with glioma-associated peritumoral edema.

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Contemporary intraoperative visualization for GBM with use of exoscope, 5-ALA fluorescence-guided surgery and tractography

Neurosurgical Focus: Video ◽

10.3171/2021.10.focvid21174 ◽

2022 ◽

Vol 6 (1) ◽

pp. V5

Keyword(s):

Diffusion Tensor ◽

High Grade Glioma ◽

Brain Regions ◽

High Grade ◽

Glioma Surgery ◽

Guided Surgery ◽

Word Finding ◽

Patient Consent ◽

Dti Fiber Tracking ◽

Intraoperative Visualization

Maximal safe resection is the primary goal of glioma surgery. By incorporating improved intraoperative visualization with the 3D exoscope combined with 5-ALA fluorescence, in addition to neuronavigation and diffusion tensor imaging (DTI) fiber tracking, the safety of resection of tumors in eloquent brain regions can be maximized. This video highlights some of the various intraoperative adjuncts used in brain tumor surgery for high-grade glioma. In this case, the authors highlight the resection of a left posterior temporal lobe high-grade glioma in a 33-year-old patient, who initially presented with seizures, word-finding difficulty, and right-sided weakness. They demonstrate the multiple surgical adjuncts used both before and during surgical resection, and how multiple adjuncts can be effectively orchestrated to make surgery in eloquent brain areas safer for patients. Patient consent was obtained for publication. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21174

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