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Feasibility of Diffusion Tractography for the Reconstruction of Intra-Thalamic and Cerebello-Thalamic Targets for Functional Neurosurgery: A Multi-Vendor Pilot Study in Four Subjects.

Jakab A, Werner B, Piccirelli M, Kovács K, Martin E, Thornton JS, Yousry T, Szekely G, O'Gorman Tuura R - Front Neuroanat (2016)

Bottom Line: While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners.DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus.In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus.

View Article: PubMed Central - PubMed

Affiliation: Center for Magnetic Resonance Imaging Research, University Children's HospitalZürich, Switzerland; Computational Imaging Research Lab, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of ViennaVienna, Austria.

ABSTRACT
Functional stereotactic neurosurgery by means of deep brain stimulation or ablation provides an effective treatment for movement disorders, but the outcome of surgical interventions depends on the accuracy by which the target structures are reached. The purpose of this pilot study was to evaluate the feasibility of diffusion tensor imaging (DTI) based probabilistic tractography of deep brain structures that are commonly used for pre- and perioperative targeting for functional neurosurgery. Three targets were reconstructed based on their significance as intervention sites or as a no-go area to avoid adverse side effects: the connections propagating from the thalamus to (1) primary and supplementary motor areas, (2) to somatosensory areas and the cerebello-thalamic tract (CTT). We evaluated the overlap of the reconstructed connectivity based targets with corresponding atlas based data, and tested the inter-subject and inter-scanner variability by acquiring repeated DTI from four volunteers, and on three MRI scanners with similar sequence parameters. Compared to a 3D histological atlas of the human thalamus, moderate overlaps of 35-50% were measured between connectivity- and atlas based volumes, while the minimal distance between the centerpoints of atlas and connectivity targets was 2.5 mm. The variability caused by the MRI scanner was similar to the inter-subject variability, except for connections with the postcentral gyrus where it was higher. While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners. DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus. In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus. Limitations of the currently used standard DTI protocols were exacerbated by large scanner-to-scanner variability of the connectivity-based targets.

No MeSH data available.


Related in: MedlinePlus

Comparison of atlas based VLpv nucleus and CBT using precentral gyrus connections.(A) Cross-sectional image derived from histological sections, in standard space (Big Brain Atlas, Amunts et al., 2013) with VLpv overlaid (red outlines) and the CBT from the precentral gyrus (green color scale); (B) 3D visualization of the CBT and atlas targets: connectivity-based targets were visualized in green color with different opacities reflecting to the summed probability across the study population (50–95th percentile range) while the VLpv was depicted in red 3D mesh; (C) Euclidian distance of the center-of-gravity of the CBT to the atlas based target: dependency on the applied threshold values; (D) volumetric overlap with atlas based targets: dependency on the applied threshold.
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Figure 2: Comparison of atlas based VLpv nucleus and CBT using precentral gyrus connections.(A) Cross-sectional image derived from histological sections, in standard space (Big Brain Atlas, Amunts et al., 2013) with VLpv overlaid (red outlines) and the CBT from the precentral gyrus (green color scale); (B) 3D visualization of the CBT and atlas targets: connectivity-based targets were visualized in green color with different opacities reflecting to the summed probability across the study population (50–95th percentile range) while the VLpv was depicted in red 3D mesh; (C) Euclidian distance of the center-of-gravity of the CBT to the atlas based target: dependency on the applied threshold values; (D) volumetric overlap with atlas based targets: dependency on the applied threshold.

Mentions: While there was a good agreement of the volumes along the antero-posterior axis of the most lateral parts of the thalamus, the connectivity patterns did not overlap with the medial parts of the VLpv or VPL nucleus, and only partially overlap with more medially located thalamic nuclei with known motor connectivity, such as the centro-median (CM) nucleus. In the midline, the VLpv was oriented more anteriorly, while the CBT defined this nucleus differently: the connectivity-based segment appeared wedge-shaped (Figures 1 and 2), with the tip oriented toward the center of the thalamus.


Feasibility of Diffusion Tractography for the Reconstruction of Intra-Thalamic and Cerebello-Thalamic Targets for Functional Neurosurgery: A Multi-Vendor Pilot Study in Four Subjects.

Jakab A, Werner B, Piccirelli M, Kovács K, Martin E, Thornton JS, Yousry T, Szekely G, O'Gorman Tuura R - Front Neuroanat (2016)

Comparison of atlas based VLpv nucleus and CBT using precentral gyrus connections.(A) Cross-sectional image derived from histological sections, in standard space (Big Brain Atlas, Amunts et al., 2013) with VLpv overlaid (red outlines) and the CBT from the precentral gyrus (green color scale); (B) 3D visualization of the CBT and atlas targets: connectivity-based targets were visualized in green color with different opacities reflecting to the summed probability across the study population (50–95th percentile range) while the VLpv was depicted in red 3D mesh; (C) Euclidian distance of the center-of-gravity of the CBT to the atlas based target: dependency on the applied threshold values; (D) volumetric overlap with atlas based targets: dependency on the applied threshold.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940380&req=5

Figure 2: Comparison of atlas based VLpv nucleus and CBT using precentral gyrus connections.(A) Cross-sectional image derived from histological sections, in standard space (Big Brain Atlas, Amunts et al., 2013) with VLpv overlaid (red outlines) and the CBT from the precentral gyrus (green color scale); (B) 3D visualization of the CBT and atlas targets: connectivity-based targets were visualized in green color with different opacities reflecting to the summed probability across the study population (50–95th percentile range) while the VLpv was depicted in red 3D mesh; (C) Euclidian distance of the center-of-gravity of the CBT to the atlas based target: dependency on the applied threshold values; (D) volumetric overlap with atlas based targets: dependency on the applied threshold.
Mentions: While there was a good agreement of the volumes along the antero-posterior axis of the most lateral parts of the thalamus, the connectivity patterns did not overlap with the medial parts of the VLpv or VPL nucleus, and only partially overlap with more medially located thalamic nuclei with known motor connectivity, such as the centro-median (CM) nucleus. In the midline, the VLpv was oriented more anteriorly, while the CBT defined this nucleus differently: the connectivity-based segment appeared wedge-shaped (Figures 1 and 2), with the tip oriented toward the center of the thalamus.

Bottom Line: While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners.DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus.In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus.

View Article: PubMed Central - PubMed

Affiliation: Center for Magnetic Resonance Imaging Research, University Children's HospitalZürich, Switzerland; Computational Imaging Research Lab, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of ViennaVienna, Austria.

ABSTRACT
Functional stereotactic neurosurgery by means of deep brain stimulation or ablation provides an effective treatment for movement disorders, but the outcome of surgical interventions depends on the accuracy by which the target structures are reached. The purpose of this pilot study was to evaluate the feasibility of diffusion tensor imaging (DTI) based probabilistic tractography of deep brain structures that are commonly used for pre- and perioperative targeting for functional neurosurgery. Three targets were reconstructed based on their significance as intervention sites or as a no-go area to avoid adverse side effects: the connections propagating from the thalamus to (1) primary and supplementary motor areas, (2) to somatosensory areas and the cerebello-thalamic tract (CTT). We evaluated the overlap of the reconstructed connectivity based targets with corresponding atlas based data, and tested the inter-subject and inter-scanner variability by acquiring repeated DTI from four volunteers, and on three MRI scanners with similar sequence parameters. Compared to a 3D histological atlas of the human thalamus, moderate overlaps of 35-50% were measured between connectivity- and atlas based volumes, while the minimal distance between the centerpoints of atlas and connectivity targets was 2.5 mm. The variability caused by the MRI scanner was similar to the inter-subject variability, except for connections with the postcentral gyrus where it was higher. While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners. DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus. In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus. Limitations of the currently used standard DTI protocols were exacerbated by large scanner-to-scanner variability of the connectivity-based targets.

No MeSH data available.


Related in: MedlinePlus