The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Sepehr Sani - One of the best experts on this subject based on the ideXlab platform.
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Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.
World Neurosurgery, 2018Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Mehmet Kocak, Sepehr SaniAbstract:Background The massa intermedia (MI) or interthalamic adhesion is an inconsistent band spanning between bilateral medial thalami that is absent in up to 20%–30% of individuals. Little is known of its significance, especially in regard to functional pathways. Probabilistic diffusion tensor imaging (DTI) has recently been used to seed the lateral habenula and define its afferent white matter pathway, the Stria Medullaris thalami (SM). We sought to determine whether the MI serves as a conduit for crossing of limbic fibers such as the SM. Methods Probabilistic DTI was performed on 10 subjects who had presence of a MI as visualized on magnetic resonance imaging. Tractography was also performed on 2 subjects without MI. Manual identification of the lateral habenula on axial T1-weighted magnetic resonance imaging was used for the initial seed region for tractography. Results In all subjects, the SM was reliably visualized. In 7 of the 10 subjects with MI, there was evidence of SM fibers that crossed to the ipsilateral hemisphere. Three subjects with small diameter MI did not have tractographic evidence of crossing SM fibers. Of the 7 subjects with crossing SM fibers within the MI, 5 showed predilection toward the right orbitofrontal cortex from both the left and right seed regions. Conclusions Probabilistic DTI provides evidence of SM fibers within the MI. Given its anatomic location as a bridging pathway between thalami, further studies are necessary to assess its role within the limbic functional network.
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Identification of the Stria Medullaris thalami using diffusion tensor imaging
NeuroImage. Clinical, 2016Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Daniel B. Eddelman, Mehmet Kocak, Sepehr SaniAbstract:Abstract Background Deep brain stimulation (DBS) via anatomical targeting of white matter tracts defined by diffusion tensor imaging (DTI) may be a useful tool in the treatment of pathologic neurophysiologic circuits implicated in certain disease states like treatment resistant depression (TRD). We sought to determine if DTI could be used to define the Stria Medullaris thalami (SM), the major afferent white matter pathway to the lateral habenula (LHb), a thalamic nucleus implicated in the pathophysiology of TRD. Methods Probabilistic DTI was performed on ten cerebral hemispheres in five patients who underwent preoperative MRI for DBS surgery. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography. Variations in tractography depending on chosen axial slice of the LHb and chosen voxel within the LHb were also assessed. Results In all hemispheres the SM was reliably visualized. Variations in chosen axial seed slice as well as variations in single seed placement did not lead to significant changes in SM tractography. Conclusions Probabilistic DTI can be used to visualize the SM which may ultimately provide utility for direct anatomic targeting in DBS surgery.
Ryan B. Kochanski - One of the best experts on this subject based on the ideXlab platform.
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Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.
World Neurosurgery, 2018Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Mehmet Kocak, Sepehr SaniAbstract:Background The massa intermedia (MI) or interthalamic adhesion is an inconsistent band spanning between bilateral medial thalami that is absent in up to 20%–30% of individuals. Little is known of its significance, especially in regard to functional pathways. Probabilistic diffusion tensor imaging (DTI) has recently been used to seed the lateral habenula and define its afferent white matter pathway, the Stria Medullaris thalami (SM). We sought to determine whether the MI serves as a conduit for crossing of limbic fibers such as the SM. Methods Probabilistic DTI was performed on 10 subjects who had presence of a MI as visualized on magnetic resonance imaging. Tractography was also performed on 2 subjects without MI. Manual identification of the lateral habenula on axial T1-weighted magnetic resonance imaging was used for the initial seed region for tractography. Results In all subjects, the SM was reliably visualized. In 7 of the 10 subjects with MI, there was evidence of SM fibers that crossed to the ipsilateral hemisphere. Three subjects with small diameter MI did not have tractographic evidence of crossing SM fibers. Of the 7 subjects with crossing SM fibers within the MI, 5 showed predilection toward the right orbitofrontal cortex from both the left and right seed regions. Conclusions Probabilistic DTI provides evidence of SM fibers within the MI. Given its anatomic location as a bridging pathway between thalami, further studies are necessary to assess its role within the limbic functional network.
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Identification of the Stria Medullaris thalami using diffusion tensor imaging
NeuroImage. Clinical, 2016Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Daniel B. Eddelman, Mehmet Kocak, Sepehr SaniAbstract:Abstract Background Deep brain stimulation (DBS) via anatomical targeting of white matter tracts defined by diffusion tensor imaging (DTI) may be a useful tool in the treatment of pathologic neurophysiologic circuits implicated in certain disease states like treatment resistant depression (TRD). We sought to determine if DTI could be used to define the Stria Medullaris thalami (SM), the major afferent white matter pathway to the lateral habenula (LHb), a thalamic nucleus implicated in the pathophysiology of TRD. Methods Probabilistic DTI was performed on ten cerebral hemispheres in five patients who underwent preoperative MRI for DBS surgery. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography. Variations in tractography depending on chosen axial slice of the LHb and chosen voxel within the LHb were also assessed. Results In all hemispheres the SM was reliably visualized. Variations in chosen axial seed slice as well as variations in single seed placement did not lead to significant changes in SM tractography. Conclusions Probabilistic DTI can be used to visualize the SM which may ultimately provide utility for direct anatomic targeting in DBS surgery.
Thomas Michaelis - One of the best experts on this subject based on the ideXlab platform.
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Chromium(VI) as a Novel MRI Contrast Agent for Cerebral White Matter: Preliminary Results in Mouse Brain
2016Co-Authors: In Vivo, Takashi Watanabe, Susann Boretius, Jens Frahm, Thomas MichaelisAbstract:This work demonstrates that intraventricular microinjections of a low dose of potassium dichromate (0.4 L of 10 mM solution) yield a specific contrast enhancement of white matter (WM) tracts in T1-weighted 3D MRI of mouse brain in vivo. Pro-nounced and persistent signal increases (40–100 % at 24 hr after injection) were observed in the corpus callosum, anterior commissure, fornix, and Stria Medullaris, as well as in the mam-millothalamic tract and fasciculus retroflexus. These results suggest that the extracellular diffusion of diamagnetic chromi-um(VI) (Cr(VI)) after injection is followed by a tissue-specific reduction to paramagnetic Cr(V) and (III), which relies predom-inantly on the oxidation of myelin lipids. Because Cr(VI)-induced contrast leads to only a mild unspecific enhancement (10–20%) of gray matter (GM) structures, such as the hippocampal for-mation, the method reveals novel information that differs from that obtainable using other paramagnetic ions, such a
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Chromium(VI) as a novel MRI contrast agent for cerebral white matter: Preliminary results in mouse brain in vivo
Magnetic resonance in medicine, 2006Co-Authors: Takashi Watanabe, Roland Tammer, Susann Boretius, Jens Frahm, Thomas MichaelisAbstract:This work demonstrates that intraventricular microinjections of a low dose of potassium dichromate (0.4 microL of 10 mM solution) yield a specific contrast enhancement of white matter (WM) tracts in T1-weighted 3D MRI of mouse brain in vivo. Pronounced and persistent signal increases (40-100% at 24 hr after injection) were observed in the corpus callosum, anterior commissure, fornix, and Stria Medullaris, as well as in the mammillothalamic tract and fasciculus retroflexus. These results suggest that the extracellular diffusion of diamagnetic chromium(VI) (Cr(VI)) after injection is followed by a tissue-specific reduction to paramagnetic Cr(V) and (III), which relies predominantly on the oxidation of myelin lipids. Because Cr(VI)-induced contrast leads to only a mild unspecific enhancement (10-20%) of gray matter (GM) structures, such as the hippocampal formation, the method reveals novel information that differs from that obtainable using other paramagnetic ions, such as manganese.
Robert J. Dawe - One of the best experts on this subject based on the ideXlab platform.
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Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.
World Neurosurgery, 2018Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Mehmet Kocak, Sepehr SaniAbstract:Background The massa intermedia (MI) or interthalamic adhesion is an inconsistent band spanning between bilateral medial thalami that is absent in up to 20%–30% of individuals. Little is known of its significance, especially in regard to functional pathways. Probabilistic diffusion tensor imaging (DTI) has recently been used to seed the lateral habenula and define its afferent white matter pathway, the Stria Medullaris thalami (SM). We sought to determine whether the MI serves as a conduit for crossing of limbic fibers such as the SM. Methods Probabilistic DTI was performed on 10 subjects who had presence of a MI as visualized on magnetic resonance imaging. Tractography was also performed on 2 subjects without MI. Manual identification of the lateral habenula on axial T1-weighted magnetic resonance imaging was used for the initial seed region for tractography. Results In all subjects, the SM was reliably visualized. In 7 of the 10 subjects with MI, there was evidence of SM fibers that crossed to the ipsilateral hemisphere. Three subjects with small diameter MI did not have tractographic evidence of crossing SM fibers. Of the 7 subjects with crossing SM fibers within the MI, 5 showed predilection toward the right orbitofrontal cortex from both the left and right seed regions. Conclusions Probabilistic DTI provides evidence of SM fibers within the MI. Given its anatomic location as a bridging pathway between thalami, further studies are necessary to assess its role within the limbic functional network.
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Identification of the Stria Medullaris thalami using diffusion tensor imaging
NeuroImage. Clinical, 2016Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Daniel B. Eddelman, Mehmet Kocak, Sepehr SaniAbstract:Abstract Background Deep brain stimulation (DBS) via anatomical targeting of white matter tracts defined by diffusion tensor imaging (DTI) may be a useful tool in the treatment of pathologic neurophysiologic circuits implicated in certain disease states like treatment resistant depression (TRD). We sought to determine if DTI could be used to define the Stria Medullaris thalami (SM), the major afferent white matter pathway to the lateral habenula (LHb), a thalamic nucleus implicated in the pathophysiology of TRD. Methods Probabilistic DTI was performed on ten cerebral hemispheres in five patients who underwent preoperative MRI for DBS surgery. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography. Variations in tractography depending on chosen axial slice of the LHb and chosen voxel within the LHb were also assessed. Results In all hemispheres the SM was reliably visualized. Variations in chosen axial seed slice as well as variations in single seed placement did not lead to significant changes in SM tractography. Conclusions Probabilistic DTI can be used to visualize the SM which may ultimately provide utility for direct anatomic targeting in DBS surgery.
Mehmet Kocak - One of the best experts on this subject based on the ideXlab platform.
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Identification of Stria Medullaris Fibers in the Massa Intermedia Using Diffusion Tensor Imaging.
World Neurosurgery, 2018Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Mehmet Kocak, Sepehr SaniAbstract:Background The massa intermedia (MI) or interthalamic adhesion is an inconsistent band spanning between bilateral medial thalami that is absent in up to 20%–30% of individuals. Little is known of its significance, especially in regard to functional pathways. Probabilistic diffusion tensor imaging (DTI) has recently been used to seed the lateral habenula and define its afferent white matter pathway, the Stria Medullaris thalami (SM). We sought to determine whether the MI serves as a conduit for crossing of limbic fibers such as the SM. Methods Probabilistic DTI was performed on 10 subjects who had presence of a MI as visualized on magnetic resonance imaging. Tractography was also performed on 2 subjects without MI. Manual identification of the lateral habenula on axial T1-weighted magnetic resonance imaging was used for the initial seed region for tractography. Results In all subjects, the SM was reliably visualized. In 7 of the 10 subjects with MI, there was evidence of SM fibers that crossed to the ipsilateral hemisphere. Three subjects with small diameter MI did not have tractographic evidence of crossing SM fibers. Of the 7 subjects with crossing SM fibers within the MI, 5 showed predilection toward the right orbitofrontal cortex from both the left and right seed regions. Conclusions Probabilistic DTI provides evidence of SM fibers within the MI. Given its anatomic location as a bridging pathway between thalami, further studies are necessary to assess its role within the limbic functional network.
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Identification of the Stria Medullaris thalami using diffusion tensor imaging
NeuroImage. Clinical, 2016Co-Authors: Ryan B. Kochanski, Robert J. Dawe, Daniel B. Eddelman, Mehmet Kocak, Sepehr SaniAbstract:Abstract Background Deep brain stimulation (DBS) via anatomical targeting of white matter tracts defined by diffusion tensor imaging (DTI) may be a useful tool in the treatment of pathologic neurophysiologic circuits implicated in certain disease states like treatment resistant depression (TRD). We sought to determine if DTI could be used to define the Stria Medullaris thalami (SM), the major afferent white matter pathway to the lateral habenula (LHb), a thalamic nucleus implicated in the pathophysiology of TRD. Methods Probabilistic DTI was performed on ten cerebral hemispheres in five patients who underwent preoperative MRI for DBS surgery. Manual identification of the LHb on axial T1 weighted MRI was used for the initial seed region for tractography. Variations in tractography depending on chosen axial slice of the LHb and chosen voxel within the LHb were also assessed. Results In all hemispheres the SM was reliably visualized. Variations in chosen axial seed slice as well as variations in single seed placement did not lead to significant changes in SM tractography. Conclusions Probabilistic DTI can be used to visualize the SM which may ultimately provide utility for direct anatomic targeting in DBS surgery.