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Gilberto R Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts <70 cm3, we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess difference...
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm 3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts 3 , we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess differences in clinical and Imaging outcomes. Good clinical outcome was defined as a 3-month modified Rankin Scale score ≤2. Results— Among patients with initial infarcts >70 cm 3 , all had poor outcomes despite a 50% recanalization rate with mean infarct growth of 114 cm 3 . These patients also had the largest mean transit time volumes ( P 3 who recanalized early had the best clinical outcomes ( P P 3 . Conclusion— This study supports the use of an acute Diffusion-Weighted Imaging lesion volume threshold as an Imaging selection criterion for intra-arterial therapy. It also confirms the importance of early reperfusion in selected patients.
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Diffusion Weighted Imaging discriminates between cytotoxic and vasogenic edema in a patient with eclampsia
Stroke, 1997Co-Authors: Pamela W Schaefer, Gilberto R Gonzalez, Ferdinand Buonanno, Lee H SchwammAbstract:Background The pathophysiology of eclampsia remains unclear. While the majority of patients develop reversible T2 hyperintense signal abnormalities on MR scans and reversible neurological deficits, some patients do develop infarctions (permanent T2 hyperintense abnormalities) and permanent neurological impairment. Routine MRI cannot prospectively differentiate between these two patient groups. Echo-planar Diffusion-Weighted Imaging, however, is a new technique that clearly differentiates between cytotoxic and vasogenic edema. Case Description A 30-year-old woman developed symptoms consistent with eclampsia 24 hours after delivering premature twins. An MRI demonstrated extensive, diffuse T2 hyperintense signal abnormalities involving subcortical white matter and adjacent gray matter with a posterior predominance, consistent with either infarction or hypertensive ischemic encephalopathy. Diffusion-Weighted images demonstrated increased Diffusion, consistent with vasogenic edema and hypertensive ischemic enc...
Pamela W Schaefer - One of the best experts on this subject based on the ideXlab platform.
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts <70 cm3, we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess difference...
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm 3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts 3 , we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess differences in clinical and Imaging outcomes. Good clinical outcome was defined as a 3-month modified Rankin Scale score ≤2. Results— Among patients with initial infarcts >70 cm 3 , all had poor outcomes despite a 50% recanalization rate with mean infarct growth of 114 cm 3 . These patients also had the largest mean transit time volumes ( P 3 who recanalized early had the best clinical outcomes ( P P 3 . Conclusion— This study supports the use of an acute Diffusion-Weighted Imaging lesion volume threshold as an Imaging selection criterion for intra-arterial therapy. It also confirms the importance of early reperfusion in selected patients.
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Diffusion Weighted Imaging discriminates between cytotoxic and vasogenic edema in a patient with eclampsia
Stroke, 1997Co-Authors: Pamela W Schaefer, Gilberto R Gonzalez, Ferdinand Buonanno, Lee H SchwammAbstract:Background The pathophysiology of eclampsia remains unclear. While the majority of patients develop reversible T2 hyperintense signal abnormalities on MR scans and reversible neurological deficits, some patients do develop infarctions (permanent T2 hyperintense abnormalities) and permanent neurological impairment. Routine MRI cannot prospectively differentiate between these two patient groups. Echo-planar Diffusion-Weighted Imaging, however, is a new technique that clearly differentiates between cytotoxic and vasogenic edema. Case Description A 30-year-old woman developed symptoms consistent with eclampsia 24 hours after delivering premature twins. An MRI demonstrated extensive, diffuse T2 hyperintense signal abnormalities involving subcortical white matter and adjacent gray matter with a posterior predominance, consistent with either infarction or hypertensive ischemic encephalopathy. Diffusion-Weighted images demonstrated increased Diffusion, consistent with vasogenic edema and hypertensive ischemic enc...
Albert J Yoo - One of the best experts on this subject based on the ideXlab platform.
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts <70 cm3, we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess difference...
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mri based selection for intra arterial stroke therapy value of pretreatment Diffusion Weighted Imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization
Stroke, 2009Co-Authors: Albert J Yoo, Luis A Verduzco, Pamela W Schaefer, Joshua A Hirsch, James D Rabinov, Gilberto R GonzalezAbstract:Background and Purpose— Recent studies demonstrate that an acute Diffusion-Weighted Imaging lesion volume >70 cm 3 predicts poor outcome in patients with stroke. We sought to determine if this threshold could identify patients treated with intra-arterial therapy who would do poorly despite reperfusion. In patients with initial infarcts 3 , we sought to determine what effect recanalization and time to recanalization had on infarct growth and functional outcome. Methods— We retrospectively studied 34 consecutive patients with anterior circulation stroke who underwent pretreatment Diffusion-Weighted Imaging and perfusion-Weighted Imaging and subsequent intra-arterial therapy. Recanalization success and time to recanalization were recorded. Initial Diffusion-Weighted Imaging and mean transit time lesion and final infarct volumes were determined. Patients were stratified based on initial infarct volume, recanalization status, and time to recanalization. Statistical tests were performed to assess differences in clinical and Imaging outcomes. Good clinical outcome was defined as a 3-month modified Rankin Scale score ≤2. Results— Among patients with initial infarcts >70 cm 3 , all had poor outcomes despite a 50% recanalization rate with mean infarct growth of 114 cm 3 . These patients also had the largest mean transit time volumes ( P 3 who recanalized early had the best clinical outcomes ( P P 3 . Conclusion— This study supports the use of an acute Diffusion-Weighted Imaging lesion volume threshold as an Imaging selection criterion for intra-arterial therapy. It also confirms the importance of early reperfusion in selected patients.
Chingpo Lin - One of the best experts on this subject based on the ideXlab platform.
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resolving crossing fibres using constrained spherical deconvolution validation using Diffusion Weighted Imaging phantom data
NeuroImage, 2008Co-Authors: Jacquesdonald Tournier, Chunhung Yeh, Fernando Calamante, Kuanhung Cho, Alan Connelly, Chingpo LinAbstract:Diffusion-Weighted Imaging can potentially be used to infer the connectivity of the human brain in vivo using fibre-tracking techniques, and is therefore of great interest to neuroscientists and clinicians. A key requirement for fibre tracking is the accurate estimation of white matter fibre orientations within each Imaging voxel. The Diffusion tensor model, which is widely used for this purpose, has been shown to be inadequate in crossing fibre regions. A number of approaches have recently been proposed to address this issue, based on high angular resolution Diffusion-Weighted Imaging (HARDI) data. In this study, an experimental model of crossing fibres, consisting of water-filled plastic capillaries, is used to thoroughly assess three such techniques: constrained spherical deconvolution (CSD), super-resolved CSD (super-CSD) and Q-ball Imaging (QBI). HARDI data were acquired over a range of crossing angles and b-values, from which fibre orientations were computed using each technique. All techniques were capable of resolving the two fibre populations down to a crossing angle of 45°, and down to 30° for super-CSD. A bias was observed in the fibre orientations estimated by QBI for crossing angles other than 90°, consistent with previous simulation results. Finally, for a 45° crossing, the minimum b-value required to resolve the fibre orientations was 4000s/mm2 for QBI, 2000s/mm2 for CSD, and 1000s/mm2 for super-CSD. The quality of estimation of fibre orientations may profoundly affect fibre tracking attempts, and the results presented provide important additional information regarding performance characteristics of well-known methods.
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resolving crossing fibres using constrained spherical deconvolution validation using Diffusion Weighted Imaging phantom data
NeuroImage, 2008Co-Authors: Jacquesdonald Tournier, Chunhung Yeh, Fernando Calamante, Kuanhung Cho, Alan Connelly, Chingpo LinAbstract:Diffusion-Weighted Imaging can potentially be used to infer the connectivity of the human brain in vivo using fibre-tracking techniques, and is therefore of great interest to neuroscientists and clinicians. A key requirement for fibre tracking is the accurate estimation of white matter fibre orientations within each Imaging voxel. The Diffusion tensor model, which is widely used for this purpose, has been shown to be inadequate in crossing fibre regions. A number of approaches have recently been proposed to address this issue, based on high angular resolution Diffusion-Weighted Imaging (HARDI) data. In this study, an experimental model of crossing fibres, consisting of water-filled plastic capillaries, is used to thoroughly assess three such techniques: constrained spherical deconvolution (CSD), super-resolved CSD (super-CSD) and Q-ball Imaging (QBI). HARDI data were acquired over a range of crossing angles and b-values, from which fibre orientations were computed using each technique. All techniques were capable of resolving the two fibre populations down to a crossing angle of 45 degrees , and down to 30 degrees for super-CSD. A bias was observed in the fibre orientations estimated by QBI for crossing angles other than 90 degrees, consistent with previous simulation results. Finally, for a 45 degrees crossing, the minimum b-value required to resolve the fibre orientations was 4000 s/mm(2) for QBI, 2000 s/mm(2) for CSD, and 1000 s/mm(2) for super-CSD. The quality of estimation of fibre orientations may profoundly affect fibre tracking attempts, and the results presented provide important additional information regarding performance characteristics of well-known methods.
Alan Connelly - One of the best experts on this subject based on the ideXlab platform.
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resolving crossing fibres using constrained spherical deconvolution validation using Diffusion Weighted Imaging phantom data
NeuroImage, 2008Co-Authors: Jacquesdonald Tournier, Chunhung Yeh, Fernando Calamante, Kuanhung Cho, Alan Connelly, Chingpo LinAbstract:Diffusion-Weighted Imaging can potentially be used to infer the connectivity of the human brain in vivo using fibre-tracking techniques, and is therefore of great interest to neuroscientists and clinicians. A key requirement for fibre tracking is the accurate estimation of white matter fibre orientations within each Imaging voxel. The Diffusion tensor model, which is widely used for this purpose, has been shown to be inadequate in crossing fibre regions. A number of approaches have recently been proposed to address this issue, based on high angular resolution Diffusion-Weighted Imaging (HARDI) data. In this study, an experimental model of crossing fibres, consisting of water-filled plastic capillaries, is used to thoroughly assess three such techniques: constrained spherical deconvolution (CSD), super-resolved CSD (super-CSD) and Q-ball Imaging (QBI). HARDI data were acquired over a range of crossing angles and b-values, from which fibre orientations were computed using each technique. All techniques were capable of resolving the two fibre populations down to a crossing angle of 45°, and down to 30° for super-CSD. A bias was observed in the fibre orientations estimated by QBI for crossing angles other than 90°, consistent with previous simulation results. Finally, for a 45° crossing, the minimum b-value required to resolve the fibre orientations was 4000s/mm2 for QBI, 2000s/mm2 for CSD, and 1000s/mm2 for super-CSD. The quality of estimation of fibre orientations may profoundly affect fibre tracking attempts, and the results presented provide important additional information regarding performance characteristics of well-known methods.
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resolving crossing fibres using constrained spherical deconvolution validation using Diffusion Weighted Imaging phantom data
NeuroImage, 2008Co-Authors: Jacquesdonald Tournier, Chunhung Yeh, Fernando Calamante, Kuanhung Cho, Alan Connelly, Chingpo LinAbstract:Diffusion-Weighted Imaging can potentially be used to infer the connectivity of the human brain in vivo using fibre-tracking techniques, and is therefore of great interest to neuroscientists and clinicians. A key requirement for fibre tracking is the accurate estimation of white matter fibre orientations within each Imaging voxel. The Diffusion tensor model, which is widely used for this purpose, has been shown to be inadequate in crossing fibre regions. A number of approaches have recently been proposed to address this issue, based on high angular resolution Diffusion-Weighted Imaging (HARDI) data. In this study, an experimental model of crossing fibres, consisting of water-filled plastic capillaries, is used to thoroughly assess three such techniques: constrained spherical deconvolution (CSD), super-resolved CSD (super-CSD) and Q-ball Imaging (QBI). HARDI data were acquired over a range of crossing angles and b-values, from which fibre orientations were computed using each technique. All techniques were capable of resolving the two fibre populations down to a crossing angle of 45 degrees , and down to 30 degrees for super-CSD. A bias was observed in the fibre orientations estimated by QBI for crossing angles other than 90 degrees, consistent with previous simulation results. Finally, for a 45 degrees crossing, the minimum b-value required to resolve the fibre orientations was 4000 s/mm(2) for QBI, 2000 s/mm(2) for CSD, and 1000 s/mm(2) for super-CSD. The quality of estimation of fibre orientations may profoundly affect fibre tracking attempts, and the results presented provide important additional information regarding performance characteristics of well-known methods.