The Experts below are selected from a list of 3918 Experts worldwide ranked by ideXlab platform
Andreas Spuler - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Study of Cerebrospinal Fluid Dynamics in a Shaken Basal Cistern after Experimental Subarachnoid
2016Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Andreas SpulerAbstract:Background: Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings: A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force
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in vitro study of cerebrospinal fluid dynamics in a shaken Basal Cistern after experimental subarachnoid hemorrhage
PLOS ONE, 2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Daniel Hänggi, K. Affeld, Andreas SpulerAbstract:Background Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force. Conclusions/Significance From this in vitro study can be inferred that patient or head shaking with large shaking angles at low frequency is a promising therapeutic strategy to increase blood clearance from the subarachnoid space.
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Model of the Basal Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Surface of the reconstructed Basal Cistern in a lateral (A) and frontal (B) view. The g-arrow indicates the longitudinal axis of the human body which is aligned with the gravitational force for a sitting patient. Photo (C) shows the corresponding wax model and photo (D) the fabricated silicone model. Arrows indicate the sites of the inflow of the blood model as well as the inflow and outflow of the CSF model.
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Anatomical data of the model Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Three orthogonal slices of the MRI data with cerebrospinal fluid in the cerebral sulci, ventricles, and Basal Cisterns indicated in pink. The three-dimensionally reconstructed Basal Cistern (red) and the ventricular system (blue) are shown for a better space orientation.
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Experimental setup.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Left: Photo of the experimental setup mounted on the optical table: (1) CCD camera; (2) rigid frame mounting the Basal Cistern model (5), light source (6) and camera (1) on two pylons (4) allowing x-axis rotation; (3) syringe pump; (7) and (8) step motor with programmable controller; (9) pulse generator. Right: Schematic drawing of the experimental setup.
Ulrich Kertzscher - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Study of Cerebrospinal Fluid Dynamics in a Shaken Basal Cistern after Experimental Subarachnoid
2016Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Andreas SpulerAbstract:Background: Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings: A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force
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in vitro study of cerebrospinal fluid dynamics in a shaken Basal Cistern after experimental subarachnoid hemorrhage
PLOS ONE, 2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Daniel Hänggi, K. Affeld, Andreas SpulerAbstract:Background Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force. Conclusions/Significance From this in vitro study can be inferred that patient or head shaking with large shaking angles at low frequency is a promising therapeutic strategy to increase blood clearance from the subarachnoid space.
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Model of the Basal Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Surface of the reconstructed Basal Cistern in a lateral (A) and frontal (B) view. The g-arrow indicates the longitudinal axis of the human body which is aligned with the gravitational force for a sitting patient. Photo (C) shows the corresponding wax model and photo (D) the fabricated silicone model. Arrows indicate the sites of the inflow of the blood model as well as the inflow and outflow of the CSF model.
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Anatomical data of the model Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Three orthogonal slices of the MRI data with cerebrospinal fluid in the cerebral sulci, ventricles, and Basal Cisterns indicated in pink. The three-dimensionally reconstructed Basal Cistern (red) and the ventricular system (blue) are shown for a better space orientation.
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Experimental setup.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Left: Photo of the experimental setup mounted on the optical table: (1) CCD camera; (2) rigid frame mounting the Basal Cistern model (5), light source (6) and camera (1) on two pylons (4) allowing x-axis rotation; (3) syringe pump; (7) and (8) step motor with programmable controller; (9) pulse generator. Right: Schematic drawing of the experimental setup.
Clare N Gallagher - One of the best experts on this subject based on the ideXlab platform.
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decompressive craniectomy in patients with traumatic brain injury are the usual indications congruent with those evaluated in clinical trials
Neurocritical Care, 2016Co-Authors: Andreas H Kramer, Nathan P Deis, Stacy Ruddell, Philippe Couillard, David A Zygun, Christopher J Doig, Clare N GallagherAbstract:In patients with traumatic brain injury (TBI), multicenter randomized controlled trials have assessed decompressive craniectomy (DC) exclusively as treatment for refractory elevation of intracranial pressure (ICP). DC reliably lowers ICP but does not necessarily improve outcomes. However, some patients undergo DC as treatment for impending or established transtentorial herniation, irrespective of ICP. We performed a population-based cohort study assessing consecutive patients with moderate–severe TBI. Indications for DC were compared with enrollment criteria for the DECRA and RESCUE-ICP trials. Of 644 consecutive patients, 51 (8 %) were treated with DC. All patients undergoing DC had compressed Basal Cisterns, 82 % had at least temporary preoperative loss of ≥1 pupillary light reflex (PLR), and 80 % had >5 mm of midline shift. Most DC procedures (67 %) were “primary,” having been performed concomitantly with evacuation of a space-occupying lesion. ICP measurements influenced the decision to perform DC in 18 % of patients. Only 10 and 16 % of patients, respectively, would have been eligible for the DECRA and RESCUE-ICP trials. DC improved Basal Cistern compression in 76 %, and midline shift in 94 % of patients. Among patients with ≥1 absent PLR at admission, DC was associated with lower mortality (46 vs. 68 %, p = 0.03), especially when the admission Marshall CT score was 3–4 (p = 0.0005). No patients treated with DC progressed to brain death. Variables predictive of poor outcome following DC included loss of PLR(s), poor motor score, midline shift ≥11 mm, and development of perioperative cerebral infarcts. DC is most often performed for clinical and radiographic evidence of herniation, rather than for refractory ICP elevation. Results of previously completed randomized trials do not directly apply to a large proportion of patients undergoing DC in practice.
Leonid Goubergrits - One of the best experts on this subject based on the ideXlab platform.
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In Vitro Study of Cerebrospinal Fluid Dynamics in a Shaken Basal Cistern after Experimental Subarachnoid
2016Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Andreas SpulerAbstract:Background: Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings: A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force
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in vitro study of cerebrospinal fluid dynamics in a shaken Basal Cistern after experimental subarachnoid hemorrhage
PLOS ONE, 2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Daniel Hänggi, K. Affeld, Andreas SpulerAbstract:Background Cerebral arterial vasospasm leads to delayed cerebral ischemia and constitutes the major delayed complication following aneurysmal subarachnoid hemorrhage. Cerebral vasospasm can be reduced by increased blood clearance from the subarachnoid space. Clinical pilot studies allow the hypothesis that the clearance of subarachnoid blood is facilitated by means of head shaking. A major obstacle for meaningful clinical studies is the lack of data on appropriate parameters of head shaking. Our in vitro study aims to provide these essential parameters. Methodology/Principal Findings A model of the Basal cerebral Cistern was derived from human magnetic resonance imaging data. Subarachnoid hemorrhage was simulated by addition of dyed experimental blood to transparent experimental cerebrospinal fluid (CSF) filling the model of the Basal cerebral Cistern. Effects of various head positions and head motion settings (shaking angle amplitudes and shaking frequencies) on blood clearance were investigated using the quantitative dye washout method. Blood washout can be divided into two phases: Blood/CSF mixing and clearance. The major effect of shaking consists in better mixing of blood and CSF thereby increasing clearance rate. Without shaking, blood/CSF mixing and blood clearance in the Basal cerebral Cistern are hampered by differences in density and viscosity of blood and CSF. Blood clearance increases with decreased shaking frequency and with increased shaking angle amplitude. Head shaking facilitates clearance by varying the direction of gravitational force. Conclusions/Significance From this in vitro study can be inferred that patient or head shaking with large shaking angles at low frequency is a promising therapeutic strategy to increase blood clearance from the subarachnoid space.
-
Model of the Basal Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Surface of the reconstructed Basal Cistern in a lateral (A) and frontal (B) view. The g-arrow indicates the longitudinal axis of the human body which is aligned with the gravitational force for a sitting patient. Photo (C) shows the corresponding wax model and photo (D) the fabricated silicone model. Arrows indicate the sites of the inflow of the blood model as well as the inflow and outflow of the CSF model.
-
Anatomical data of the model Cistern.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Three orthogonal slices of the MRI data with cerebrospinal fluid in the cerebral sulci, ventricles, and Basal Cisterns indicated in pink. The three-dimensionally reconstructed Basal Cistern (red) and the ventricular system (blue) are shown for a better space orientation.
-
Experimental setup.
2012Co-Authors: Ulrich Kertzscher, Torsten Schneider, Leonid Goubergrits, Klaus Affeld, Daniel Hänggi, Andreas SpulerAbstract:Left: Photo of the experimental setup mounted on the optical table: (1) CCD camera; (2) rigid frame mounting the Basal Cistern model (5), light source (6) and camera (1) on two pylons (4) allowing x-axis rotation; (3) syringe pump; (7) and (8) step motor with programmable controller; (9) pulse generator. Right: Schematic drawing of the experimental setup.
Andreas H Kramer - One of the best experts on this subject based on the ideXlab platform.
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decompressive craniectomy in patients with traumatic brain injury are the usual indications congruent with those evaluated in clinical trials
Neurocritical Care, 2016Co-Authors: Andreas H Kramer, Nathan P Deis, Stacy Ruddell, Philippe Couillard, David A Zygun, Christopher J Doig, Clare N GallagherAbstract:In patients with traumatic brain injury (TBI), multicenter randomized controlled trials have assessed decompressive craniectomy (DC) exclusively as treatment for refractory elevation of intracranial pressure (ICP). DC reliably lowers ICP but does not necessarily improve outcomes. However, some patients undergo DC as treatment for impending or established transtentorial herniation, irrespective of ICP. We performed a population-based cohort study assessing consecutive patients with moderate–severe TBI. Indications for DC were compared with enrollment criteria for the DECRA and RESCUE-ICP trials. Of 644 consecutive patients, 51 (8 %) were treated with DC. All patients undergoing DC had compressed Basal Cisterns, 82 % had at least temporary preoperative loss of ≥1 pupillary light reflex (PLR), and 80 % had >5 mm of midline shift. Most DC procedures (67 %) were “primary,” having been performed concomitantly with evacuation of a space-occupying lesion. ICP measurements influenced the decision to perform DC in 18 % of patients. Only 10 and 16 % of patients, respectively, would have been eligible for the DECRA and RESCUE-ICP trials. DC improved Basal Cistern compression in 76 %, and midline shift in 94 % of patients. Among patients with ≥1 absent PLR at admission, DC was associated with lower mortality (46 vs. 68 %, p = 0.03), especially when the admission Marshall CT score was 3–4 (p = 0.0005). No patients treated with DC progressed to brain death. Variables predictive of poor outcome following DC included loss of PLR(s), poor motor score, midline shift ≥11 mm, and development of perioperative cerebral infarcts. DC is most often performed for clinical and radiographic evidence of herniation, rather than for refractory ICP elevation. Results of previously completed randomized trials do not directly apply to a large proportion of patients undergoing DC in practice.
