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Jaco J M Zwanenburg - One of the best experts on this subject based on the ideXlab platform.
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velocity and pulsatility measures in the Perforating Arteries of the basal ganglia at 3t mri in reference to 7t mri
Frontiers in Neuroscience, 2021Co-Authors: Tine Arts, G J Biessels, Timion A Meijs, Heynric B Grotenhuis, Michiel Voskuil, Jeroen C W Siero, Jaco J M ZwanenburgAbstract:Cerebral Perforating artery flow velocity and pulsatility can be measured using 7 tesla (T) MRI. Enabling these flow metrics on more widely available 3T systems would make them more employable. It is currently unknown whether these measurements can be performed at 3T MRI due to the lower signal-to-noise ratio (SNR). Therefore, the aim of this study is to investigate if flow velocity and pulsatility in the Perforating Arteries of the basal ganglia (BG) can be measured at 3T MRI and assess the agreement with 7T MRI measurements as reference. Twenty-nine subjects were included, of which 14 patients with aortic coarctation [median age 29 years (21-72)] and 15 controls [median age 27 years (22-64)]. Using a cardiac-gated 2D phase-contrast MRI sequence BG Perforating Arteries were imaged at 3T and 7T MRI and Perforating artery density (N density , #/cm2), flow velocity (V mean , cm/s) and pulsatility index (PI) were determined. Agreement between scanner modalities was assessed using correlation and difference plots with linear regression. A p-value ≤ 0.05 indicated statistical significance. It was shown that Perforating artery flow velocity and pulsatility can be measured at 3T MRI (N density = 0.21 ± 0.11; V mean = 6.04 ± 1.27; PI = 0.49 ± 0.19), although values differed from 7T MRI measurements (N density = 0.95 ± 0.21; V mean = 3.89 ± 0.56; PI = 0.28 ± 0.08). The number of detected Arteries was lower at 3T (5 ± 3) than 7T MRI (24 ± 6), indicating that 3T MRI is on average a factor 4.8 less sensitive to detect cerebral Perforating Arteries. Comparison with 7T MRI as reference showed some agreement in N density , but little to no agreement for V mean and PI. Equalizing the modalities' sensitivity by comparing the detected Arteries on 7T MRI with the highest velocity with all vessels detected on 3T MRI, showed some improvement in agreement for PI, but not for V mean . This study shows that it is possible to measure cerebral Perforating artery flow velocity and pulsatility at 3T MRI, although an approximately fivefold sample size is needed at 3T relative to 7T MRI for a given effect size, and the measurements should be performed with equal scanner field strength and protocol.
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higher pulsatility in cerebral Perforating Arteries in patients with small vessel disease related stroke a 7t mri study
Stroke, 2019Co-Authors: Lennart J Geurts, Peter R. Luijten, Jaco J M Zwanenburg, Catharina J M Klijn, G J BiesselsAbstract:Background and Purpose- Cerebral small vessel disease (SVD) is a major cause of stroke and dementia, but underlying disease mechanisms are still largely unknown, partly because of the difficulty in assessing small vessel function in vivo. We developed a method to measure blood flow velocity pulsatility in Perforating Arteries in the basal ganglia and semioval center. We aimed to determine whether this novel method could detect functional abnormalities at the level of the small vessels in patients with stroke attributable to SVD. Methods- We investigated 10 patients with lacunar infarction (mean age 61 years, 80% men), 11 patients with deep intracerebral hemorrhage (ICH) considered to be caused by SVD (ICH, mean age 58 years, 82% men) and 18 healthy controls that were age- and sex-matched. We performed 2-dimensional phase contrast magnetic resonance imaging at 7 T to measure time-resolved blood flow velocity in cerebral Perforating Arteries of the semioval center and the basal ganglia. We compared the number of detected Arteries, pulsatility index and mean velocity between the patient groups and controls. Results- In the basal ganglia, the number of detected perforators was lower in lacunar infarction (26±9, P=0.01) and deep ICH patients (28±6, P=0.02) than in controls (35±7). The pulsatility index in the basal ganglia was higher in lacunar infarction (1.07±0.13, P=0.03), and deep ICH patients (1.02±0.11, P=0.11), than in controls (0.94±0.10). Observations in the semioval center were similar. Number of detected perforators was lower in lacunar infarction (32±18, P=0.06), and deep ICH patients (28±18, P=0.02), than in controls (45±16). The pulsatility index was higher in lacunar infarction (1.18±0.15, P=0.02), and deep ICH patients (1.17±0.14, P=0.045) than in controls (1.08±0.07). No velocity differences were detected. Conclusions- This exploratory study shows that SVD can be expressed in terms of functional measures, such as pulsatility index, which are derived directly from the small vessels themselves. Future studies may use this technique to further unravel the mechanisms underlying SVD.
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vascular reactivity in small cerebral Perforating Arteries with 7 t phase contrast mri a proof of concept study
NeuroImage, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jeroen C W Siero, Alex A Bhogal, Jaco J M ZwanenburgAbstract:Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral Perforating Arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2. The hypercapnic challenge increased (fit ± standard error) flow velocity by 0.7 ± 0.3%/mmHg in the CSO (P < 0.01). Moreover, the number of detected perforators (mean [range]) increased from 63 [27-88] to 108 [61-178] (P < 0.001). In the BG, the hypercapnic challenge increased flow velocity by 1.6 ± 0.5%/mmHg (P < 0.001), and the number of detected perforators increased from 48 [24-66] to 63 [32-91] (P < 0.01). The flow in the MCA increased by 5.2 ± 1.4%/mmHg (P < 0.01). Small vessel specific reactivity can now be measured in perforators of the CSO and BG, using 2D phase contrast at 7 T.
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better and faster velocity pulsatility assessment in cerebral white matter Perforating Arteries with 7t quantitative flow mri through improved slice profile acquisition scheme and postprocessing
Magnetic Resonance in Medicine, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jaco J M ZwanenburgAbstract:Purpose A previously published cardiac-gated 2D Qflow protocol at 7 T in cerebral Perforating Arteries was optimized to reduce velocity underestimation and improve temporal resolution. Methods First, the signal-to-noise ratio (SNR) gain of the velocity measurement (SNRv) was tested for two signal averages versus one. Second, the decrease in velocity underestimation with a tilted optimized nonsaturating excitation (TONE) pulse was tested. Third, the decrease in pulsatility index (PI) underestimation through improved temporal resolution was tested. Test-retest agreement was measured for the resulting acquisition in older volunteers (mean age 63 years), and the results were compared with the other volunteers (mean age 26 years). Results Using two signal averages increased SNRv by only 12% (P = 0.04), probably due to motion of the subvoxel-size Arteries. The TONE decreased velocity underestimation, thereby increasing the mean velocity from 0.52 to 0.67 cm/s (P < 0.001). The PI increased substantially with increasing temporal resolution. The test-retest agreement showed good coefficients of repeatability of 0.18 cm/s for velocity and 0.14 for PI. The measured velocity was lower in the older group: 0.42 versus 0.51 cm/s (P = 0.05). Conclusions The optimized sequence yields better velocity and PI estimates in small vessels, has twice as good test-retest agreement, and has a suitable scan time for use in patients. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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assessment of blood flow velocity and pulsatility in cerebral Perforating Arteries with 7 t quantitative flow mri
NMR in Biomedicine, 2016Co-Authors: Willem H Bouvy, Lennart J Geurts, Hugo J Kuijf, P R Luijten, L J Kappelle, G J Biessels, Jaco J M ZwanenburgAbstract:Thus far, blood flow velocity measurements with MRI have only been feasible in large cerebral blood vessels. High-field-strength MRI may now permit velocity measurements in much smaller Arteries. The aim of this proof of principle study was to measure the blood flow velocity and pulsatility of cerebral Perforating Arteries with 7-T MRI. A two-dimensional (2D), single-slice quantitative flow (Qflow) sequence was used to measure blood flow velocities during the cardiac cycle in Perforating Arteries in the basal ganglia (BG) and semioval centre (CSO), from which a mean normalised pulsatility index (PI) per region was calculated (n = 6 human subjects, aged 23–29 years). The precision of the measurements was determined by repeated imaging and performance of a Bland–Altman analysis, and confounding effects of partial volume and noise on the measurements were simulated. The median number of Arteries included was 14 in CSO and 19 in BG. In CSO, the average velocity per volunteer was in the range 0.5–1.0 cm/s and PI was 0.24–0.39. In BG, the average velocity was in the range 3.9–5.1 cm/s and PI was 0.51–0.62. Between repeated scans, the precision of the average, maximum and minimum velocity per vessel decreased with the size of the Arteries, and was relatively low in CSO and BG compared with the M1 segment of the middle cerebral artery. The precision of PI per region was comparable with that of M1. The simulations proved that velocities can be measured in vessels with a diameter of more than 80 µm, but are underestimated as a result of partial volume effects, whilst pulsatility is overestimated. Blood flow velocity and pulsatility in cerebral Perforating Arteries have been measured directly in vivo for the first time, with moderate to good precision. This may be an interesting metric for the study of haemodynamic changes in aging and cerebral small vessel disease. © 2015 The Authors NMR in Biomedicine Published by John Wiley & Sons Ltd.
Peter R. Luijten - One of the best experts on this subject based on the ideXlab platform.
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higher pulsatility in cerebral Perforating Arteries in patients with small vessel disease related stroke a 7t mri study
Stroke, 2019Co-Authors: Lennart J Geurts, Peter R. Luijten, Jaco J M Zwanenburg, Catharina J M Klijn, G J BiesselsAbstract:Background and Purpose- Cerebral small vessel disease (SVD) is a major cause of stroke and dementia, but underlying disease mechanisms are still largely unknown, partly because of the difficulty in assessing small vessel function in vivo. We developed a method to measure blood flow velocity pulsatility in Perforating Arteries in the basal ganglia and semioval center. We aimed to determine whether this novel method could detect functional abnormalities at the level of the small vessels in patients with stroke attributable to SVD. Methods- We investigated 10 patients with lacunar infarction (mean age 61 years, 80% men), 11 patients with deep intracerebral hemorrhage (ICH) considered to be caused by SVD (ICH, mean age 58 years, 82% men) and 18 healthy controls that were age- and sex-matched. We performed 2-dimensional phase contrast magnetic resonance imaging at 7 T to measure time-resolved blood flow velocity in cerebral Perforating Arteries of the semioval center and the basal ganglia. We compared the number of detected Arteries, pulsatility index and mean velocity between the patient groups and controls. Results- In the basal ganglia, the number of detected perforators was lower in lacunar infarction (26±9, P=0.01) and deep ICH patients (28±6, P=0.02) than in controls (35±7). The pulsatility index in the basal ganglia was higher in lacunar infarction (1.07±0.13, P=0.03), and deep ICH patients (1.02±0.11, P=0.11), than in controls (0.94±0.10). Observations in the semioval center were similar. Number of detected perforators was lower in lacunar infarction (32±18, P=0.06), and deep ICH patients (28±18, P=0.02), than in controls (45±16). The pulsatility index was higher in lacunar infarction (1.18±0.15, P=0.02), and deep ICH patients (1.17±0.14, P=0.045) than in controls (1.08±0.07). No velocity differences were detected. Conclusions- This exploratory study shows that SVD can be expressed in terms of functional measures, such as pulsatility index, which are derived directly from the small vessels themselves. Future studies may use this technique to further unravel the mechanisms underlying SVD.
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vascular reactivity in small cerebral Perforating Arteries with 7 t phase contrast mri a proof of concept study
NeuroImage, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jeroen C W Siero, Alex A Bhogal, Jaco J M ZwanenburgAbstract:Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral Perforating Arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2. The hypercapnic challenge increased (fit ± standard error) flow velocity by 0.7 ± 0.3%/mmHg in the CSO (P < 0.01). Moreover, the number of detected perforators (mean [range]) increased from 63 [27-88] to 108 [61-178] (P < 0.001). In the BG, the hypercapnic challenge increased flow velocity by 1.6 ± 0.5%/mmHg (P < 0.001), and the number of detected perforators increased from 48 [24-66] to 63 [32-91] (P < 0.01). The flow in the MCA increased by 5.2 ± 1.4%/mmHg (P < 0.01). Small vessel specific reactivity can now be measured in perforators of the CSO and BG, using 2D phase contrast at 7 T.
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better and faster velocity pulsatility assessment in cerebral white matter Perforating Arteries with 7t quantitative flow mri through improved slice profile acquisition scheme and postprocessing
Magnetic Resonance in Medicine, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jaco J M ZwanenburgAbstract:Purpose A previously published cardiac-gated 2D Qflow protocol at 7 T in cerebral Perforating Arteries was optimized to reduce velocity underestimation and improve temporal resolution. Methods First, the signal-to-noise ratio (SNR) gain of the velocity measurement (SNRv) was tested for two signal averages versus one. Second, the decrease in velocity underestimation with a tilted optimized nonsaturating excitation (TONE) pulse was tested. Third, the decrease in pulsatility index (PI) underestimation through improved temporal resolution was tested. Test-retest agreement was measured for the resulting acquisition in older volunteers (mean age 63 years), and the results were compared with the other volunteers (mean age 26 years). Results Using two signal averages increased SNRv by only 12% (P = 0.04), probably due to motion of the subvoxel-size Arteries. The TONE decreased velocity underestimation, thereby increasing the mean velocity from 0.52 to 0.67 cm/s (P < 0.001). The PI increased substantially with increasing temporal resolution. The test-retest agreement showed good coefficients of repeatability of 0.18 cm/s for velocity and 0.14 for PI. The measured velocity was lower in the older group: 0.42 versus 0.51 cm/s (P = 0.05). Conclusions The optimized sequence yields better velocity and PI estimates in small vessels, has twice as good test-retest agreement, and has a suitable scan time for use in patients. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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Visualization of perivascular spaces and Perforating Arteries with 7 T magnetic resonance imaging.
Investigative radiology, 2014Co-Authors: Willem H Bouvy, Peter R. Luijten, Hugo J Kuijf, G J Biessels, L. Jaap Kappelle, Jaco J M ZwanenburgAbstract:ObjectivesThe objectives of this study were to explore the possibilities of 7 T brain magnetic resonance imaging to visualize perivascular spaces (PVS) and to depict their related blood vessels.Materials and MethodsFive subjects aged 19 to 27 years and 5 subjects aged 51 to 72 years were scanned. Hi
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Perforating Arteries originating from the posterior communicating artery a 7 0 tesla mri study
European Radiology, 2009Co-Authors: Mandy M.a. Conijn, J. Hendrikse, Taro Takahara, M. I. Geerlings, Jaco J M Zwanenburg, Willem Th P M Mali, Peter R. LuijtenAbstract:The aim of this study was to investigate the ability of time-of-flight (TOF) magnetic resonance (MR) angiography at 7.0 Tesla to show the Perforating branches of the posterior communicating artery (PCoA), and to investigate the presence of such visible Perforating branches in relation to the size of the feeding PCoA. The secondary aim was to visualise and describe the anterior choroidal artery and the Perforating branches of the P1-segment of posterior cerebral artery (P1). Forty-six healthy volunteers underwent TOF MR angiography at 7.0 Tesla. With 7.0-Tesla imaging, we visualised for the first time Perforating Arteries originating from the PCoA in vivo without the use of contrast agents. A Perforating artery from the PCoA was found in a large proportion of the PCoAs (64%). The presence was associated with a larger diameter of the underlying PCoA (1.23 versus 1.06 mm, P = 0.03). The anterior choroidal artery was visible bilaterally in all participants. In 83% of all P1s, one or two Perforating branches were visible. Non-invasive assessment of the Perforating Arteries of the PCoA together with the anterior choroidal artery and the Perforating Arteries of the P1 may increase our understanding of infarcts in the deep brain structures supplied by these Arteries.
G J Biessels - One of the best experts on this subject based on the ideXlab platform.
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velocity and pulsatility measures in the Perforating Arteries of the basal ganglia at 3t mri in reference to 7t mri
Frontiers in Neuroscience, 2021Co-Authors: Tine Arts, G J Biessels, Timion A Meijs, Heynric B Grotenhuis, Michiel Voskuil, Jeroen C W Siero, Jaco J M ZwanenburgAbstract:Cerebral Perforating artery flow velocity and pulsatility can be measured using 7 tesla (T) MRI. Enabling these flow metrics on more widely available 3T systems would make them more employable. It is currently unknown whether these measurements can be performed at 3T MRI due to the lower signal-to-noise ratio (SNR). Therefore, the aim of this study is to investigate if flow velocity and pulsatility in the Perforating Arteries of the basal ganglia (BG) can be measured at 3T MRI and assess the agreement with 7T MRI measurements as reference. Twenty-nine subjects were included, of which 14 patients with aortic coarctation [median age 29 years (21-72)] and 15 controls [median age 27 years (22-64)]. Using a cardiac-gated 2D phase-contrast MRI sequence BG Perforating Arteries were imaged at 3T and 7T MRI and Perforating artery density (N density , #/cm2), flow velocity (V mean , cm/s) and pulsatility index (PI) were determined. Agreement between scanner modalities was assessed using correlation and difference plots with linear regression. A p-value ≤ 0.05 indicated statistical significance. It was shown that Perforating artery flow velocity and pulsatility can be measured at 3T MRI (N density = 0.21 ± 0.11; V mean = 6.04 ± 1.27; PI = 0.49 ± 0.19), although values differed from 7T MRI measurements (N density = 0.95 ± 0.21; V mean = 3.89 ± 0.56; PI = 0.28 ± 0.08). The number of detected Arteries was lower at 3T (5 ± 3) than 7T MRI (24 ± 6), indicating that 3T MRI is on average a factor 4.8 less sensitive to detect cerebral Perforating Arteries. Comparison with 7T MRI as reference showed some agreement in N density , but little to no agreement for V mean and PI. Equalizing the modalities' sensitivity by comparing the detected Arteries on 7T MRI with the highest velocity with all vessels detected on 3T MRI, showed some improvement in agreement for PI, but not for V mean . This study shows that it is possible to measure cerebral Perforating artery flow velocity and pulsatility at 3T MRI, although an approximately fivefold sample size is needed at 3T relative to 7T MRI for a given effect size, and the measurements should be performed with equal scanner field strength and protocol.
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higher pulsatility in cerebral Perforating Arteries in patients with small vessel disease related stroke a 7t mri study
Stroke, 2019Co-Authors: Lennart J Geurts, Peter R. Luijten, Jaco J M Zwanenburg, Catharina J M Klijn, G J BiesselsAbstract:Background and Purpose- Cerebral small vessel disease (SVD) is a major cause of stroke and dementia, but underlying disease mechanisms are still largely unknown, partly because of the difficulty in assessing small vessel function in vivo. We developed a method to measure blood flow velocity pulsatility in Perforating Arteries in the basal ganglia and semioval center. We aimed to determine whether this novel method could detect functional abnormalities at the level of the small vessels in patients with stroke attributable to SVD. Methods- We investigated 10 patients with lacunar infarction (mean age 61 years, 80% men), 11 patients with deep intracerebral hemorrhage (ICH) considered to be caused by SVD (ICH, mean age 58 years, 82% men) and 18 healthy controls that were age- and sex-matched. We performed 2-dimensional phase contrast magnetic resonance imaging at 7 T to measure time-resolved blood flow velocity in cerebral Perforating Arteries of the semioval center and the basal ganglia. We compared the number of detected Arteries, pulsatility index and mean velocity between the patient groups and controls. Results- In the basal ganglia, the number of detected perforators was lower in lacunar infarction (26±9, P=0.01) and deep ICH patients (28±6, P=0.02) than in controls (35±7). The pulsatility index in the basal ganglia was higher in lacunar infarction (1.07±0.13, P=0.03), and deep ICH patients (1.02±0.11, P=0.11), than in controls (0.94±0.10). Observations in the semioval center were similar. Number of detected perforators was lower in lacunar infarction (32±18, P=0.06), and deep ICH patients (28±18, P=0.02), than in controls (45±16). The pulsatility index was higher in lacunar infarction (1.18±0.15, P=0.02), and deep ICH patients (1.17±0.14, P=0.045) than in controls (1.08±0.07). No velocity differences were detected. Conclusions- This exploratory study shows that SVD can be expressed in terms of functional measures, such as pulsatility index, which are derived directly from the small vessels themselves. Future studies may use this technique to further unravel the mechanisms underlying SVD.
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vascular reactivity in small cerebral Perforating Arteries with 7 t phase contrast mri a proof of concept study
NeuroImage, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jeroen C W Siero, Alex A Bhogal, Jaco J M ZwanenburgAbstract:Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral Perforating Arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2. The hypercapnic challenge increased (fit ± standard error) flow velocity by 0.7 ± 0.3%/mmHg in the CSO (P < 0.01). Moreover, the number of detected perforators (mean [range]) increased from 63 [27-88] to 108 [61-178] (P < 0.001). In the BG, the hypercapnic challenge increased flow velocity by 1.6 ± 0.5%/mmHg (P < 0.001), and the number of detected perforators increased from 48 [24-66] to 63 [32-91] (P < 0.01). The flow in the MCA increased by 5.2 ± 1.4%/mmHg (P < 0.01). Small vessel specific reactivity can now be measured in perforators of the CSO and BG, using 2D phase contrast at 7 T.
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better and faster velocity pulsatility assessment in cerebral white matter Perforating Arteries with 7t quantitative flow mri through improved slice profile acquisition scheme and postprocessing
Magnetic Resonance in Medicine, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jaco J M ZwanenburgAbstract:Purpose A previously published cardiac-gated 2D Qflow protocol at 7 T in cerebral Perforating Arteries was optimized to reduce velocity underestimation and improve temporal resolution. Methods First, the signal-to-noise ratio (SNR) gain of the velocity measurement (SNRv) was tested for two signal averages versus one. Second, the decrease in velocity underestimation with a tilted optimized nonsaturating excitation (TONE) pulse was tested. Third, the decrease in pulsatility index (PI) underestimation through improved temporal resolution was tested. Test-retest agreement was measured for the resulting acquisition in older volunteers (mean age 63 years), and the results were compared with the other volunteers (mean age 26 years). Results Using two signal averages increased SNRv by only 12% (P = 0.04), probably due to motion of the subvoxel-size Arteries. The TONE decreased velocity underestimation, thereby increasing the mean velocity from 0.52 to 0.67 cm/s (P < 0.001). The PI increased substantially with increasing temporal resolution. The test-retest agreement showed good coefficients of repeatability of 0.18 cm/s for velocity and 0.14 for PI. The measured velocity was lower in the older group: 0.42 versus 0.51 cm/s (P = 0.05). Conclusions The optimized sequence yields better velocity and PI estimates in small vessels, has twice as good test-retest agreement, and has a suitable scan time for use in patients. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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assessment of blood flow velocity and pulsatility in cerebral Perforating Arteries with 7 t quantitative flow mri
NMR in Biomedicine, 2016Co-Authors: Willem H Bouvy, Lennart J Geurts, Hugo J Kuijf, P R Luijten, L J Kappelle, G J Biessels, Jaco J M ZwanenburgAbstract:Thus far, blood flow velocity measurements with MRI have only been feasible in large cerebral blood vessels. High-field-strength MRI may now permit velocity measurements in much smaller Arteries. The aim of this proof of principle study was to measure the blood flow velocity and pulsatility of cerebral Perforating Arteries with 7-T MRI. A two-dimensional (2D), single-slice quantitative flow (Qflow) sequence was used to measure blood flow velocities during the cardiac cycle in Perforating Arteries in the basal ganglia (BG) and semioval centre (CSO), from which a mean normalised pulsatility index (PI) per region was calculated (n = 6 human subjects, aged 23–29 years). The precision of the measurements was determined by repeated imaging and performance of a Bland–Altman analysis, and confounding effects of partial volume and noise on the measurements were simulated. The median number of Arteries included was 14 in CSO and 19 in BG. In CSO, the average velocity per volunteer was in the range 0.5–1.0 cm/s and PI was 0.24–0.39. In BG, the average velocity was in the range 3.9–5.1 cm/s and PI was 0.51–0.62. Between repeated scans, the precision of the average, maximum and minimum velocity per vessel decreased with the size of the Arteries, and was relatively low in CSO and BG compared with the M1 segment of the middle cerebral artery. The precision of PI per region was comparable with that of M1. The simulations proved that velocities can be measured in vessels with a diameter of more than 80 µm, but are underestimated as a result of partial volume effects, whilst pulsatility is overestimated. Blood flow velocity and pulsatility in cerebral Perforating Arteries have been measured directly in vivo for the first time, with moderate to good precision. This may be an interesting metric for the study of haemodynamic changes in aging and cerebral small vessel disease. © 2015 The Authors NMR in Biomedicine Published by John Wiley & Sons Ltd.
Lennart J Geurts - One of the best experts on this subject based on the ideXlab platform.
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higher pulsatility in cerebral Perforating Arteries in patients with small vessel disease related stroke a 7t mri study
Stroke, 2019Co-Authors: Lennart J Geurts, Peter R. Luijten, Jaco J M Zwanenburg, Catharina J M Klijn, G J BiesselsAbstract:Background and Purpose- Cerebral small vessel disease (SVD) is a major cause of stroke and dementia, but underlying disease mechanisms are still largely unknown, partly because of the difficulty in assessing small vessel function in vivo. We developed a method to measure blood flow velocity pulsatility in Perforating Arteries in the basal ganglia and semioval center. We aimed to determine whether this novel method could detect functional abnormalities at the level of the small vessels in patients with stroke attributable to SVD. Methods- We investigated 10 patients with lacunar infarction (mean age 61 years, 80% men), 11 patients with deep intracerebral hemorrhage (ICH) considered to be caused by SVD (ICH, mean age 58 years, 82% men) and 18 healthy controls that were age- and sex-matched. We performed 2-dimensional phase contrast magnetic resonance imaging at 7 T to measure time-resolved blood flow velocity in cerebral Perforating Arteries of the semioval center and the basal ganglia. We compared the number of detected Arteries, pulsatility index and mean velocity between the patient groups and controls. Results- In the basal ganglia, the number of detected perforators was lower in lacunar infarction (26±9, P=0.01) and deep ICH patients (28±6, P=0.02) than in controls (35±7). The pulsatility index in the basal ganglia was higher in lacunar infarction (1.07±0.13, P=0.03), and deep ICH patients (1.02±0.11, P=0.11), than in controls (0.94±0.10). Observations in the semioval center were similar. Number of detected perforators was lower in lacunar infarction (32±18, P=0.06), and deep ICH patients (28±18, P=0.02), than in controls (45±16). The pulsatility index was higher in lacunar infarction (1.18±0.15, P=0.02), and deep ICH patients (1.17±0.14, P=0.045) than in controls (1.08±0.07). No velocity differences were detected. Conclusions- This exploratory study shows that SVD can be expressed in terms of functional measures, such as pulsatility index, which are derived directly from the small vessels themselves. Future studies may use this technique to further unravel the mechanisms underlying SVD.
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vascular reactivity in small cerebral Perforating Arteries with 7 t phase contrast mri a proof of concept study
NeuroImage, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jeroen C W Siero, Alex A Bhogal, Jaco J M ZwanenburgAbstract:Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral Perforating Arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2. The hypercapnic challenge increased (fit ± standard error) flow velocity by 0.7 ± 0.3%/mmHg in the CSO (P < 0.01). Moreover, the number of detected perforators (mean [range]) increased from 63 [27-88] to 108 [61-178] (P < 0.001). In the BG, the hypercapnic challenge increased flow velocity by 1.6 ± 0.5%/mmHg (P < 0.001), and the number of detected perforators increased from 48 [24-66] to 63 [32-91] (P < 0.01). The flow in the MCA increased by 5.2 ± 1.4%/mmHg (P < 0.01). Small vessel specific reactivity can now be measured in perforators of the CSO and BG, using 2D phase contrast at 7 T.
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better and faster velocity pulsatility assessment in cerebral white matter Perforating Arteries with 7t quantitative flow mri through improved slice profile acquisition scheme and postprocessing
Magnetic Resonance in Medicine, 2018Co-Authors: Lennart J Geurts, Peter R. Luijten, G J Biessels, Jaco J M ZwanenburgAbstract:Purpose A previously published cardiac-gated 2D Qflow protocol at 7 T in cerebral Perforating Arteries was optimized to reduce velocity underestimation and improve temporal resolution. Methods First, the signal-to-noise ratio (SNR) gain of the velocity measurement (SNRv) was tested for two signal averages versus one. Second, the decrease in velocity underestimation with a tilted optimized nonsaturating excitation (TONE) pulse was tested. Third, the decrease in pulsatility index (PI) underestimation through improved temporal resolution was tested. Test-retest agreement was measured for the resulting acquisition in older volunteers (mean age 63 years), and the results were compared with the other volunteers (mean age 26 years). Results Using two signal averages increased SNRv by only 12% (P = 0.04), probably due to motion of the subvoxel-size Arteries. The TONE decreased velocity underestimation, thereby increasing the mean velocity from 0.52 to 0.67 cm/s (P < 0.001). The PI increased substantially with increasing temporal resolution. The test-retest agreement showed good coefficients of repeatability of 0.18 cm/s for velocity and 0.14 for PI. The measured velocity was lower in the older group: 0.42 versus 0.51 cm/s (P = 0.05). Conclusions The optimized sequence yields better velocity and PI estimates in small vessels, has twice as good test-retest agreement, and has a suitable scan time for use in patients. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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assessment of blood flow velocity and pulsatility in cerebral Perforating Arteries with 7 t quantitative flow mri
NMR in Biomedicine, 2016Co-Authors: Willem H Bouvy, Lennart J Geurts, Hugo J Kuijf, P R Luijten, L J Kappelle, G J Biessels, Jaco J M ZwanenburgAbstract:Thus far, blood flow velocity measurements with MRI have only been feasible in large cerebral blood vessels. High-field-strength MRI may now permit velocity measurements in much smaller Arteries. The aim of this proof of principle study was to measure the blood flow velocity and pulsatility of cerebral Perforating Arteries with 7-T MRI. A two-dimensional (2D), single-slice quantitative flow (Qflow) sequence was used to measure blood flow velocities during the cardiac cycle in Perforating Arteries in the basal ganglia (BG) and semioval centre (CSO), from which a mean normalised pulsatility index (PI) per region was calculated (n = 6 human subjects, aged 23–29 years). The precision of the measurements was determined by repeated imaging and performance of a Bland–Altman analysis, and confounding effects of partial volume and noise on the measurements were simulated. The median number of Arteries included was 14 in CSO and 19 in BG. In CSO, the average velocity per volunteer was in the range 0.5–1.0 cm/s and PI was 0.24–0.39. In BG, the average velocity was in the range 3.9–5.1 cm/s and PI was 0.51–0.62. Between repeated scans, the precision of the average, maximum and minimum velocity per vessel decreased with the size of the Arteries, and was relatively low in CSO and BG compared with the M1 segment of the middle cerebral artery. The precision of PI per region was comparable with that of M1. The simulations proved that velocities can be measured in vessels with a diameter of more than 80 µm, but are underestimated as a result of partial volume effects, whilst pulsatility is overestimated. Blood flow velocity and pulsatility in cerebral Perforating Arteries have been measured directly in vivo for the first time, with moderate to good precision. This may be an interesting metric for the study of haemodynamic changes in aging and cerebral small vessel disease. © 2015 The Authors NMR in Biomedicine Published by John Wiley & Sons Ltd.
Zihao Zhang - One of the best experts on this subject based on the ideXlab platform.
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optimized inner volume 3d tse for high resolution vessel wall imaging of intracranial Perforating Arteries at 7t
Frontiers in Neuroscience, 2021Co-Authors: Qingle Kong, Dehe Weng, Yan Zhuo, Zihao ZhangAbstract:The impairment of microvessels can lead to neurologic diseases such as stroke and vascular dementia. The imaging of lumen and vessel wall of Perforating Arteries requires an extremely high resolution due to their small caliber size. Current imaging techniques have the difficulty in observing the wall of Perforating Arteries. In this study, we developed a 3D inner-volume (IV) TSE (SPACE) sequence with optimized 2D spatially selective excitation (SSE) RF pulses. The optimized SSE RF pulses were designed through a series of optimization including iterative RF pulse design, trajectory optimization, and phase convention of Carr-Purcell-Meiboom-Gill (CPMG) condition to meet the Perforating Arteries imaging demands. High resolution of isotropic 0.30 mm within 10 min was achieved for the black- blood images of lenticulostriate artery (LSA). The LSA lumen and vessel wall were imaged by the IV-SPACE sequence simultaneously. Images obtained by the optimized RF pulse has fewer aliasing artifacts from outside of ROI than the traditional pulse. The IV-SPACE images showed clearer delineation of vessel wall and lumen of LSA than conventional SPACE images. IV-SPACE might be a promising method for detecting microvasculopathies of cerebral vascular diseases.
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optimized inner volume 3d tse for high resolution vessel wall imaging of intracranial Perforating Arteries at 7t
Frontiers in Neuroscience, 2021Co-Authors: Qingle Kong, Dehe Weng, Yan Zhuo, Zihao ZhangAbstract:The impairment of microvessels can lead to neurologic diseases such as stroke and vascular dementia. The imaging of lumen and vessel wall of Perforating Arteries requires an extremely high resolution due to their small caliber size. Current imaging techniques have the difficulty in observing the wall of Perforating Arteries. In this study, we developed a 3D inner-volume (IV) TSE (SPACE) sequence with optimized 2D spatially selective excitation (SSE) RF pulses. The optimized SSE RF pulses were designed through a series of optimization including iterative RF pulse design, trajectory optimization, and phase convention of Carr-Purcell-Meiboom-Gill (CPMG) condition to meet the Perforating Arteries imaging demands. High resolution of isotropic 0.30mm within ten minutes was achieved for the black- blood images of lenticulostriate artery (LSA). The LSA lumen and vessel wall were imaged by the IV-SPACE sequence simultaneously. Images obtained by the optimized RF pulse has fewer aliasing artifacts from outside of ROI than the traditional pulse. The IV-SPACE images showed clearer delineation of vessel wall and lumen of LSA than conventional SPACE images. IV-SPACE might be a promising method for detecting microvasculopathies of cerebral vascular diseases.
