The Experts below are selected from a list of 3633 Experts worldwide ranked by ideXlab platform
Linda Knutsson - One of the best experts on this subject based on the ideXlab platform.
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perfusion mri of brain tumours a comparative study of pseudo continuous arterial spin labelling and Dynamic Susceptibility Contrast imaging
Neuroradiology, 2010Co-Authors: Hanna Jarnum, Elena Steffensen, Linda Knutsson, Ernsttorben Wilhelm Frund, Carsten Wiberg Simonsen, Soren Lundbyechristensen, Ajit Shankaranarayanan, David C Alsop, Finn Taagehoj JensenAbstract:Introduction The purpose of this study was to compare the non-invasive 3D pseudo-continuous arterial spin labelling (PC ASL) technique with the clinically established Dynamic Susceptibility Contrast perfusion magnetic resonance imaging (DSC-MRI) for evaluation of brain tumours.
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Absolute quantification of perfusion using Dynamic Susceptibility Contrast MRI: pitfalls and possibilities
Magnetic Resonance Materials in Physics Biology and Medicine, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Ronnie WirestamAbstract:Absolute quantification of cerebral blood flow, cerebral blood volume and mean transit time is desirable in the determination of tissue viability thresholds and tissue at risk in acute ischaemic stroke, as well as in cases where a global reduction in cerebral blood flow is expected, for example, in patients with dementia or depressive disorders. Absolute values are also useful when comparing sequential examinations of tissue perfusion parameters, for example, in the monitoring and follow-up of various kinds of therapy. Regardless of the method employed, a number of assumptions and approximations must be made to obtain absolute measures of perfusion. Furthermore, the different stages of data acquisition and processing are associated with various degrees of uncertainty. In this review, the problems of particular relevance to absolute quantification of cerebral perfusion parameters using Dynamic Susceptibility Contrast magnetic resonance imaging are discussed, and possible solutions are outlined.
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absolute quantification of cerebral blood flow correlation between Dynamic Susceptibility Contrast mri and model free arterial spin labeling
Magnetic Resonance Imaging, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Stig Holtas, Danielle Van Westen, Esben Thade Petersen, Karin Markenroth Bloch, Ronnie WirestamAbstract:PURPOSE: To compare absolute cerebral blood flow (CBF) estimates obtained by model-free arterial spin labeling (ASL) and Dynamic Susceptibility Contrast MRI (DSC-MRI), corrected for partial volume effects (PVEs). METHODS: CBF was measured using DSC-MRI and model-free ASL (quantitative signal targeting with alternating radiofrequency labeling of arterial regions) at 3 T in 15 subjects with brain tumor, and the two modalities were compared with regard to CBF estimates in normal gray matter (GM) and DSC-to-ASL CBF ratios in selected tumor regions. The DSC-MRI CBF maps were calculated using a global arterial input function (AIF) from the sylvian-fissure region, but, in order to minimize PVEs, the AIF time integral was rescaled by a venous output function time integral obtained from the sagittal sinus. RESULTS: In GM, the average DSC-MRI CBF estimate was 150+/-45 ml/(min 100 g) (mean+/-SD) while the corresponding ASL CBF was 44+/-10 ml/(min 100 g). The linear correlation between GM CBF estimates obtained by DSC-MRI and ASL was r=.89, and observed DSC-to-ASL CBF ratios differed by less than 3% between GM and tumor regions. CONCLUSIONS: A satisfactory positive linear correlation between the CBF estimates obtained by model-free ASL and DSC-MRI was observed, and DSC-to-ASL CBF ratios showed no obvious tissue dependence. (Less)
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absolute quantification of cerebral blood flow correlation between Dynamic Susceptibility Contrast mri and model free arterial spin labeling
Magnetic Resonance Imaging, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Stig Holtas, Esben Thade Petersen, Karin Markenroth Bloch, Danielle Van Westen, Ronnie WirestamAbstract:PURPOSE: To compare absolute cerebral blood flow (CBF) estimates obtained by model-free arterial spin labeling (ASL) and Dynamic Susceptibility Contrast MRI (DSC-MRI), corrected for partial volume effects (PVEs). METHODS: CBF was measured using DSC-MRI and model-free ASL (quantitative signal targeting with alternating radiofrequency labeling of arterial regions) at 3 T in 15 subjects with brain tumor, and the two modalities were compared with regard to CBF estimates in normal gray matter (GM) and DSC-to-ASL CBF ratios in selected tumor regions. The DSC-MRI CBF maps were calculated using a global arterial input function (AIF) from the sylvian-fissure region, but, in order to minimize PVEs, the AIF time integral was rescaled by a venous output function time integral obtained from the sagittal sinus. RESULTS: In GM, the average DSC-MRI CBF estimate was 150+/-45 ml/(min 100 g) (mean+/-SD) while the corresponding ASL CBF was 44+/-10 ml/(min 100 g). The linear correlation between GM CBF estimates obtained by DSC-MRI and ASL was r=.89, and observed DSC-to-ASL CBF ratios differed by less than 3% between GM and tumor regions. CONCLUSIONS: A satisfactory positive linear correlation between the CBF estimates obtained by model-free ASL and DSC-MRI was observed, and DSC-to-ASL CBF ratios showed no obvious tissue dependence.
Maria Luisa Garre - One of the best experts on this subject based on the ideXlab platform.
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pediatric astrocytic tumor grading comparison between arterial spin labeling and Dynamic Susceptibility Contrast mri perfusion
Neuroradiology, 2018Co-Authors: Giovanni Morana, Maarten H Lequin, Domenico Tortora, Serena Stagliano, Paolo Nozza, Samantha Mascelli, Mariasavina Severino, Gianluca Piatelli, Alessandro Consales, Maria Luisa GarreAbstract:Purpose The aim of this study was to compare arterial spin labeling (ASL) and Dynamic Susceptibility Contrast (DSC) MRI perfusion with respect to diagnostic performance in tumor grading in pediatric patients with low- and high-grade astrocytic tumors (AT).
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pediatric astrocytic tumor grading comparison between arterial spin labeling and Dynamic Susceptibility Contrast mri perfusion
Neuroradiology, 2018Co-Authors: Giovanni Morana, Maarten H Lequin, Domenico Tortora, Serena Stagliano, Paolo Nozza, Samantha Mascelli, Mariasavina Severino, Gianluca Piatelli, Alessandro Consales, Maria Luisa GarreAbstract:The aim of this study was to compare arterial spin labeling (ASL) and Dynamic Susceptibility Contrast (DSC) MRI perfusion with respect to diagnostic performance in tumor grading in pediatric patients with low- and high-grade astrocytic tumors (AT). We retrospectively analyzed 37 children with histologically proven treatment naive low- and high-grade AT who underwent concomitant pre-operative ASL and DSC MRI perfusion. Studies were performed on a 1.5 T scanner, and a pulsed technique was used for ASL. DSC data were post-processed with a leakage correction software. Normalization of tumor perfusion parameters was performed with contralateral normal appearing gray matter. Normalized cerebral blood volume (nCBV) values in the most perfused area of each neoplasm were compared with normalized DSC-derived cerebral blood flow (nDSC-CBF) and ASL-derived cerebral blood flow (nASL-CBF) data, and correlated with WHO tumor grade. Statistics included Pearson’s chi-square and Mann-Whitney U tests, Spearman’s rank correlation, and receiver operating characteristic (ROC) analysis. A significant correlation was demonstrated between DSC and ASL data (p < 0.001). Significant differences in terms of DSC and ASL data were found between low- and high-grade AT (p < 0.001). ROC analysis demonstrated similar performances between all parameters in predicting tumor grade (nCBV: AUC 0.96, p < 0.001; nDSC-CBF: AUC 0.98, p < 0.001; nASL-CBF: AUC 0.96, p < 0.001). Normalized pulsed ASL performed with a 1.5 T scanner provides comparable results to DSC MRI perfusion in pediatric AT and may allow distinction between high- and low-grade AT.
Ronnie Wirestam - One of the best experts on this subject based on the ideXlab platform.
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Absolute quantification of perfusion using Dynamic Susceptibility Contrast MRI: pitfalls and possibilities
Magnetic Resonance Materials in Physics Biology and Medicine, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Ronnie WirestamAbstract:Absolute quantification of cerebral blood flow, cerebral blood volume and mean transit time is desirable in the determination of tissue viability thresholds and tissue at risk in acute ischaemic stroke, as well as in cases where a global reduction in cerebral blood flow is expected, for example, in patients with dementia or depressive disorders. Absolute values are also useful when comparing sequential examinations of tissue perfusion parameters, for example, in the monitoring and follow-up of various kinds of therapy. Regardless of the method employed, a number of assumptions and approximations must be made to obtain absolute measures of perfusion. Furthermore, the different stages of data acquisition and processing are associated with various degrees of uncertainty. In this review, the problems of particular relevance to absolute quantification of cerebral perfusion parameters using Dynamic Susceptibility Contrast magnetic resonance imaging are discussed, and possible solutions are outlined.
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absolute quantification of cerebral blood flow correlation between Dynamic Susceptibility Contrast mri and model free arterial spin labeling
Magnetic Resonance Imaging, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Stig Holtas, Danielle Van Westen, Esben Thade Petersen, Karin Markenroth Bloch, Ronnie WirestamAbstract:PURPOSE: To compare absolute cerebral blood flow (CBF) estimates obtained by model-free arterial spin labeling (ASL) and Dynamic Susceptibility Contrast MRI (DSC-MRI), corrected for partial volume effects (PVEs). METHODS: CBF was measured using DSC-MRI and model-free ASL (quantitative signal targeting with alternating radiofrequency labeling of arterial regions) at 3 T in 15 subjects with brain tumor, and the two modalities were compared with regard to CBF estimates in normal gray matter (GM) and DSC-to-ASL CBF ratios in selected tumor regions. The DSC-MRI CBF maps were calculated using a global arterial input function (AIF) from the sylvian-fissure region, but, in order to minimize PVEs, the AIF time integral was rescaled by a venous output function time integral obtained from the sagittal sinus. RESULTS: In GM, the average DSC-MRI CBF estimate was 150+/-45 ml/(min 100 g) (mean+/-SD) while the corresponding ASL CBF was 44+/-10 ml/(min 100 g). The linear correlation between GM CBF estimates obtained by DSC-MRI and ASL was r=.89, and observed DSC-to-ASL CBF ratios differed by less than 3% between GM and tumor regions. CONCLUSIONS: A satisfactory positive linear correlation between the CBF estimates obtained by model-free ASL and DSC-MRI was observed, and DSC-to-ASL CBF ratios showed no obvious tissue dependence. (Less)
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absolute quantification of cerebral blood flow correlation between Dynamic Susceptibility Contrast mri and model free arterial spin labeling
Magnetic Resonance Imaging, 2010Co-Authors: Linda Knutsson, Freddy Ståhlberg, Stig Holtas, Esben Thade Petersen, Karin Markenroth Bloch, Danielle Van Westen, Ronnie WirestamAbstract:PURPOSE: To compare absolute cerebral blood flow (CBF) estimates obtained by model-free arterial spin labeling (ASL) and Dynamic Susceptibility Contrast MRI (DSC-MRI), corrected for partial volume effects (PVEs). METHODS: CBF was measured using DSC-MRI and model-free ASL (quantitative signal targeting with alternating radiofrequency labeling of arterial regions) at 3 T in 15 subjects with brain tumor, and the two modalities were compared with regard to CBF estimates in normal gray matter (GM) and DSC-to-ASL CBF ratios in selected tumor regions. The DSC-MRI CBF maps were calculated using a global arterial input function (AIF) from the sylvian-fissure region, but, in order to minimize PVEs, the AIF time integral was rescaled by a venous output function time integral obtained from the sagittal sinus. RESULTS: In GM, the average DSC-MRI CBF estimate was 150+/-45 ml/(min 100 g) (mean+/-SD) while the corresponding ASL CBF was 44+/-10 ml/(min 100 g). The linear correlation between GM CBF estimates obtained by DSC-MRI and ASL was r=.89, and observed DSC-to-ASL CBF ratios differed by less than 3% between GM and tumor regions. CONCLUSIONS: A satisfactory positive linear correlation between the CBF estimates obtained by model-free ASL and DSC-MRI was observed, and DSC-to-ASL CBF ratios showed no obvious tissue dependence.
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assessment of regional cerebral blood flow by Dynamic Susceptibility Contrast mri using different deconvolution techniques
Magnetic Resonance in Medicine, 2000Co-Authors: Ronnie Wirestam, Leif Ostergaard, Linda Andersson, Max Bolling, Juhapetri Aunola, Arne Lindgren, Bo Geijer, Stig Holtas, Freddy StåhlbergAbstract:Regional cerebral blood flow (rCBF) was assessed using Dynamic Susceptibility-Contrast MRI at 1.5 T. A simultaneous dual FLASH pulse sequence and Gd-DTPA-BMA (0.3 mmol/kg b.w.) were used for examination of 43 volunteers, measuring rCBF in frontal white matter (WM) and in gray matter in the thalamus (GM). Arterial input functions (AIFs) were registered 1) in the carotid artery and 2) in an artery within the GM/WM slice. The measured concentration-vs. -time curve was deconvolved with the AIF using both Fourier Transform (FT) and Singular Value Decomposition (SVD). Relative rCBF was given by the height of the deconvolved response curve. For each volunteer, eight different rCBF maps were calculated, representing different combinations of deconvolution techniques, AIFs, and filters. The average GM-WM rCBF ratios ranged from 2.0-2.2, depending on methodology. Absolute rCBF was 68 +/- 28 ml/(min 100 g) in GM and 35 +/- 13 ml/(min 100g) in WM (mean +/- SD, n = 39). GM-WM rCBF ratios obtained using SVD were 6-10% higher than corresponding ratios obtained using FT.
Andrew C Peet - One of the best experts on this subject based on the ideXlab platform.
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a comparison of pseudo continuous arterial spin labelling and Dynamic Susceptibility Contrast mri with and without Contrast agent leakage correction in paediatric brain tumours
British Journal of Radiology, 2019Co-Authors: Jan Novak, Stephanie Withey, Shaheen Lateef, Lesley Macpherson, Benjamin Pinkey, Andrew C PeetAbstract:Objective:To investigate correlations between MRI perfusion metrics measured by Dynamic Susceptibility Contrast and arterial spin labelling in paediatric brain tumours.Methods:15 paediatric patient...
Giovanni Morana - One of the best experts on this subject based on the ideXlab platform.
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pediatric astrocytic tumor grading comparison between arterial spin labeling and Dynamic Susceptibility Contrast mri perfusion
Neuroradiology, 2018Co-Authors: Giovanni Morana, Maarten H Lequin, Domenico Tortora, Serena Stagliano, Paolo Nozza, Samantha Mascelli, Mariasavina Severino, Gianluca Piatelli, Alessandro Consales, Maria Luisa GarreAbstract:Purpose The aim of this study was to compare arterial spin labeling (ASL) and Dynamic Susceptibility Contrast (DSC) MRI perfusion with respect to diagnostic performance in tumor grading in pediatric patients with low- and high-grade astrocytic tumors (AT).
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pediatric astrocytic tumor grading comparison between arterial spin labeling and Dynamic Susceptibility Contrast mri perfusion
Neuroradiology, 2018Co-Authors: Giovanni Morana, Maarten H Lequin, Domenico Tortora, Serena Stagliano, Paolo Nozza, Samantha Mascelli, Mariasavina Severino, Gianluca Piatelli, Alessandro Consales, Maria Luisa GarreAbstract:The aim of this study was to compare arterial spin labeling (ASL) and Dynamic Susceptibility Contrast (DSC) MRI perfusion with respect to diagnostic performance in tumor grading in pediatric patients with low- and high-grade astrocytic tumors (AT). We retrospectively analyzed 37 children with histologically proven treatment naive low- and high-grade AT who underwent concomitant pre-operative ASL and DSC MRI perfusion. Studies were performed on a 1.5 T scanner, and a pulsed technique was used for ASL. DSC data were post-processed with a leakage correction software. Normalization of tumor perfusion parameters was performed with contralateral normal appearing gray matter. Normalized cerebral blood volume (nCBV) values in the most perfused area of each neoplasm were compared with normalized DSC-derived cerebral blood flow (nDSC-CBF) and ASL-derived cerebral blood flow (nASL-CBF) data, and correlated with WHO tumor grade. Statistics included Pearson’s chi-square and Mann-Whitney U tests, Spearman’s rank correlation, and receiver operating characteristic (ROC) analysis. A significant correlation was demonstrated between DSC and ASL data (p < 0.001). Significant differences in terms of DSC and ASL data were found between low- and high-grade AT (p < 0.001). ROC analysis demonstrated similar performances between all parameters in predicting tumor grade (nCBV: AUC 0.96, p < 0.001; nDSC-CBF: AUC 0.98, p < 0.001; nASL-CBF: AUC 0.96, p < 0.001). Normalized pulsed ASL performed with a 1.5 T scanner provides comparable results to DSC MRI perfusion in pediatric AT and may allow distinction between high- and low-grade AT.
