17 results on '"Alina G. van der Giessen"'
Search Results
2. Averaging Centerlines: Mean Shift on Paths.
- Author
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Theo van Walsum, Michiel Schaap, Coert Metz, Alina G. van der Giessen, and Wiro J. Niessen
- Published
- 2008
- Full Text
- View/download PDF
3. Semi-Automatic Coronary Artery Centerline Extraction in Computed Tomography Angiography Data.
- Author
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Coert Metz, Michiel Schaap, Alina G. van der Giessen, Theo van Walsum, and Wiro J. Niessen
- Published
- 2007
- Full Text
- View/download PDF
4. Standardized evaluation methodology and reference database for evaluating coronary artery centerline extraction algorithms.
- Author
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Michiel Schaap, Coert Metz, Theo van Walsum, Alina G. van der Giessen, Annick C. Weustink, Nico Mollet, Christian Bauer 0001, Hrvoje Bogunovic, Carlos Castro-Gonzalez, Xiang Deng, Engin Dikici, Thomas O'Donnell, Michel Frenay, Ola Friman, Marcela Hernández Hoyos, Pieter H. Kitslaar, Karl Krissian, Caroline Kühnel, Miguel A. Luengo-Oroz, Maciej Orkisz, örjan Smedby, Martin Styner, Andrzej Szymczak, Hüseyin Tek, Chunliang Wang, Simon K. Warfield, Sebastian Zambal, Yong Zhang, Gabriel P. Krestin, and Wiro J. Niessen
- Published
- 2009
- Full Text
- View/download PDF
5. A CT-based medina classification in coronary bifurcations: Does the lumen assessment provide sufficient information?
- Author
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Frank J. H. Gijsen, Jade Ottema, Stella-Lida Papadopoulou, Johan C.H. Schuurbiers, Jolanda J. Wentzel, Chrysafios Girasis, Pim J. de Feyter, Alina G. van der Giessen, Hector M. Garcia-Garcia, and Alexia Rossi
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Coronary angiography ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Computed tomography ,General Medicine ,medicine.disease ,Stenosis ,Main vessel ,Side branch ,Plaque area ,medicine ,Flow divider ,Radiology, Nuclear Medicine and imaging ,Radiology ,10. No inequality ,Cardiology and Cardiovascular Medicine ,business ,Lumen (unit) - Abstract
Aims To evaluate the distribution of atherosclerosis at bifurcations with computed tomography coronary angiography (CTCA) and propose a novel CT-Medina classification for bifurcation lesions. Methods In 26 patients (age 55 ± 10 years, 81% male) imaged with CTCA, 39 bifurcations were studied. The bifurcations analysis included the proximal main vessel, the distal main vessel and the side branch (SB). Plaque contours were manually traced on CTCA; the lumen, vessel and plaque area were measured, as well as plaque burden (%). The carina cross-sections were divided into four equal parts according to the expected wall shear stress (WSS) to assess circumferential plaque distribution. All the bifurcation lesions were classified using the Medina classification and a novel CT-Medina classification combining lumen narrowing and plaque burden ≥70%. Results Presence of severe plaque (plaque burden ≥70%) by CTCA was demonstrated in 12.8% (5/39) of the proximal segments, 15.4% (6/39) of the distal segments and 7.7% (3/39) of the SB segments. The thickest plaque was located more often in low WSS parts of the carina cross-sections, whereas the flow divider was rarely affected. Although in the majority of bifurcations plaque was present, based on the Medina classification 92% of the assessed bifurcations were identified as 0,0,0. Characterization of bifurcation lesions using the new CT-Medina classification provided additional information in seven cases (18%) compared to the Medina classification Conclusion Atherosclerotic plaque is widely present in all bifurcation segments, even in the absence of coronary lumen stenosis. A CT-Medina classification combining lumen and plaque parameters is more informative than angiographic classification of bifurcation lesions and could potentially facilitate the decision-making on the treatment of these lesions. © 2014 Wiley Periodicals, Inc.
- Published
- 2014
6. Detection and quantification of coronary atherosclerotic plaque by 64-slice multidetector CT: A systematic head-to-head comparison with intravascular ultrasound
- Author
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Alina G. van der Giessen, Nico R. Mollet, Koen Nieman, Hui-Ling Li, Stella-Lida Papadopoulou, Michiel Schaap, Frank J. H. Gijsen, Pim J. de Feyter, Ermanno Capuano, Robert-Jan van Geuns, Johan C.H. Schuurbiers, Anoeshka S. Dharampal, Lisan A. Neefjes, Cardiology, Radiology & Nuclear Medicine, and Cardiothoracic Surgery
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medicine.medical_specialty ,Head to head ,Coronary Artery Disease ,Multidetector ct ,Imaging modalities ,Multidetector Computed Tomography ,Multidetector computed tomography ,Intravascular ultrasound ,medicine ,Humans ,cardiovascular diseases ,Acute Coronary Syndrome ,Coronary atherosclerosis ,Ultrasonography ,medicine.diagnostic_test ,business.industry ,Calcinosis ,Middle Aged ,Plaque, Atherosclerotic ,Coronary arteries ,medicine.anatomical_structure ,cardiovascular system ,Female ,Radiology ,Cardiology and Cardiovascular Medicine ,business ,Wall thickness - Abstract
Objective: We evaluated the ability of 64-slice multidetector computed tomography (MDCT)-derived plaque parameters to detect and quantify coronary atherosclerosis, using intravascular ultrasound (IVUS) as the reference standard. Methods: In 32 patients, IVUS and 64-MDCT was performed. The MDCT and IVUS datasets of 44 coronary arteries were co-registered using a newly developed fusion technique and quantitative parameters were derived from both imaging modalities. The threshold of >0.5mm of maximum wall thickness was used to establish plaque presence on MDCT and IVUS. Results: We analyzed 1364 coregistered 1-mm coronary cross-sections and 255 segments of 5-mm length. Compared with IVUS, 64-MDCT enabled correct detection in 957 of 1109 cross-sections containing plaque (sensitivity 86%). In 180 of 255 cross-sections atherosclerosis was correctly excluded (specificity 71%). On the segmental level, MDCT detected 213 of 220 segments with any atherosclerotic plaque (sensitivity 96%), whereas the presence of any plaque was correctly ruled out in 28 of 32 segments (specificity 88%). Interobserver agreement for the detection of atherosclerotic cross-sections was moderate (Cohen's kappa coefficient K = 0.51), but excellent for the atherosclerotic segments (K = 1.0). Pearson's correlation coefficient for vessel plaque volumes measured by MDCT and IVUS was r = 0.91 (p < 0.001). Bland-Altman analysis showed a slight non-significant underestimation of any plaque volume by MDCT (p = 0.5), with a trend to underestimate noncalcified and overestimate mixed/calcified plaque volumes (p = 0.22 and p = 0.87 respectively). Conclusion: MDCT is able to detect and quantify atherosclerotic plaque. Further improvement in CT resolution is necessary for more reliable assessment of very small and distal coronary plaques. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
- Published
- 2011
7. Reproducibility, Accuracy, and Predictors of Accuracy for the Detection of Coronary Atherosclerotic Plaque Composition by Computed Tomography An Ex Vivo Comparison to Intravascular Ultrasound
- Author
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Udo Hoffmann, Patrick M. Donelly, Michael Toepker, Christopher Raffle, Hang Lee, Thomas Irlbeck, Jolanda J. Wentzel, Alina G. van der Giessen, Pál Maurovich-Horvat, Fabian Bamberg, Frank J. H. Gijsen, Christopher L. Schlett, Theo van Walsum, Cardiothoracic Surgery, Radiology & Nuclear Medicine, and Cardiology
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Male ,medicine.medical_specialty ,Computed tomography ,Coronary Artery Disease ,Sensitivity and Specificity ,Imaging phantom ,Predictive Value of Tests ,Intravascular ultrasound ,medicine ,Confidence Intervals ,Odds Ratio ,Humans ,Radiology, Nuclear Medicine and imaging ,Ultrasonography, Interventional ,Aged ,Reproducibility ,medicine.diagnostic_test ,business.industry ,Reproducibility of Results ,General Medicine ,Middle Aged ,Coronary Vessels ,Coronary arteries ,medicine.anatomical_structure ,ROC Curve ,Area Under Curve ,Angiography ,Multivariate Analysis ,Female ,Radiology ,Tomography ,business ,Tomography, X-Ray Computed ,Ex vivo - Abstract
Purpose: To determine the reproducibility, accuracy, and predictors of accuracy of computed tomography (CT) angiography to detect and characterize coronary atherosclerotic plaque as compared with intravascular ultrasound. Methods: Ten ex vivo human coronary arteries were imaged in a moving phantom by dual-source CT (collimation: 0.6 mm, reconstructed slice thickness: 0.4 mm) and intravascular ultrasound (IVUS). Coregistered crosssections were assessed at 0.4 mm intervals for the presence and composition of atherosclerotic plaque (noncalcified, mixed, and calcified) on CT and IVUS by independent readers to determine reader agreement and diagnostic accuracy. Quantitative measurements of lumen and plaque area, plaque eccentricity, and intimal thickness on IVUS were used to determine predictors for the detection of noncalcified plaque by CT. Results: Within 1002 coregistered cross-sections, the interobserver agreement to detect plaque on CT was K = 0.48, K = 0.42, and K = 1.00 for noncalcified, mixed, and calcified plaque; respectively. The sensitivity and specificity of CT was 57% out of 84% for noncalcified, 32% of 92% for mixed, and 56% of 93% for calcified plaque when compared with IVUS; respectively. Misclassification occurred in 68% of mixed and 43% of noncalcified plaques. The odds of detecting noncalcified plaque in CT independently increased by 56% (95% CI: 47%-77%, P < 0.0001) with every 0.1 mm increase in maximum intimal thickness as measured by IVUS. Detection rate for noncalcified plaques was poor for plaques 1 mm maximal intimal thickness (90%). Conclusion: Reader agreement and diagnostic accuracy for the detection of coronary atherosclerotic plaque vary with plaque composition. Intimal thickness independently predicts detection of noncalcified plaque by CT with excellent sensitivity for >1 mm thick plaques.
- Published
- 2010
8. Plaque and shear stress distribution in human coronary bifurcations: a multislice computed tomography study
- Author
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Willem B. Meijboom, Frank J. H. Gijsen, Antonius F.W. van der Steen, Pim J. de Feyter, Jolanda J. Wentzel, Alina G. van der Giessen, Nico R. Mollet, Frans N. van de Vosse, Cardiothoracic Surgery, Cardiology, Radiology & Nuclear Medicine, and Cardiovascular Biomechanics
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Male ,Pathology ,medicine.medical_specialty ,Computed tomography ,Coronary Artery Disease ,Coronary Angiography ,Imaging, Three-Dimensional ,Coronary Circulation ,MSCT ,Shear stress ,medicine ,Humans ,Multislice ,Aged ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Calcinosis ,Multislice computed tomography ,Anatomy ,Middle Aged ,Stress distribution ,Atherosclerosis ,Coronary Bifurcations ,Coronary heart disease ,Disease Progression ,cardiovascular system ,Flow divider ,Radiographic Image Interpretation, Computer-Assisted ,Female ,Stress, Mechanical ,Tomography, X-Ray Computed ,Cardiology and Cardiovascular Medicine ,business ,circulatory and respiratory physiology - Abstract
Aims: Early atherosclerosis is located in low wall shear-stress (WSS) regions, however plaques are also found in the high WSS sensing flow divider walls of coronary bifurcations. We assessed the plaque distribution and morphology near bifurcations non-invasively with 64-slice computed tomography in relation to the WSS distribution. Methods and results: We inspected 65 cross-sections near coronary bifurcations for the presence of plaque. Cross-sections were divided into four equal parts, which we numbered according to expected levels of WSS, with part I the lowest WSS (outer wall) and increasing WSS's in part II (inner bend), III (outer bend) and IV (flow divider). Of the cross-sections 88% had plaque. Of all parts I, 72% contained plaque. This was 62%, 38% and 31% in parts II, III and IV. In cross-sections with only 1 or 2 parts inflicted, plaque was found in part I and/or II in 94%. In 93% of the cross-sections with the flow divider inflicted, parts I and/or II were also inflicted. Plaque was never found exclusively in the flow divider part IV. Conclusions: We demonstrated that plaque is mostly present in low WSS regions, whereas plaque in high WSS regions is accompanied by plaque in adjacent low WSS regions. It is therefore plausible that plaque grows from the outer wall (low WSS) of the bifurcation towards the flow divider (high WSS).
- Published
- 2009
9. A CT-based Medina classification in coronary bifurcations: does the lumen assessment provide sufficient information?
- Author
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Stella-Lida, Papadopoulou, Chrysafios, Girasis, Frank J, Gijsen, Alexia, Rossi, Jade, Ottema, Alina G, van der Giessen, Johan C, Schuurbiers, Hector M, Garcia-Garcia, Pim J, de Feyter, and Jolanda J, Wentzel
- Subjects
Male ,Multidetector Computed Tomography ,Humans ,Reproducibility of Results ,Female ,Acute Coronary Syndrome ,Middle Aged ,Coronary Angiography ,Coronary Vessels ,Follow-Up Studies ,Retrospective Studies - Abstract
To evaluate the distribution of atherosclerosis at bifurcations with computed tomography coronary angiography (CTCA) and propose a novel CT-Medina classification for bifurcation lesions.In 26 patients (age 55 ± 10 years, 81% male) imaged with CTCA, 39 bifurcations were studied. The bifurcations analysis included the proximal main vessel, the distal main vessel and the side branch (SB). Plaque contours were manually traced on CTCA; the lumen, vessel and plaque area were measured, as well as plaque burden (%). The carina cross-sections were divided into four equal parts according to the expected wall shear stress (WSS) to assess circumferential plaque distribution. All the bifurcation lesions were classified using the Medina classification and a novel CT-Medina classification combining lumen narrowing and plaque burden ≥70%.Presence of severe plaque (plaque burden ≥70%) by CTCA was demonstrated in 12.8% (5/39) of the proximal segments, 15.4% (6/39) of the distal segments and 7.7% (3/39) of the SB segments. The thickest plaque was located more often in low WSS parts of the carina cross-sections, whereas the flow divider was rarely affected. Although in the majority of bifurcations plaque was present, based on the Medina classification 92% of the assessed bifurcations were identified as 0,0,0. Characterization of bifurcation lesions using the new CT-Medina classification provided additional information in seven cases (18%) compared to the Medina classificationAtherosclerotic plaque is widely present in all bifurcation segments, even in the absence of coronary lumen stenosis. A CT-Medina classification combining lumen and plaque parameters is more informative than angiographic classification of bifurcation lesions and could potentially facilitate the decision-making on the treatment of these lesions.
- Published
- 2013
10. The influence of boundary conditions on wall shear stress distribution in patients specific coronary trees
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Pierre André Doriot, Antonius F.W. van der Steen, Harald C. Groen, Frank J. H. Gijsen, Alina G. van der Giessen, Jolanda J. Wentzel, Frans N. van de Vosse, Pim J. de Feyter, Cardiothoracic Surgery, Radiology & Nuclear Medicine, Cardiology, Biomedical Engineering, and Cardiovascular Biomechanics
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Male ,medicine.medical_specialty ,Flow (psychology) ,Biophysics ,Biomedical Engineering ,Hemodynamics ,Geometry ,Wall shear stress ,Stress, Physiological ,MSCT ,Shear stress ,medicine ,Humans ,Orthopedics and Sports Medicine ,Mathematics ,Boundary conditions ,Rehabilitation ,Models, Cardiovascular ,Coronary Vessels ,Surgery ,Volumetric flow rate ,Coronary arteries ,Flow conditions ,medicine.anatomical_structure ,cardiovascular system ,Outflow ,Female ,Tomography ,Coronary trees ,Blood Flow Velocity - Abstract
Patient specific geometrical data on human coronary arteries can be reliably obtained multislice computer tomography (MSCT) imaging. MSCT cannot provide hemodynamic variables, and the outflow through the side branches must be estimated. The impact of two different models to determine flow through the side branches on the wall shear stress (WSS) distribution in patient specific geometries is evaluated. Murray's law predicts that the flow ratio through the side branches scales with the ratio of the diameter of the side branches to the third power. The empirical model is based on flow measurements performed by Doriot et al. (2000) in angiographically normal coronary arteries. The fit based on these measurements showed that the flow ratio through the side branches can best be described with a power of 2.27. The experimental data imply that Murray's law underestimates the flow through the side branches. We applied the two models to study the WSS distribution in 6 coronary artery trees. Under steady flow conditions, the average WSS between the side branches differed significantly for the two models: the average WSS was 8% higher for Murray's law and the relative difference ranged from -5% to +27%. These differences scale with the difference in flow rate. Near the bifurcations, the differences in WSS were more pronounced: the size of the low WSS regions was significantly larger when applying the empirical model (13%), ranging from -12% to +68%. Predicting outflow based on Murray's law underestimates the flow through the side branches. Especially near side branches, the regions where atherosclerotic plaques preferentially develop, the differences are significant and application of Murray's law underestimates the size of the low WSS region. (C) 2011 Elsevier Ltd. All rights reserved.
- Published
- 2010
11. Standardized evaluation methodology and reference database for evaluating coronary artery centerline extraction algorithms
- Author
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Annick C. Weustink, Chunliang Wang, Yong Zhang, Caroline Kühnel, Wiro J. Niessen, Simon K. Warfield, Hrvoje Bogunovic, Andrzej Szymczak, Ola Friman, Sebastian Zambal, Xiang Deng, Thomas F. O'Donnell, Nico R. Mollet, Christian Bauer, Huseyin Tek, Örjan Smedby, Karl Krissian, Carlos Castro, Michiel Schaap, Gabriel P. Krestin, Alina G. van der Giessen, Marcela Hernández Hoyos, Martin Styner, Coert Metz, Theo van Walsum, Pieter H. Kitslaar, Michel Frenay, Maciej Orkisz, Engin Dikici, Miguel Luengo-Oroz, Centre de Recherche et d'Application en Traitement de l'Image et du Signal (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Supérieure Chimie Physique Électronique de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Grupo IMAGINE, Universidad de los Andes [Bogota] (UNIANDES), Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales (MOTIVATE), Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Medical Informatics, Cardiothoracic Surgery, Radiology & Nuclear Medicine, and Urology
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Research groups ,Software Validation ,Health Informatics ,Coronary Angiography ,Sensitivity and Specificity ,Article ,030218 nuclear medicine & medical imaging ,Pattern Recognition, Automated ,03 medical and health sciences ,0302 clinical medicine ,Software ,[INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing ,Reference Values ,Medical imaging ,medicine ,[INFO.INFO-IM]Computer Science [cs]/Medical Imaging ,Humans ,Radiology, Nuclear Medicine and imaging ,Reference standards ,Computed tomography angiography ,Netherlands ,Radiological and Ultrasound Technology ,medicine.diagnostic_test ,business.industry ,Reproducibility of Results ,Computer Graphics and Computer-Aided Design ,[INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation ,Clinical Practice ,Radiographic Image Enhancement ,Reference values ,[INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV] ,Reference database ,Radiographic Image Interpretation, Computer-Assisted ,Computer Vision and Pattern Recognition ,business ,Tomography, X-Ray Computed ,Algorithm ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing ,030217 neurology & neurosurgery ,Algorithms - Abstract
Efficiently obtaining a reliable coronary artery centerline from computed tomography angiography data is relevant in clinical practice. Whereas numerous methods have been presented for this purpose, up to now no standardized evaluation methodology has been published to reliably evaluate and compare the performance of the existing or newly developed coronary artery centerline extraction algorithms. This paper describes a standardized evaluation methodology and reference database for the quantitative evaluation of coronary artery centerline extraction algorithms. The contribution of this work is fourfold: (1) a method is described to create a consensus centerline with multiple observers, (2) well-defined measures are presented for the evaluation of coronary artery centerline extraction algorithms, (3) a database containing 32 cardiac CTA datasets with corresponding reference standard is described and made available. and (4) 13 coronary artery centerline extraction algorithms, implemented by different research groups, are quantitatively evaluated and compared. The presented evaluation framework is made available to the medical imaging community for benchmarking existing or newly developed coronary centerline extraction algorithms. (C) 2009 Elsevier B.V. All rights reserved.
- Published
- 2009
12. Coronary Lumen Segmentation Using Graph Cuts and Robust Kernel Regression
- Author
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Wiro J. Niessen, Alina G. van der Giessen, Nico R. Mollet, Annick C. Weustink, Coert Metz, Lisan A. Neefjes, Theo van Walsum, Michiel Schaap, and Jolanda J. Wentzel
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Image quality ,Computer science ,business.industry ,Pattern recognition ,Regression analysis ,Image segmentation ,Coronary arteries ,medicine.anatomical_structure ,Sørensen–Dice coefficient ,Cut ,medicine ,Medical imaging ,Kernel regression ,Computer vision ,Artificial intelligence ,business - Abstract
This paper presents a novel method for segmenting the coronary lumen in CTA data. The method is based on graph cuts, with edge-weights depending on the intensity of the centerline, and robust kernel regression. A quantitative evaluation in 28 coronary arteries from 12 patients is performed by comparing the semi-automatic segmentations to manual annotations. This evaluation showed that the method was able to segment the coronary arteries with high accuracy, compared to manually annotated segmentations, which is reflected in a Dice coefficient of 0.85 and average symmetric surface distance of 0.22 mm.
- Published
- 2009
13. Averaging centerlines: mean shift on paths
- Author
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Theo, van Walsum, Michiel, Schaap, Coert T, Metz, Alina G, van der Giessen, and Wiro J, Niessen
- Subjects
Radiographic Image Enhancement ,Imaging, Three-Dimensional ,Artificial Intelligence ,Radiographic Image Interpretation, Computer-Assisted ,Reproducibility of Results ,Coronary Angiography ,Sensitivity and Specificity ,Algorithms ,Pattern Recognition, Automated - Abstract
Generation of a reference standard from multiple manually annotated datasets is a non-trivial problem. This paper discusses the weighted averaging of 3D open curves, which we used to generate a reference standard for vessel tracking data. We show how weighted averaging can be implemented by applying the Mean Shift algorithm to paths, and discuss the details of our implementation. Our approach can handle cases where the observer centerlines take different branches in a natural way. The method has been evaluated on synthetic data, and has been used to generate reference centerlines for evaluation of vessel tracking algorithms.
- Published
- 2008
14. Vascular Remodeling During Atherosclerotic Plaque Build Up Is Controlled by the Plaque Free Part of the Vessel Wall
- Author
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Harald C. Groen, Gaston A. Rodriguez-Granillo, Alina G. van der Giessen, Rose van der Giessen, Pim J. de Feyter, Jolanda J. Wentzel, Johan C.H. Schuurbiers, and Frank J. H. Gijsen
- Subjects
Pathology ,medicine.medical_specialty ,medicine.diagnostic_test ,Endothelium ,business.industry ,Lumen (anatomy) ,Endothelium dependent ,Free wall ,medicine.anatomical_structure ,Intravascular ultrasound ,Plaque area ,Medicine ,Eccentric ,business ,Artery - Abstract
Glagov et al. observed that positive, compensatory vascular remodeling during plaque build up prevents lumen narrowing until plaque burden, this is the relative plaque area to media bounded area, exceeds a threshold of 40% [1]. Until now it is not clear what mechanism controls the compensatory vascular remodeling during the atherosclerotic plaque build up and what determines absence or limits compensatory vascular remodeling. Plaque burden does not seem to reflect a parameter, which could serve as a limiting step in the known control process in the vascular system. For instance, healthy arteries control vascular remodeling by fluid flow induced shear stress via a number of endothelium dependent pathways [2]. The endothelium at the atherosclerotic plaque side is considered to be dysfunctional [2] and might thereby limit the remodeling process. Since plaques are mostly eccentric, we hypothesize that the healthy part of the artery (or plaque free wall) will respond to changes in shear stress and will determine the capacity of the arteries to remodel up till the moment of complete circumferential involvement of the disease. We investigated whether the size of the plaque free wall contributes to vascular remodeling over a 3 year period using serial intravascular ultrasound measurements by determining 1) the frequency of positive remodeling in segments with varying size of plaque free vessel wall 2) the degree of vascular remodeling for segments with varying size of plaque free vessel wall.Copyright © 2008 by ASME
- Published
- 2008
15. Averaging Centerlines: Mean Shift on Paths
- Author
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Wiro J. Niessen, Theo van Walsum, Michiel Schaap, Alina G. van der Giessen, and Coert Metz
- Subjects
Euclidean distance ,Computer science ,Mean-shift ,Observer (special relativity) ,Data mining ,computer.software_genre ,Algorithm ,computer - Abstract
Generation of a reference standard from multiple manually annotated datasets is a non-trivial problem. This paper discusses the weighted averaging of 3D open curves, which we used to generate a reference standard for vessel tracking data. We show how weighted averaging can be implemented by applying the Mean Shift algorithm to paths, and discuss the details of our implementation. Our approach can handle cases where the observer centerlines take different branches in a natural way. The method has been evaluated on synthetic data, and has been used to generate reference centerlines for evaluation of vessel tracking algorithms.
- Published
- 2008
16. Plaque and Shear Stress Distribution in Human Coronary Bifurcations: a Multi-Slice Computed Tomography Study
- Author
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Alina G. van der Giessen, Pim J. de Feyter, Frank J. H. Gijsen, Antonius F.W. van der Steen, Frans N. van de Vosse, and Jolanda J. Wentzel
- Subjects
medicine.medical_specialty ,Materials science ,medicine.diagnostic_test ,cardiovascular system ,medicine ,Shear stress ,Computed tomography ,Multi slice ,Radiology ,Anatomy ,circulatory and respiratory physiology - Abstract
Aims: Early atherosclerosis is located in low wall shear-stress (WSS) regions, however plaques are also found in the high WSS sensing flowdivider walls of coronary bifurcations. We assessed the plaque distribution and morphology near bifurcations non-invasively with 64 slice computed tomography (MSCT) in relation to the WSS distribution. Methods and results: We inspected 65 cross-sections near coronary bifurcations for the presence of plaque. Cross-sections were divided into four equal parts, which we numbered according to expected levels of WSS, with part I the lowest WSS (outer wall) and increasing WSS’s in part II (inner bend), III (outer bend) and IV (flowdivider). Of the cross-sections 88% had plaque. Of all parts I, 72% contained plaque. This was 62%, 38% and 31% in parts II, III and IV. In cross-sections with only 1 or 2 parts inflicted, plaque was found in part I and/or II in 94%. In 93% of the cross-sections with the flowdivider inflicted, parts I and/or II were also inflicted. Plaque was never found exclusively in the flowdivider part IV. Conclusions: We demonstrated that plaque is mostly present in low WSS regions, whereas plaque in high WSS regions is accompanied by plaque in adjacent low WSS regions. It is therefore plausible that plaque grows from the outer wall (low WSS) of the bifurcation towards the flowdivider (high WSS).
- Published
- 2007
17. In Vivo 3D Distribution of Lipid-Core Plaque in Human Coronary Artery as Assessed by Fusion of Near Infrared Spectroscopy-Intravascular Ultrasound and Multislice Computed Tomography Scan
- Author
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Alina G. van der Giessen, Jolanda J. Wentzel, Frits Mastik, Evelyn Regar, Scot Garg, Antonius F.W. van der Steen, Frank J. H. Gijsen, Patrick W. Serruys, Carl Schultz, Cardiology, and Cardiothoracic Surgery
- Subjects
Male ,Acute coronary syndrome ,Pathology ,medicine.medical_specialty ,Endothelium ,Coronary Artery Disease ,Coronary Angiography ,Imaging, Three-Dimensional ,Intravascular ultrasound ,medicine ,Shear stress ,Humans ,Radiology, Nuclear Medicine and imaging ,Myocardial infarction ,Ultrasonography, Interventional ,Spectroscopy, Near-Infrared ,medicine.diagnostic_test ,business.industry ,Coronary Stenosis ,Middle Aged ,medicine.disease ,Coronary Vessels ,Lipids ,Plaque, Atherosclerotic ,Coronary arteries ,medicine.anatomical_structure ,Tomography, X-Ray Computed ,Cardiology and Cardiovascular Medicine ,business ,Artery ,Lumen (unit) - Abstract
There is ample evidence that the development of acute coronary syndrome is linked to the presence of lipid-core, necrotic plaque. However, there is little information on the natural history of lipid-core plaques in humans. A close link between structural changes of atherosclerotic plaques over time to the local shear stress conditions in the arterial system has been reported.1 Although low shear stress is recognized for its proatherogenic impact on the endothelium,1 its role in plaque composition, destabilization, and rupture is less clear. The current paradigm postulates that low shear stress is a necessary condition for plaque accumulation. However, once lumen narrowing occurs because of plaque, local shear stress increases.2 We describe an approach that allows studying the interaction of lipid-core plaque accumulation and local shear stress in a correct anatomic 3D reconstruction of coronary arteries in living patients. A 61-year-old man with a history of myocardial infarction and stenting of the right coronary …
- Published
- 2010
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