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Wong KKL, Wang D, Ko JKL, Mazumdar J, Le TT, Ghista D. Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures. Biomed Eng Online 2017; 16:35. [PMID: 28327144 PMCID: PMC5359907 DOI: 10.1186/s12938-017-0326-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/13/2017] [Indexed: 11/10/2022] Open
Abstract
Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.
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Affiliation(s)
- Kelvin K. L. Wong
- School of Medicine, University of Western Sydney, Campbelltown, Sydney, NSW 2560 Australia
- School of Medicine, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Defeng Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jacky K. L. Ko
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jagannath Mazumdar
- Centre for Biomedical Engineering and School of Electrical and Electronics Engineering, University of Adelaide, Adelaide, SA 5005 Australia
| | - Thu-Thao Le
- National Heart Centre, Mistri Wing, 17 Third Hospital Avenue, Singapore, 168752 Singapore
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ZHAO XI, LIU YOUJUN, DING JINLI, REN XIAOCHEN, BAI FAN, ZHANG MINGZI, MA LIANCAI, WANG WENXIN, XIE JINSHENG, QIAO AIKE. HEMODYNAMIC EFFECTS OF THE ANASTOMOSES IN THE MODIFIED BLALOCK–TAUSSIG SHUNT: A NUMERICAL STUDY USING A 0D/3D COUPLING METHOD. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500177] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The modified Blalock–Taussig (BT) shunt is a palliative surgery which can help the tetralogy of Fallot (TOF) patient increase the blood oxygen saturation by interposing a systemic-to-pulmonary artery shunt. Two typical anastomotic shapes are frequently used in clinical practice: the end-to-side (ETS) and the side-to-side (STS) anastomosis. This paper examines the hemodynamic influence of the anastomotic shape in the modified BT shunt. Three models with different anastomotic shapes were reconstructed. The ETS anastomoses were applied in the first model. For the innominate artery (IA) and the pulmonary artery (PA) in the second model, the ETS and the STS anastomosis were applied, respectively. Finally, the STS anastomoses were applied in the third model. The 0D/3D coupling method was used to perform a numerical simulation by coupling the three-dimensional (3D) artery model with a zero-dimensional (0D) lumped parameter model for the cardiovascular system. The simulation results showed that the perfusion into the left and right PA in Model 1 was unbalanced. Swirling flow appeared in the shunt in Model 3, but the shunt flow rate in Model 3 was lower. The ETS anastomosis at the PA may cause unbalanced blood perfusion into the left and right PA. Conversely, the STS anastomosis can make the blood perfusion more balanced. Otherwise, the STS anastomosis at the IA could generate a swirling flow in the shunt which may provide a better hemodynamic environment while decreasing the pulmonary perfusion.
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Affiliation(s)
- XI ZHAO
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - YOUJUN LIU
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - JINLI DING
- Department of Diagnostic Radiology, Beijing You An Hospital affiliated to Capital Medical University, No. 8, Xi Tou Tiao, You An Men, Fengtai District, Beijing 100069, P. R. China
| | - XIAOCHEN REN
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - FAN BAI
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - MINGZI ZHANG
- Graduate School of Engineering, Tohoku University, Ohta Laboratory, Institute of Fluid Science, 2-1-1 Katahira Aoba-ku Sendai Miyagi 980-8577, Japan
| | - LIANCAI MA
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - WENXIN WANG
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - JINSHENG XIE
- Beijing An Zhen Hospital affiliated to Capital Medical University, No. 2 Anzhen Road Chaoyang District, Beijing 100029, P. R. China
| | - AIKE QIAO
- College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
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Xiong H, Liu X, Tian X, Pu L, Zhang H, Lu M, Huang W, Zhang YT. A numerical study of the effect of varied blood pressure on the stability of carotid atherosclerotic plaque. Biomed Eng Online 2014; 13:152. [PMID: 25413300 PMCID: PMC4277844 DOI: 10.1186/1475-925x-13-152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 10/22/2014] [Indexed: 12/18/2022] Open
Abstract
Background Blood pressure (BP) is associated with early atherosclerosis and plaque
rupture because the BP variability can significantly affect the blood flow
velocity and shear stress over the plaque. However, the mechanical response of BP
variability to the plaque remains unclear. Therefore, we investigated the
correlation between different maximum systolic blood pressure (SBP) and the stress
distribution on plaque, as well as the stress over the plaque and blood velocity
around the plaque using different BP variations, which are the BP variability in
different phases during one cardiac cycle and beat-to-beat BP variability. Method We established a two-dimensional artery model with stenosis at the degree of
62.5%. Eight combinations of pulsatile pressure gradients between the inflow and
outflow were implemented at the model. Three levels of fibrous cap thickness were
taken into consideration to investigate the additional effect on the BP
variability. Wall shear stress and stress/strain distribution over the plaque were
derived as well as the oscillation shear index (OSI) to analyze the impact of the
changing rate of BP. Result The stresses at diastole were 2.5% ± 1.8% lower than that at systole under the
same pressure drop during one cycle. It was also found that elevated SBP might
cause the immediate increment of stress in the present cycle (292% ± 72.3%), but
slight reduction in the successive cycle (0.48% ± 0.4%). Conclusion The stress/strain distribution over the plaque is sensitive to the BP
variability during one cardiac cycle, and the beat-to-beat BP variability could
cause considerable impact on the progression of atherosclerosis in
long-term.
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Affiliation(s)
| | | | | | | | - Heye Zhang
- Key Lab of Health Informatics of Chinese Academy of Sciences, Shenzhen, China.
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Chen C, Wang Y, Yu J, Zhou Z, Shen L, Chen YQ. Automatic motion analysis system for pyloric flow in ultrasonic videos. IEEE J Biomed Health Inform 2014; 18:130-8. [PMID: 24403410 DOI: 10.1109/jbhi.2013.2272090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ultrasonography has been widely used to evaluate duodenogastric reflux (DGR). But to the best of our knowledge, no automatic analysis system was developed to realize the quantitative computer-aided analysis. In this paper, we propose a system to perform the automatic detection of DGR in the ultrasonic image sequences by applying the automatic motion analysis. The motion field is estimated based on image velocimetry. Then, an intelligent motion analysis is applied. For the DGR detection, the motion and structural information is combined to analyze the transploric motion of the fluid. In order to test the performance of the proposed system, we designed the experiment with the real and synthetic ultrasonic data. The proposed system achieved a good performance in the DGR detection. The automatic results were accordant with the gold standard in analyzing the fluid motion. The proposed system is supposed to be a promising tool for the study and evaluation of DGR.
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Pitts KL, Fenech M. An analytic study on the effect of alginate on the velocity profiles of blood in rectangular microchannels using microparticle image velocimetry. PLoS One 2013; 8:e72909. [PMID: 24023655 PMCID: PMC3758353 DOI: 10.1371/journal.pone.0072909] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/13/2013] [Indexed: 11/18/2022] Open
Abstract
It is desired to understand the effect of alginic acid sodium salt from brown algae (alginate) as a viscosity modifier on the behavior of blood in vitro using a micro-particle image velocimetry (µPIV) system. The effect of alginate on the shape of the velocity profile, the flow rate and the maximum velocity achieved in rectangular microchannels channels are measured. The channels were constructed of polydimethylsiloxane (PDMS), a biocompatible silicone. Porcine blood cells suspended in saline was used as the working fluid at twenty percent hematocrit (H = 20). While alginate was only found to have minimal effect on the maximum velocity and the flow rate achieved, it was found to significantly affect the shear rate at the wall by between eight to a hundred percent.
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Affiliation(s)
- Katie L. Pitts
- Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, Canada
| | - Marianne Fenech
- Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, Canada
- Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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Jia H, Wang C, Wang G, Qu L, Chen W, Chan Q, Zhao B. Impact of 3.0 T Cardiac MR Imaging Using Dual-Source Parallel Radiofrequency Transmission with Patient-Adaptive B1 Shimming. PLoS One 2013; 8:e66946. [PMID: 23825592 PMCID: PMC3688956 DOI: 10.1371/journal.pone.0066946] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 05/14/2013] [Indexed: 11/18/2022] Open
Abstract
Objectives To prospectively evaluate the impact of 3.0 T Cardiac MR imaging using dual-source parallel radiofrequency (RF) transmission with patient-adaptive B1 shimming compared with single-source RF transmission in the RF homogeneity, image contrast and image quality. Methods The study was approved by the local institutional review board, and all subjects provided written informed consent. Fourteen healthy volunteers were examined at 3.0 T MR, with both the conventional single-source and the new dual-source RF transmission. B1 calibrations (RF shimming) of the heart region were performed to acquire a percent of the prescribed flip angle (FA) of B1 maps, which were used for quantitative assessment of RF homogeneity. Contrast ratios (CRs) between ventricular blood pool and septum were calculated on balanced-turbo field echo (B-TFE) cine images. The off-resonance artifacts of cine images were blindly assessed by two radiologists according to a 4-point grading-scale. Results A significantly lower mean coefficients of variance of the achieved FA with dual-source revealed better RF homogeneity compared to single-source (P = 0.0094). Dual-source RF shimming significantly increased the CRs (P<0.05) and reduced the off-resonance artifacts of B-TFE cine images (P<0.05). Inter-observer agreement for the off-resonance artifacts of B-TFE cine images was good to excellent (k >0.65). Conclusions Dual-source parallel RF transmission significantly improves the RF homogeneity, increases image contrast and reduces image artifacts of cardiac B-TFE images compared to single-source mode. This may be of value in reducing the observer-dependence of cardiac MR images and enhancing diagnostic confidence for clinical practice using CMR at 3.0 T.
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Affiliation(s)
- Haipeng Jia
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China
| | - Cuiyan Wang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China
| | - Guangbin Wang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China
| | - Lei Qu
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China
| | - Weibo Chen
- MR Research Collaboration, Philips. Ltd. China, Shanghai, China
| | - Queenie Chan
- MR Research Collaboration, Philips. Ltd. China, Shanghai, China
| | - Bin Zhao
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China
- * E-mail:
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Li Y, Hua Y, Fang J, Wang C, Qiao L, Wan C, Mu D, Zhou K. Performance of different scan protocols of fetal echocardiography in the diagnosis of fetal congenital heart disease: a systematic review and meta-analysis. PLoS One 2013; 8:e65484. [PMID: 23750263 PMCID: PMC3672155 DOI: 10.1371/journal.pone.0065484] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 04/26/2013] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE The rapid progress in fetal echocardiography has lead to early detection of congenital heart diseases. Increasing evidences have shown that prenatal diagnosis could be life saving in certain cases. However, there is no agreement on which protocol is most adaptive diagnostic one. Thus, we use meta-analysis to conduct a pooled performance test on 5 diagnostic protocols. METHODS We searched PUBMED, EMBASE, the Cochrane Central Register of Controlled Trials and WHO clinical trails registry center to identify relevant studies up to August, 2012. We performed meta-analysis in a fixed/random-effect model using Meta-disc 1.4. We used STATA 11.0 to estimate the publication bias and SPSS 17.0 to evaluate variance. RESULTS We use results from 81 studies in 63 articles to analyze the pooled accuracy. The overall performance of pooled sensitivities of spatiotemporal image correlation (STIC), extend cardiac echography examination (ECEE) and 4 chambers view + outflow tract view + 3 vessels and trachea view (4 CV+OTV+3 VTV) were around 0.90, which was significant higher than that of 4 chambers view + outflow tract view or 3 vessels and trachea view (4 CV+OTV/3 VTV) and 4 chambers view (4 CV). Unfortunately the pooled specificity of STIC was 0.92, which was significant lower than that of other 4 protocols which reached at 1.00. The area under the summary receiver operating characteristic curves value of STIC, ECEE, 4 CV+OTV+3 VTV, 4 CV+OTV/3 VTV and 4 CV were 0.9700, 0.9971, 0.9983, 0.9929 and 0.9928 respectively. CONCLUSION These results suggest a great diagnostic potential for fetal echocardiography detection as a reliable method of fetal congenital heart disease. But at least 3 sections view (4 CV, OTV and 3 VTV) should be included in scan protocol, while the STIC can be used to provide more information for local details of defects, and can not be used to make a definite diagnosis alone with its low specificity.
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Affiliation(s)
- Yifei Li
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- West China Medical School of Sichuan University, Chengdu, Sichuan, China
| | - Yimin Hua
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Program for Changjiang Scholars and Innovative Research Team in University, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jie Fang
- State Key Laboratory of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Chuan Wang
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- West China Medical School of Sichuan University, Chengdu, Sichuan, China
| | - Lina Qiao
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Program for Changjiang Scholars and Innovative Research Team in University, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Chaomin Wan
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Program for Changjiang Scholars and Innovative Research Team in University, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Dezhi Mu
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Program for Changjiang Scholars and Innovative Research Team in University, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Kaiyu Zhou
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Ministry of Education Key Laboratory of Women and Children’s Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Program for Changjiang Scholars and Innovative Research Team in University, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
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WONG KELVINKL, SUN ZHONGHUA, TU JIYUAN. MEDICAL IMAGING AND COMPUTER-AIDED FLOW ANALYSIS OF A HEART WITH ATRIAL SEPTAL DEFECT. J MECH MED BIOL 2012. [DOI: 10.1142/s0219519412500248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Computer-aided magnetic resonance (MR) fluid motion tracking and cardiac vorticity quantification of the right atrial flow is implemented in this study to suggest a new method for the diagnosis of an atrial septal defect (ASD). MR signals of blood moving in a cardiac chamber can be represented as an image and vary in intensity at every consecutive cardiac phase. A method was devised to perform flow analysis using MR imaging without modification of scan mode or protocol that allows velocity encoding. A single vortex or multiple vortices may appear in the cardiac chamber. However, velocity fields in any flow scenario are normally unable to reveal information for a concise analysis; therefore, in addition to velocity maps, vorticity flow maps on which the velocity field is superimposed are presented. Through a case study, the difference in vortex strengths pre- and post-atrial septal occlusion can be examined, and the results can be verified using computational fluid dynamics. Based on this framework, the degree of vortical flow was assessed for the right atrium of a subject with atrial septal defect. A relationship can be established between right atrial vorticity and the ASD. As such, there is clear utility of the developed system in its potential as a prognostic and investigative tool for the quantitative assessment of cardiac abnormalities parallel to examining magnetic resonance images.
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Affiliation(s)
- KELVIN K. L. WONG
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, VIC 3083, Australia
| | - ZHONGHUA SUN
- Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth 6845, Australia
| | - JIYUAN TU
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, VIC 3083, Australia
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Medical image diagnostics based on computer-aided flow analysis using magnetic resonance images. Comput Med Imaging Graph 2012; 36:527-41. [PMID: 22575846 DOI: 10.1016/j.compmedimag.2012.04.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/24/2022]
Abstract
Most of the cardiac abnormalities have an implication on hemodynamics and affect cardiovascular health. Diagnostic imaging modalities such as computed tomography and magnetic resonance imaging provide excellent anatomical information on myocardial structures, but fail to show the cardiac flow and detect heart defects in vivo condition. The computerized technique for fluid motion estimation by pixel intensity tracking based on magnetic resonance signals represents a promising technique for functional assessment of cardiovascular disease, as it can provide functional information of the heart in addition to analysis of its anatomy. Cardiovascular flow characteristics can be measured in both normal controls and patients with cardiac abnormalities such as atrial septal defect, thus, enabling identification of the underlying causes of these flow phenomena. This review paper focuses on an overview of a flow analysis scheme based on computer-aided evaluation of magnetic resonance intensity images, in comparison with other commonly used medical imaging modalities. Details of the proposed technique are provided with validations being conducted at selected abnormal cardiovascular patients. It is expected that this new technique can potentially extend applications for characterizing cardiovascular defects and their hemodynamic behavior.
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Wong KKL, Tu J, Kelso RM, Worthley SG, Sanders P, Mazumdar J, Abbott D. Cardiac flow component analysis. Med Eng Phys 2009; 32:174-88. [PMID: 20022796 DOI: 10.1016/j.medengphy.2009.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 11/24/2022]
Abstract
In a chamber of the heart, large-scale vortices are shown to exist as the result of the dynamic blood flow and unique morphological changes of the chamber wall. As the cardiovascular flow varies over a cardiac cycle, there is a need for a robust quantification method to analyze its vorticity and circulation. We attempt to measure vortex characteristics by means of two-dimensional vorticity maps and vortex circulation. First, we develop vortex component analysis by segmenting the vortices using an data clustering algorithm before histograms of their vorticity distribution are generated. The next stage is to generate the statistics of the vorticity maps for each phase of the cardiac cycle to allow analysis of the flow. This is followed by evaluating the circulation of each segmented vortex. The proposed approach is dedicated to examining vortices within the human heart chamber. The vorticity field can indicate the strength and number of large-scale vortices in the chamber. We provide the results of the flow analysis after vorticity map segmentation and the statistical properties that characterize the vorticity components. The success of the cardiac measurement and analysis is illustrated by a case study of the right atrium. Our investigation shows that it is possible to utilize a data clustering algorithm to segment vortices after vorticity mapping, and that the vorticity and circulation analysis of a chamber vorticity can provide new insights into the blood flow within the cardiovascular structure.
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Affiliation(s)
- Kelvin K L Wong
- School of Aerospace, Mechanical & Manufacturing Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia.
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