151
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Rayz VL, Saloner D, Rayz JM, Raskin V. Cognitive Imaging. INTERNATIONAL JOURNAL OF COGNITIVE INFORMATICS AND NATURAL INTELLIGENCE 2018. [DOI: 10.4018/ijcini.2018040101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This article, an extended version of ICCI*CC-2017 paper, co-authored by biomedical engineers specializing in brain blood circulation modeling and by experts in meaning-based NLP. This article suggests a cognitive computing technology for medical imaging analysis that removes image artifacts resulting in visual deviations from reality, such as discontinuous blood vessels or two vessels shown merged when they are not. It is implemented by supplying the pertinent knowledge that humans have to the computer and letting it initiate the corrective post-processing. The existing OST resource is centered on the ontology that is made to accommodate the domain with a minor adjustment effort; however, any ontology can be used, as demonstrated in this article. The examples from the ontology demonstrate the disparities between what the image shows and what the human knows. The computer detects them autonomously and can initiate the appropriate post-processing. If and when this cognitive imaging prevails, the post-processed images may replace the current ones as legitimate artifact-free MRIs.
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152
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Brinjikji W, Chung B, Yong-Hong D, Wald JT, Mut F, Kadirvel R, Kallmes DF, Rouchaud A, Lanzino G, Cebral JR. Hemodynamic characteristics of stable and unstable vertebrobasilar dolichoectatic and fusiform aneurysms. J Neurointerv Surg 2018; 10:1102-1107. [DOI: 10.1136/neurintsurg-2018-013756] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/20/2018] [Accepted: 02/21/2018] [Indexed: 11/04/2022]
Abstract
Background and purposeVertebrobasilar dolichoectatic and fusiform aneurysms (VBDAs) are known to have a poor natural history, with high rates of growth, rupture, and stroke. The purpose of this study was to identify hemodynamic characteristics that differ between VBDAs associated with growth, rupture, and stroke.Materials and methodsVBDAs with CT angiography or MR angiography followed longitudinally without treatment were studied. Unstable aneurysms were defined as those that grew or ruptured during follow-up. Aneurysms associated with stroke were defined as those associated with posterior circulation infarct at follow-up. Baseline data, including demographics, comorbidities, and aneurysm morphology and size were collected. Image based computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups (stable vs unstable and no stroke vs stroke) using the Wilcoxon test.ResultsA total of 37 VBDAs were included (24 stable, 13 unstable; 30 no stroke, 7 stroke). Unstable aneurysms had lower shear rates (P=0.05), blood flow velocity (P=0.03), and lower vorticity (P=0.049) than stable aneurysms. In addition, unstable aneurysms had higher mean oscillatory shear indices (P=0.001). There were no differences in the hemodynamic characteristics of aneurysms in the stroke group compared with the non-stroke group.ConclusionThis small study suggests there may be hemodynamic differences between unstable and stable VBDAs. Unstable VBDAs appear to be under lower flow conditions with lower velocity, vorticity, and shear rates, and have more oscillatory flow. There was no difference in the hemodynamic characteristics of aneurysms in the stroke and no stroke group.
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153
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Spazzapan M, Sastry P, Dunning J, Nordsletten D, de Vecchi A. The Use of Biophysical Flow Models in the Surgical Management of Patients Affected by Chronic Thromboembolic Pulmonary Hypertension. Front Physiol 2018; 9:223. [PMID: 29593574 PMCID: PMC5859070 DOI: 10.3389/fphys.2018.00223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/28/2018] [Indexed: 11/21/2022] Open
Abstract
Introduction: Chronic Thromboembolic Pulmonary Hypertension (CTEPH) results from progressive thrombotic occlusion of the pulmonary arteries. It is treated by surgical removal of the occlusion, with success rates depending on the degree of microvascular remodeling. Surgical eligibility is influenced by the contributions of both the thrombus occlusion and microvasculature remodeling to the overall vascular resistance. Assessing this is challenging due to the high inter-individual variability in arterial morphology and physiology. We investigated the potential of patient-specific computational flow modeling to quantify pressure gradients in the pulmonary arteries of CTEPH patients to assist the decision-making process for surgical eligibility. Methods: Detailed segmentations of the pulmonary arteries were created from postoperative chest Computed Tomography scans of three CTEPH patients. A focal stenosis was included in the original geometry to compare the pre- and post-surgical hemodynamics. Three-dimensional flow simulations were performed on each morphology to quantify velocity-dependent pressure changes using a finite element solver coupled to terminal 2-element Windkessel models. In addition to transient flow simulations, a parametric modeling approach based on constant flow simulations is also proposed as faster technique to estimate relative pressure drops through the proximal pulmonary vasculature. Results: An asymmetrical flow split between left and right pulmonary arteries was observed in the stenosed models. Removing the proximal obstruction resulted in a reduction of the right-left pressure imbalance of up to 18%. Changes were also observed in the wall shear stresses and flow topology, where vortices developed in the stenosed model while the non-stenosed retained a helical flow. The predicted pressure gradients from constant flow simulations were consistent with the ones measured in the transient flow simulations. Conclusion: This study provides a proof of concept that patient-specific computational modeling can be used as a noninvasive tool for assisting surgical decisions in CTEPH based on hemodynamics metrics. Our technique enables determination of the proximal relative pressure, which could subsequently be compared to the total pressure drop to determine the degree of distal and proximal vascular resistance. In the longer term this approach has the potential to form the basis for a more quantitative classification system of CTEPH types.
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Affiliation(s)
- Martina Spazzapan
- King's College London, GKT School of Medical Education, London, United Kingdom
| | - Priya Sastry
- Cardiothoracic Surgery Unit, Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - John Dunning
- Cardiothoracic Surgery Unit, Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - David Nordsletten
- King's College London, School of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, London, United Kingdom
| | - Adelaide de Vecchi
- King's College London, School of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, London, United Kingdom
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154
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Varble N, Trylesinski G, Xiang J, Snyder K, Meng H. Identification of vortex structures in a cohort of 204 intracranial aneurysms. J R Soc Interface 2018; 14:rsif.2017.0021. [PMID: 28539480 DOI: 10.1098/rsif.2017.0021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/27/2017] [Indexed: 12/28/2022] Open
Abstract
An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the Q-criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction (vVF) and the surface vortex fraction (sVF). Computational fluid dynamics simulations showed that the sVF, but not the vVF, discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.
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Affiliation(s)
- Nicole Varble
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Gabriel Trylesinski
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA.,Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Kenneth Snyder
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA.,Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY, USA.,Department of Radiology, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Hui Meng
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA .,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA.,Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY, USA.,Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA
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155
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A Novel Plasma-Based Fluid for Particle Image Velocimetry (PIV): In-Vitro Feasibility Study of Flow Diverter Effects in Aneurysm Model. Ann Biomed Eng 2018; 46:841-848. [PMID: 29488139 DOI: 10.1007/s10439-018-2002-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/22/2018] [Indexed: 10/17/2022]
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156
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Rafat M, Stone HA, Auguste DT, Dabagh M, Randles A, Heller M, Rabinov JD. Impact of diversity of morphological characteristics and Reynolds number on local hemodynamics in basilar aneurysms. AIChE J 2018. [DOI: 10.1002/aic.16091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Marjan Rafat
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Howard A. Stone
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Debra T. Auguste
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Mahsa Dabagh
- Dept. of Biomedical EngineeringDuke UniversityDurham NC 27708
| | - Amanda Randles
- Dept. of Biomedical EngineeringDuke UniversityDurham NC 27708
| | - Martin Heller
- Dept. of Micro‐ and NanotechnologyTechnical University of Denmark, DTU NanotechKongens Lyngby DK‐2800 Denmark
| | - James D. Rabinov
- Dept. of Radiology and NeurosurgeryMassachusetts General HospitalBoston MA 02114
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157
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Dacron graft as replacement to dissected aorta: A three-dimensional fluid-structure-interaction analysis. J Mech Behav Biomed Mater 2018; 78:329-341. [DOI: 10.1016/j.jmbbm.2017.11.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 11/20/2017] [Indexed: 11/21/2022]
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158
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Murphy PA, Butty VL, Boutz PL, Begum S, Kimble AL, Sharp PA, Burge CB, Hynes RO. Alternative RNA splicing in the endothelium mediated in part by Rbfox2 regulates the arterial response to low flow. eLife 2018; 7:29494. [PMID: 29293084 PMCID: PMC5771670 DOI: 10.7554/elife.29494] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/30/2017] [Indexed: 12/13/2022] Open
Abstract
Low and disturbed blood flow drives the progression of arterial diseases including atherosclerosis and aneurysms. The endothelial response to flow and its interactions with recruited platelets and leukocytes determine disease progression. Here, we report widespread changes in alternative splicing of pre-mRNA in the flow-activated murine arterial endothelium in vivo. Alternative splicing was suppressed by depletion of platelets and macrophages recruited to the arterial endothelium under low and disturbed flow. Binding motifs for the Rbfox-family are enriched adjacent to many of the regulated exons. Endothelial deletion of Rbfox2, the only family member expressed in arterial endothelium, suppresses a subset of the changes in transcription and RNA splicing induced by low flow. Our data reveal an alternative splicing program activated by Rbfox2 in the endothelium on recruitment of platelets and macrophages and demonstrate its relevance in transcriptional responses during flow-driven vascular inflammation.
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Affiliation(s)
- Patrick A Murphy
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States
| | | | - Paul L Boutz
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States
| | - Shahinoor Begum
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Howard Hughes Medical Institute, United States
| | - Amy L Kimble
- Center for Vascular Biology, UCONN Health, Farmington, United States
| | - Phillip A Sharp
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Department of Biology, MIT, Cambridge, United States
| | | | - Richard O Hynes
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Department of Biology, MIT, Cambridge, United States.,Howard Hughes Medical Institute, United States
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159
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Nakai Y, Hamada H, Kittaka D, Noda C, Sato H, Kato K. [Standardization of Analysis Conditions and Prediction of Increase Prediction Using Blood Flow Analysis Software for Cerebral Aneurysms: Phantom Study and Clinical Study]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2018; 74:1275-1285. [PMID: 30464095 DOI: 10.6009/jjrt.2018_jsrt_74.11.1275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In recent years, reports have been made that predict the state of aneurysm by performing computational fluid dynamics (CFD) analysis using cerebral aneurysm blood flow analysis software. However, analysis results are not constant and there are various opinions, and it is conceivable that the image quality and analysis conditions of medical images used for CFD analysis are not standardized. In this study, CFD analysis of cerebral aneurysm phantom was performed, and image quality and analysis conditions were standardized. Then, we investigated whether increase of cerebral aneurysm and prediction of rupture are possible. From this study, stable results of wall shear stress analysis were obtained under slice thickness 1.0 mm or less, CT value 400 HU or more, reconstruction function as soft part function, image SD under 10 HU. In addition, as the size of the cerebral aneurysm became larger, wall shear stress tended to be lower, and the same tendency was shown also in clinical cases. Although CFD analysis using software dedicated to blood flow analysis did not reach the prediction of rupture, it can be evaluated based on the quantitative values for the aneurysm increase at the preceding stage and plays an important role in prediction there is a possibility.
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Affiliation(s)
- Yuichi Nakai
- Department of Radiological Technology, Showa University Northern Yokohama Hospital
| | - Hiroki Hamada
- Department of Radiological Technology, Showa University Hospital
| | - Daisuke Kittaka
- Department of Radiological Technology, Showa University Hospital
| | - Chikara Noda
- Department of Radiological Technology, Showa University Northern Yokohama Hospital
- Graduate School of Health Sciences, Showa University
| | - Hisaya Sato
- Department of Radiological Technology, Showa University Hospital
- Graduate School of Health Sciences, Showa University
| | - Kyoichi Kato
- Graduate School of Health Sciences, Showa University
- Department of Unification Radiological Technology, Showa University
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160
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Ii S, Adib MAHM, Watanabe Y, Wada S. Physically consistent data assimilation method based on feedback control for patient-specific blood flow analysis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2910. [PMID: 28618187 DOI: 10.1002/cnm.2910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 06/12/2017] [Accepted: 06/12/2017] [Indexed: 06/07/2023]
Abstract
This paper presents a novel data assimilation method for patient-specific blood flow analysis based on feedback control theory called the physically consistent feedback control-based data assimilation (PFC-DA) method. In the PFC-DA method, the signal, which is the residual error term of the velocity when comparing the numerical and reference measurement data, is cast as a source term in a Poisson equation for the scalar potential field that induces flow in a closed system. The pressure values at the inlet and outlet boundaries are recursively calculated by this scalar potential field. Hence, the flow field is physically consistent because it is driven by the calculated inlet and outlet pressures, without any artificial body forces. As compared with existing variational approaches, although this PFC-DA method does not guarantee the optimal solution, only one additional Poisson equation for the scalar potential field is required, providing a remarkable improvement for such a small additional computational cost at every iteration. Through numerical examples for 2D and 3D exact flow fields, with both noise-free and noisy reference data as well as a blood flow analysis on a cerebral aneurysm using actual patient data, the robustness and accuracy of this approach is shown. Moreover, the feasibility of a patient-specific practical blood flow analysis is demonstrated.
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Affiliation(s)
- Satoshi Ii
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
| | - Mohd Azrul Hisham Mohd Adib
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
| | - Yoshiyuki Watanabe
- Graduate School of Medicine, Osaka University, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shigeo Wada
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
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161
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Fujimura S, Takao H, Suzuki T, Dahmani C, Ishibashi T, Mamori H, Yamamoto M, Murayama Y. A new combined parameter predicts re-treatment for coil-embolized aneurysms: a computational fluid dynamics multivariable analysis study. J Neurointerv Surg 2017; 10:791-796. [PMID: 29246907 PMCID: PMC6204940 DOI: 10.1136/neurintsurg-2017-013433] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 11/07/2022]
Abstract
Purpose Coil embolization is a minimally invasive method used to treat cerebral aneurysms. Although this endovascular treatment has a high success rate, aneurysmal re-treatment due to recanalization remains a major problem of this method. The purpose of this study was to determine a combined parameter that can be useful for predicting aneurysmal re-treatment due to recanalization. Methods Patient-specific geometries were used to retrospectively analyze the blood flow for 26 re-treated and 74 non-retreated aneurysms. Post-operatively aneurysms were evaluated at 12-month follow-up. The hemodynamic differences between the re-treatment and non-retreatment aneurysms were analyzed before and after coil embolization using computation fluid dynamics. Basic fluid characteristics, rates of change, morphological factors of aneurysms and patient-specific clinical information were examined. Multivariable analysis and logistic regression analysis were performed to determine a combined parameter—re-treatment predictor (RP). Results Among examined hemodynamic, morphological, and clinical parameters, slight reduction of blood flow velocity rate in the aneurysm, slight increase of pressure rate at the aneurysmal neck and neck area, and hypertension were the main factors contributing to re-treatment. Notably, hemodynamic parameters between re-treatment and non-retreatment groups before embolization were similar: however, we observed significant differences between the groups in the post-embolization average velocity and the rate of reduction in this velocity in the aneurysmal dome. Conclusions The combined parameter, RP, which takes into consideration hemodynamic, morphological, and clinical parameters, accurately predicts aneurysm re-treatment. Calculation of RP before embolization may be able to predict the aneurysms that will require re-treatment.
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Affiliation(s)
- Soichiro Fujimura
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.,Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Suzuki
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Chihebeddine Dahmani
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.,Sliemens Health K.K, Tokyo, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroya Mamori
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
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162
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Hemodynamics of Focal Versus Global Growth of Small Cerebral Aneurysms. Clin Neuroradiol 2017; 29:285-293. [DOI: 10.1007/s00062-017-0640-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/12/2017] [Indexed: 10/18/2022]
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163
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Mannino RG, Pandian NK, Jain A, Lam WA. Engineering "Endothelialized" Microfluidics for Investigating Vascular and Hematologic Processes Using Non-Traditional Fabrication Techniques. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 5:13-20. [PMID: 29756078 DOI: 10.1016/j.cobme.2017.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Investigating the complex interplay between blood cells and the endothelium is crucial in understanding the pathophysiology of many diseases. Observation of the in vivo vasculature is difficult due to the complexities of vessel geometry, limited visualization capability, as well as variability and complexity inherent to biologic systems. Therefore, in vitro systems serve as ideal tools to study these cellular interactions. Microfluidic technologies are an ideal tool for recapitulating the vasculature in vivo as they can be used to fabricate fluidic channels on the size scale capillaries using gas permeable, biologically inert, and optically transparent substrates. Microfluidic channels can be vascularized by coating the inner surface of the microchannels with a confluent monolayer of endothelial cells, representing a reductionist, tightly controlled, in vitro model of the microvasculature. In this review, we present advances in the field of "endothelialized" microfluidics, focusing specifically on non-traditional fabrication and endothelialization techniques. We then summarize the various applications of endothelialized microfluidics, and speculate on the future directions of the field, including the exciting applications to personalized medicine.
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Affiliation(s)
- Robert G Mannino
- The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, GA
- The Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA
- Emory University School of Medicine, Department of Pediatrics, Division of Pediatric Hematology/Oncology, Atlanta, GA
- Children's Healthcare of Atlanta, Aflac Cancer & Blood Disorders Center
- Institute of Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA
| | - Navaneeth Kr Pandian
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX
| | - Abhishek Jain
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX
| | - Wilbur A Lam
- The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, Atlanta, GA
- The Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA
- Emory University School of Medicine, Department of Pediatrics, Division of Pediatric Hematology/Oncology, Atlanta, GA
- Children's Healthcare of Atlanta, Aflac Cancer & Blood Disorders Center
- Institute of Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA
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164
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Varble N, Kono K, Rajabzadeh-Oghaz H, Meng H. Rupture Resemblance Models May Correlate to Growth Rates of Intracranial Aneurysms: Preliminary Results. World Neurosurg 2017; 110:e794-e805. [PMID: 29180083 DOI: 10.1016/j.wneu.2017.11.093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND Treatment of intracranial aneurysms (IAs) is largely guided by IA size and growth. Preliminary investigations have found a relationship between clinical factors and growth; yet, the relationship between morphologic and hemodynamic risk prediction models in IA growth is unknown. METHODS We analyzed serial images of 5 growing and 6 stable IAs. Rupture resemblance scores (RRSs) were calculated from three-dimensional segmented images and computational fluid dynamics simulations. The morphologic (RRSM), hemodynamic (RRSH), and combination (RRSC) scores leveraged IA size ratio, wall shear stress, and oscillatory shear index. Comparisons of RRS and morphologic and hemodynamic characteristics were made between growing and stable IAs at the baseline time point and between the baseline and follow-up time points of the growing IAs. In addition, we investigated the correlation of growth rate and RRS and the hemodynamics of growing and stable regions were compared. RESULTS Our results indicate that there is no statistical difference in IAs at the baseline time point; however, growing IAs tend to have a higher aspect ratio (P = 0.066), undulation index (P = 0.086), and RRSC (P = 0.86). In addition, we found a significant correlation between growth rate and baseline RRS of all 3 models (RRSM, r = 0.874, P < 0.001; RRSH, r = 0.727, P = 0.011; RRSC, r = 0.815, P = 0.002). We also found that growing IAs significantly increased in aspect ratio (P = 0.034), size ratio (P = 0.034), and RRSM (P = 0.034). Our results show that stable and growing regions had statistically different wall shear stress and oscillatory shear index. CONCLUSIONS Based on this preliminary study, we conjecture that aneurysms that resemble ruptured IAs may grow faster.
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Affiliation(s)
- Nicole Varble
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Kenichi Kono
- Department of Neurosurgery, Wakayama Rosai Hospital, Wakayama, Japan; Department of Neurosurgery, Showa University Fujigaoka Hospital, Kanagawa, Japan.
| | - Hamidreza Rajabzadeh-Oghaz
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Hui Meng
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA; Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA; Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York, USA
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165
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Li W, Liu J, Zhang Y, Wang K, Tian Z, Zhang Q, Jiang C, Yang X, Wang Y. Flow Diversion and Outcomes of Vertebral Fusiform Aneurysms After Stent-Only Treatment: A Hemodynamic Study. World Neurosurg 2017; 107:202-210. [DOI: 10.1016/j.wneu.2017.07.157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 10/19/2022]
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166
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Chen L, Mossa-Basha M, Balu N, Canton G, Sun J, Pimentel K, Hatsukami TS, Hwang JN, Yuan C. Development of a quantitative intracranial vascular features extraction tool on 3D MRA using semiautomated open-curve active contour vessel tracing. Magn Reson Med 2017; 79:3229-3238. [PMID: 29044753 DOI: 10.1002/mrm.26961] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/13/2017] [Accepted: 09/18/2017] [Indexed: 01/26/2023]
Abstract
PURPOSE To develop a quantitative intracranial artery measurement technique to extract comprehensive artery features from time-of-flight MR angiography (MRA). METHODS By semiautomatically tracing arteries based on an open-curve active contour model in a graphical user interface, 12 basic morphometric features and 16 basic intensity features for each artery were identified. Arteries were then classified as one of 24 types using prediction from a probability model. Based on the anatomical structures, features were integrated within 34 vascular groups for regional features of vascular trees. Eight 3D MRA acquisitions with intracranial atherosclerosis were assessed to validate this technique. RESULTS Arterial tracings were validated by an experienced neuroradiologist who checked agreement at bifurcation and stenosis locations. This technique achieved 94% sensitivity and 85% positive predictive values (PPV) for bifurcations, and 85% sensitivity and PPV for stenosis. Up to 1,456 features, such as length, volume, and averaged signal intensity for each artery, as well as vascular group in each of the MRA images, could be extracted to comprehensively reflect characteristics, distribution, and connectivity of arteries. Length for the M1 segment of the middle cerebral artery extracted by this technique was compared with reviewer-measured results, and the intraclass correlation coefficient was 0.97. CONCLUSION A semiautomated quantitative method to trace, label, and measure intracranial arteries from 3D-MRA was developed and validated. This technique can be used to facilitate quantitative intracranial vascular research, such as studying cerebrovascular adaptation to aging and disease conditions. Magn Reson Med 79:3229-3238, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Li Chen
- Department of Electrical Engineering, University of Washington, Seattle, Washington, USA
| | - Mahmud Mossa-Basha
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Niranjan Balu
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Gador Canton
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Jie Sun
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Kristi Pimentel
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Thomas S Hatsukami
- Department of Surgery, University of Washington, Seattle, Washington, USA
| | - Jenq-Neng Hwang
- Department of Electrical Engineering, University of Washington, Seattle, Washington, USA
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, Washington, USA
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167
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Shamloo A, Nejad MA, Saeedi M. Fluid–structure interaction simulation of a cerebral aneurysm: Effects of endovascular coiling treatment and aneurysm wall thickening. J Mech Behav Biomed Mater 2017; 74:72-83. [DOI: 10.1016/j.jmbbm.2017.05.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 12/01/2022]
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168
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Varble N, Rajabzadeh-Oghaz H, Wang J, Siddiqui A, Meng H, Mowla A. Differences in Morphologic and Hemodynamic Characteristics for "PHASES-Based" Intracranial Aneurysm Locations. AJNR Am J Neuroradiol 2017; 38:2105-2110. [PMID: 28912279 DOI: 10.3174/ajnr.a5341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/09/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Several recent prospective studies have found that unruptured intracranial aneurysms at various anatomic locations have different propensities for future rupture. This study aims to uncover the lack of understanding regarding rupture-prone characteristics, such as morphology and hemodynamic factors, associated with different intracranial aneurysm location. MATERIALS AND METHODS We investigated the characteristics of 311 unruptured aneurysms at our center. Based on the PHASES study, we separated and compared morphologic and hemodynamic characteristics among 3 aneurysm location groups: 1) internal carotid artery; 2) middle cerebral artery; and 3) anterior communicating, posterior communicating, and posterior circulation arteries. RESULTS A mixed model statistical analysis showed that size ratio, low wall shear stress area, and pressure loss coefficient were different between the intracranial aneurysm location groups. In addition, a pair-wise comparison showed that ICA aneurysms had lower size ratios, lower wall shear stress areas, and lower pressure loss coefficients compared with MCA aneurysms and compared with the group of anterior communicating, posterior communicating, and posterior circulation aneurysms. There were no statistical differences between MCA aneurysms and the group of anterior communicating, posterior communicating, and posterior circulation aneurysms for morphologic or hemodynamic characteristics. CONCLUSIONS ICA aneurysms may be subjected to less rupture-prone morphologic and hemodynamic characteristics compared with other locations, which could explain the decreased rupture propensity of intracranial aneurysms at this location.
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Affiliation(s)
- N Varble
- From the Department of Mechanical and Aerospace Engineering (N.V., H.R.-O., H.M.).,Toshiba Stroke and Vascular Research Center (N.V., H.R.-O., A.S., H.M.)
| | - H Rajabzadeh-Oghaz
- From the Department of Mechanical and Aerospace Engineering (N.V., H.R.-O., H.M.).,Toshiba Stroke and Vascular Research Center (N.V., H.R.-O., A.S., H.M.)
| | - J Wang
- Departments of Biostatistics (J.W., A.M.)
| | - A Siddiqui
- Toshiba Stroke and Vascular Research Center (N.V., H.R.-O., A.S., H.M.).,Neurosurgery (A.S., H.M.)
| | - H Meng
- From the Department of Mechanical and Aerospace Engineering (N.V., H.R.-O., H.M.).,Toshiba Stroke and Vascular Research Center (N.V., H.R.-O., A.S., H.M.).,Neurosurgery (A.S., H.M.).,Biomedical Engineering (H.M.)
| | - A Mowla
- Departments of Biostatistics (J.W., A.M.) .,Neurology (A.M.), University at Buffalo, State University of New York, Buffalo, New York
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169
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Longo M, Granata F, Racchiusa S, Mormina E, Grasso G, Longo GM, Garufi G, Salpietro FM, Alafaci C. Role of Hemodynamic Forces in Unruptured Intracranial Aneurysms: An Overview of a Complex Scenario. World Neurosurg 2017; 105:632-642. [DOI: 10.1016/j.wneu.2017.06.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/04/2017] [Accepted: 06/05/2017] [Indexed: 12/16/2022]
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170
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Association of wall shear stress with intracranial aneurysm rupture: systematic review and meta-analysis. Sci Rep 2017; 7:5331. [PMID: 28706287 PMCID: PMC5509692 DOI: 10.1038/s41598-017-05886-w] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/31/2017] [Indexed: 11/24/2022] Open
Abstract
To evaluate the relationship between wall shear stress (WSS) magnitude and cerebral aneurysm rupture and provide new insight into the disparate computational fluid dynamics (CFD) findings concerning the role of WSS in intracranial aneurysm (IA) rupture. A systematic electronic database (PubMed, Medline, Springer, and EBSCO) search was conducted for all accessible published articles up to July 1, 2016, with no restriction on the publication year. Abstracts, full-text manuscripts, and the reference lists of retrieved articles were analyzed. Random effects meta-analysis was used to pool the complication rates across studies. Twenty-two studies containing CFD data on 1257 patients with aneurysms were included in the analysis. A significantly higher rate of low WSS (0–1.5 Pa) was found in ruptured aneurysms (odds ratio [OR] 2.17; 95% confidence interval [CI], 1.73–2.62). The pooled analyses across 14 studies with low WSS showed significantly lower mean WSS (0.64 vs. 1.4 Pa) (p = 0.037) in the ruptured group. This meta-analysis provides evidence that decreased local WSS may be an important predictive parameter of IA rupture.
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171
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Computational Fluid Dynamics Simulation of Hemodynamic Alterations in Sigmoid Sinus Diverticulum and Ipsilateral Upstream Sinus Stenosis After Stent Implantation in Patients with Pulsatile Tinnitus. World Neurosurg 2017; 106:308-314. [PMID: 28698087 DOI: 10.1016/j.wneu.2017.06.168] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the relationships between upstream venous sinus stenosis and pulsatile tinnitus (PT), and to assess the correlation with diverticulum growth and the effectiveness of stent implantation. METHODS Patient-specific geometric models were constructed using computed tomography venography images from a patient with PT, with sigmoid sinus diverticulum, and with upstream transverse sinus stenosis, in whom stenting of the upstream sinus stenosis alone achieved complete remission of PT. Computational fluid dynamics simulation based on this patient-specific geometry was performed using commercially available finite element software (ANSYS-14) to qualitatively and quantitatively compare the flow velocity, flow rate, velocity vector, pressure, vorticity, and wall shear stress on the affected side transverse and sigmoid sinuses, before and after stent implantation. RESULTS Stenting improved the flow direction and magnitude. After stenting, the flow pattern became smoother and more regular. High-speed blood flow at the level of the diverticulum neck was confined to a smaller area, and its direction changed from approximately perpendicular to the diverticular dome to the distal side of the diverticular neck. The diverticulum showed obvious flow reduction, with decreases of 80.7%, 68.7%, 96.1%, and 91.3% in peak velocity, inflow rate, pressure gradient, and peak vorticity, respectively. The abnormally low wall shear stress at the dome of diverticulum was eliminated. CONCLUSIONS Our findings strongly support a major role of diverticulum stenosis before in PT development and suggest that such stenosis is a causative factor of diverticulum growth. They also confirm the effectiveness of stent implantation for the treatment of PT.
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172
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Chien A, Lau V, Yi Q, Chang W. Posterior communicating artery aneurysms demonstrate faster interval growth than other growing aneurysms. Neuroradiol J 2017. [PMID: 28648102 DOI: 10.1177/1971400917709621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Posterior communicating artery aneurysms are often associated with a high rupture risk. This study compares the differences in the rate of growth and morphological characteristics between growing posterior communicating artery aneurysms and other types of growing aneurysms. Materials and methods Thirteen patients with growing internal carotid artery aneurysms were scanned using Siemens 64 slice computed tomography scanners. Three patients had ophthalmic aneurysms, three had superior hypophyseal aneurysms and seven had posterior communicating artery aneurysms. Each aneurysm case had three distinct time points, with an average separation time of 1.3 ± 0.6 years. Annual aneurysm dimensional growth, annual volume growth, annual increase in surface area, size ratio, aspect ratio, and non-sphericity index were analysed. Results Posterior communicating artery aneurysms demonstrated significantly higher annual increases in dimensional growth, volume and surface area when compared to other internal carotid artery aneurysms. Posterior communicating artery aneurysms also demonstrated a significantly higher increase in aspect ratio, size ratio and lower non-sphericity index. Discussion Posterior communicating artery aneurysms had significantly greater growth per year when compared to other types of internal carotid artery aneurysms, and had different morphological characteristics.
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Affiliation(s)
- Aichi Chien
- Division of Interventional Neuroradiology, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, USA
| | - Vicky Lau
- Division of Interventional Neuroradiology, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, USA
| | - Quan Yi
- Division of Interventional Neuroradiology, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, USA
| | - Warren Chang
- Division of Interventional Neuroradiology, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, USA
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173
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Kaneko N, Mashiko T, Namba K, Tateshima S, Watanabe E, Kawai K. A patient-specific intracranial aneurysm model with endothelial lining: a novel in vitro approach to bridge the gap between biology and flow dynamics. J Neurointerv Surg 2017; 10:306-309. [PMID: 28652298 DOI: 10.1136/neurintsurg-2017-013087] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/02/2017] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To develop an in vitro model for studying the biological effect of complex-flow stress on endothelial cells in three-dimensional (3D) patient-specific vascular geometry. MATERIALS AND METHODS A vessel replica was fabricated with polydimethylsiloxanes using 3D printing technology from vascular image data acquired by rotational angiography. The vascular model was coated with fibronectin and immersed in a tube filled with a cell suspension of endothelium, and then cultured while being slowly rotated in three dimensions. Culture medium with viscosity was perfused in the circulation with the endothelialized vascular model. A computational fluid dynamics (CFD) study was conducted using perfusion conditions used in the flow experiment. The morphology of endothelial cells was observed under a confocal microscope. RESULTS The CFD study showed low wall shear stress and circulating flow in the apex of the basilar tip aneurysm, with linear flow in the parent artery. Confocal imaging demonstrated that the inner surface of the vascular model was evenly covered with monolayer endothelial cells. After 24 h of flow circulation, endothelial cells in the parent artery exhibited a spindle shape and aligned with the flow direction. In contrast, endothelial cells in the aneurysmal apex were irregular in shape and size. CONCLUSIONS A geometrically realistic intracranial aneurysm model with live endothelial lining was successfully developed. This in vitro model enables a new research approach combining study of the biological impact of complex flow on endothelial cells with CFD analysis and patient information, including the presence of aneurysmal growth or rupture.
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Affiliation(s)
- Naoki Kaneko
- Department of Neurosurgery, Jichi Medical University, Shimotsuke, Japan.,Division of Interventional Neuroradiology, University of California, Los Angeles, Los Angeles, California, USA
| | - Toshihiro Mashiko
- Department of Neurosurgery, Jichi Medical University, Shimotsuke, Japan
| | - Katsunari Namba
- Department of Endovascular Surgery, Jichi Medical University, Shimotsuke, Japan
| | - Satoshi Tateshima
- Division of Interventional Neuroradiology, University of California, Los Angeles, Los Angeles, California, USA
| | - Eiju Watanabe
- Department of Neurosurgery, Jichi Medical University, Shimotsuke, Japan
| | - Kensuke Kawai
- Department of Neurosurgery, Jichi Medical University, Shimotsuke, Japan
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174
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The more saccular, the worse? J Thorac Cardiovasc Surg 2017; 153:1421. [PMID: 28526102 DOI: 10.1016/j.jtcvs.2017.02.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 02/15/2017] [Indexed: 11/21/2022]
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175
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CHEN YAN, FANG YIBIN, YANG PENGFEI, HUANG QINGHAI, LIU JIANMIN. WHICH MORPHOLOGIC AND HEMODYNAMIC CHARACTERISTICS PREDICT INTRACRANIAL FUSIFORM ANEURYSMS RUPTURE? A PATIENT-SPECIFIC COMPUTATIONAL FLUID DYNAMICS STUDY. J MECH MED BIOL 2017. [DOI: 10.1142/s0219519417500701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To identify hemodynamic and morphological parameters leading to increased risk of intracranial fusiform aneurysms (IFA) rupture using computational fluid dynamics (CFDs). A total of 24 patient-specific fusiform aneurysms models on vertebral artery were reconstructed from 3D angiography images. 11 ruptured cases and 13 unruptured cases were included. Morphologic parameters were measured and CFD parameters were calculated using CFD simulation. The length of the aneurysm is significantly shorter in ruptured group than in unruptured group. The ratio of the width to the length of an aneurysm (WLR) and the ratio of the cross-section area to the length of an aneurysm (ALR) to the averaged cross sectional areas of the inlet and outlet of the parent artery (ALaR) were significantly higher in ruptured group compared with unruptured group. Wall shear stress (WSS) of the aneurysm was normalized to the WSS of the parent artery. Hemodynamically, only low WSS was associated with higher risk of rupture. Ruptured IFAs are shorter, have bigger WLR, ALaR, and lower WSS, compared with unruptured IFAs.
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Affiliation(s)
- YAN CHEN
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, P. R. China
| | - YI-BIN FANG
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, P. R. China
| | - PENG-FEI YANG
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, P. R. China
| | - QING-HAI HUANG
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, P. R. China
| | - JIAN-MIN LIU
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, P. R. China
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176
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Botar CC, Tóth ÁÁ, Klisurić OR, Nićiforović DD, Vučaj Ćirilović VA, Till VE. Dynamic simulation and Doppler Ultrasonography validation of blood flow behavior in Abdominal Aortic Aneurysm. Phys Med 2017; 37:1-8. [DOI: 10.1016/j.ejmp.2017.03.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 03/20/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022] Open
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177
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Burlakoti A, Kumaratilake J, Taylor J, Massy-Westropp N, Henneberg M. The cerebral basal arterial network: morphometry of inflow and outflow components. J Anat 2017; 230:833-841. [PMID: 28370065 DOI: 10.1111/joa.12604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2017] [Indexed: 12/20/2022] Open
Abstract
The aim of this project was to study how the morphology of the incoming and outgoing arterial components of the cerebral basal arterial network influence the blood flow to the brain. The cerebral basal arterial network consists of the circulus arteriosus cerebri anteriorly and the basilar artery posteriorly. Diameters of inflow vessels (bilateral vertebral and internal carotid arteries), connecting vessels (anterior communicating, basilar and bilateral posterior communicating arteries) and outflow vessels (anterior, middle and posterior cerebral arteries) were measured and cross-sectional areas calculated in 51 cadaveric brain specimens. The individual and the average cross-sectional areas of inflow arteries (51.43 mm2 ) were significantly bigger than the major outflow arteries (37.76 mm2 ) but smaller than the combined cross-sectional areas of outflow (37.76 mm2 ) and connecting (25.33 mm2 ) arteries. The difference in the size of arterial cross-sectional area and the presence of the connecting arteries in the cerebral basal arterial network provides a mechanism for lowering peaks in pressure, and demonstrates a function of the cerebral basal arterial network.
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Affiliation(s)
- Arjun Burlakoti
- School of Health Sciences, University of South Australia, Adelaide, SA, Australia.,Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Jaliya Kumaratilake
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Jamie Taylor
- Magnetic Resonance Imaging Centre, Royal Adelaide Hospital, Adelaide, SA, Australia
| | | | - Maciej Henneberg
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
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178
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Varble N, Xiang J, Lin N, Levy E, Meng H. Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms. J Biomech Eng 2016; 138:061009. [PMID: 27109451 DOI: 10.1115/1.4033477] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Indexed: 11/08/2022]
Abstract
Recent high-resolution computational fluid dynamics (CFD) studies have detected persistent flow instability in intracranial aneurysms (IAs) that was not observed in previous in silico studies. These flow fluctuations have shown incidental association with rupture in a small aneurysm dataset. The aims of this study are to explore the capabilities and limitations of a commercial cfd solver in capturing such velocity fluctuations, whether fluctuation kinetic energy (fKE) as a marker to quantify such instability could be a potential parameter to predict aneurysm rupture, and what geometric parameters might be associated with such fluctuations. First, we confirmed that the second-order discretization schemes and high spatial and temporal resolutions are required to capture these aneurysmal flow fluctuations. Next, we analyzed 56 patient-specific middle cerebral artery (MCA) aneurysms (12 ruptured) by transient, high-resolution CFD simulations with a cycle-averaged, constant inflow boundary condition. Finally, to explore the mechanism by which such flow instabilities might arise, we investigated correlations between fKE and several aneurysm geometrical parameters. Our results show that flow instabilities were present in 8 of 56 MCA aneurysms, all of which were unruptured bifurcation aneurysms. Statistical analysis revealed that fKE could not differentiate ruptured from unruptured aneurysms. Thus, our study does not lend support to these flow instabilities (based on a cycle-averaged constant inflow as opposed to peak velocity) being a marker for rupture. We found a positive correlation between fKE and aneurysm size as well as size ratio. This suggests that the intrinsic flow instability may be associated with the breakdown of an inflow jet penetrating the aneurysm space.
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179
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Jordanski M, Radovic M, Milosevic Z, Filipovic N, Obradovic Z. Machine Learning Approach for Predicting Wall Shear Distribution for Abdominal Aortic Aneurysm and Carotid Bifurcation Models. IEEE J Biomed Health Inform 2016; 22:537-544. [PMID: 28113333 DOI: 10.1109/jbhi.2016.2639818] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Computer simulations based on the finite element method represent powerful tools for modeling blood flow through arteries. However, due to its computational complexity, this approach may be inappropriate when results are needed quickly. In order to reduce computational time, in this paper, we proposed an alternative machine learning based approach for calculation of wall shear stress (WSS) distribution, which may play an important role in mechanisms related to initiation and development of atherosclerosis. In order to capture relationships between geometric parameters, blood density, dynamic viscosity and velocity, and WSS distribution of geometrically parameterized abdominal aortic aneurysm (AAA) and carotid bifurcation models, we proposed multivariate linear regression, multilayer perceptron neural network and Gaussian conditional random fields (GCRF). Results obtained in this paper show that machine learning approaches can successfully predict WSS distribution at different cardiac cycle time points. Even though all proposed methods showed high potential for WSS prediction, GCRF achieved the highest coefficient of determination (0.930-0.948 for AAA model and 0.946-0.954 for carotid bifurcation model) demonstrating benefits of accounting for spatial correlation. The proposed approach can be used as an alternative method for real time calculation of WSS distribution.
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180
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Pulsatility Index as a Diagnostic Parameter of Reciprocating Wall Shear Stress Parameters in Physiological Pulsating Waveforms. PLoS One 2016; 11:e0166426. [PMID: 27893801 PMCID: PMC5125588 DOI: 10.1371/journal.pone.0166426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/28/2016] [Indexed: 11/28/2022] Open
Abstract
Arterial wall shear stress (WSS) parameters are widely used for prediction of the initiation and development of atherosclerosis and arterial pathologies. Traditional clinical evaluation of arterial condition relies on correlations of WSS parameters with average flow rate (Q) and heart rate (HR) measurements. We show that for pulsating flow waveforms in a straight tube with flow reversals that lead to significant reciprocating WSS, the measurements of HR and Q are not sufficient for prediction of WSS parameters. Therefore, we suggest adding a third quantity—known as the pulsatility index (PI)—which is defined as the peak-to-peak flow rate amplitude normalized by Q. We examine several pulsating flow waveforms with and without flow reversals using a simulation of a Womersley model in a straight rigid tube and validate the simulations through experimental study using particle image velocimetry (PIV). The results indicate that clinically relevant WSS parameters such as the percentage of negative WSS (P[%]), oscillating shear index (OSI) and the ratio of minimum to maximum shear stress rates (min/max), are better predicted when the PI is used in conjunction with HR and Q. Therefore, we propose to use PI as an additional and essential diagnostic quantity for improved predictability of the reciprocating WSS.
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181
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Natsume K, Shiiya N, Takehara Y, Sugiyama M, Satoh H, Yamashita K, Washiyama N. Characterizing saccular aortic arch aneurysms from the geometry-flow dynamics relationship. J Thorac Cardiovasc Surg 2016; 153:1413-1420.e1. [PMID: 28027791 DOI: 10.1016/j.jtcvs.2016.11.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/26/2016] [Accepted: 11/04/2016] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Low wall shear stress (WSS) has been reported to be associated with accelerated atherosclerosis, aneurysm growth, or rupture. We evaluated the geometry of aortic arch aneurysms and their relationship with WSS by using the 4-dimensional flow magnetic resonance imaging to better characterize the saccular aneurysms. METHODS We analyzed the geometry in 100 patients using multiplanar reconstruction of computed tomography. We evaluated WSS and vortex flow using 4-dimensional flow magnetic resonance imaging in 16 of them, which were compared with 8 age-matched control subjects and eight healthy young volunteers. RESULTS Eighty-two patients had a saccular aneurysm, and 18 had a fusiform aneurysm. External diameter/aneurysm length ratio and sac depth/neck width ratio of the fusiform aneurysms were constant at 0.76 ± 0.18 and 0.23 ± 0.09, whereas those of saccular aneurysms, especially those involving the outer curvature, were higher and more variable. Vortex flow was always present in the aneurysms, resulting in low WSS. When the sac depth/neck width ratio was less than 0.8, peak WSS correlated inversely with luminal diameter even in the saccular aneurysms. When this ratio exceeded 0.8, which was the case only with the saccular aneurysms, such correlation no longer existed and WSS was invariably low. CONCLUSIONS Fusiform aneurysms elongate as they dilate, and WSS is lower as the diameter is larger. Saccular aneurysms dilate without proportionate elongation, and they, especially those occupying the inner curvature, have higher and variable sac depth/neck width ratio. When this ratio exceeds 0.8, WSS is low regardless of diameter, which may explain their malignant clinical behavior.
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Affiliation(s)
- Kayoko Natsume
- First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
| | - Norihiko Shiiya
- First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Yasuo Takehara
- Department of Radiology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Masataka Sugiyama
- Department of Radiology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Hiroshi Satoh
- Department of Internal Medicine III, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Katsushi Yamashita
- First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Naoki Washiyama
- First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan
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182
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Vali A, Abla AA, Lawton MT, Saloner D, Rayz VL. Computational Fluid Dynamics modeling of contrast transport in basilar aneurysms following flow-altering surgeries. J Biomech 2016; 50:195-201. [PMID: 27890537 DOI: 10.1016/j.jbiomech.2016.11.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 10/20/2022]
Abstract
In vivo measurement of blood velocity fields and flow descriptors remains challenging due to image artifacts and limited resolution of current imaging methods; however, in vivo imaging data can be used to inform and validate patient-specific computational fluid dynamics (CFD) models. Image-based CFD can be particularly useful for planning surgical interventions in complicated cases such as fusiform aneurysms of the basilar artery, where it is crucial to alter pathological hemodynamics while preserving flow to the distal vasculature. In this study, patient-specific CFD modeling was conducted for two basilar aneurysm patients considered for surgical treatment. In addition to velocity fields, transport of contrast agent was simulated for the preoperative and postoperative conditions using two approaches. The transport of a virtual contrast passively following the flow streamlines was simulated to predict post-surgical flow regions prone to thrombus deposition. In addition, the transport of a mixture of blood with an iodine-based contrast agent was modeled to compare and verify the CFD results with X-ray angiograms. The CFD-predicted patterns of contrast flow were qualitatively compared to in vivo X-ray angiograms acquired before and after the intervention. The results suggest that the mixture modeling approach, accounting for the flow rates and properties of the contrast injection, is in better agreement with the X-ray angiography data. The virtual contrast modeling assessed the residence time based on flow patterns unaffected by the injection procedure, which makes the virtual contrast modeling approach better suited for prediction of thrombus deposition, which is not limited to the peri-procedural state.
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Affiliation(s)
- Alireza Vali
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Adib A Abla
- Department of Neurosurgery, University of Arkansas for Medical Science, AR, USA
| | - Michael T Lawton
- Department of Neurological Surgery, University of California, San Francisco, CA, USA
| | - David Saloner
- Department of Radiology and Biomedical Imaging University of California, San Francisco, CA, USA
| | - Vitaliy L Rayz
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Mechanical Engineering, University of Wisconsin, Milwaukee, WI, USA.
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183
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Aoki T. [Future prospects for the development of a novel medical therapy for intracranial aneurysm]. Nihon Yakurigaku Zasshi 2016; 148:86-91. [PMID: 27478047 DOI: 10.1254/fpj.148.86] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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184
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Jou L, Britz G. Correlation Between Aneurysm Size and Hemodynamics in One Individual with Multiple Small Intracranial Aneurysms. Cureus 2016; 8:e683. [PMID: 27555981 PMCID: PMC4981414 DOI: 10.7759/cureus.683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Objective A large number of cases are needed in the patient-specific modeling of intracranial aneurysms to establish the statistical significance due to individual variation of risk factors that are difficult to account for. However, these risk factors are critical in hemorrhage risk as demonstrated in large clinical studies. Rupture risks for aneurysms in an individual are easier to compare because these aneurysms are under the same physiological environment, and their only differences are the local hemodynamic factors associated with their anatomic locations. Methods Eight small aneurysms (< 7 mm) from one individual were analyzed using patient-specific hemodynamic modeling. Four scenarios with different perfusion assumptions were performed to account for the flow rate at two smaller communicating arteries. Wall shear stresses (WSS) at these aneurysms were compared to determine their relationship with the aneurysm size. Results Each of the three largest aneurysms is either the most proximal or distal aneurysm in a given artery so that blood pressure does not have a direct influence on aneurysm size. No wall shear stress-derived hemodynamic variables are found to be related to aneurysm size. Discussion A study of multiple aneurysms from one individual offers a unique opportunity to examine various hemodynamic factors without selection biases. Aneurysms greater than 4 mm (Group 1) have a higher product of maximum WSS and area of low WSS; aneurysms smaller than 4 mm (Group 2) have a lower product of maximum WSS and area of low WSS. In addition, aneurysm size is linearly correlated with the flow rate at the parent artery in each group.
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Affiliation(s)
- Liangder Jou
- Department of Neurosurgery, Houston Methodist Hospital
| | - Gavin Britz
- Department of Neurosurgery, Houston Methodist Hospital
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185
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Aoki T, Yamamoto K, Fukuda M, Shimogonya Y, Fukuda S, Narumiya S. Sustained expression of MCP-1 by low wall shear stress loading concomitant with turbulent flow on endothelial cells of intracranial aneurysm. Acta Neuropathol Commun 2016; 4:48. [PMID: 27160403 PMCID: PMC4862234 DOI: 10.1186/s40478-016-0318-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 08/18/2015] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Enlargement of a pre-existing intracranial aneurysm is a well-established risk factor of rupture. Excessive low wall shear stress concomitant with turbulent flow in the dome of an aneurysm may contribute to progression and rupture. However, how stress conditions regulate enlargement of a pre-existing aneurysm remains to be elucidated. RESULTS Wall shear stress was calculated with 3D-computational fluid dynamics simulation using three cases of unruptured intracranial aneurysm. The resulting value, 0.017 Pa at the dome, was much lower than that in the parent artery. We loaded wall shear stress corresponding to the value and also turbulent flow to the primary culture of endothelial cells. We then obtained gene expression profiles by RNA sequence analysis. RNA sequence analysis detected hundreds of differentially expressed genes among groups. Gene ontology and pathway analysis identified signaling related with cell division/proliferation as overrepresented in the low wall shear stress-loaded group, which was further augmented by the addition of turbulent flow. Moreover, expression of some chemoattractants for inflammatory cells, including MCP-1, was upregulated under low wall shear stress with concomitant turbulent flow. We further examined the temporal sequence of expressions of factors identified in an in vitro study using a rat model. No proliferative cells were detected, but MCP-1 expression was induced and sustained in the endothelial cell layer. CONCLUSIONS Low wall shear stress concomitant with turbulent flow contributes to sustained expression of MCP-1 in endothelial cells and presumably plays a role in facilitating macrophage infiltration and exacerbating inflammation, which leads to enlargement or rupture.
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186
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Sarrami-Foroushani A, Nasr Esfahany M, Saligheh Rad H, Firouznia K, Shakiba M, Ghanaati H. Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise. IRANIAN JOURNAL OF RADIOLOGY 2016; 13:e18217. [PMID: 27110332 PMCID: PMC4837368 DOI: 10.5812/iranjradiol.18217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/18/2014] [Accepted: 07/20/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics. OBJECTIVES This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics. PATIENTS AND METHODS Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling. RESULTS Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate. CONCLUSION Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated.
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Affiliation(s)
| | - Mohsen Nasr Esfahany
- Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran
- Corresponding author: Mohsen Nasr Esfahany, Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran. Tel: +98-3133915631, Fax: +98-3113912677, E-mail:
| | - Hamidreza Saligheh Rad
- Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Kavous Firouznia
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Madjid Shakiba
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ghanaati
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
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187
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Beller E, Klopp D, Göttler J, Kaesmacher J, Zimmer C, Kirschke JS, Prothmann S. Closed-Cell Stent-Assisted Coiling of Intracranial Aneurysms: Evaluation of Changes in Vascular Geometry Using Digital Subtraction Angiography. PLoS One 2016; 11:e0153403. [PMID: 27073908 PMCID: PMC4830582 DOI: 10.1371/journal.pone.0153403] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/29/2016] [Indexed: 11/18/2022] Open
Abstract
Background Stent-assisted coil embolization (SACE) plays an important role in the treatment of intracranial aneurysms. The purpose of this study was to investigate geometrical changes caused by closed-cell design stents in bifurcation and sidewall aneurysms. Methods 31 patients with 34 aneurysms underwent SACE with closed-cell design stents. Inflow angle α, determined by aneurysm neck and afferent vessel, and angle between afferent and efferent vessel close to (δ1), respectively, more remote from the aneurysm neck (δ2) were graphically determined in 2D angiography projections. Results Stent assisted coiling resulted in a significant increase of all three angles from a mean value (±SEM) of α = 119° (±6.5°) pretreatment to 130° (±6.6°) posttreatment (P ≤ .001), δ1 = 129° (±6.4°) to 139° (±6.1°), (P ≤ .001) and δ2 = 115° (±8.4°) to 126° (±7.5°), (P ≤ .01). Angular change of δ1 in AcomA aneurysms was significant greater compared to sidewall aneurysms (26°±4.9° versus 8°± 2.3°, P ≤ .05). The initial angle of δ1 and δ2 revealed a significantly inverse relationship to the angle increase (δ1: r = -0.41, P ≤ .05 and δ2: r = -0.47, P ≤ .01). Moreover, angle δ1 was significantly higher in unruptured compared to ruptured aneurysms (135°±7.1° versus 103°±10.8°, P ≤ .05). Conclusion Stent deployment modulates the geometry of the aneurysm-vessel complex, which may lead to favorable hemodynamic changes more similar to unruptured than to ruptured aneurysms. Our findings also suggest that the more acute-angled aneurysm-vessel anatomy, the larger the angular change. Further studies are needed to investigate whether these changes improve the clinical outcome.
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Affiliation(s)
- Ebba Beller
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | | | - Jens Göttler
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Johannes Kaesmacher
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Claus Zimmer
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jan S Kirschke
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sascha Prothmann
- Abteilung für Diagnostische und Interventionelle Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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188
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Brinjikji W, Chung BJ, Jimenez C, Putman C, Kallmes DF, Cebral JR. Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location: a pilot study. J Neurointerv Surg 2016; 9:376-380. [PMID: 27048958 DOI: 10.1136/neurintsurg-2016-012327] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/08/2016] [Accepted: 03/12/2016] [Indexed: 11/03/2022]
Abstract
BACKGROUND While clinical and angiographic risk factors for intracranial aneurysm instability are well established, it is reasonable to postulate that intra-aneurysmal hemodynamics also have a role in aneurysm instability. OBJECTIVE To identify hemodynamic characteristics that differ between radiologically unstable and stable unruptured intracranial aneurysms. MATERIALS AND METHODS 12 pairs of unruptured intracranial aneurysms with a 3D rotational angiographic set of images and followed up longitudinally without treatment were studied. Each pair consisted of one stable aneurysm (no change on serial imaging) and one unstable aneurysm (demonstrated growth of at least 1 mm diameter or ruptured during follow-up) of matching size (within 10%) and locations. Patient-specific computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups using the paired Wilcoxon test. RESULTS The area of the aneurysm under low wall shear stress (low shear stress area (LSA)) was 2.26 times larger in unstable aneurysms than in stable aneurysms (p=0.0499). The mean aneurysm vorticity was smaller by a factor of 0.57 in unstable aneurysms compared with stable aneurysms (p=0.0499). No statistically significant differences in geometric variables or shape indices were found. CONCLUSIONS This pilot study suggests there may be hemodynamic differences between unstable and stable unruptured cerebral aneurysms. In particular, the area under low wall shear stress was larger in unstable aneurysms. These findings should be considered tentative until confirmed by future larger studies.
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Affiliation(s)
| | - Bong Jae Chung
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Carlos Jimenez
- Department of Neurosurgery, University of Antioquia, Medellin, Colombia
| | - Christopher Putman
- Department of Interventional Neuroradiology, Inova Fairfax Hospital, Falls Church, Virginia, USA
| | - David F Kallmes
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Juan R Cebral
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
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189
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Basic Principles of Hemodynamics and Cerebral Aneurysms. World Neurosurg 2016; 88:311-319. [DOI: 10.1016/j.wneu.2016.01.031] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 01/03/2016] [Accepted: 01/05/2016] [Indexed: 11/18/2022]
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190
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Yoon NK, McNally S, Taussky P, Park MS. Imaging of cerebral aneurysms: a clinical perspective. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s40809-016-0016-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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191
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Ramachandran M, Retarekar R, Raghavan ML, Berkowitz B, Dickerhoff B, Correa T, Lin S, Johnson K, Hasan D, Ogilvy C, Rosenwasser R, Torner J, Bogason E, Stapleton CJ, Harbaugh RE. Assessment of image-derived risk factors for natural course of unruptured cerebral aneurysms. J Neurosurg 2016; 124:288-95. [DOI: 10.3171/2015.2.jns142265] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECT
The goal of this prospective longitudinal study was to test whether image-derived metrics can differentiate unruptured aneurysms that will become unstable (grow and/or rupture) from those that will remain stable.
METHODS
One hundred seventy-eight patients harboring 198 unruptured cerebral aneurysms for whom clinical observation and follow-up with imaging surveillance was recommended at 4 clinical centers were prospectively recruited into this study. Imaging data (predominantly CT angiography) at initial presentation was recorded. Computational geometry was used to estimate numerous metrics of aneurysm morphology that described the size and shape of the aneurysm. The nonlinear, finite element method was used to estimate uniform pressure-induced peak wall tension. Computational fluid dynamics was used to estimate blood flow metrics. The median follow-up period was 645 days. Longitudinal outcome data on these aneurysm patients—whether their aneurysms grew or ruptured (the unstable group) or remained unchanged (the stable group)—was documented based on follow-up at 4 years after the beginning of recruitment.
RESULTS
Twenty aneurysms (10.1%) grew, but none ruptured. One hundred forty-nine aneurysms (75.3%) remained stable and 29 (14.6%) were lost to follow-up. None of the metrics—including aneurysm size, nonsphericity index, peak wall tension, and low shear stress area—differentiated the stable from unstable groups with statistical significance.
CONCLUSIONS
The findings in this highly selected group do not support the hypothesis that image-derived metrics can predict aneurysm growth in patients who have been selected for observation and imaging surveillance. If aneurysm shape is a significant determinant of invasive versus expectant management, selection bias is a key limitation of this study.
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Affiliation(s)
| | | | | | | | | | - Tatiana Correa
- 1Department of Biomedical Engineering, University of Iowa
| | - Steve Lin
- 1Department of Biomedical Engineering, University of Iowa
| | - Kevin Johnson
- 2Department of Neurosurgery, University of Iowa Hospitals and Clinics; and
| | - David Hasan
- 2Department of Neurosurgery, University of Iowa Hospitals and Clinics; and
| | - Christopher Ogilvy
- 3Department of Surgery, Division of Neurosurgery, Beth Israel Deaconess Medical Center; and
| | - Robert Rosenwasser
- 4Department of Neurosurgery, Jefferson University Hospital, Philadelphia
| | - James Torner
- 5Department of Epidemiology, University of Iowa, Iowa City, Iowa
| | - Einar Bogason
- 6Department of Neurosurgery, Penn State University, Hershey; and
| | | | - Robert E. Harbaugh
- 6Department of Neurosurgery, Penn State University, Hershey; and
- 8Department of Engineering Science and Mechanics, Pennsylvania State University, State College, Pennsylvania
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192
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Aramburu J, Antón R, Borro D, Rivas A, Larraona GS, Ramos JC, Finol EA. A methodology for assessing local bifurcated blood vessel shape variations. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/1/015001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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193
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Frösen J. Flow Dynamics of Aneurysm Growth and Rupture: Challenges for the Development of Computational Flow Dynamics as a Diagnostic Tool to Detect Rupture-Prone Aneurysms. ACTA NEUROCHIRURGICA. SUPPLEMENT 2016; 123:89-95. [PMID: 27637634 DOI: 10.1007/978-3-319-29887-0_13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Saccular intracranial aneurysm (sIA) is a relatively common disease that can potentially cause a devastating, life-threatening intracranial hemorrhage. Many sIAs never rupture and thus do not necessitate interventions, making the detection of rupture-prone sIAs a very relevant clinical problem. Moreover, because currently available methods to prevent sIA rupture have significant risks of morbidity and mortality, diagnostic tools that can predict imminent rupture and help plan proper timing of prophylactic interventions, can improve patient care. Hemorrhage from an sIA occurs when hemodynamic stress exceeds sIA wall strength. Computational fluid dynamics (CFD) is a tool with which the hemodynamic stress to which the sIA wall is exposed can be determined non-invasively. Studies using CFD in sIAs have demonstrated associations of wall shear stress (WSS) with aneurysm growth, fragile sIA wall, and sIA rupture; these studies show the potential of CFD as a diagnostic tool. This review discusses the limitations of CFD and of the studies performed, and what needs to be done in order to develop CFD into a useful diagnostic tool to determine aneurysm-specific rupture risk.
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Affiliation(s)
- Juhana Frösen
- Department of Neurosurgery, Kuopio University Hospital, Puijonlaaksontie 2, Kuopio, 00029, Finland.
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194
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Lv N, Yu Y, Xu J, Karmonik C, Liu J, Huang Q. Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy. J Neurosurg 2015; 125:264-8. [PMID: 26636379 DOI: 10.3171/2015.6.jns15267] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Unruptured posterior communicating artery (PCoA) aneurysms with oculomotor nerve palsy (ONP) have a very high risk of rupture. This study investigated the hemodynamic and morphological characteristics of intracranial aneurysms with high rupture risk by analyzing PCoA aneurysms with ONP. METHODS Fourteen unruptured PCoA aneurysms with ONP, 33 ruptured PCoA aneurysms, and 21 asymptomatic unruptured PCoA aneurysms were included in this study. The clinical, morphological, and hemodynamic characteristics were compared among the different groups. RESULTS The clinical characteristics did not differ among the 3 groups (p > 0.05), whereas the morphological and hemodynamic analyses showed that size, aspect ratio, size ratio, undulation index, nonsphericity index, ellipticity index, normalized wall shear stress (WSS), and percentage of low WSS area differed significantly (p < 0.05) among the 3 groups. Furthermore, multiple comparisons revealed that these parameters differed significantly between the ONP group and the asymptomatic unruptured group and between the ruptured group and the asymptomatic unruptured group, except for size, which differed significantly only between the ONP group and the asymptomatic unruptured group (p = 0.0005). No morphological or hemodynamic parameters differed between the ONP group and the ruptured group. CONCLUSIONS Unruptured PCoA aneurysms with ONP demonstrated a distinctive morphological-hemodynamic pattern that was significantly different compared with asymptomatic unruptured PCoA aneurysms and was similar to ruptured PCoA aneurysms. The larger size, more irregular shape, and lower WSS might be related to the high rupture risk of PCoA aneurysms.
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Affiliation(s)
- Nan Lv
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China; and
| | - Ying Yu
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China; and
| | - Jinyu Xu
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China; and
| | - Christof Karmonik
- Cerebrovascular Center, Department of Neurosurgery, Houston Methodist, Houston, Texas
| | - Jianmin Liu
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China; and
| | - Qinghai Huang
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China; and
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195
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Tarnoki AD, Tarnoki DL, Littvay L, Garami Z, Karlinger K, Berczi V. Genetic and Environmental Effects on the Abdominal Aortic Diameter Development. Arq Bras Cardiol 2015; 106:13-7. [PMID: 26559855 PMCID: PMC4728590 DOI: 10.5935/abc.20150140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 09/02/2015] [Indexed: 11/29/2022] Open
Abstract
Background Configuration of the abdominal aorta is related to healthy aging and a variety of
disorders. Objectives We aimed to assess heritable and environmental effects on the abdominal aortic
diameter. Methods 114 adult (69 monozygotic, 45 same-sex dizygotic) twin pairs (mean age 43.6
± 16.3 years) underwent abdominal ultrasound with Esaote MyLab 70X
ultrasound machine to visualize the abdominal aorta below the level of the origin
of the renal arteries and 1-3 cm above the bifurcation. Results Age- and sex-adjusted heritability of the abdominal aortic diameter below the
level of the origin of the renal arteries was 40% [95% confidence interval (CI),
14 to 67%] and 55% above the aortic bifurcation (95% CI, 45 to 70%). None of the
aortic diameters showed common environmental effects, but unshared environmental
effects were responsible for 60% and 45% of the traits, respectively. Conclusions Our analysis documents the moderate heritability and its segment-specific
difference of the abdominal aortic diameter. The moderate part of variance was
explained by unshared environmental components, emphasizing the importance of
lifestyle factors in primary prevention. Further studies in this field may guide
future gene-mapping efforts and investigate specific lifestyle factors to prevent
abdominal aortic dilatation and its complications.
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Affiliation(s)
| | - David Laszlo Tarnoki
- Department of Radiology and Oncotherapy, Semmelweis University, Budapest, Hungary
| | | | - Zsolt Garami
- Houston Methodist DeBakey Heart & Vascular Center, The Houston Methodist Hospital, Houston, TX, USA
| | - Kinga Karlinger
- Department of Radiology and Oncotherapy, Semmelweis University, Budapest, Hungary
| | - Viktor Berczi
- Department of Radiology and Oncotherapy, Semmelweis University, Budapest, Hungary
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196
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McGah PM, Nerva JD, Morton RP, Barbour MC, Levitt MR, Mourad PD, Kim LJ, Aliseda A. In vitro validation of endovascular Doppler-derived flow rates in models of the cerebral circulation. Physiol Meas 2015; 36:2301-17. [PMID: 26450643 PMCID: PMC4684705 DOI: 10.1088/0967-3334/36/11/2301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study presents validation of endovascular Doppler velocimetry-based volumetric flow rate measurements conducted in a pulsatile flow loop simulating conditions in both the internal carotid and basilar artery. In vitro models of cerebral vessels, each containing an aneurysm, were fabricated from patient anatomies extracted from 3D rotational angiography. Flow velocity measurements were collected with three different experimental techniques: an endovascular Doppler wire, Particle Image Velocimetry, and a time-resolved ultrasonic flow meter. Womersley's theory of pulsatile flow in a cylindrical vessel was used to compute time-resolved volumetric flow rates from the endovascular Doppler velocity. The volumetric flow rates computed from the Doppler measurements were compared to those from the Particle Image Velocimetry profile measurements, and the direct measurements from the ultrasonic flow meter. The study establishes confidence intervals for any systematic or random errors associated with the wire-derived flow rates as benchmarked to the other two modalities. There is an approximately 10% random error in the Doppler-derived peak and time-averaged flow rates. There is a measurable uniform bias, about 15% too low, in the time-averaged Doppler-derived flow rates. There is also a small proportional bias in the peak systolic Doppler-derived flow rates. Potential sources of error are also discussed.
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Affiliation(s)
- P M McGah
- Department of Mechanical Engineering, University of Washington, Stevens Way, Box 352600, Seattle, Washington, US
| | - J D Nerva
- Department of Neurological Surgery, Harborview Medical Center, 325 9th Ave, Box 359924, Seattle, Washington, US
| | - R P Morton
- Department of Neurological Surgery, Harborview Medical Center, 325 9th Ave, Box 359924, Seattle, Washington, US
| | - M C Barbour
- Department of Mechanical Engineering, University of Washington, Stevens Way, Box 352600, Seattle, Washington, US
| | - M R Levitt
- Department of Neurological Surgery, Harborview Medical Center, 325 9th Ave, Box 359924, Seattle, Washington, US
| | - P D Mourad
- Department of Neurological Surgery, Harborview Medical Center, 325 9th Ave, Box 359924, Seattle, Washington, US
| | - L J Kim
- Department of Neurological Surgery, Harborview Medical Center, 325 9th Ave, Box 359924, Seattle, Washington, US
| | - A Aliseda
- Department of Mechanical Engineering, University of Washington, Stevens Way, Box 352600, Seattle, Washington, US
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197
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Chang W, Huang M, Chien A. Emerging techniques for evaluation of the hemodynamics of intracranial vascular pathology. Neuroradiol J 2015; 28:19-27. [PMID: 25924168 DOI: 10.15274/nrj-2014-10115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Advances in imaging modalities have improved the assessment of intracranial hemodynamics using non-invasive techniques. This review examines new imaging modalities and clinical applications of currently available techniques, describes pathophysiology and future directions in hemodynamic analysis of intracranial stenoses, aneurysms and arteriovenous malformations and explores how hemodynamic analysis may have prognostic value in predicting clinical outcomes and assist in risk stratification. The advent of new technologies such as pseudo-continuous arterial spin labeling, accelerated magnetic resonance angiography (MRA) techniques, 4D digital subtraction angiography, and improvements in clinically available techniques such as phase-contrast MRA may change the landscape of vascular imaging and modify current clinical practice guidelines.
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Affiliation(s)
| | | | - Aichi Chien
- UCLA Department of Radiology; Los Angeles, CA, USA
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198
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Gester K, Lüchtefeld I, Büsen M, Sonntag SJ, Linde T, Steinseifer U, Cattaneo G. In Vitro Evaluation of Intra-Aneurysmal, Flow-Diverter-Induced Thrombus Formation: A Feasibility Study. AJNR Am J Neuroradiol 2015; 37:490-6. [PMID: 26450536 DOI: 10.3174/ajnr.a4555] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 08/10/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial aneurysm treatment by flow diverters aims at triggering intra-aneurysmal thrombosis. By combining in vitro blood experiments with particle imaging velocimetry measurements, we investigated the time-resolved thrombus formation triggered by flow diverters. MATERIALS AND METHODS Two test setups were built, 1 for particle imaging velocimetry and 1 for blood experiments, both generating the same pulsatile flow and including a silicone aneurysm model. Tests without flow diverters and with 2 different flow-diverter sizes (diameter: 4.5 and 4.0 mm) were performed. In the blood experiments, the intra-aneurysmal flow was monitored by using Doppler sonography. The experiments were stopped at 3 different changes of the spatial extent of the signal. RESULTS No thrombus was detected in the aneurysm model without the flow diverter. Otherwise, thrombi were observed in all aneurysm models with flow diverters. The thrombi grew from the proximal side of the aneurysm neck with fibrin threads connected to the flow diverter and extending across the aneurysm. The thrombus resulting from the 4.0-mm flow diverter grew along the aneurysm wall as a solid and organized thrombus, which correlates with the slower velocities near the wall detected by particle imaging velocimetry. The thrombus that evolved by using the 4.5-mm flow diverter showed no identifiable growing direction. The entire thrombus presumably resulted from stagnation of blood and correlates with the central vortex detected by particle imaging velocimetry. CONCLUSIONS We showed the feasibility of in vitro investigation of time-resolved thrombus formation in the presence of flow diverters.
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Affiliation(s)
- K Gester
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - I Lüchtefeld
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - M Büsen
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - S J Sonntag
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - T Linde
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - U Steinseifer
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - G Cattaneo
- Acandis GmbH & Co KG (G.C.), Pforzheim, Germany
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199
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Association of Intraluminal Thrombus, Hemodynamic Forces, and Abdominal Aortic Aneurysm Expansion Using Longitudinal CT Images. Ann Biomed Eng 2015; 44:1502-14. [PMID: 26429788 DOI: 10.1007/s10439-015-1461-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/14/2015] [Indexed: 12/22/2022]
Abstract
While hemodynamic forces and intraluminal thrombus (ILT) are believed to play important roles on abdominal aortic aneurysm (AAA), it has been suggested that hemodynamic forces and ILT also interact with each other, making it a complex problem. There is, however, a pressing need to understand relationships among three factors: hemodynamics, ILT accumulation, and AAA expansion for AAA prognosis. Hence this study used longitudinal computer tomography scans from 14 patients and analyzed the relationship between them. Hemodynamic forces, represented by wall shear stress (WSS), were obtained from computational fluid dynamics; ILT accumulation was described by ILT thickness distribution changes between consecutives scans, and ILT accumulation and AAA expansion rates were estimated from changes in ILT and AAA volume. Results showed that, while low WSS was observed at regions where ILT accumulated, the rate at which ILT accumulated occurred at the same rate as the aneurysm expansion. Comparison between AAAs with and without thrombus showed that aneurysm with ILT recorded lower values of WSS and higher values of AAA expansion than those without thrombus. Findings suggest that low WSS may promote ILT accumulation and submit the idea that by increasing WSS levels ILT accumulation may be prevented.
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200
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Nayak KS, Nielsen JF, Bernstein MA, Markl M, D Gatehouse P, M Botnar R, Saloner D, Lorenz C, Wen H, S Hu B, Epstein FH, N Oshinski J, Raman SV. Cardiovascular magnetic resonance phase contrast imaging. J Cardiovasc Magn Reson 2015; 17:71. [PMID: 26254979 PMCID: PMC4529988 DOI: 10.1186/s12968-015-0172-7] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/16/2015] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today's latest technology.
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Affiliation(s)
- Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, California, 90089-2564, USA.
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | | | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, IL, USA.
| | - Peter D Gatehouse
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK.
| | - Rene M Botnar
- Cardiovascular Imaging, Imaging Sciences Division, Kings's College London, London, UK.
| | - David Saloner
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Christine Lorenz
- Center for Applied Medical Imaging, Siemens Corporation, Baltimore, MD, USA.
| | - Han Wen
- Imaging Physics Laboratory, National Heart Lung and Blood Institute, Bethesda, MD, USA.
| | - Bob S Hu
- Palo Alto Medical Foundation, Palo Alto, CA, USA.
| | - Frederick H Epstein
- Departments of Radiology and Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
| | - John N Oshinski
- Departments of Radiology and Biomedical Engineering, Emory University School of Medicine, Atlanta, GA, USA.
| | - Subha V Raman
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA.
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