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Menon K, Khan MO, Sexton ZA, Richter J, Nguyen PK, Malik SB, Boyd J, Nieman K, Marsden AL. Personalized coronary and myocardial blood flow models incorporating CT perfusion imaging and synthetic vascular trees. NPJ IMAGING 2024; 2:9. [PMID: 38706558 PMCID: PMC11062925 DOI: 10.1038/s44303-024-00014-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 02/25/2024] [Indexed: 05/07/2024]
Abstract
Computational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges - incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature. It includes image-based coronary anatomies combined with synthetic vasculature for arteries below the imaging resolution, myocardial blood flow simulated using Darcy models, and systemic circulation represented as lumped-parameter networks. We propose an optimization-based method to personalize multiscale coronary flow simulations by assimilating clinical CT myocardial perfusion imaging and cardiac function measurements to yield patient-specific flow distributions and model parameters. Using this proof-of-concept study on a cohort of six patients, we reveal substantial differences in flow distributions and clinical diagnosis metrics between the proposed personalized framework and empirical methods based purely on anatomy; these errors cannot be predicted a priori. This suggests virtual treatment planning tools would benefit from increased personalization informed by emerging imaging methods.
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Affiliation(s)
- Karthik Menon
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA USA
| | - Muhammed Owais Khan
- Department of Electrical, Computer, and Biomedical Engineering, Toronto Metropolitan University, Toronto, ON Canada
| | | | - Jakob Richter
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA USA
| | - Patricia K. Nguyen
- VA Palo Alto Healthcare System, Palo Alto, CA USA
- Division of Cardiovascular Medicine, Stanford School of Medicine, Stanford, CA USA
| | | | - Jack Boyd
- Department of Cardiothoracic Surgery, Stanford School of Medicine, Stanford, CA USA
| | - Koen Nieman
- Division of Cardiovascular Medicine, Stanford School of Medicine, Stanford, CA USA
- Department of Radiology, Stanford School of Medicine, Stanford, CA USA
| | - Alison L. Marsden
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA USA
- Department of Bioengineering, Stanford University, Stanford, CA USA
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2
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Menon K, Khan MO, Sexton ZA, Richter J, Nieman K, Marsden AL. Personalized coronary and myocardial blood flow models incorporating CT perfusion imaging and synthetic vascular trees. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.17.23294242. [PMID: 37645850 PMCID: PMC10462196 DOI: 10.1101/2023.08.17.23294242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Computational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges - incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature. It includes image-based coronary models combined with synthetic vasculature for arteries below the imaging resolution, myocardial blood flow simulated using Darcy models, and systemic circulation represented as lumped-parameter networks. Personalized flow distributions and model parameters are informed by clinical CT myocardial perfusion imaging and cardiac function using surrogate-based optimization. We reveal substantial differences in flow distributions and clinical diagnosis metrics between the proposed personalized framework and empirical methods based on anatomy; these errors cannot be predicted a priori. This suggests virtual treatment planning tools would benefit from increased personalization informed by emerging imaging methods.
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Affiliation(s)
- Karthik Menon
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Muhammed Owais Khan
- Department of Electrical, Computer, and Biomedical Engineering, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Zachary A Sexton
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Jakob Richter
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA, USA
| | - Koen Nieman
- Departments of Radiology and Medicine (Cardiovascular Medicine), Stanford School of Medicine, Stanford, CA, USA
| | - Alison L Marsden
- Department of Pediatrics (Cardiology), Stanford School of Medicine, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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3
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Vigneshwaran V, Sy CL, Smaill BH, Sands GB, Smith NP. Extended-volume image-derived models of coronary microcirculation. Microcirculation 2023; 30:e12820. [PMID: 37392132 DOI: 10.1111/micc.12820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/10/2023] [Accepted: 06/06/2023] [Indexed: 07/03/2023]
Abstract
OBJECTIVE Recent advances in tissue clearing and high-throughput imaging have enabled the acquisition of extended-volume microvasculature images at a submicron resolution. The objective of this study was to extract information from this type of images by integrating a sequence of 3D image processing steps on Terabyte scale datasets. METHODS We acquired coronary microvasculature images throughout an entire short-axis slice of a 3-month-old Wistar-Kyoto rat heart. This dataset covered 13 × 10 × 0.6 mm at a resolution of 0.933 × 0.933 × 1.866 μm and occupied 700 Gigabytes of disk space. We used chunk-based image segmentation, combined with an efficient graph generation technique, to quantify the microvasculature in the large-scale images. Specifically, we focused on the microvasculature with a vessel diameter up to 15 μm. RESULTS Morphological data for the complete short-axis ring were extracted within 16 h using this pipeline. From the analyses, we identified that microvessel lengths in the rat coronary microvasculature varied from 6 to 300 μm. However, their distribution was heavily skewed toward shorter lengths, with a mode of 16.5 μm. In contrast, vessel diameters ranged from 3 to 15 μm and had an approximately normal distribution of 6.5 ± 2 μm. CONCLUSION The tools and techniques from this study will serve other investigations into the microcirculation, and the wealth of data from this study will enable the analysis of biophysical mechanisms using computer models.
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Affiliation(s)
- Vibujithan Vigneshwaran
- Auckland Bioengineering Institute, Auckland, New Zealand
- Department of Radiology, University of Calgary, Calgary, Alberta, Canada
| | | | - Bruce H Smaill
- Auckland Bioengineering Institute, Auckland, New Zealand
| | | | - Nicolas P Smith
- Auckland Bioengineering Institute, Auckland, New Zealand
- Victoria University of Wellington, New Zealand
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4
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Naessens DMP, Dobbe JGG, de Vos J, VanBavel E, Bakker ENTP. Mapping Solute Clearance From the Mouse Hippocampus Using a 3D Imaging Cryomicrotome. Front Neurosci 2021; 15:631325. [PMID: 33867918 PMCID: PMC8044999 DOI: 10.3389/fnins.2021.631325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
The hippocampus is susceptible to protein aggregation in neurodegenerative diseases such as Alzheimer's disease. This protein accumulation is partially attributed to an impaired clearance; however, the removal pathways for fluids and waste products are not fully understood. The aim of this study was therefore to map the clearance pathways from the mouse brain. A mixture of two fluorescently labeled tracers with different molecular weights was infused into the hippocampus. A small subset of mice (n = 3) was sacrificed directly after an infusion period of 10 min to determine dispersion of the tracer due to the infusion, while another group was sacrificed after spreading of the tracers for an additional 80 min (n = 7). Upon sacrifice, mice were frozen and sectioned as a whole by the use of a custom-built automated imaging cryomicrotome. Detailed 3D reconstructions were created to map the tracer spreading. We observed that tracers distributed over the hippocampus and entered adjacent brain structures, such as the cortex and cerebroventricular system. An important clearance pathway was found along the ventral part of the hippocampus and its bordering interpeduncular cistern. From there, tracers left the brain via the subarachnoid spaces in the directions of both the nose and the spinal cord. Although both tracers followed the same route, the small tracer distributed further, implying a major role for diffusion in addition to convection. Taken together, these results reveal an important clearance pathway of solutes from the hippocampus.
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Affiliation(s)
- Daphne M P Naessens
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Johannes G G Dobbe
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Movement Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
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Celaya-Alcala JT, Lee GV, Smith AF, Li B, Sakadžić S, Boas DA, Secomb TW. Simulation of oxygen transport and estimation of tissue perfusion in extensive microvascular networks: Application to cerebral cortex. J Cereb Blood Flow Metab 2021; 41:656-669. [PMID: 32501155 PMCID: PMC7922761 DOI: 10.1177/0271678x20927100] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/23/2020] [Accepted: 02/15/2020] [Indexed: 12/13/2022]
Abstract
Advanced imaging techniques have made available extensive three-dimensional microvascular network structures. Simulation of oxygen transport by such networks requires information on blood flow rates and oxygen levels in vessels crossing boundaries of the imaged region, which is difficult to obtain experimentally. Here, a computational method is presented for estimating blood flow rates, oxygen levels, tissue perfusion and oxygen extraction, based on incomplete boundary conditions. Flow rates in all segments are estimated using a previously published method. Vessels crossing the region boundary are classified as arterioles, capillaries or venules. Oxygen levels in inflowing capillaries are assigned based on values in outflowing capillaries, and similarly for venules. Convective and diffusive oxygen transport is simulated. Contributions of each vessel to perfusion are computed in proportion to the decline in oxygen concentration along that vessel. For a vascular network in the mouse cerebral cortex, predicted tissue oxygen levels show a broad distribution, with 99% of tissue in the range of 20 to 80 mmHg under reference conditions, and steep gradients near arterioles. Perfusion and extraction estimates are consistent with experimental values. A 30% reduction in perfusion or a 30% increase in oxygen demand, relative to reference levels, is predicted to result in tissue hypoxia.
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Affiliation(s)
| | - Grace V Lee
- Program in Applied Mathematics,
University of Arizona, Tucson, AZ, USA
| | - Amy F Smith
- Department of Physiology, University
of Arizona, Tucson, AZ, USA
| | - Bohan Li
- Department of Mathematics,
University of Arizona, Tucson, AZ, USA
| | - Sava Sakadžić
- Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School,
Boston, MA, USA
| | - David A Boas
- Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School,
Boston, MA, USA
- Department of Biomedical
Engineering, Boston University, Boston, MA, USA
| | - Timothy W Secomb
- Department of Mathematics,
University of Arizona, Tucson, AZ, USA
- Program in Applied Mathematics,
University of Arizona, Tucson, AZ, USA
- Department of Physiology, University
of Arizona, Tucson, AZ, USA
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6
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Schwarz JCV, van Lier MGJTB, van den Wijngaard JPHM, Siebes M, VanBavel E. Topologic and Hemodynamic Characteristics of the Human Coronary Arterial Circulation. Front Physiol 2020; 10:1611. [PMID: 32038291 PMCID: PMC6989553 DOI: 10.3389/fphys.2019.01611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/23/2019] [Indexed: 11/26/2022] Open
Abstract
Background Many processes contributing to the functional and structural regulation of the coronary circulation have been identified. A proper understanding of the complex interplay of these processes requires a quantitative systems approach that includes the complexity of the coronary network. The purpose of this study was to provide a detailed quantification of the branching characteristics and local hemodynamics of the human coronary circulation. Methods The coronary arteries of a human heart were filled post-mortem with fluorescent replica material. The frozen heart was alternately cut and block-face imaged using a high-resolution imaging cryomicrotome. From the resulting 3D reconstruction of the left coronary circulation, topological (node and loop characteristics), topographic (diameters and length of segments), and geometric (position) properties were analyzed, along with predictions of local hemodynamics (pressure and flow). Results The reconstructed left coronary tree consisted of 202,184 segments with diameters ranging from 30 μm to 4 mm. Most segments were between 100 μm and 1 mm long. The median segment length was similar for diameters ranging between 75 and 200 μm. 91% of the nodes were bifurcations. These bifurcations were more symmetric and less variable in smaller vessels. Most of the pressure drop occurred in vessels between 200 μm and 1 mm in diameter. Downstream conductance variability affected neither local pressure nor median local flow and added limited extra variation of local flow. The left coronary circulation perfused 358 cm3 of myocardium. Median perfused volume at a truncation level of 100 to 200 μm was 20 mm3 with a median perfusion of 5.6 ml/min/g and a high local heterogeneity. Conclusion This study provides the branching characteristics and hemodynamic analysis of the left coronary arterial circulation of a human heart. The resulting model can be deployed for further hemodynamic studies at the whole organ and local level.
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Affiliation(s)
- Janina C V Schwarz
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | | | - Maria Siebes
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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7
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High-Resolution Episcopic Microscopy (HREM): Looking Back on 13 Years of Successful Generation of Digital Volume Data of Organic Material for 3D Visualisation and 3D Display. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9183826] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
High-resolution episcopic microscopy (HREM) is an imaging technique that permits the simple and rapid generation of three-dimensional (3D) digital volume data of histologically embedded and physically sectioned specimens. The data can be immediately used for high-detail 3D analysis of a broad variety of organic materials with all modern methods of 3D visualisation and display. Since its first description in 2006, HREM has been adopted as a method for exploring organic specimens in many fields of science, and it has recruited a slowly but steadily growing user community. This review aims to briefly introduce the basic principles of HREM data generation and to provide an overview of scientific publications that have been published in the last 13 years involving HREM imaging. The studies to which we refer describe technical details and specimen-specific protocols, and provide examples of the successful use of HREM in biological, biomedical and medical research. Finally, the limitations, potentials and anticipated further improvements are briefly outlined.
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8
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Vigneshwaran V, Sands GB, LeGrice IJ, Smaill BH, Smith NP. Reconstruction of coronary circulation networks: A review of methods. Microcirculation 2019; 26:e12542. [DOI: 10.1111/micc.12542] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/25/2019] [Accepted: 02/27/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Vibujithan Vigneshwaran
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Faculty of Engineering University of Auckland Auckland New Zealand
| | - Gregory B. Sands
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Ian J. LeGrice
- Department of Physiology University of Auckland Auckland New Zealand
| | - Bruce H. Smaill
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Nicolas P. Smith
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Faculty of Engineering University of Auckland Auckland New Zealand
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9
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Bedussi B, van der Wel NN, de Vos J, van Veen H, Siebes M, VanBavel E, Bakker EN. Paravascular channels, cisterns, and the subarachnoid space in the rat brain: A single compartment with preferential pathways. J Cereb Blood Flow Metab 2017; 37:1374-1385. [PMID: 27306753 PMCID: PMC5453458 DOI: 10.1177/0271678x16655550] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent evidence suggests an extensive exchange of fluid and solutes between the subarachnoid space and the brain interstitium, involving preferential pathways along blood vessels. We studied the anatomical relations between brain vasculature, cerebrospinal fluid compartments, and paravascular spaces in male Wistar rats. A fluorescent tracer was infused into the cisterna magna, without affecting intracranial pressure. Tracer distribution was analyzed using a 3D imaging cryomicrotome, confocal microscopy, and correlative light and electron microscopy. We found a strong 3D colocalization of tracer with major arteries and veins in the subarachnoid space and large cisterns, attributed to relatively large subarachnoid space volumes around the vessels. Confocal imaging confirmed this colocalization and also revealed novel cisternal connections between the subarachnoid space and ventricles. Unlike the vessels in the subarachnoid space, penetrating arteries but not veins were surrounded by tracer. Correlative light and electron microscopy images indicated that this paravascular space was located outside of the endothelial layer in capillaries and just outside of the smooth muscle cells in arteries. In conclusion, the cerebrospinal fluid compartment, consisting of the subarachnoid space, cisterns, ventricles, and para-arteriolar spaces, forms a continuous and extensive network that surrounds and penetrates the rat brain, in which mixing may facilitate exchange between interstitial fluid and cerebrospinal fluid.
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Affiliation(s)
- Beatrice Bedussi
- 1 Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Nicole N van der Wel
- 2 Department of Cell Biology and Histology, Electron Microscopy Centre Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Judith de Vos
- 1 Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Henk van Veen
- 2 Department of Cell Biology and Histology, Electron Microscopy Centre Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maria Siebes
- 1 Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Ed VanBavel
- 1 Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Erik Ntp Bakker
- 1 Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
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10
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Schwarz JCV, van Lier MGJTB, Bakker ENTP, de Vos J, Spaan JAE, VanBavel E, Siebes M. Optimization of Vascular Casting for Three-Dimensional Fluorescence Cryo-Imaging of Collateral Vessels in the Ischemic Rat Hindlimb. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:77-87. [PMID: 28228173 DOI: 10.1017/s1431927617000095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Development of collateral vessels, arteriogenesis, may protect against tissue ischemia, however, quantitative data on this process remain scarce. We have developed a technique for replicating the entire arterial network of ischemic rat hindlimbs in three dimensions (3D) based on vascular casting and automated sequential cryo-imaging. Various dilutions of Batson's No. 17 with methyl methacrylate were evaluated in healthy rats, with further protocol optimization in ischemic rats. Penetration of the resin into the vascular network greatly depended on dilution; the total length of casted vessels below 75 µm was 13-fold higher at 50% dilution compared with the 10% dilution. Dilutions of 25-30%, with transient clamping of the healthy iliac artery, were optimal for imaging the arterial network in unilateral ischemia. This protocol completely filled the lumina of small arterioles and collateral vessels. These appeared as thin anastomoses in healthy legs and increasingly larger vessels during ligation (median diameter 1 week: 63 µm, 4 weeks: 127 µm). The presented combination of quality casts with high-resolution cryo-imaging enables automated, detailed 3D analysis of collateral adaptation, which furthermore can be combined with co-registered 3D distributions of fluorescent molecular imaging markers reflecting biological activity or perfusion.
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Affiliation(s)
- Janina C V Schwarz
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Jos A E Spaan
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics,Academic Medical Center,University of Amsterdam,Meibergdreef 9, 1105 AZ Amsterdam,The Netherlands
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11
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Qin W, Roberts MA, Qi X, Murry CE, Zheng Y, Wang RK. Depth-resolved 3D visualization of coronary microvasculature with optical microangiography. Phys Med Biol 2016; 61:7536-7550. [PMID: 27716639 DOI: 10.1088/0031-9155/61/21/7536] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In this study, we propose a novel implementation of optical coherence tomography-based angiography combined with ex vivo perfusion of fixed hearts to visualize coronary microvascular structure and function. The extracorporeal perfusion of Intralipid solution allows depth-resolved angiographic imaging, control of perfusion pressure, and high-resolution optical microangiography. The imaging technique offers new opportunities for microcirculation research in the heart, which has been challenging due to motion artifacts and the lack of independent control of pressure and flow. With the ability to precisely quantify structural and functional features, this imaging platform has broad potential for the study of the pathophysiology of microvasculature in the heart as well as other organs.
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Affiliation(s)
- Wan Qin
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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12
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van Lier MGJTB, Oost E, Spaan JAE, van Horssen P, van der Wal AC, vanBavel E, Siebes M, van den Wijngaard JPHM. Transmural distribution and connectivity of coronary collaterals within the human heart. Cardiovasc Pathol 2016; 25:405-12. [PMID: 27421093 DOI: 10.1016/j.carpath.2016.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/10/2016] [Accepted: 06/28/2016] [Indexed: 11/30/2022] Open
Abstract
Despite the importance of collateral vessels in human hearts, a detailed analysis of their distribution within the coronary vasculature based on three-dimensional vascular reconstructions is lacking. This study aimed to classify the transmural distribution and connectivity of coronary collaterals in human hearts. One normotrophic human heart and one hypertrophied human heart with fibrosis in the inferior wall from a previous infarction were obtained. After filling the coronary arteries with fluorescent replica material, hearts were frozen and alternately cut and block-face imaged using an imaging cryomicrotome. Transmural distribution, connectivity, and diameter of collaterals were determined. Numerous collateral vessels were found (normotrophic heart: 12.3 collaterals/cm(3); hypertrophied heart: 3.7 collaterals/cm(3)), with 97% and 92%, respectively, of the collaterals located within the perfusion territories (intracoronary collaterals). In the normotrophic heart, intracoronary collaterals {median diameter [interquartile range (IQR)]: 91.4 [73.0-115.7] μm} were most prevalent (74%) within the left anterior descending (LAD) territory. Intercoronary collaterals [median diameter (IQR): 94.3 (79.9-107.4) μm] were almost exclusively (99%) found between the LAD and the left circumflex artery (LCX). In the hypertrophied heart, intracoronary collaterals [median diameter (IQR): 101.1 (84.8-126.0) μm] were located within both the LAD (48%) and LCX (46%) territory. Intercoronary collaterals [median diameter (IQR): 97.8 (89.3-111.2) μm] were most prevalent between the LAD-LCX (68%) and LAD-right coronary artery (28%). This study shows that human hearts have abundant coronary collaterals within all flow territories and layers of the heart. The majority of these collaterals are small intracoronary collaterals, which would have remained undetected by clinical imaging techniques.
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Affiliation(s)
- Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Elco Oost
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Jos A E Spaan
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Allard C van der Wal
- Department of Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Ed vanBavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Jeroen P H M van den Wijngaard
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands.
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13
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Rivolo S, Hadjilucas L, Sinclair M, van Horssen P, van den Wijngaard J, Wesolowski R, Chiribiri A, Siebes M, Smith NP, Lee J. Impact of coronary bifurcation morphology on wave propagation. Am J Physiol Heart Circ Physiol 2016; 311:H855-H870. [PMID: 27402665 PMCID: PMC5114464 DOI: 10.1152/ajpheart.00130.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/05/2016] [Indexed: 01/09/2023]
Abstract
The branching pattern of the coronary vasculature is a key determinant of its function and plays a crucial role in shaping the pressure and velocity wave forms measured for clinical diagnosis. However, although multiple scaling laws have been proposed to characterize the branching pattern, the implications they have on wave propagation remain unassessed to date. To bridge this gap, we have developed a new theoretical framework by combining the mathematical formulation of scaling laws with the wave propagation theory in the pulsatile flow regime. This framework was then validated in multiple species using high-resolution cryomicrotome images of porcine, canine, and human coronary networks. Results demonstrate that the forward well-matchedness (no reflection for pressure/flow waves traveling from the coronary stem toward the microcirculation) is a salient feature in the coronary vasculature, and this result remains robust under many scenarios of the underlying pulse wave speed distribution assumed in the network. This result also implies a significant damping of the backward traveling waves, especially for smaller vessels (radius, <0.3 mm). Furthermore, the theoretical prediction of increasing area ratios (ratio between the area of the mother and daughter vessels) in more symmetric bifurcations found in the distal circulation was confirmed by experimental measurements. No differences were observed by clustering the vessel segments in terms of transmurality (from epicardium to endocardium) or perfusion territories (left anterior descending, left circumflex, and right coronary artery).
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Affiliation(s)
- Simone Rivolo
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union
| | - Lucas Hadjilucas
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union
| | - Matthew Sinclair
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeroen van den Wijngaard
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Roman Wesolowski
- Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union; and
| | - Amedeo Chiribiri
- Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union; and
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Nicolas P Smith
- Faculty of Engineering, The University of Auckland, Auckland, New Zealand
| | - Jack Lee
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, European Union;
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14
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Hakimzadeh N, van Lier MGJTB, van Horssen P, Daal M, Ly DH, Belterman C, Coronel R, Spaan JAE, Siebes M. Selective subepicardial localization of monocyte subsets in response to progressive coronary artery constriction. Am J Physiol Heart Circ Physiol 2016; 311:H239-50. [PMID: 27208158 DOI: 10.1152/ajpheart.00187.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/13/2016] [Indexed: 12/22/2022]
Abstract
Following myocardial infarction and atherosclerotic lesion development, monocytes contribute to myocardial protection and repair, while also partaking in myocardial ischemic injury. The balance of proinflammatory and reparative monocyte subsets is crucial in governing these therapeutic and pathological outcomes. Myocardial ischemic damage displays heterogeneity across the myocardium, whereby the subendocardium shows greatest vulnerability to ischemic damage. In this study we examined the transmural distribution of monocyte subsets in response to gradual coronary artery occlusion. CD14(+) monocytes were isolated from peripheral blood of New Zealand White rabbits and divided into two subgroups based on the expression of CD62L. We employed a rabbit model of progressive coronary artery obstruction to induce chronic myocardial ischemia and reinfused fluorescently labeled autologous monocytes. The distribution of fluorescently labeled autologous monocytes was examined with a high-resolution three-dimensional imaging cryomicrotome. The subepicardial layer contained the largest infiltration of both monocyte subgroups, with a significantly greater proportion of CD14(+)CD62L(+) monocytes at the time when the ischemic area was at a maximum. By targeting CD13(+) angiogenic vessels, we confirmed the presence of angiogenesis in epicardial and midmyocardial regions. These myocardial regions demonstrated the highest level of infiltration of both monocyte subsets. Furthermore, CD14(+)CD62L(+) monocytes showed significantly greater migration towards monocyte chemoattractant protein-1, greater adhesive capacity, and higher expression of C-C chemokine receptor type-2 relative to CD14(+)CD62L(-) monocytes. In conclusion, we note selective subepicardial distribution of monocyte subpopulations, with changes in proportion depending on the time after onset of coronary narrowing. Selective homing is supported by divergent migratory properties of each respective monocyte subgroup.
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Affiliation(s)
- Nazanin Hakimzadeh
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Mariah Daal
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Duy Ha Ly
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Charly Belterman
- Deptartment of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - Ruben Coronel
- Deptartment of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and IHU Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France
| | - Jos A E Spaan
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands;
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15
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Groot Nibbelink M, Daoudi K, Slegers S, Grootendorst D, Dantuma M, Steenbergen W, Karperien M, Manohar S, van Apeldoorn A. Opening the "White Box" in Tissue Engineering: Visualization of Cell Aggregates in Optically Scattering Scaffolds. Tissue Eng Part C Methods 2016; 22:534-42. [PMID: 27056242 DOI: 10.1089/ten.tec.2015.0462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The noninvasive and longitudinal imaging of cells or cell aggregates in large optically scattering scaffolds is still a largely unresolved problem in tissue engineering. In this work, we investigated the potential of near-infrared (NIR) photoacoustic (PA) tomography imaging to address this issue. We used clinically relevant sizes of highly light scattering polyethersulfone multibore(®) hollow fiber scaffolds seeded with cells. Since cells have little optical absorption at NIR wavelengths, we studied labeling of cells with absorbers. Four NIR labels were examined for their suitability based on absorption characteristics, resistance to bleaching, and influence on cell viability. On the basis of these criteria, carbon nanoparticles proved most suitable in a variety of cells. For PA imaging, we used a research setup, based on computed tomography geometry. As proof of principle, using this imager we monitored the distribution and clustering of labeled rat insulinoma beta cell aggregates in the scaffolds. This was performed for the duration of 1 week in a nondestructive manner. The results were validated using fluorescence imaging, histology, and light microscopy imaging. Based on our findings, we conclude that PA tomography is a powerful tool for the nondestructive imaging of cells in optically scattering tissue-engineered scaffolds.
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Affiliation(s)
- Milou Groot Nibbelink
- 1 Developmental Bioengineering, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Khalid Daoudi
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Sanne Slegers
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands .,3 Albert Schweitzer Hospital , Dordrecht, The Netherlands
| | - Diederik Grootendorst
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Maura Dantuma
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Wiendelt Steenbergen
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Marcel Karperien
- 1 Developmental Bioengineering, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Srirang Manohar
- 2 Biomedical Photonic Imaging, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
| | - Aart van Apeldoorn
- 1 Developmental Bioengineering, MIRA Institute of Biomedical Technology and Technical Medicine, University of Twente , Enschede, The Netherlands
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16
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Chabiniok R, Wang VY, Hadjicharalambous M, Asner L, Lee J, Sermesant M, Kuhl E, Young AA, Moireau P, Nash MP, Chapelle D, Nordsletten DA. Multiphysics and multiscale modelling, data-model fusion and integration of organ physiology in the clinic: ventricular cardiac mechanics. Interface Focus 2016; 6:20150083. [PMID: 27051509 PMCID: PMC4759748 DOI: 10.1098/rsfs.2015.0083] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
With heart and cardiovascular diseases continually challenging healthcare systems worldwide, translating basic research on cardiac (patho)physiology into clinical care is essential. Exacerbating this already extensive challenge is the complexity of the heart, relying on its hierarchical structure and function to maintain cardiovascular flow. Computational modelling has been proposed and actively pursued as a tool for accelerating research and translation. Allowing exploration of the relationships between physics, multiscale mechanisms and function, computational modelling provides a platform for improving our understanding of the heart. Further integration of experimental and clinical data through data assimilation and parameter estimation techniques is bringing computational models closer to use in routine clinical practice. This article reviews developments in computational cardiac modelling and how their integration with medical imaging data is providing new pathways for translational cardiac modelling.
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Affiliation(s)
- Radomir Chabiniok
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - Vicky Y. Wang
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Myrianthi Hadjicharalambous
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Liya Asner
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Maxime Sermesant
- Inria, Asclepios team, 2004 route des Lucioles BP 93, Sophia Antipolis Cedex 06902, France
| | - Ellen Kuhl
- Departments of Mechanical Engineering, Bioengineering, and Cardiothoracic Surgery, Stanford University, 496 Lomita Mall, Durand 217, Stanford, CA 94306, USA
| | - Alistair A. Young
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Philippe Moireau
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - Martyn P. Nash
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
- Department of Engineering Science, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Dominique Chapelle
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - David A. Nordsletten
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
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17
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Lee J, Nordsletten D, Cookson A, Rivolo S, Smith N. In silico coronary wave intensity analysis: application of an integrated one-dimensional and poromechanical model of cardiac perfusion. Biomech Model Mechanobiol 2016; 15:1535-1555. [PMID: 27008197 PMCID: PMC5106513 DOI: 10.1007/s10237-016-0782-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 03/08/2016] [Indexed: 01/09/2023]
Abstract
Coronary wave intensity analysis (cWIA) is a diagnostic technique based on invasive measurement of coronary pressure and velocity waveforms. The theory of WIA allows the forward- and backward-propagating coronary waves to be separated and attributed to their origin and timing, thus serving as a sensitive and specific cardiac functional indicator. In recent years, an increasing number of clinical studies have begun to establish associations between changes in specific waves and various diseases of myocardium and perfusion. These studies are, however, currently confined to a trial-and-error approach and are subject to technological limitations which may confound accurate interpretations. In this work, we have developed a biophysically based cardiac perfusion model which incorporates full ventricular–aortic–coronary coupling. This was achieved by integrating our previous work on one-dimensional modelling of vascular flow and poroelastic perfusion within an active myocardial mechanics framework. Extensive parameterisation was performed, yielding a close agreement with physiological levels of global coronary and myocardial function as well as experimentally observed cumulative wave intensity magnitudes. Results indicate a strong dependence of the backward suction wave on QRS duration and vascular resistance, the forward pushing wave on the rate of myocyte tension development, and the late forward pushing wave on the aortic valve dynamics. These findings are not only consistent with experimental observations, but offer a greater specificity to the wave-originating mechanisms, thus demonstrating the value of the integrated model as a tool for clinical investigation.
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Affiliation(s)
- Jack Lee
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK.
| | - David Nordsletten
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Andrew Cookson
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Simone Rivolo
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Nicolas Smith
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
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18
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Wuttisarnwattana P, Gargesha M, Hof WV, Cooke KR, Wilson DL. Automatic Stem Cell Detection in Microscopic Whole Mouse Cryo-Imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:819-29. [PMID: 26552080 PMCID: PMC4873963 DOI: 10.1109/tmi.2015.2497285] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
With its single cell sensitivity over volumes as large as or larger than a mouse, cryo-imaging enables imaging of stem cell biodistribution, homing, engraftment, and molecular mechanisms. We developed and evaluated a highly automated software tool to detect fluorescently labeled stem cells within very large ( ∼ 200 GB) cryo-imaging datasets. Cell detection steps are: preprocess, remove immaterial regions, spatially filter to create features, identify candidate pixels, classify pixels using bagging decision trees, segment cell patches, and perform 3D labeling. There are options for analysis and visualization. To train the classifier, we created synthetic images by placing realistic digital cell models onto cryo-images of control mice devoid of cells. Very good cell detection results were (precision=98.49%, recall=99.97%) for synthetic cryo-images, (precision=97.81%, recall=97.71%) for manually evaluated, actual cryo-images, and false positives in control mice. An α-multiplier applied to features allows one to correct for experimental variations in cell brightness due to labeling. On dim cells (37% of standard brightness), with correction, we improved recall (49.26%→ 99.36%) without a significant drop in precision (99.99%→ 99.75%) . With tail vein injection, multipotent adult progenitor cells in a graft-versus-host-disease model in the first days post injection were predominantly found in lung, liver, spleen, and bone marrow. Distribution was not simply related to blood flow. The lung contained clusters of cells while other tissues contained single cells. Our methods provided stem cell distribution anywhere in mouse with single cell sensitivity. Methods should provide a rational means of evaluating dosing, delivery methods, cell enhancements, and mechanisms for therapeutic cells.
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Affiliation(s)
- Patiwet Wuttisarnwattana
- Department of Computer Engineering, Chiang Mai University, Chiang Mai, Thailand, and Biomedical Engineering Center, Chiang Mai University, Chiang Mai, Thailand
| | | | - Wouter van’t Hof
- Cell Processing Facility, Cleveland Cord Blood Center, Cleveland, OH, USA
| | - Kenneth R. Cooke
- Department of Pediatric Oncology, Johns Hopkins University, Baltimore, MD, USA
| | - David L. Wilson
- D.L. Wilson is with Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA, Department of Radiology, University Hospitals of Cleveland, Cleveland, OH, USA and BioInVision, Inc., Mayfield Village, OH, USA
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19
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van Horssen P, van Lier MGJTB, van den Wijngaard JPHM, VanBavel E, Hoefer IE, Spaan JAE, Siebes M. Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume. Am J Physiol Heart Circ Physiol 2016; 310:H839-46. [PMID: 26825519 DOI: 10.1152/ajpheart.00728.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/19/2016] [Indexed: 11/22/2022]
Abstract
Computational predictions of the functional stenosis severity from coronary imaging data use an allometric scaling law to derive hyperemic blood flow (Q) from coronary arterial volume (V), Q = αV(β) Reliable estimates of α and β are essential for meaningful flow estimations. We hypothesize that the relation between Q and V depends on imaging resolution. In five canine hearts, fluorescent microspheres were injected into the left anterior descending coronary artery during maximal hyperemia. The coronary arteries of the excised heart were filled with fluorescent cast material, frozen, and processed with an imaging cryomicrotome to yield a three-dimensional representation of the coronary arterial network. The effect of limited image resolution was simulated by assessing scaling law parameters from the virtual arterial network at 11 truncation levels ranging from 50 to 1,000 μm segment radius. Mapped microsphere locations were used to derive the corresponding relative Q using a reference truncation level of 200 μm. The scaling law factor α did not change with truncation level, despite considerable intersubject variability. In contrast, the scaling law exponent β decreased from 0.79 to 0.55 with increasing truncation radius and was significantly lower for truncation radii above 500 μm vs. 50 μm (P< 0.05). Hyperemic Q was underestimated for vessel truncation above the reference level. In conclusion, flow-crown volume relations confirmed overall power law behavior; however, this relation depends on the terminal vessel radius that can be visualized. The scaling law exponent β should therefore be adapted to the resolution of the imaging modality.
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Affiliation(s)
- P van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - M G J T B van Lier
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - J P H M van den Wijngaard
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - E VanBavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - I E Hoefer
- Department of Experimental Cardiology, Utrecht Medical Center, Utrecht, The Netherlands
| | - J A E Spaan
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
| | - M Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
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20
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van Lier MG, Lopriore E, Vandenbussche FP, Streekstra GJ, Siebes M, Nikkels PG, Oepkes D, van Gemert MJ, van den Wijngaard JP. Acardiac twinning: High resolution three-dimensional reconstruction of a low resistance case. ACTA ACUST UNITED AC 2015; 106:213-7. [DOI: 10.1002/bdra.23477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/14/2015] [Accepted: 11/23/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Monique G.J.T.B. van Lier
- Department of Biomedical Engineering and Physics; Academic Medical Center-University of Amsterdam; Amsterdam The Netherlands
| | - Enrico Lopriore
- Division of Neonatology; Department of Pediatrics; Leiden University Medical Center; Leiden
| | | | - Geert J. Streekstra
- Department of Biomedical Engineering and Physics; Academic Medical Center-University of Amsterdam; Amsterdam The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics; Academic Medical Center-University of Amsterdam; Amsterdam The Netherlands
| | - Peter G.J. Nikkels
- Department of Pathology; University Medical Center and Wilhelmina Children's Hospital; Utrecht The Netherlands
| | - Dick Oepkes
- Department of Obstetrics; Leiden University Medical Center; Leiden
| | - Martin J.C. van Gemert
- Department of Biomedical Engineering and Physics; Academic Medical Center-University of Amsterdam; Amsterdam The Netherlands
| | - Jeroen P.H.M. van den Wijngaard
- Department of Biomedical Engineering and Physics; Academic Medical Center-University of Amsterdam; Amsterdam The Netherlands
- Department of Clinical Chemistry and Laboratory Medicine; Leiden University Medical Center; Leiden The Netherlands
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21
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Bedussi B, van Lier MGJTB, Bartstra JW, de Vos J, Siebes M, VanBavel E, Bakker ENTP. Clearance from the mouse brain by convection of interstitial fluid towards the ventricular system. Fluids Barriers CNS 2015; 12:23. [PMID: 26435380 PMCID: PMC4593194 DOI: 10.1186/s12987-015-0019-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/14/2015] [Indexed: 11/10/2022] Open
Abstract
Background In the absence of a true lymphatic system in the brain parenchyma, alternative clearance pathways for excess fluid and waste products have been proposed. Suggested mechanisms for clearance implicate a role for brain interstitial and cerebrospinal fluids. However, the proposed direction of flow, the anatomical structures involved, and the driving forces are controversial. Methods To trace the distribution of interstitial and cerebrospinal fluid in the brain, and to identify the anatomical structures involved, we infused a mix of fluorescent tracers with different sizes into the cisterna magna or striatum of mouse brains. We subsequently performed confocal fluorescence imaging of horizontal brain sections and made 3D reconstructions of the mouse brain and vasculature. Results We observed a distribution pattern of tracers from the parenchyma to the ventricular system, from where tracers mixed with the cerebrospinal fluid, reached the subarachnoid space, and left the brain via the cribriform plate and the nose. Tracers also entered paravascular spaces around arteries both after injection in the cisterna magna and striatum, but this appeared to be of minor importance. Conclusion These data suggest a bulk flow of interstitial fluid from the striatum towards the adjacent lateral ventricle. Tracers may enter arterial paravascular spaces from two sides, both through bulk flow from the parenchyma and through mixing of CSF in the subarachnoid space. Disturbances in this transport pathway could influence the drainage of amyloid β and other waste products, which may be relevant for the pathophysiology of Alzheimer’s disease. Electronic supplementary material The online version of this article (doi:10.1186/s12987-015-0019-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Beatrice Bedussi
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Jonas W Bartstra
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Academic Medical Center, Room L0-119. Meibergdreef 9, PO Box: 22660, 1105 AZ, Amsterdam, The Netherlands.
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22
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Sinclair MD, Lee J, Cookson AN, Rivolo S, Hyde ER, Smith NP. Measurement and modeling of coronary blood flow. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 7:335-56. [PMID: 26123867 DOI: 10.1002/wsbm.1309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 01/10/2023]
Abstract
Ischemic heart disease that comprises both coronary artery disease and microvascular disease is the single greatest cause of death globally. In this context, enhancing our understanding of the interaction of coronary structure and function is not only fundamental for advancing basic physiology but also crucial for identifying new targets for treating these diseases. A central challenge for understanding coronary blood flow is that coronary structure and function exhibit different behaviors across a range of spatial and temporal scales. While experimental studies have sought to understand this feature by isolating specific mechanisms, in tandem, computational modeling is increasingly also providing a unique framework to integrate mechanistic behaviors across different scales. In addition, clinical methods for assessing coronary disease severity are continuously being informed and updated by findings in basic physiology. Coupling these technologies, computational modeling of the coronary circulation is emerging as a bridge between the experimental and clinical domains, providing a framework to integrate imaging and measurements from multiple sources with mathematical descriptions of governing physical laws. State-of-the-art computational modeling is being used to combine mechanistic models with data to provide new insight into coronary physiology, optimization of medical technologies, and new applications to guide clinical practice.
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Affiliation(s)
- Matthew D Sinclair
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Andrew N Cookson
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Simone Rivolo
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Eoin R Hyde
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK.,Department of Engineering, University of Auckland, Auckland, New Zealand
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23
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Sinclair M, Lee J, Schuster A, Chiribiri A, van den Wijngaard J, van Horssen P, Siebes M, Spaan JAE, Nagel E, Smith NP. Microsphere skimming in the porcine coronary arteries: Implications for flow quantification. Microvasc Res 2015; 100:59-70. [PMID: 25963318 DOI: 10.1016/j.mvr.2015.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/28/2015] [Accepted: 04/17/2015] [Indexed: 11/25/2022]
Abstract
Particle skimming is a phenomenon where particles suspended in fluid flowing through vessels distribute disproportionately to bulk fluid volume at junctions. Microspheres are considered a gold standard of intra-organ perfusion measurements and are used widely in studies of flow distribution and quantification. It has previously been hypothesised that skimming at arterial junctions is responsible for a systematic over-estimation of myocardial perfusion from microspheres at the subendocardium. Our objective is to integrate coronary arterial structure and microsphere distribution, imaged at high resolution, to test the hypothesis of microsphere skimming in a porcine left coronary arterial (LCA) network. A detailed network was reconstructed from cryomicrotome imaging data and a Poiseuille flow model was used to simulate flow. A statistical approach using Clopper-Pearson confidence intervals was applied to determine the prevalence of skimming at bifurcations in the LCA. Results reveal that microsphere skimming is most prevalent at bifurcations in the larger coronary arteries, namely the epicardial and transmural arteries. Bifurcations at which skimming was identified have significantly more asymmetric branching parameters. This finding suggests that when using thin transmural segments to quantify flow from microspheres, a skimming-related deposition bias may result in underestimation of perfusion in the subepicardium, and overestimation in the subendocardium.
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Affiliation(s)
- Matthew Sinclair
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Andreas Schuster
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany; German Centre for Cardiovascular Research (DZHK, Partner Site Göttingen), Göttingen, Germany
| | - Amedeo Chiribiri
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Jeroen van den Wijngaard
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Jos A E Spaan
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Eike Nagel
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Engineering, University of Auckland, Auckland, New Zealand.
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24
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Schuster A, Sinclair M, Zarinabad N, Ishida M, van den Wijngaard JPHM, Paul M, van Horssen P, Hussain ST, Perera D, Schaeffter T, Spaan JAE, Siebes M, Nagel E, Chiribiri A. A quantitative high resolution voxel-wise assessment of myocardial blood flow from contrast-enhanced first-pass magnetic resonance perfusion imaging: microsphere validation in a magnetic resonance compatible free beating explanted pig heart model. Eur Heart J Cardiovasc Imaging 2015; 16:1082-92. [PMID: 25812572 DOI: 10.1093/ehjci/jev023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/30/2015] [Indexed: 11/13/2022] Open
Abstract
AIMS To assess the feasibility of high-resolution quantitative cardiovascular magnetic resonance (CMR) voxel-wise perfusion imaging using clinical 1.5 and 3 T sequences and to validate it using fluorescently labelled microspheres in combination with a state of the art imaging cryomicrotome in a novel, isolated blood-perfused MR-compatible free beating pig heart model without respiratory motion. METHODS AND RESULTS MR perfusion imaging was performed in pig hearts at 1.5 (n = 4) and 3 T (n = 4). Images were acquired at physiological flow ('rest'), reduced flow ('ischaemia'), and during adenosine-induced hyperaemia ('stress') in control and coronary occlusion conditions. Fluorescently labelled microspheres and known coronary myocardial blood flow represented the reference standards for quantitative perfusion validation. For the comparison with microspheres, the LV was divided into 48 segments based on a subdivision of the 16 AHA segments into subendocardial, midmyocardial, and subepicardial subsegments. Perfusion quantification of the time-signal intensity curves was performed using a Fermi function deconvolution. High-resolution quantitative voxel-wise perfusion assessment was able to distinguish between occluded and remote myocardium (P < 0.001) and between rest, ischaemia, and stress perfusion conditions at 1.5 T (P < 0.001) and at 3 T (P < 0.001). CMR-MBF estimates correlated well with the microspheres at the AHA segmental level at 1.5 T (r = 0.94, P < 0.001) and at 3 T (r = 0.96, P < 0.001) and at the subendocardial, midmyocardial, and subepicardial level at 1.5 T (r = 0.93, r = 0.9, r = 0.88, P < 0.001, respectively) and at 3 T (r = 0.91, r = 0.95, r = 0.84, P < 0.001, respectively). CONCLUSION CMR-derived voxel-wise quantitative blood flow assessment is feasible and very accurate compared with microspheres. This technique is suitable for both clinically used field strengths and may provide the tools to assess extent and severity of myocardial ischaemia.
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Affiliation(s)
- Andreas Schuster
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK Department of Cardiology and Pneumology and German Centre for Cardiovascular Research (DZHK, Partner Site Göttingen), Georg-August-University, Göttingen, Germany
| | - Matthew Sinclair
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | - Niloufar Zarinabad
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | - Masaki Ishida
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | | | - Matthias Paul
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Shazia T Hussain
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | - Divaka Perera
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK King's College London BHF Centre of Excellence, NIHR Biomedical Research Centre and Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Tobias Schaeffter
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
| | - Jos A E Spaan
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Eike Nagel
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK Division of Cardiovascular Imaging, Goethe University Frankfurt and German Centre for Cardiovascular Research (DZHK, Partner Site Rhine-Main), Frankfurt, Germany
| | - Amedeo Chiribiri
- Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation (BHF) Centre of Excellence, National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas' Hospital, Lambeth Palace Road, London, UK
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Quantitative detection of drug dose and spatial distribution in the lung revealed by Cryoslicing Imaging. J Pharm Biomed Anal 2015; 102:129-36. [DOI: 10.1016/j.jpba.2014.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/06/2014] [Accepted: 09/01/2014] [Indexed: 12/21/2022]
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Schuster A, Zarinabad N, Ishida M, Sinclair M, van den Wijngaard JP, Morton G, Hautvast GL, Bigalke B, van Horssen P, Smith N, Spaan JA, Siebes M, Chiribiri A, Nagel E. Quantitative assessment of magnetic resonance derived myocardial perfusion measurements using advanced techniques: microsphere validation in an explanted pig heart system. J Cardiovasc Magn Reson 2014; 16:82. [PMID: 25315438 PMCID: PMC4195947 DOI: 10.1186/s12968-014-0082-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/11/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cardiovascular Magnetic Resonance (CMR) myocardial perfusion imaging has the potential to evolve into a method allowing full quantification of myocardial blood flow (MBF) in clinical routine. Multiple quantification pathways have been proposed. However at present it remains unclear which algorithm is the most accurate. An isolated perfused, magnetic resonance (MR) compatible pig heart model allows very accurate titration of MBF and in combination with high-resolution assessment of fluorescently-labeled microspheres represents a near optimal platform for validation. We sought to investigate which algorithm is most suited to quantify myocardial perfusion by CMR at 1.5 and 3 Tesla using state of the art CMR perfusion techniques and quantification algorithms. METHODS First-pass perfusion CMR was performed in an MR compatible blood perfused pig heart model. We acquired perfusion images at physiological flow ("rest"), reduced flow ("ischaemia") and during adenosine-induced hyperaemia ("hyperaemia") as well as during coronary occlusion. Perfusion CMR was performed at 1.5 Tesla (n = 4 animals) and at 3 Tesla (n = 4 animals). Fluorescently-labeled microspheres and externally controlled coronary blood flow served as reference standards for comparison of different quantification strategies, namely Fermi function deconvolution (Fermi), autoregressive moving average modelling (ARMA), exponential basis deconvolution (Exponential) and B-spline basis deconvolution (B-spline). RESULTS All CMR derived MBF estimates significantly correlated with microsphere results. The best correlation was achieved with Fermi function deconvolution both at 1.5 Tesla (r = 0.93, p < 0.001) and at 3 Tesla (r = 0.9, p < 0.001). Fermi correlated significantly better with the microspheres than all other methods at 3 Tesla (p < 0.002). B-spline performed worse than Fermi and Exponential at 1.5 Tesla and showed the weakest correlation to microspheres (r = 0.74, p < 0.001). All other comparisons were not significant. At 3 Tesla exponential deconvolution performed worst (r = 0.49, p < 0.001). CONCLUSIONS CMR derived quantitative blood flow estimates correlate with true myocardial blood flow in a controlled animal model. Amongst the different techniques, Fermi function deconvolution was the most accurate technique at both field strengths. Perfusion CMR based on Fermi function deconvolution may therefore emerge as a useful clinical tool providing accurate quantitative blood flow assessment.
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Affiliation(s)
- Andreas Schuster
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
- Department of Cardiology and Pneumology and German Centre for Cardiovascular Research (DZHK, Partner Site Göttingen), Georg-August-University, Göttingen, Germany.
| | - Niloufar Zarinabad
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | - Masaki Ishida
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | - Matthew Sinclair
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | | | - Geraint Morton
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | | | - Boris Bigalke
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
- Medizinische Klinik III, Kardiologie und Kreislauferkrankungen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
| | - Pepijn van Horssen
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
| | - Nicolas Smith
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | - Jos Ae Spaan
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
| | - Maria Siebes
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands.
| | - Amedeo Chiribiri
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
| | - Eike Nagel
- Division of Imaging Sciences and Biomedical Engineering; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, The Rayne Institute, St. Thomas´ Hospital, London, UK.
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Hakimzadeh N, van Horssen P, van Lier MGJTB, van den Wijngaard JPHM, Belterman C, Coronel R, Piek JJ, Verberne HJ, Spaan JAE, Siebes M. Detection and quantification methods of monocyte homing in coronary vasculature with an imaging cryomicrotome. J Mol Cell Cardiol 2014; 76:196-204. [PMID: 25179912 DOI: 10.1016/j.yjmcc.2014.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/07/2014] [Accepted: 08/25/2014] [Indexed: 11/18/2022]
Abstract
Cellular imaging modalities are important for revealing the behavior and role of monocytes in response to neovascularization progression in coronary artery disease. In this study we aimed to develop methods for high-resolution three-dimensional (3D) imaging and quantification of monocytes relative to the entire coronary artery network using a novel episcopic imaging modality. In a series of ex vivo experiments, human umbilical vein endothelial cells and CD14+ monocytes were labeled with fluorescent live cell tracker probes and infused into the coronary artery network of excised rat hearts by a Langendorff perfusion method. Coronary arteries were subsequently infused with fluorescent vascular cast material and processed with an imaging cryomicrotome, whereby each heart was consecutively cut (5 μm slice thickness) and block face imaged at appropriate excitation and emission wavelengths. The resulting image stacks yielded 3D reconstructions of the vascular network and the location of cells administered. Successful detection and quantification of single cells and cell clusters were achieved relative to the coronary network using customized particle detection software. These methods were then applied to an in vivo rabbit model of chronic myocardial ischemia in which autologous monocytes were isolated from peripheral blood, labeled with a fluorescent live cell tracker probe and re-infused into the host animal. The processed 3D image stacks revealed homing of monocytes to the ischemic myocardial tissue. Monocytes detected in the ischemic tissue were predominantly concentrated in the mid-myocardium. Vessel segmentation identified coronary collateral connections relative to monocyte localization. This study established a novel imaging platform to efficiently determine the localization of monocytes in relation to the coronary microvascular network. These techniques are invaluable for investigating the role of monocyte populations in the progression of coronary neovascularization in animal models of chronic and sub-acute myocardial ischemia.
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Affiliation(s)
- Nazanin Hakimzadeh
- Dept. of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Pepijn van Horssen
- Dept. of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Monique G J T B van Lier
- Dept. of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Charly Belterman
- Dept. of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ruben Coronel
- Dept. of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jan J Piek
- Dept. of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Hein J Verberne
- Dept. of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jos A E Spaan
- Dept. of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maria Siebes
- Dept. of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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van Horssen P, Siebes M, Spaan JAE, Hoefer IE, van den Wijngaard JPHM. Innate collateral segments are predominantly present in the subendocardium without preferential connectivity within the left ventricular wall. J Physiol 2013; 592:1047-60. [PMID: 24366260 DOI: 10.1113/jphysiol.2013.258855] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Functional collateral vessels often stem from outward remodelling of pre-existing connections between perfusion territories. Knowledge of the distribution and morphology of innate collateral connections may help in identifying myocardial areas with protection against risk for ischaemia. The coronary network of six healthy canine hearts was investigated with an imaging cryomicrotome. Innate collateral connections ranged from 286 to 1015 μm in diameter. Left ventricular collateral density (number per gram of tissue) was about five in the subendocardium vs. 2.5 in the mid-myocardium (P < 0.01) and 1.3 in the epicardium (P < 0.01). Subendocardial collateral connections were oriented parallel to the long axis of the heart. For the major coronary arteries, five times more intracoronary than intercoronary connections were found, while their median diameter and interquartile range were not significantly different, at 96.1 (16.9) vs. 94.7 (18.9) μm. Collateral vessels connecting crowns from sister branches from a stem are denoted intercrown connections and those within crowns intracrown connections. The number of intercrown connections was related to the mean tissue weight of the crowns (y = 0.73x - 0.33, r2 = 0.85, P < 0.0001). This relation was likewise found to describe intercoronary connections. The median collateral diameter and length were independent of the tissue volumes bridged. We conclude that connectivity and morphology of the innate collateral network are distributed with no preference for intra- or intercrown connections, independent of stem diameter, including epicardial arteries. This renders all sites of the myocardium equally protected in case of coronary artery disease. The orientation of subendocardial collateral vessels indicates the longitudinal direction of subendocardial collateral flow.
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Affiliation(s)
- Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center - University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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van Horssen P, van den Wijngaard JPHM, Brandt MJ, Hoefer IE, Spaan JAE, Siebes M. Perfusion territories subtended by penetrating coronary arteries increase in size and decrease in number toward the subendocardium. Am J Physiol Heart Circ Physiol 2013; 306:H496-504. [PMID: 24363303 DOI: 10.1152/ajpheart.00584.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Blood flow distribution within the myocardium and the location and extent of areas at risk in case of coronary artery disease are dependent on the distribution and morphology of intramural vascular crowns. Knowledge of the intramural vasculature is essential in novel multiscale and multiphysics modeling of the heart. For this study, eight canine hearts were analyzed with an imaging cryomicrotome, developed to acquire high-resolution spatial data on three-dimensional vascular structures. The obtained vasculature was skeletonized, and for each penetrating artery starting from the epicardium, the dependent vascular crown was defined. Three-dimensional Voronoi tessellation was applied with the end points of the terminal segments as center points. The centroid of end points in each branch allowed classification of the corresponding perfusion territories in subendocardial, midmyocardial, and subepicardial. Subendocardial regions have relatively few territories of about 0.5 ml in volume having their own penetrating artery at the epicardium, whereas the subepicardium is perfused by a multitude of small perfusion territories, in the order of 0.01 ml. Vascular volume density of small arteries up till 400 μm was 3.2% at the subendocardium territories but only 0.8% in the subepicardium territories. Their higher volume density corresponds to compensation for flow impeding forces by cardiac contraction. These density differences result in different scaling law properties of vascular volume and tissue mass per territory type. This novel three-dimensional quantitative analysis may form the basis for patient-specific computational models on coronary perfusion and aid the interpretation of image-based clinical methods for assessing the transmural perfusion distribution.
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Affiliation(s)
- P van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and
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Hyde ER, Cookson AN, Lee J, Michler C, Goyal A, Sochi T, Chabiniok R, Sinclair M, Nordsletten DA, Spaan J, van den Wijngaard JPHM, Siebes M, Smith NP. Multi-Scale Parameterisation of a Myocardial Perfusion Model Using Whole-Organ Arterial Networks. Ann Biomed Eng 2013; 42:797-811. [DOI: 10.1007/s10439-013-0951-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Accepted: 11/20/2013] [Indexed: 01/13/2023]
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Contrast Agent Bolus Dispersion in a Realistic Coronary Artery Geometry: Influence of Outlet Boundary Conditions. Ann Biomed Eng 2013; 42:787-96. [DOI: 10.1007/s10439-013-0950-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/19/2013] [Indexed: 01/02/2023]
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32
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Nolte F, Hyde ER, Rolandi C, Lee J, van Horssen P, Asrress K, van den Wijngaard JPHM, Cookson AN, van de Hoef T, Chabiniok R, Razavi R, Michler C, Hautvast GLTF, Piek JJ, Breeuwer M, Siebes M, Nagel E, Smith NP, Spaan JAE. Myocardial perfusion distribution and coronary arterial pressure and flow signals: clinical relevance in relation to multiscale modeling, a review. Med Biol Eng Comput 2013; 51:1271-86. [DOI: 10.1007/s11517-013-1088-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/11/2013] [Indexed: 01/25/2023]
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Kassab GS, Algranati D, Lanir Y. Myocardial-vessel interaction: role of LV pressure and myocardial contractility. Med Biol Eng Comput 2013; 51:729-39. [DOI: 10.1007/s11517-013-1072-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 03/28/2013] [Indexed: 01/27/2023]
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Kerfoot E, Lamata P, Niederer S, Hose R, Spaan J, Smith N. Share and enjoy: anatomical models database--generating and sharing cardiovascular model data using web services. Med Biol Eng Comput 2013; 51:1181-90. [PMID: 23436208 DOI: 10.1007/s11517-012-1023-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 12/19/2012] [Indexed: 11/26/2022]
Abstract
Sharing data between scientists and with clinicians in cardiac research has been facilitated significantly by the use of web technologies. The potential of this technology has meant that information sharing has been routinely promoted through databases that have encouraged stakeholder participation in communities around these services. In this paper we discuss the Anatomical Model Database (AMDB) (Gianni et al. Functional imaging and modeling of the heart. Springer, Heidelberg, 2009; Gianni et al. Phil Trans Ser A Math Phys Eng Sci 368:3039-3056, 2010) which both facilitate a database-centric approach to collaboration, and also extends this framework with new capabilities for creating new mesh data. AMDB currently stores cardiac geometric models described in Gianni et al. (Functional imaging and modelling of the heart. Springer, Heidelberg, 2009), a number of additional cardiac models describing geometry and functional properties, and most recently models generated using a web service. The functional models represent data from simulations in geometric form, such as electrophysiology or mechanics, many of which are present in AMDB as part of a benchmark study. Finally, the heartgen service has been added for producing left or bi-ventricle models derived from binary image data using the methods described in Lamata et al. (Med Image Anal 15:801-813, 2011). The results can optionally be hosted on AMDB alongside other community-provided anatomical models. AMDB is, therefore, a unique database storing geometric data (rather than abstract models or image data) combined with a powerful web service for generating new geometric models.
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Michler C, Cookson AN, Chabiniok R, Hyde E, Lee J, Sinclair M, Sochi T, Goyal A, Vigueras G, Nordsletten DA, Smith NP. A computationally efficient framework for the simulation of cardiac perfusion using a multi-compartment Darcy porous-media flow model. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:217-232. [PMID: 23345266 DOI: 10.1002/cnm.2520] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/10/2012] [Accepted: 09/19/2012] [Indexed: 06/01/2023]
Abstract
We present a method to efficiently simulate coronary perfusion in subject-specific models of the heart within clinically relevant time frames. Perfusion is modelled as a Darcy porous-media flow, where the permeability tensor is derived from homogenization of an explicit anatomical representation of the vasculature. To account for the disparity in length scales present in the vascular network, in this study, this approach is further refined through the implementation of a multi-compartment medium where each compartment encapsulates the spatial scales in a certain range by using an effective permeability tensor. Neighbouring compartments then communicate through distributed sources and sinks, acting as volume fluxes. Although elegant from a modelling perspective, the full multi-compartment Darcy system is computationally expensive to solve. We therefore enhance computational efficiency of this model by reducing the N-compartment system of Darcy equations to N pressure equations, and N subsequent projection problems to recover the Darcy velocity. The resulting 'reduced' Darcy formulation leads to a dramatic reduction in algebraic-system size and is therefore computationally cheaper to solve than the full multi-compartment Darcy system. A comparison of the reduced and the full formulation in terms of solution time and memory usage clearly highlights the superior performance of the reduced formulation. Moreover, the implementation of flux and, specifically, impermeable boundary conditions on arbitrarily curved boundaries such as epicardium and endocardium is straightforward in contrast to the full Darcy formulation. Finally, to demonstrate the applicability of our methodology to a personalized model and its solvability in clinically relevant time frames, we simulate perfusion in a subject-specific model of the left ventricle.
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Affiliation(s)
- C Michler
- Department of Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London SE1 7EH, UK
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Parameterisation of multi-scale continuum perfusion models from discrete vascular networks. Med Biol Eng Comput 2013; 51:557-70. [PMID: 23345008 PMCID: PMC3627025 DOI: 10.1007/s11517-012-1025-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 12/21/2012] [Indexed: 10/28/2022]
Abstract
Experimental data and advanced imaging techniques are increasingly enabling the extraction of detailed vascular anatomy from biological tissues. Incorporation of anatomical data within perfusion models is non-trivial, due to heterogeneous vessel density and disparate radii scales. Furthermore, previous idealised networks have assumed a spatially repeating motif or periodic canonical cell, thereby allowing for a flow solution via homogenisation. However, such periodicity is not observed throughout anatomical networks. In this study, we apply various spatial averaging methods to discrete vascular geometries in order to parameterise a continuum model of perfusion. Specifically, a multi-compartment Darcy model was used to provide vascular scale separation for the fluid flow. Permeability tensor fields were derived from both synthetic and anatomically realistic networks using (1) porosity-scaled isotropic, (2) Huyghe and Van Campen, and (3) projected-PCA methods. The Darcy pressure fields were compared via a root-mean-square error metric to an averaged Poiseuille pressure solution over the same domain. The method of Huyghe and Van Campen performed better than the other two methods in all simulations, even for relatively coarse networks. Furthermore, inter-compartment volumetric flux fields, determined using the spatially averaged discrete flux per unit pressure difference, were shown to be accurate across a range of pressure boundary conditions. This work justifies the application of continuum flow models to characterise perfusion resulting from flow in an underlying vascular network.
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van den Wijngaard JPHM, Schwarz JCV, van Horssen P, van Lier MGJTB, Dobbe JGG, Spaan JAE, Siebes M. 3D Imaging of vascular networks for biophysical modeling of perfusion distribution within the heart. J Biomech 2012; 46:229-39. [PMID: 23237670 DOI: 10.1016/j.jbiomech.2012.11.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 11/09/2012] [Indexed: 02/07/2023]
Abstract
One of the main determinants of perfusion distribution within an organ is the structure of its vascular network. Past studies were based on angiography or corrosion casting and lacked quantitative three dimensional, 3D, representation. Based on branching rules and other properties derived from such imaging, 3D vascular tree models were generated which were rather useful for generating and testing hypotheses on perfusion distribution in organs. Progress in advanced computational models for prediction of perfusion distribution has raised the need for more realistic representations of vascular trees with higher resolution. This paper presents an overview of the different methods developed over time for imaging and modeling the structure of vascular networks and perfusion distribution, with a focus on the heart. The strengths and limitations of these different techniques are discussed. Episcopic fluorescent imaging using a cryomicrotome is presently being developed in different laboratories. This technique is discussed in more detail, since it provides high-resolution 3D structural information that is important for the development and validation of biophysical models but also for studying the adaptations of vascular networks to diseases. An added advantage of this method being is the ability to measure local tissue perfusion. Clinically, indices for patient-specific coronary stenosis evaluation derived from vascular networks have been proposed and high-resolution noninvasive methods for perfusion distribution are in development. All these techniques depend on a proper representation of the relevant vascular network structures.
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Affiliation(s)
- Jeroen P H M van den Wijngaard
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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38
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Abstract
OBJECTIVE Recent methods for imaging microvascular structures provide geometrical data on networks containing thousands of segments. Prediction of functional properties, such as solute transport, requires information on blood flow rates also, but experimental measurement of many individual flows is difficult. Here, a method is presented for estimating flow rates in a microvascular network based on incomplete information on the flows in the boundary segments that feed and drain the network. METHODS With incomplete boundary data, the equations governing blood flow form an underdetermined linear system. An algorithm was developed that uses independent information about the distribution of wall shear stresses and pressures in microvessels to resolve this indeterminacy, by minimizing the deviation of pressures and wall shear stresses from target values. RESULTS The algorithm was tested using previously obtained experimental flow data from four microvascular networks in the rat mesentery. With two or three prescribed boundary conditions, predicted flows showed relatively small errors in most segments and fewer than 10% incorrect flow directions on average. CONCLUSIONS The proposed method can be used to estimate flow rates in microvascular networks, based on incomplete boundary data, and provides a basis for deducing functional properties of microvessel networks.
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Affiliation(s)
- Brendan C. Fry
- Program in Applied Mathematics, University of Arizona, Tucson, AZ USA
| | - Jack Lee
- Department of Biomedical Engineering, King’s College London, UK
| | - Nicolas P. Smith
- Department of Biomedical Engineering, King’s College London, UK
- Department of Computer Science, University of Oxford, Oxford, UK
| | - Timothy W. Secomb
- Program in Applied Mathematics, University of Arizona, Tucson, AZ USA
- Department of Physiology, University of Arizona, Tucson, AZ USA
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39
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Detection and quantification of fluorescent cell clusters in cryo-imaging. Int J Biomed Imaging 2012; 2012:698413. [PMID: 22481905 PMCID: PMC3317210 DOI: 10.1155/2012/698413] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Accepted: 12/16/2011] [Indexed: 01/27/2023] Open
Abstract
We developed and evaluated an algorithm for enumerating fluorescently labeled cells (e.g., stem and cancer cells) in mouse-sized, microscopic-resolution, cryo-image volumes. Fluorescent cell clusters were detected, segmented, and then fit with a model which incorporated a priori information about cell size, shape, and intensity. The robust algorithm performed well in phantom and tissue imaging tests, including accurate (<2% error) counting of cells in mouse. Preliminary experiments demonstrate that cryo-imaging and software can uniquely analyze delivery, homing to an organ and tissue distribution of stem cell therapeutics.
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Cookson A, Lee J, Michler C, Chabiniok R, Hyde E, Nordsletten D, Sinclair M, Siebes M, Smith N. A novel porous mechanical framework for modelling the interaction between coronary perfusion and myocardial mechanics. J Biomech 2011; 45:850-5. [PMID: 22154392 PMCID: PMC3334269 DOI: 10.1016/j.jbiomech.2011.11.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2011] [Indexed: 12/01/2022]
Abstract
The strong coupling between the flow in coronary vessels and the mechanical deformation of the myocardial tissue is a central feature of cardiac physiology and must therefore be accounted for by models of coronary perfusion. Currently available geometrically explicit vascular models fail to capture this interaction satisfactorily, are numerically intractable for whole organ simulations, and are difficult to parameterise in human contexts. To address these issues, in this study, a finite element formulation of an incompressible, poroelastic model of myocardial perfusion is presented. Using high-resolution ex vivo imaging data of the coronary tree, the permeability tensors of the porous medium were mapped onto a mesh of the corresponding left ventricular geometry. The resultant tensor field characterises not only the distinct perfusion regions that are observed in experimental data, but also the wide range of vascular length scales present in the coronary tree, through a multi-compartment porous model. Finite deformation mechanics are solved using a macroscopic constitutive law that defines the coupling between the fluid and solid phases of the porous medium. Results are presented for the perfusion of the left ventricle under passive inflation that show wall-stiffening associated with perfusion, and that show the significance of a non-hierarchical multi-compartment model within a particular perfusion territory.
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Affiliation(s)
- A.N. Cookson
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - J. Lee
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - C. Michler
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - R. Chabiniok
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - E. Hyde
- Department of Computer Science, Oxford OX1 3QD, UK
| | - D.A. Nordsletten
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - M. Sinclair
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
| | - M. Siebes
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, 1105 AZ, The Netherlands
| | - N.P. Smith
- Imaging Sciences & Biomedical Engineering Division, St Thomas' Hospital, King's College London, SE1 7EH, UK
- Corresponding author.
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41
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The Nightingale Prize 2011 for best MBEC paper in 2010. Med Biol Eng Comput 2011; 49:1353-4. [PMID: 22095317 PMCID: PMC3223592 DOI: 10.1007/s11517-011-0846-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 11/09/2011] [Indexed: 12/01/2022]
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42
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van de Hoef TP, Nolte F, Rolandi MC, Piek JJ, van den Wijngaard JPHM, Spaan JAE, Siebes M. Coronary pressure-flow relations as basis for the understanding of coronary physiology. J Mol Cell Cardiol 2011; 52:786-93. [PMID: 21840314 DOI: 10.1016/j.yjmcc.2011.07.025] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 12/21/2022]
Abstract
Recent technological advancements in the area of intracoronary physiology, as well as non-invasive contrast perfusion imaging, allow to make clinical decisions with respect to percutaneous coronary interventions and to identify microcirculatory coronary pathophysiology. The basic characteristics of coronary hemodynamics, as described by pressure-flow relations in the normal and diseased heart, need to be understood for a proper interpretation of these physiological measurements. Especially the hyperemic coronary pressure-flow relation, as well as the influence of cardiac function on it, bears great clinical significance. The interaction of a coronary stenosis with the coronary pressure-flow relation can be understood from the stenosis pressure drop-flow velocity relationship. Based on these relationships the clinically applied concepts of coronary flow velocity reserve, fractional flow reserve, stenosis resistance and microvascular resistance are discussed. Attention is further paid to the heterogeneous nature of myocardial perfusion, the vulnerability of the subendocardium and the role of collateral flow on hyperemic coronary pressure-flow relations. This article is part of a Special Issue entitled "Coronary Blood Flow".
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Affiliation(s)
- Tim P van de Hoef
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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43
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Lagerveld BW, van Horssen P, Laguna MP, van den Wijngaard JP, Siebes M, Wijkstra H, de la Rosette JJ, Spaan JA. Gradient Changes in Porcine Renal Arterial Vascular Anatomy and Blood Flow After Cryoablation. J Urol 2011; 186:681-6. [DOI: 10.1016/j.juro.2011.03.146] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Indexed: 11/28/2022]
Affiliation(s)
- Brunolf W. Lagerveld
- Department of Urology, St. Lucas Andreas Hospital and Onze Lieve Vrouwe Gasthuis, Academic Medical Centre, University of Amsterdam, The Netherlands
- Department of Urology, Academic Medical Centre, University of Amsterdam, The Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academic Medical Centre, University of Amsterdam, The Netherlands
| | - M. Pilar Laguna
- Department of Urology, Academic Medical Centre, University of Amsterdam, The Netherlands
| | | | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academic Medical Centre, University of Amsterdam, The Netherlands
| | - Hessel Wijkstra
- Department of Urology, Academic Medical Centre, University of Amsterdam, The Netherlands
| | | | - Jos A.E. Spaan
- Department of Biomedical Engineering and Physics, Academic Medical Centre, University of Amsterdam, The Netherlands
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44
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van den Wijngaard JPHM, Schulten H, van Horssen P, ter Wee RD, Siebes M, Post MJ, Spaan JAE. Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone. Am J Physiol Heart Circ Physiol 2011; 300:H1930-7. [DOI: 10.1152/ajpheart.00403.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the current paradigm on coronary collateral development, it is assumed that these vessels develop consequentially from increased fluid shear stress (FSS) through preexisting collateral arteries. The increased FSS follows from an increase in pressure gradient between the region at risk and well-perfused surroundings. The objective of this study was to test the hypothesis that, in the heart, collateral connections can form in the absence of an increased FFS and consequentially at any depth and region within the ventricular wall. In Yorkshire pigs, gradual left circumflex coronary artery occlusion was obtained over 6 wk by an ameroid constrictor, whereas the control group underwent a sham operation. Hearts were harvested and subsequently processed in an imaging cryomicrotome, resulting in 40-μm voxel resolution three-dimensional reconstructions of the intramural vascular vessels. Dedicated software segmented the intramural vessels and all continuous vascular pathways containing a collateral connection. In the ameroid group, 192 collaterals, 22–1,049 μm in diameter, were detected with 62% within the subendocardium. Sixty percent of collaterals bridged from the left anterior descending artery to left circumflex coronary artery. A novel result is that 25% ( n = 48) of smaller-radius collaterals ( P = 0.047) connected with both origin and terminus in the nontarget area where perfusion was assumed uncompromised. In the porcine heart, collateral vessels develop not only in ischemic border zones with increased FSS but also away from such border zones where increased FSS is unlikely. The majority of collaterals were located at the subendocardium, corresponding to the region with highest prevalence for ischemia.
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Affiliation(s)
| | - Henny Schulten
- Department of Physiology, University of Maastricht, Maastricht, The Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering and Physics, Academisch Medisch Centrum, Amsterdam; and
| | - Rene D. ter Wee
- Department of Biomedical Engineering and Physics, Academisch Medisch Centrum, Amsterdam; and
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Academisch Medisch Centrum, Amsterdam; and
| | - Mark J. Post
- Department of Physiology, University of Maastricht, Maastricht, The Netherlands
| | - Jos A. E. Spaan
- Department of Biomedical Engineering and Physics, Academisch Medisch Centrum, Amsterdam; and
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45
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Smith N, de Vecchi A, McCormick M, Nordsletten D, Camara O, Frangi AF, Delingette H, Sermesant M, Relan J, Ayache N, Krueger MW, Schulze WHW, Hose R, Valverde I, Beerbaum P, Staicu C, Siebes M, Spaan J, Hunter P, Weese J, Lehmann H, Chapelle D, Rezavi R. euHeart: personalized and integrated cardiac care using patient-specific cardiovascular modelling. Interface Focus 2011; 1:349-64. [PMID: 22670205 DOI: 10.1098/rsfs.2010.0048] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/04/2011] [Indexed: 01/09/2023] Open
Abstract
The loss of cardiac pump function accounts for a significant increase in both mortality and morbidity in Western society, where there is currently a one in four lifetime risk, and costs associated with acute and long-term hospital treatments are accelerating. The significance of cardiac disease has motivated the application of state-of-the-art clinical imaging techniques and functional signal analysis to aid diagnosis and clinical planning. Measurements of cardiac function currently provide high-resolution datasets for characterizing cardiac patients. However, the clinical practice of using population-based metrics derived from separate image or signal-based datasets often indicates contradictory treatments plans owing to inter-individual variability in pathophysiology. To address this issue, the goal of our work, demonstrated in this study through four specific clinical applications, is to integrate multiple types of functional data into a consistent framework using multi-scale computational modelling.
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Affiliation(s)
- Nic Smith
- Imaging Sciences and Biomedical Engineering Division , St Thomas' Hospital, King's College London , London , UK
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46
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Kaneko N, Matsuda R, Toda M, Shimamoto K. Three-dimensional reconstruction of the human capillary network and the intramyocardial micronecrosis. Am J Physiol Heart Circ Physiol 2011; 300:H754-61. [DOI: 10.1152/ajpheart.00486.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three-dimensional reconstruction of the human heart was performed to define the structure of the intramyocardial microvasculature. A total of 200 consecutive serial sections of 6 μm each were prepared from the left ventricular tissue of an autopsied human heart with normal coronary arteries. The corresponding arteriole, venule, and all capillaries were reconstructed using three-dimensional software. The capillary network extended right and left along the cardiomyocyte with major and minor axes of about 130 and 120 μm, respectively. The capillary length from an arteriole to an adjacent venule was about 350 μm. Two types of sack-like structures, the precapillary sinus and the capillary sinus, were present in the capillary network, and many capillaries diverged from these sinuses. The cardiomyocytes were covered with reticular capillaries. In contrast, the precapillary and capillary sinuses were surrounded by many cardiomyocytes. The arterial and venous capillaries were positioned alternately, forming a lattice pattern. Intramyocardial microcirculatory units forming a capillary network from an arteriole to adjacent venules on both sides were present. The sizes of myocardial micronecroses corresponded to that of the intramyocardial microcirculatory unit. These results show that the capillary network is an ordered and anatomically regulated structure and that the microcirculatory unit and the precapillary and capillary sinuses may play an important role in maintaining the intramyocardial microcirculation during contraction and relaxation.
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Affiliation(s)
| | - Ryuko Matsuda
- Preventive Medical Science for the Heart, Dokkyo Medical University, Mibu, Tochigi
| | - Masashi Toda
- Department of R and D Planning, Aetas Pharma, Chuo-ku, Tokyo; and
| | - Ken Shimamoto
- Department of Cardiology, Tokyo Women's Medical University, Aoyama Hospital, Minato-ku, Tokyo, Japan
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47
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Waters SL, Alastruey J, Beard DA, Bovendeerd PHM, Davies PF, Jayaraman G, Jensen OE, Lee J, Parker KH, Popel AS, Secomb TW, Siebes M, Sherwin SJ, Shipley RJ, Smith NP, van de Vosse FN. Theoretical models for coronary vascular biomechanics: progress & challenges. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 104:49-76. [PMID: 21040741 PMCID: PMC3817728 DOI: 10.1016/j.pbiomolbio.2010.10.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 09/17/2010] [Accepted: 10/06/2010] [Indexed: 01/09/2023]
Abstract
A key aim of the cardiac Physiome Project is to develop theoretical models to simulate the functional behaviour of the heart under physiological and pathophysiological conditions. Heart function is critically dependent on the delivery of an adequate blood supply to the myocardium via the coronary vasculature. Key to this critical function of the coronary vasculature is system dynamics that emerge via the interactions of the numerous constituent components at a range of spatial and temporal scales. Here, we focus on several components for which theoretical approaches can be applied, including vascular structure and mechanics, blood flow and mass transport, flow regulation, angiogenesis and vascular remodelling, and vascular cellular mechanics. For each component, we summarise the current state of the art in model development, and discuss areas requiring further research. We highlight the major challenges associated with integrating the component models to develop a computational tool that can ultimately be used to simulate the responses of the coronary vascular system to changing demands and to diseases and therapies.
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Affiliation(s)
- Sarah L Waters
- Oxford Centre for Industrial and Applied mathematics, Mathematical Institute, 24-29 St Giles', Oxford, OX1 3LB, UK.
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48
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Krishnamurthi G, Wang CY, Steyer G, Wilson DL. Removal of subsurface fluorescence in cryo-imaging using deconvolution. OPTICS EXPRESS 2010; 18:22324-38. [PMID: 20941133 PMCID: PMC3408948 DOI: 10.1364/oe.18.022324] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We compared image restoration methods [Richardson-Lucy (RL), Wiener, and Next-image] with measured "scatter" point-spread-functions, for removing subsurface fluorescence from section-and-image cryo-image volumes. All methods removed haze, delineated single cells from clusters, and improved visualization, but RL best represented structures. Contrast-to-noise and contrast-to-background improvement from RL and Wiener were comparable and 35% better than Next-image. Concerning detection of labeled cells, ROC analyses showed RL ≈Wiener > Next-image >> no processing. Next-image was faster than other methods and less prone to image processing artifacts. RL is recommended for the best restoration of the shape and size of fluorescent structures.
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Affiliation(s)
- Ganapathy Krishnamurthi
- 10900 Euclid Avenue, Wickenden Bldg, School of Biomedical Engineering, Cleveland OH 44106,
USA
| | - Charlie Y. Wang
- 10900 Euclid Avenue, Wickenden Bldg, School of Biomedical Engineering, Cleveland OH 44106,
USA
- Department of Radiology, Case Western Reserve University and Case Medical Center, Cleveland OH 44106,
USA
| | - Grant Steyer
- 10900 Euclid Avenue, Wickenden Bldg, School of Biomedical Engineering, Cleveland OH 44106,
USA
| | - David L. Wilson
- 10900 Euclid Avenue, Wickenden Bldg, School of Biomedical Engineering, Cleveland OH 44106,
USA
- Department of Radiology, Case Western Reserve University and Case Medical Center, Cleveland OH 44106,
USA
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49
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Improved detection of fluorescently labeled microspheres and vessel architecture with an imaging cryomicrotome. Med Biol Eng Comput 2010; 48:735-44. [PMID: 20574721 PMCID: PMC2903706 DOI: 10.1007/s11517-010-0652-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/06/2010] [Indexed: 12/27/2022]
Abstract
Due to spectral overlap, the number of fluorescent labels for imaging cryomicrotome detection was limited to 4. The aim of this study was to increase the separation of fluorescent labels. In the new imaging cryomicrotome, the sample is cut in slices of 40 μm. Six images are taken for each cutting plane. Correction for spectral overlap is based on linear combinations of fluorescent images. Locations of microspheres are determined by using the system point spread function. Five differently colored microspheres were injected in vivo distributed over two major coronaries, the left anterior descending and left circumflex artery. Under absence of collateral flow, microspheres outside of target perfusion territories were not found and the procedure did not generate false positive detection when spectral overlap was relevant. In silico-generated microspheres were used to test the effect of background image, transparency correction, and color separation. The percentage of microspheres undetected was 2.3 ± 0.8% in the presence and 1.5 ± 0.4% in the absence of background structures with a density of 900 microspheres per color per cm3. The image analysis method presented here, allows for an increased number of experimental conditions that can be investigated in studies of regional myocardial perfusion.
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50
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Goyal A, van den Wijngaard J, van Horssen P, Grau V, Spaan J, Smith N. Intramural spatial variation of optical tissue properties measured with fluorescence microsphere images of porcine cardiac tissue. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:1408-11. [PMID: 19964525 DOI: 10.1109/iembs.2009.5334174] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This proceeding studies the optical fluorescence images of a porcine heart filled with microspheres of two colors, carmine and red. A significant difference in the total optical tissue attenuation coefficient was observed between excitation and emission for both carmine (excitation - 13+/-4(1/mm) and emission - 9.4+/-3(1/mm)) and red (excitation -29+/-5(1/mm) and emission - 25+/-5(1/mm)), indicating that optical tissue properties can change significantly for a small change in light wavelength. The above-mentioned large ranges of variation observed in the tissue attenuation coefficient for excitation and emission (both for carmine and red) suggest significant intramural variation of optical properties across the entire organ. Patterns of global spatial variation in optical attenuation properties in tissue across the entire organ were observed. A novel method using fluorescence microsphere images is presented for measurement of the tissue attenuation's intramural variation across an entire organ.
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Affiliation(s)
- Ayush Goyal
- Computational Biology, Computing Laboratory, University of Oxford, United Kingdom
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