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Abstract
4D Flow is an emerging MR technique enabling three-dimensional and cardiac phase-resolved flowmetry with ECG-gated phase-contrast MRI that increased the speed of data acquisitions, accuracy and robustness. The method is promoting researches in areas that have not been fully addressed before in the cardiovascular system, such as flowmetry of the bloodstream across the valves, within the heart chambers, complexed flow dynamics such as vortex, helical or retrograde. Wall shear stress and other potential biomarkers derived from 4D Flow are known to be related to vascular wall diseases such as atherosclerosis. In this review, fundamental concepts of 4D Flow technique and post-processing, benefits and limitations as well as its clinical applications are discussed, and the importance of quality control and validation of the method is emphasized. New ideas inspired by 4D Flow can help clinicians and MR scientists further understand the role of flow dynamics in health sciences, diseases and various aspects of cardiovascular physiology.
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Affiliation(s)
- Yasuo Takehara
- Department of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University, Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
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2
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Min ZG, Shan HR, Xu L, Yan S, Sheng XX, Ji J, Cao ZH. Spontaneous isolated dissection and atherosclerotic plaques of superior mesenteric artery: the vastly different occurrence site suggests the opposite haemodynamic aetiology. Br J Radiol 2017; 90:20170178. [PMID: 28555503 DOI: 10.1259/bjr.20170178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE The development of atherosclerotic plaques and spontaneous isolated dissection (SID) of the superior mesenteric artery (SMA) was considered to be related to opposite haemodynamics. The purpose of this study was to compare their occurrence sites and the morphology of the SMA to confirm the haemodynamic aetiologies. METHODS 57 patients with SID and 64 patients with atherosclerotic plaques were compared about patient characteristics, location of SID and plaque, the distance from lesion to the aortic ostia, SMA branching angle and inlet diameter of the SMA. RESULTS The location of SID and plaque was very different (p < 0.001). The anterior wall was the most common entry site of SIDSMA (84.0%) but the least frequent origin site of atherosclerotic plaques (7.8%). The posterior, left and right walls were the frequent origin sites of atherosclerotic plaques (total 92.2%) but not for SIDSMA. Most plaques started from the aortic ostia, and their average distance to the aortic ostia was significantly less than the distance from the entry site to the aortic ostia of SIDSMA (p < 0.001). No significant difference was found between SIDSMA and the plaque groups in the branching angle and inlet diameter of the SMA. CONCLUSION The vastly different sites of SIDSMA and atherosclerotic plaque indicate their opposite haemodynamic aetiology. Advances in knowledge: By comparing the location of the two diseases, we demonstrate their different haemodynamic causes.
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Affiliation(s)
- Zhi-Gang Min
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Hai-Rong Shan
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Long Xu
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Su Yan
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Xue-Xia Sheng
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Jian Ji
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
| | - Zhi-Hong Cao
- Department of Radiology, Yixing Hospital Affiliated of Jiangsu University, Yixing, Jiangsu Province, China
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Lee CJ, Uemiya N, Ishihara S, Zhang Y, Qian Y. A comparison of estimation methods for computational fluid dynamics outflow boundary conditions using patient-specific carotid artery. Proc Inst Mech Eng H 2013; 227:663-71. [DOI: 10.1177/0954411913479540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Computational fluid dynamics simulations can provide important hemodynamic insights for investigating the effectiveness of carotid artery stenting, but its accuracy is dependent on the boundary conditions such as the outflow pressure, which is difficult to obtain by measurements. Many computational fluid dynamics simulations assume that the outflow pressure is constant ( P = 0), but this method is likely to produce different results compared to clinical measurements. We have developed an alternative estimation method called the minimum energy loss method based on the concept of energy loss minimization at flow bifurcation. This new method has been tested on computational fluid dynamics simulation of two patients treated with carotid artery stenting, and its flow ratio at internal carotid artery and wall shear stress distribution was compared with the constant zero outlet pressure method. Three different procedure stages (prestent, poststent, and follow-up) were analyzed. The internal carotid artery flow ratio using the minimum energy loss method generally matched well with ultrasound measurements, but the internal carotid artery flow ratio based on zero outlet pressure method showed a large difference. Wall shear stress distributions varied between methods in response to the change in internal carotid artery flow rate. This study demonstrates the importance of accurate outlet boundary condition for assessing the long-term efficacy of carotid artery stenting and the risk of restenosis in treated patients.
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Affiliation(s)
- Chang-Joon Lee
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Nahoko Uemiya
- Department of Endovascular Neurosurgery, Saitama Medical University International Medical Center, Saitama, Japan
| | - Shoichiro Ishihara
- Department of Endovascular Neurosurgery, Saitama Medical University International Medical Center, Saitama, Japan
| | - Yu Zhang
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Yi Qian
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
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4
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Halliday I, Atherton M, Care C, Collins M, Evans D, Evans P, Hose D, Khir A, König C, Krams R, Lawford P, Lishchuk S, Pontrelli G, Ridger V, Spencer T, Ventikos Y, Walker D, Watton P. Multi-scale interaction of particulate flow and the artery wall. Med Eng Phys 2011; 33:840-8. [DOI: 10.1016/j.medengphy.2010.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 08/05/2010] [Accepted: 09/10/2010] [Indexed: 10/18/2022]
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5
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Díaz-Zuccarini V, Lawford PV. An in-silico future for the engineering of functional tissues and organs. Organogenesis 2011; 6:245-51. [PMID: 21220955 DOI: 10.4161/org.6.4.13284] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Vanessa Díaz-Zuccarini
- University College London, Department of Mechanical Engineering, Torrington Place, London, UK.
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Singh PK, Marzo A, Howard B, Rufenacht DA, Bijlenga P, Frangi AF, Lawford PV, Coley SC, Hose DR, Patel UJ. Effects of smoking and hypertension on wall shear stress and oscillatory shear index at the site of intracranial aneurysm formation. Clin Neurol Neurosurg 2010; 112:306-13. [PMID: 20096503 DOI: 10.1016/j.clineuro.2009.12.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 11/06/2009] [Accepted: 12/28/2009] [Indexed: 10/19/2022]
Abstract
OBJECTIVE The mechanisms by which smoking and hypertension lead to increased incidence of intracranial aneurysm (IA) formation remain poorly understood. The current study investigates the effects of these risk factors on wall shear stress (WSS) and oscillatory shear index (OSI) at the site of IA initiation. METHODS Two (n=2) IAs from two patients with history of smoking and hypertension were artificially removed with the help of software @neuFuse (Supercomputing Solutions, Bologna, Italy) and the vessel geometry reconstructed to mimic the condition prior to IA formation. Two computational fluid dynamics (CFD) analyses were performed on each data-set by using in turn the normal physiological values of blood viscosity (BV), and high BV values specific to smoking and hypertension, obtained from literature. RESULTS At normal BV, high WSS (>15 Pa) was observed at the site of IA initiation in both patients. When BV values specific to smoking and hypertension were used, both the areas affected by high WSS (>15 Pa) and the maximum WSS were increased whilst the magnitude and distribution of OSI showed no significant change. CONCLUSIONS Long-term exposure to high WSS may result in an increased risk of IA development. An incremental increase in areas of high WSS observed secondary to smoking and hypertension may indicate a further increase in the risk of IA initiation. Interestingly, the relationship between BV and the area of increased WSS was not linear, reflecting the need for patient-specific CFD analysis.
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Affiliation(s)
- Pankaj K Singh
- Department of Medical Physics, Royal Hallamshire Hospital, Sheffield, UK.
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7
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Geometric Variability of the Abdominal Aorta and Its Major Peripheral Branches. Ann Biomed Eng 2010; 38:824-40. [DOI: 10.1007/s10439-010-9925-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 01/07/2010] [Indexed: 10/20/2022]
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Hammer S, Jeays A, Allan PL, Hose R, Barber D, Easson WJ, Hoskins PR. Acquisition of 3-D arterial geometries and integration with computational fluid dynamics. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:2069-2083. [PMID: 19828230 DOI: 10.1016/j.ultrasmedbio.2009.06.1099] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 06/19/2009] [Accepted: 06/25/2009] [Indexed: 05/28/2023]
Abstract
A system for acquisition of 3-D arterial ultrasound geometries and integration with computational fluid dynamics (CFD) is described. The 3-D ultrasound is based on freehand B-mode imaging with positional information obtained using an optical tracking system. A processing chain was established, allowing acquisition of cardiac-gated 3-D data and segmentation of arterial geometries using a manual method and a semi-automated method, 3D meshing and CFD. The use of CFD allowed visualization of flow streamlines, 2-D velocity contours and 3-D wall shear stress. Three-dimensional positional accuracy was 0.17-1.8mm, precision was 0.06-0.47mm and volume accuracy was 4.4-15%. Patients with disease and volunteers were scanned, with data collection from one or more of the carotid bifurcation, femoral bifurcation and abdominal aorta. An initial comparison between a manual segmentation method and a semi-automated method suggested some advantages to the semi-automated method, including reduced operator time and the production of smooth surfaces suitable for CFD, but at the expense of over-smoothing in the diseased region. There were considerable difficulties with artefacts and poor image quality, resulting in 3-D geometry data that was unsuitable for CFD. These artefacts were exacerbated in disease, which may mean that future effort, in the integration of 3-D arterial geometry and CFD for clinical use, may best be served using alternative 3-D imaging modalities such as magnetic resonance imaging and computed tomography.
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Affiliation(s)
- Steven Hammer
- Medical Physics, Sheffield University, Sheffield, UK
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Axner L, Hoekstra AG, Jeays A, Lawford P, Hose R, Sloot PMA. Simulations of time harmonic blood flow in the Mesenteric artery: comparing finite element and lattice Boltzmann methods. Biomed Eng Online 2009; 8:23. [PMID: 19799782 PMCID: PMC2764713 DOI: 10.1186/1475-925x-8-23] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 10/02/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Systolic blood flow has been simulated in the abdominal aorta and the superior mesenteric artery. The simulations were carried out using two different computational hemodynamic methods: the finite element method to solve the Navier Stokes equations and the lattice Boltzmann method. RESULTS We have validated the lattice Boltzmann method for systolic flows by comparing the velocity and pressure profiles of simulated blood flow between methods. We have also analyzed flow-specific characteristics such as the formation of a vortex at curvatures and traces of flow. CONCLUSION The lattice Boltzmann Method is as accurate as a Navier Stokes solver for computing complex blood flows. As such it is a good alternative for computational hemodynamics, certainly in situation where coupling to other models is required.
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Affiliation(s)
- Lilit Axner
- Section Computational Science, Laboratory for Computing, System Architecture and Programming, Faculty of Science, University of Amsterdam, Science Park 107, 1098 XG Amsterdam, The Netherlands
| | - Alfons G Hoekstra
- Section Computational Science, Laboratory for Computing, System Architecture and Programming, Faculty of Science, University of Amsterdam, Science Park 107, 1098 XG Amsterdam, The Netherlands
| | - Adam Jeays
- Department of Medical Physics and Clinical Engineering, University of Sheffield I Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK
| | - Pat Lawford
- Department of Medical Physics and Clinical Engineering, University of Sheffield I Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK
| | - Rod Hose
- Department of Medical Physics and Clinical Engineering, University of Sheffield I Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK
| | - Peter MA Sloot
- Section Computational Science, Laboratory for Computing, System Architecture and Programming, Faculty of Science, University of Amsterdam, Science Park 107, 1098 XG Amsterdam, The Netherlands
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The role of computational fluid dynamics in the management of unruptured intracranial aneurysms: a clinicians' view. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2009:760364. [PMID: 19696903 PMCID: PMC2729101 DOI: 10.1155/2009/760364] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 04/24/2009] [Accepted: 06/09/2009] [Indexed: 11/18/2022]
Abstract
Objective. The
importance of hemodynamics in the
etiopathogenesis of intracranial aneurysms (IAs)
is widely accepted. Computational fluid dynamics
(CFD) is being used increasingly for hemodynamic
predictions. However, alogn with the continuing
development and validation of these
tools, it is imperative to collect
the opinion of the clinicians.
Methods. A workshop on CFD was
conducted during the European Society of
Minimally Invasive Neurological Therapy (ESMINT)
Teaching Course, Lisbon, Portugal.
36 delegates, mostly clinicians,
performed supervised CFD analysis for an IA, using the
@neuFuse software developed within the European
project @neurIST. Feedback on the workshop was
collected and analyzed. The
performance was assessed on a scale of 1 to 4
and, compared with experts' performance.
Results. Current dilemmas in
the management of unruptured IAs remained the
most important motivating factor to attend the
workshop and majority of participants showed interest in participating in a
multicentric trial. The participants achieved
an average score of 2.52 (range 0–4) which was 63% (range 0–100%) of an expert user. Conclusions.
Although participants showed a manifest interest
in CFD, there was a clear
lack of awareness concerning the role of
hemodynamics in the etiopathogenesis of IAs and
the use of CFD in this context. More efforts
therefore are required to enhance understanding of the
clinicians in the subject.
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Marzo A, Singh P, Reymond P, Stergiopulos N, Patel U, Hose R. Influence of inlet boundary conditions on the local haemodynamics of intracranial aneurysms. Comput Methods Biomech Biomed Engin 2009; 12:431-44. [DOI: 10.1080/10255840802654335] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Sutter R, Heilmaier C, Lutz AM, Weishaupt D, Seifert B, Willmann JK. MR angiography with parallel acquisition for assessment of the visceral arteries: comparison with conventional MR angiography and 64-detector-row computed tomography. Eur Radiol 2009; 19:2679-88. [PMID: 19526242 DOI: 10.1007/s00330-009-1473-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/01/2009] [Accepted: 04/24/2009] [Indexed: 12/31/2022]
Abstract
The purpose of the study was to retrospectively compare three-dimensional gadolinium-enhanced magnetic resonance angiography (conventional MRA) with MRA accelerated by a parallel acquisition technique (fast MRA) for the assessment of visceral arteries, using 64-detector-row computed tomography angiography (MDCTA) as the reference standard. Eighteen patients underwent fast MRA (imaging time 17 s), conventional MRA (29 s) and MDCTA of the abdomen and pelvis. Two independent readers assessed subjective image quality and the presence of arterial stenosis. Data were analysed on per-patient and per-segment bases. Fast MRA yielded better subjective image quality in all segments compared with conventional MRA (P = 0.012 for reader 1, P = 0.055 for reader 2) because of fewer motion-induced artefacts. Sensitivity and specificity of fast MRA for the detection of arterial stenosis were 100% for both readers. Sensitivity of conventional MRA was 89% for both readers, and specificity was 100% (reader 1) and 99% (reader 2). Differences in sensitivity between the two types of MRA were not significant for either reader. Interobserver agreement for the detection of arterial stenosis was excellent for fast (kappa = 1.00) and good for conventional MRA (kappa = 0.76). Thus, subjective image quality of visceral arteries remains good on fast MRA compared with conventional MRA, and the two techniques do not differ substantially in the grading of arterial stenosis, despite the markedly reduced acquisition time of fast MRA.
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Affiliation(s)
- Reto Sutter
- Institute of Diagnostic Radiology, University Hospital Zurich, Zurich, Switzerland
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Abstract
The gastrointestinal (GI) tract is the system of organs within multi-cellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. The various patterns of GI tract function are generated by the integrated behaviour of multiple tissues and cell types. A thorough study of the GI tract requires understanding of the interactions between cells, tissues and gastrointestinal organs in health and disease. This depends on knowledge, not only of numerous cellular ionic current mechanisms and signal transduction pathways, but also of large scale GI tissue structures and the special distribution of the nervous network. A unique way of coping with this explosion in complexity is mathematical and computational modelling; providing a computational framework for the multilevel modelling and simulation of the human gastrointestinal anatomy and physiology. The aim of this review is to describe the current status of biomechanical modelling work of the GI tract in humans and animals, which can be further used to integrate the physiological, anatomical and medical knowledge of the GI system. Such modelling will aid research and ensure that medical professionals benefit, through the provision of relevant and precise information about the patient’s condition and GI remodelling in animal disease models. It will also improve the accuracy and efficiency of medical procedures, which could result in reduced cost for diagnosis and treatment.
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Lawford P, Ventikos Y, Khir A, Atherton M, Evans D, Hose D, Care C, Watton P, Halliday I, Walker D, Hollis A, Collins M. Modelling the interaction of haemodynamics and the artery wall: Current status and future prospects. Biomed Pharmacother 2008; 62:530-5. [DOI: 10.1016/j.biopha.2008.07.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 07/01/2008] [Indexed: 10/21/2022] Open
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Liao D, Lelic D, Gao F, Drewes AM, Gregersen H. Biomechanical functional and sensory modelling of the gastrointestinal tract. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2008; 366:3281-3299. [PMID: 18593660 DOI: 10.1098/rsta.2008.0091] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The aim of this review is to describe the biomechanical, functional and sensory modelling work that can be used to integrate the physiological, anatomical and medical knowledge of the gastrointestinal (GI) system. The computational modelling in the GI tract was designed, implemented and evaluated using a series of information and communication technologies-based tools. These tools modelled the morphometry, biomechanics, functions and sensory aspects of the human GI tract. The research presented in this review is based on the virtual physiological human concept that pursues a holistic approach to representation of the human body. Such computational modelling combines imaging data, GI physiology, the gut-brain axis, geometrical and biomechanical reconstruction, and computer graphics for mechanical, electronic and pain analysis. The developed modelling will aid research and ensure that medical professionals benefit through the provision of relevant and precise information about a patient's condition. It will also improve the accuracy and efficiency of the medical procedures that could result in reduced cost for diagnosis and treatment.
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Affiliation(s)
- Donghua Liao
- Mech-Sense, Aalborg Hospital Science and Innovation Centre, Søndre Skovvej 15, 9000 Aalborg, Denmark.
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Jeays AD, Lawford PV, Gillott R, Spencer PA, Bardhan KD, Hose DR. A framework for the modeling of gut blood flow regulation and postprandial hyperaemia. World J Gastroenterol 2007; 13:1393-8. [PMID: 17457971 PMCID: PMC4146924 DOI: 10.3748/wjg.v13.i9.1393] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After a meal the activity of the gut increases markedly as digestion takes place. Associated with this increase in activity is an increase in blood flow, which has been shown to be dependent on factors such as caloric content and constitution of the meal. Much qualitative work has been carried out regarding mechanisms for the presence of food in a section of gut producing increased blood flow to that section, but there are still many aspects of this process that are not fully understood. In this paper we briefly review current knowledge on several relevant areas relating to gut blood flow, focusing on quantitative data where available and highlighting areas where further research is needed. We then present new data on the effect of feeding on flow in the superior mesenteric artery. Finally, we describe a framework for combining this data to produce a single model describing the mechanisms involved in postprandial hyperaemia. For a section of the model, where appropriate data are available, preliminary results are presented.
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