In-vivo flow simulation in coronary arteries based on computed tomography datasets: feasibility and initial results

Frauenfelder, Thomas; Boutsianis, Evangelos; Schertler, Thomas; Husmann, Lars; Leschka, Sebastian; Poulikakos, Dimos; Marinček, Borut; Alkadhi, Hatem

doi:10.1007/s00330-006-0465-1

Cited by 59 publications

(43 citation statements)

References 45 publications

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“…For a similar study, Pivkin et al, 2005 used a sinusoidal velocity waveform. Other investigations have defined steady state boundary conditions (Soulis et al, 2006) or used a reference waveform from previous literature (Frauenfelder et al, 2007;Glor et al, 2003;Johnston et al, 2006). Few studies have paired in vivo geometries with corresponding in vivo flow.…”

Section: In Vivo Coronary Artery Studymentioning

confidence: 99%

Coronary artery flow measurement using navigator echo gated phase contrast magnetic resonance velocity mapping at 3.0 T

Johnson

Sharma

Oshinski

2008

Journal of Biomechanics

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A validation study and early results for noninvasive, in vivo measurement of coronary artery blood flow using phase contrast magnetic resonance imaging (PC-MRI) at 3.0 Tesla is presented. Accuracy of coronary artery blood flow measurements by phase contrast MRI is limited by heart and respiratory motion as well as the small size of the coronary arteries. In this study, a navigator-echo gated, cine phase velocity mapping technique is described to obtain time-resolved velocity and flow waveforms of small diameter vessels at 3.0 Tesla. Phantom experiments using steady, laminar flow are presented to validate the technique and show flow rates measured by 3.0 Tesla phase contrast MRI to be accurate within 15% of true flow rates. Subsequently, in vivo scans on healthy volunteers yield velocity measurements for blood flow in the right, left anterior descending, and left circumflex arteries. Measurements of average, cross-sectional velocity were obtainable in 224/243 (92%) of the cardiac phases. Time-averaged, cross-sectional velocity of the blood flow was 6.8±4.3 cm/s in the LAD, 8.0 ±3.8 cm/s in the LCX, and 6.0±1.6 cm/s in the RCA.

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Section: In Vivo Coronary Artery Studymentioning

confidence: 99%

Coronary artery flow measurement using navigator echo gated phase contrast magnetic resonance velocity mapping at 3.0 T

Johnson

Sharma

Oshinski

2008

Journal of Biomechanics

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“…Some assumed the blood flow in coronary arteries to be laminar (7)(8)(9)(10)(11)(12)(13)(14) and behave as Newtonian fluid (8,(15)(16)(17) and some studied turbulence transition and non-Newtonian effects considering idealized straight arterial model with single model stenosis obstruction (11,15,(17)(18)(19)(20)(21). Several experimental investigations have been carried out on flow disturbances in the downstream region of idealized modeled stenosis (18,22,23).…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Mahalingam¹,

Gawandalkar²,

Kini³

et al. 2016

Cardiovasc. Diagn. Ther.

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Background: Local hemodynamics plays an important role in atherogenesis and the progression of coronary atherosclerosis disease (CAD). The primary biological effect due to blood turbulence is the change in wall shear stress (WSS) on the endothelial cell membrane, while the local oscillatory nature of the blood flow affects the physiological changes in the coronary artery. In coronary arteries, the blood flow Reynolds number ranges from few tens to several hundreds and hence it is generally assumed to be laminar while calculating the WSS calculations. However, the pulsatile blood flow through coronary arteries under stenotic condition could result in transition from laminar to turbulent flow condition.Methods: In the present work, the onset of turbulent transition during pulsatile flow through coronary arteries for varying degree of stenosis (i.e., 0%, 30%, 50% and 70%) is quantitatively analyzed by calculating the turbulent parameters distal to the stenosis. Also, the effect of turbulence transition on hemodynamic parameters such as WSS and oscillatory shear index (OSI) for varying degree of stenosis is quantified. The validated transitional shear stress transport (SST) k-ω model used in the present investigation is the best suited Reynolds averaged Navier-Stokes turbulence model to capture the turbulent transition. The arterial wall is assumed to be rigid and the dynamic curvature effect due to myocardial contraction on the blood flow has been neglected.Results: Our observations shows that for stenosis 50% and above, the WSS avg , WSS max and OSI calculated using turbulence model deviates from laminar by more than 10% and the flow disturbances seems to significantly increase only after 70% stenosis. Our model shows reliability and completely validated.Conclusions: Blood flow through stenosed coronary arteries seems to be turbulent in nature for area stenosis above 70% and the transition to turbulent flow begins from 50% stenosis.

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“…86) Recently, it is reported that endothelial shear stress can be evaluated by CCTA. [87][88][89][90] Plaque may be assessed by adding physiological information such as FFR and shear stress more comprehensively. As the result, plaque vulnerability could be evaluated more accurately.…”

Section: Problem In Plaque Evaluation By Cctamentioning

confidence: 99%

Plaque Evaluation by Coronary CT Angiography

2014

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Acute coronary syndromes (ACS) often occurs suddenly without precursor symptom. 1, 2) It is one of the important challenge for cardiologists to predict and prevent ACS. However, there is no method established. ACS is caused mainly by occlusion of thrombus. So, it is important to identify plaque that causes thrombotic occlusion at high rates (i.e.. vulnerable plaque) to solve this problem. Braunwald mentioned that Framingham risk score was insufficient in stratification of ACS onset. He expected to find higher risk group that onset ACS by 15% or more within one year by noninvasive vulnerable plaque imaging. He also predicted that very high risk group that onset ACS more than 25% a year by invasive imaging. of 213 patients from cardiac sudden death using hierarchical analysis. 7) As a result, the most important elements that discriminated plaque characteristics were thickness of fibrous cap, fibroatheroma (almost always >85 μm), ruptured plaques (<55 μm) and TCFA (between 55 and 85 μm). However, clinically, the thickness of fibrous cap can be measured only by optical coherence tomography (OCT). If this element is excluded, level of macrophage inflammation and necrotic core size were useful for discriminating vulnerable plaque in analysis. Although ACS were supposed to develop by rupture irrespective of significant stenosis of plaque, in 70% of ruptured plaque, cross-sectional area showed >75% and only about 5% showed stenosis of <50%.In TCFA, about 40% showed cross-sectional vascular area >75% and only 10% showed <50%. It is arguable whether disassociation of stenosis level distribution of ruptured plaques and TCFA is caused by rapid increase of plaque before rupture or TCFA with higher stenosis level has higher risk. Anyway, it was suggested that not only plaque characteristics evaluation but also plaque volume and stenosis level were important for identification of vulnerable plaque. In PROSPECT study where future cardiac event for non culprit lesions of ACS patients whose revascularization was successful was studied prospectively using virtual histology intra- Coronary CT angiography (CCTA) is the most promising, noninvasive tool that allows the visualization of plaque morphology. Plaque morphology characterized by positive remodeling, low attenuation plaque and napkin-ring sign in CCTA has been regarded as rupture-prone vulnerable plaques which account for about 60% of all vulnerable plaques and cause plaque rupture. Currently, importance of stenosis level and plaque volume for vulnerable plaque assessment has been recognized. CCTA is also useful from viewpoint of these evaluations. However, it is considered that evaluation by using CT number that is one of important factors of plaque evaluation is affected various factors. There remain several problems in objectivity and quantitative evaluation. Recently we developed a novel method for evaluating characteristics of plaque in more objective and quantitative way and reported the usability. Moreover, it may be possible to diagnose vulnerable plaque more correct...

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In-vivo flow simulation in coronary arteries based on computed tomography datasets: feasibility and initial results

Cited by 59 publications

References 45 publications

Coronary artery flow measurement using navigator echo gated phase contrast magnetic resonance velocity mapping at 3.0 T

Coronary artery flow measurement using navigator echo gated phase contrast magnetic resonance velocity mapping at 3.0 T

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Plaque Evaluation by Coronary CT Angiography

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