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

Johnson, Karen M.; Sharma, Puneet; Oshinski, John N.

doi:10.1016/j.jbiomech.2007.10.010

Cited by 60 publications

(51 citation statements)

References 40 publications

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“…We expect both to influence the reported results in a quantitative manner, but not qualitatively. While patientspecific inlet waveforms could principally be obtained using magnetic resonance imaging (25), noninvasive in vivo pressure measurements in the coronary arteries are currently not possible. A further simplification that may influence the results is that the arterial wall is assumed to be rigid.…”

Section: Coincidence Of High-ldl Concentration With Plaque Locationmentioning

confidence: 99%

Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states

Olgaç¹,

Poulikakos²,

Saur³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

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Olgac U, Poulikakos D, Saur SC, Alkadhi H, Kurtcuoglu V. Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states. Am J Physiol Heart Circ Physiol 296: H1969 -H1982, 2009. First published March 27, 2009 doi:10.1152/ajpheart.01182.2008.-We calculate low-density lipoprotein (LDL) transport from blood into arterial walls in a three-dimensional, patient-specific model of a human left coronary artery. The in vivo anatomy data are obtained from computed tomography images of a patient with coronary artery disease. Models of the artery anatomy in its healthy and diseased states are derived after segmentation of the vessel lumen, with and without the detected plaque, respectively. Spatial shear stress distribution at the endothelium is determined through the reconstruction of the arterial blood flow field using computational fluid dynamics. The arterial endothelium is represented by a shear stress-dependent, threepore model, taking into account blood plasma and LDL passage through normal junctions, leaky junctions, and the vesicular pathway. Intraluminal pressures of 70 and 120 mmHg are employed as the normal and hypertensive operating pressures, respectively. By applying our model to both the healthy and diseased states, we show that the location of the plaque in the diseased state corresponds to one of the two sites with predicted high-LDL concentration in the healthy state. We further show that, in the diseased state, the site with high-LDL concentration has shifted distal to the plaque, which is in agreement with the clinical observation that plaques generally grow in the downstream direction. We also demonstrate that hypertension leads to increased number of regions with high-LDL concentration, elucidating one of the ways in which hypertension may promote atherosclerosis.low-density lipoprotein transport; lipid accumulation; patient-specific simulations; atherosclerosis; leaky junction ATHEROSCLEROSIS, A PROGRESSIVE disease characterized by the accumulation of lipids in the arterial walls, is the primary cause of heart disease and stroke (37). Locally elevated concentrations of low-density lipoprotein (LDL) are considered to be the initiator of atherosclerotic plaque formation (37,46,48). Therefore, transport of LDL into arterial walls has been the subject of various experimental (8,11,35,39,47,48) and computational investigations (2,29,43,50,52,53,55,56,59).Computational LDL transport models, as recently reviewed by Khakpour and Vafai (28), are categorized into three types: wall-free models, homogenous wall models, and multilayer wall models. In the simple wall-free models, fluid dynamics and LDL transport are calculated solely in the artery lumen. A constant filtration velocity and LDL flux, defined by an overall mass transfer coefficient, are generally applied on the lumenside artery surface. The main drawback of wall-free models is that they do not provide any information on the transmural flow and solute dynamics in the arterial...

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Section: Coincidence Of High-ldl Concentration With Plaque Locationmentioning

confidence: 99%

Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states

Olgaç¹,

Poulikakos²,

Saur³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

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“…Along the cross-section there was a greater density of cells towards the proximal layer with cell sizes in contact with the wall being three times smaller than cells within the center of the flow field for each tested mesh density. Pulse cycle independence was found after the third cycle with a time step size of 0.005 s. Figure 3 shows the comparison of the in vitro replication of the LAD, LCX 13 and RCA 51 flowrate waveforms with a period of 0.83 s. There was a maximum difference of 10.3, 10.8, and 9.3% between the required and measured flow rates within the LAD, LCX and RCA respectively. The pressure pulse for each model was within the physiological pressure ranges for all coronary vessels.…”

Section: Numerical Obtained Wall Shear Stress (Wss) Valuesmentioning

confidence: 95%

The Effects That Cardiac Motion has on Coronary Hemodynamics and Catheter Trackability Forces for the Treatment of Coronary Artery Disease: An In Vitro Assessment

Morris

Fahy

Stefanov

et al. 2015

Cardiovasc Eng Tech

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The coronary arterial tree experiences large displacements due to the contraction and expansion of the cardiac muscle and may influence coronary haemodynamics and stent placement. The accurate measurement of catheter trackability forces within physiological relevant test systems is required for optimum catheter design. The effects of cardiac motion on coronary flowrates, pressure drops, and stent delivery has not been previously experimentally assessed. A cardiac simulator was designed and manufactured which replicates physiological coronary flowrates and cardiac motion within a patient-specific geometry. A motorized delivery system delivered a commercially available coronary stent system and monitored the trackability forces along three phantom patient-specific thin walled compliant coronary vessels supported by a dynamic cardiac phantom model. Pressure drop variation is more sensitive to cardiac motion than outlet flowrates. Maximum pressure drops varied from 7 to 49 mmHg for a stenosis % area reduction of 56 to 90%. There was a strong positive linear correlation of cumulative trackability force with the cumulative curvature. The maximum trackability forces and curvature ranged from 0.24 to 0.87 N and 0.06 to 0.22 mm(-1) respectively for all three vessels. There were maximum and average percentage differences in trackability forces of (23-49%) and (1.9-5.2%) respectively when comparing a static pressure case with the inclusion of pulsatile flow and cardiac motion. Cardiac motion with pulsatile flow significantly altered (p value <0.001) the trackability forces along the delivery pathways with high local percentage variations and pressure drop measurements.

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“…A further limitation that influences the results is that inflow and outflow rates and also outlet pressures are not patientspecific. In order to exert more accurate boundary conditions, magnetic resonance imaging (to obtain inflow rates [15]) and lumped parameter models (to obtain outflow boundary conditions [22,27,47]) should be applied. According to various studies, in addition to WSS, its spatial and temporal gradients influence the performance of the endothelium layer [13,23,32].…”

Section: Limitations Of the Researchmentioning

confidence: 99%

Image-based computational simulation of sub-endothelial LDL accumulation in a human right coronary artery

Nouri

Jalali

Karimi

et al. 2015

Computers in Biology and Medicine

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

Cited by 60 publications

References 40 publications

Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states

Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states

The Effects That Cardiac Motion has on Coronary Hemodynamics and Catheter Trackability Forces for the Treatment of Coronary Artery Disease: An In Vitro Assessment

Image-based computational simulation of sub-endothelial LDL accumulation in a human right coronary artery

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