Simulating photon scattering effects in structurally detailed ventricular models using a Monte Carlo approach.
Simulating photon scattering effects in structurally detailed ventricular models using a Monte Carlo approach.
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DOI：
10.3389/fphys.2014.00338
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发表时间：
2014
影响因子：
4
通讯作者：
Plank G
中科院分区：
文献类型：
--
作者：
Bishop MJ;Plank G
已知在心脏内的电激活的光学成像期间的光散射显著地扭曲光学记录的动作电位（AP）上行，以及影响心室组织对强电击的测量响应的幅度。基于光子扩散方程的建模方法最近已经在量化和帮助理解所产生的失真的起源方面发挥了作用。然而，它们无法忠实地表示非散射介质的区域，例如在实验期间充满灌注液的心肌内的小腔。随机蒙特卡罗（MC）方法允许模拟和跟踪单个光子“包”，因为它们通过具有不同散射特性的组织传播。在这里，我们提出了一种新的应用程序的光子散射模拟的MC方法，适用于第一次在非结构化，四面体，有限元计算心室模型的心脏光学映射信号的模拟。该方法忠实地允许在高度详细的、解剖学上复杂的基于MR的模型上模拟光学信号，包括精细尺度解剖结构和壁内腔的表示。我们发现，光学动作电位上行延长接近大subepicardial血管比远离血管，有时有一个独特的“驼峰”形态。此外，我们发现了一种新的机制，通过这种机制，血管腔周围的光子散射效应与休克期间腔周围强去极化/超极化组织的“虚拟电极”区域相互作用，显著降低了表观光学测量的心外膜极化。因此，我们证明了这种新的光学映射模拟方法的重要性，沿着高度解剖详细的模型，以充分研究电生理现象驱动的精细尺度结构异质性。
Light scattering during optical imaging of electrical activation within the heart is known to significantly distort the optically-recorded action potential (AP) upstroke, as well as affecting the magnitude of the measured response of ventricular tissue to strong electric shocks. Modeling approaches based on the photon diffusion equation have recently been instrumental in quantifying and helping to understand the origin of the resulting distortion. However, they are unable to faithfully represent regions of non-scattering media, such as small cavities within the myocardium which are filled with perfusate during experiments. Stochastic Monte Carlo (MC) approaches allow simulation and tracking of individual photon “packets” as they propagate through tissue with differing scattering properties. Here, we present a novel application of the MC method of photon scattering simulation, applied for the first time to the simulation of cardiac optical mapping signals within unstructured, tetrahedral, finite element computational ventricular models. The method faithfully allows simulation of optical signals over highly-detailed, anatomically-complex MR-based models, including representations of fine-scale anatomy and intramural cavities. We show that optical action potential upstroke is prolonged close to large subepicardial vessels than further away from vessels, at times having a distinct “humped” morphology. Furthermore, we uncover a novel mechanism by which photon scattering effects around vessels cavities interact with “virtual-electrode” regions of strong de-/hyper-polarized tissue surrounding cavities during shocks, significantly reducing the apparent optically-measured epicardial polarization. We therefore demonstrate the importance of this novel optical mapping simulation approach along with highly anatomically-detailed models to fully investigate electrophysiological phenomena driven by fine-scale structural heterogeneity.
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影响因子：
48
作者：
Bub, Gil;Tecza, Matthias;Helmes, Michiel;Lee, Peter;Kohl, Peter
通讯作者：
Kohl, Peter
影响因子：
3.8
作者：
ARRIDGE, SR;SCHWEIGER, M;DELPY, DT
通讯作者：
DELPY, DT
影响因子：
3.4
作者：
Bishop, MJ;Rodriguez, B;Gavaghan, DJ
通讯作者：
Gavaghan, DJ
DOI：
10.1152/ajpheart.2000.279.3.h1055
发表时间：
2000-09-01
影响因子：
4.8
作者：
Efimov, IR;Aguel, F;Trayanova, N
通讯作者：
Trayanova, N
影响因子：
4.6
作者：
Ding, L;Splinter, R;Knisley, SB
通讯作者：
Knisley, SB