Lee Kyung Eun, Lee Seo Ho, Shin Eun-Seok, Shim Eun Bo
Department of Mechanical and Biomedical Engineering, Kangwon National University, Kangwondaehak-gil, Chuncheon-si, Kangwon-do, 200-701, Republic of Korea.
Department of Cardiology, University of Ulsan College of Medicine, Ulsan, South Korea.
Biomed Eng Online. 2017 Jun 26;16(1):83. doi: 10.1186/s12938-017-0365-4.
Hemodynamic simulation for quantifying fractional flow reserve (FFR) is often performed in a patient-specific geometry of coronary arteries reconstructed from the images from various imaging modalities. Because optical coherence tomography (OCT) images can provide more precise vascular lumen geometry, regardless of stenotic severity, hemodynamic simulation based on OCT images may be effective. The aim of this study is to perform OCT-FFR simulations by coupling a 3D CFD model from geometrically correct OCT images with a LPM based on vessel lengths extracted from CAG data with clinical validations for the present method.
To simulate coronary hemodynamics, we developed a fast and accurate method that combined a computational fluid dynamics (CFD) model of an OCT-based region of interest (ROI) with a lumped parameter model (LPM) of the coronary microvasculature and veins. Here, the LPM was based on vessel lengths extracted from coronary X-ray angiography (CAG) images. Based on a vessel length-based approach, we describe a theoretical formulation for the total resistance of the LPM from a three-dimensional (3D) CFD model of the ROI.
To show the utility of this method, we present calculated examples of FFR from OCT images. To validate the OCT-based FFR calculation (OCT-FFR) clinically, we compared the computed OCT-FFR values for 17 vessels of 13 patients with clinically measured FFR (M-FFR) values.
A novel formulation for the total resistance of LPM is introduced to accurately simulate a 3D CFD model of the ROI. The simulated FFR values compared well with clinically measured ones, showing the accuracy of the method. Moreover, the present method is fast in terms of computational time, enabling clinicians to provide solutions handled within the hospital.
用于量化血流储备分数（FFR）的血流动力学模拟通常在根据各种成像模态的图像重建的患者特异性冠状动脉几何结构中进行。由于光学相干断层扫描（OCT）图像可以提供更精确的血管腔几何结构，而与狭窄严重程度无关，基于OCT图像的血流动力学模拟可能是有效的。本研究的目的是通过将基于几何正确的OCT图像的三维计算流体动力学（CFD）模型与基于从冠状动脉造影（CAG）数据中提取的血管长度并经过临床验证的集总参数模型（LPM）相结合，来进行OCT-FFR模拟。
为了模拟冠状动脉血流动力学，我们开发了一种快速准确的方法，该方法将基于OCT的感兴趣区域（ROI）的计算流体动力学（CFD）模型与冠状动脉微血管和静脉的集总参数模型（LPM）相结合。在此，LPM基于从冠状动脉X射线血管造影（CAG）图像中提取的血管长度。基于基于血管长度的方法，我们从ROI的三维（3D）CFD模型描述了LPM总阻力的理论公式。
为了展示该方法的实用性，我们给出了从OCT图像计算FFR的示例。为了在临床上验证基于OCT的FFR计算（OCT-FFR），我们将13例患者的17条血管的计算得到的OCT-FFR值与临床测量的FFR（M-FFR）值进行了比较。
引入了一种新的LPM总阻力公式，以准确模拟ROI的3D CFD模型。模拟的FFR值与临床测量值比较良好，表明了该方法的准确性。此外，本方法在计算时间方面很快，使临床医生能够在医院内提供处理方案。
