A novel methodology for personalized simulations of ventricular hemodynamics from noninvasive imaging data.
Current state-of-the-art imaging techniques can provide quantitative information to characterize ventricular function within the limits of the spatiotemporal resolution achievable in a realistic acquisition time. These imaging data can be used to personalize computer models, which in turn can help treatment planning by quantifying biomarkers that cannot be directly imaged, such as flow energy, shear stress and pressure gradients. To date, computer models have typically relied on invasive pressure measurements to be made patient-specific. When these data are not available, the scope and validity of the models are limited. To address this problem, we propose a new methodology for modeling patient-specific hemodynamics based exclusively on noninvasive velocity and anatomical data from 3D+t echocardiography or Magnetic Resonance Imaging (MRI). Numerical simulations of the cardiac cycle are driven by the image-derived velocities prescribed at the model boundaries using a penalty method that recovers a physical solution by minimizing the energy imparted to the system. This numerical approach circumvents the mathematical challenges due to the poor conditioning that arises from the imposition of boundary conditions on velocity only. We demonstrate that through this technique we are able to reconstruct given flow fields using Dirichlet only conditions. We also perform a sensitivity analysis to investigate the accuracy of this approach for different images with varying spatiotemporal resolution. Finally, we examine the influence of noise on the computed result, showing robustness to unbiased noise with an average error in the simulated velocity approximately 7% for a typical voxel size of 2mm(3) and temporal resolution of 30ms. The methodology is eventually applied to a patient case to highlight the potential for a direct clinical translation.
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK. Electronic address: adelaide.de_vecchi@kcl.ac.uk.
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de Vecchi
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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Gomez
Evelina London Children's Hospital, London SE1 7EH, UK.
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Pushparajah
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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Schaeffter
Evelina London Children's Hospital, London SE1 7EH, UK.
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Simpson
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK; Evelina London Children's Hospital, London SE1 7EH, UK.
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Razavi
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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Penney
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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Smith
Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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Nordsletten
D001783:Blood Flow Velocity; D003198:Computer Simulation; D019560:Echocardiography, Three-Dimensional; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008955:Models, Cardiovascular; D062211:Spatio-Temporal Analysis; D016276:Ventricular Function
3D blood flow reconstruction; B-Mode and Color Doppler echocardiography; Cardiac hemodynamics; PC-MRI; Personalized computational modeling