The impact of shape uncertainty on aortic‐valve pressure‐drop computations. (23rd August 2021)

• Record Type: Journal Article
• Authors: Hoeijmakers, M. J. M. M.; Huberts, W.; Rutten, M. C. M.; van de Vosse, F. N.
• Is Part Of: International journal for numerical methods in biomedical engineering. Volume 37:Number 10(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-23
• Subjects: aortic valve stenosis -- computational fluid dynamics -- meta‐modeling -- sensitivity analysis -- statistical shape modeling -- uncertainty quantification; Biomedical engineering -- Periodicals; Imaging systems in medicine -- Periodicals; Numerical analysis -- Periodicals; Engineering mathematics -- Periodicals; 610.28
• DOI: 10.1002/cnm.3518
• Languages: English
• ISSNs: 2040-7939

Abstract

Abstract: Patient‐specific image‐based computational fluid dynamics (CFD) is widely adopted in the cardiovascular research community to study hemodynamics, and will become increasingly important for personalized medicine. However, segmentation of the flow domain is not exact and geometric uncertainty can be expected which propagates through the computational model, leading to uncertainty in model output. Seventy‐four aortic‐valves were segmented from computed tomography images at peak systole. Statistical shape modeling was used to obtain an approximate parameterization of the original segmentations. This parameterization was used to train a meta‐model that related the first five shape mode coefficients and flowrate to the CFD‐computed transvalvular pressure‐drop. Consequently, shape uncertainty in the order of 0.5 and 1.0 mm was emulated by introducing uncertainty in the shape mode coefficients. A global variance‐based sensitivity analysis was performed to quantify output uncertainty and to determine relative importance of the shape modes. The first shape mode captured the opening/closing behavior of the valve and uncertainty in this mode coefficient accounted for more than 90% of the output variance. However, sensitivity to shape uncertainty is patient‐specific, and the relative importance of the fourth shape mode coefficient tended to increase with increases in valvular area. These results show that geometric uncertainty in the order of image voxel size may lead to substantial uncertainty in CFD‐computed transvalvular pressure‐drops. Moreover, this illustrates that it is essential to assess the impact of geometric uncertainty on model output, and that this should be thoroughly quantified for applications that wish to use image‐based CFD models. Abstract : Patient‐specific, complex, 3D computational fluid dynamics (CFD) simulations have become common practice in the field of cardiovascular research. Although such simulations can yield insight from a research perspective, the effect of shape uncertainty is generally not considered. In this work we quantified how shape uncertainty of aortic valve segmentations may affect uncertainty in CFD‐computed transvalvular pressure‐drops. We show that shape uncertainty in the order of image resolution may introduce substantial uncertainty in simulation results and should thus be thoroughly quantified.