Real-World Variability in the Prediction of Intracranial Aneurysm Wall Shear Stress: The 2015 International Aneurysm CFD Challenge

Purpose—Image-based computational fluid dynamics (CFD) is widely used to predict intracranial aneurysm wall shear stress (WSS), particularly with the goal of improving rupture risk assessment. Nevertheless, concern has been expressed over the variability of predicted WSS and inconsistent associations with rupture. Previous challenges, and studies from individual groups, have focused on individual aspects of the image-based CFD pipeline. The aim of this Challenge was to quantify the total variability of the whole pipeline. Methods—3D rotational angiography image volumes of five middle cerebral artery aneurysms were provided to participants, who were free to choose their segmentation methods boundary conditions, and CFD solver and settings. Participants were asked to fill out a questionnaire about their solution strategies and experience with aneurysm CFD, and provide surface distributions of WSS magnitude, from which we objectively derived a variety of hemodynamic parameters. Results—A total of 28 datasets were submitted, from 26 teams with varying levels of self-assessed experience. Wide variability of segmentations, CFD model extents, and inflow rates resulted in interquartile ranges of sac average WSS up to 56%, which reduced to < 30% after normalizing by parent artery WSS. Sac-maximum WSS and low shear area were more variable, while rank-ordering of cases by low or high shear showed only modest consensus among teams. Experience was not a significant predictor of variability. Conclusions—Wide variability exists in the prediction of intracranial aneurysm WSS. While segmentation and CFD solver techniques may be difficult to standardize across groups, our findings suggest that some of the variability in image-based CFD could be reduced by establishing guidelines for model extents, inflow rates, and blood properties, and by encouraging the reporting of normalized hemodynamic parameters.Fil: Valen-Sendstad, Kristian. Simula Research Laboratory and Center for Cardiological Innovation; NoruegaFil: Bergersen, Aslak W.. University of Oslo; NoruegaFil: Shimogonya, Yuji. Nihon University; JapónFil: Goubergrits, Leonid. Charite´ – Universita¨tsmedizin Berlin; AlemaniaFil: Bruening, Jan. Charité – Universitätsmedizin Berlin; AlemaniaFil: Pallares, Jordi. Universitat Rovira I Virgili; EspañaFil: Cito, Salvatore. Universitat Rovira I Virgili; EspañaFil: Piskin, Senol. University Of Texas At San Antonio.; Estados UnidosFil: Pekkan, Kerem. Koc University; TurquíaFil: Geers, Arjan J.. Universitat Pompeu Fabra; EspañaFil: Larrabide, Ignacio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rapaka, Saikiran. Siemens Medical Solutions USA Inc; Estados UnidosFil: Mihalef, Viorel. Siemens Medical Solutions USA Inc; Estados UnidosFil: Fu, Wenyu. Beijing Union University; ChinaFil: Qiao, Aike. Beijing University of Technology; ChinaFil: Jain, Kartik. Simula Research Laboratory and Center for Cardiological Innovation; Noruega. University of Siegen; Alemania. University of Zürich; SuizaFil: Roller, Sabine. University of Siegen; AlemaniaFil: Mardal, Kent-Andre. Simula Research Laboratory and Center for Cardiological Innovation; Noruega. University of Oslo; NoruegaFil: Kamakoti, Ramji. Dassault Systemes; FranciaFil: Spirka, Thomas. Simpleware Software Solutions; Reino UnidoFil: Ashton, Neil. University of Oxford; Reino UnidoFil: Revell, Alistair. University of Manchester; Reino UnidoFil: Aristokleous, Nicolas. University of Limerick; IrlandaFil: Houston, J. Graeme. University of Dundee; Reino UnidoFil: Tsuji, Masanori. Mie Chuo Medical Center; JapónFil: Ishida, Fujimaro. Mie Chuo Medical Center; JapónFil: Menon, Prahlad G.. University of Pittsburgh; Estados UnidosFil: Browne, Leonard D.. University of Limerick; IrlandaFil: Broderick, Stephen. University of Limerick; IrlandaFil: Shojima, Masaaki. University of Tokyo; JapónFil: Koizumi, Satoshi. University of Tokyo; JapónFil: Barbour, Michael. University of Washington; Estados UnidosFil: Aliseda, Alberto. University of Washington; Estados UnidosFil: Morales, Hernán G.. Medisys - Philips Research Paris; FranciaFil: Lefèvre, Thierry. Medisys - Philips Research Paris; FranciaFil: Hodis, Simona. Texas A&M University - Kingsville; Estados UnidosFil: Al-Smadi, Yahia M.. Jordan University of Science and Technology; JordaniaFil: Tran, Justin S.. Stanford University; Estados UnidosFil: Marsden, Alison L.. Stanford University; Estados UnidosFil: Vaippummadhom, Sreeja. EinNel Technlogies; IndiaFil: Einstein, G. Albert. EinNel Technlogies; IndiaFil: Brown, Alistair G.. Siemens PLM Software; Estados UnidosFil: Debus, Kristian. Siemens PLM Software; Estados UnidosFil: Niizuma, Kuniyasu. Tohoku University; JapónFil: Rashad, Sherif. Tohoku University; JapónFil: Sugiyama, Shin-ichiro. Kohnan Hospital; JapónFil: Owais Khan, M.. University of Toronto; CanadáFil: Updegrove, Adam R.. University of California at Berkeley; Estados UnidosFil: Shadden, Shawn C.. University of California at Berkeley; Estados UnidosFil: Cornelissen, Bart M. W.. Academic Medical Center; Países BajosFil: Majoie, Charles B. L. M.. Academic Medical Center; Países BajosFil: Berg, Philipp. University of Magdeburg; AlemaniaFil: Saalfield, Sylvia. University of Magdeburg; AlemaniaFil: Kono, Kenichi. Wakayama Rosai Hospital; JapónFil: Steinman, David A.. University of Toronto; Canad