Flow Diverter CFD Challenge 2016

This site is created and maintained by Kenichi Kono
Last update on September 12, 2016

Announcement of the FD CFD Challenge 2016

The pdf file of this page for print is available here.
The pdf file of detail instructions is available.

Link to the prvious CFD Challenge 2015

September 12, 2016

(A) Summary of the Challenge
1.      The gInternational Flow Diverter CFD Challenge 2016h has been launched.

2.      Flow diverter (FD) stents are used to treat intracranial aneurysms. However, it is not easy for clinicians to predict occlusion/thrombosis of aneurysms after FD placements.

3.      In this challenge, participants will be asked to predict occlusion/thrombosis for three aneurysms that were in fact treated by FD. STL files will be provided.

4.      All participants will be asked to perform CFD simulations of aneurysms before FD placement. However, CFD simulations of aneurysms after FD placement are not mandatory. This requirement will reduce the burden of participants because virtual deployment of FD is technically demanding.

5.      The deadline of data submission is October 31st.

6.      The results will be announced and discussed at the ICS (Interdisciplinary Cerebrovascular Symposium) at Kobe, Japan in November 26-27, 2016, organized by Prof. Sakai.

7.      If the results are interesting, we will consider submission of publications. However, at this point, all that we can promise to participants is that we share results with participants.

8.      This challenge is voluntarily organized by Dr. Kono as chief director of this challenge, Dr. Shojima, Prof. Ohta, and Prof. Sakai, with no conflict of interests. The challenge does not belong to any organizations.

(B) Details of the Challenge
Aneurysm Computational Fluid Dynamics (CFD) Challenge is an international event that assesses the accuracy and agreement of CFD predictions in intracranial flows done by multiple engineers. CFD has gained much interest over the past years and is arguably a useful tool for future clinical use. However, skepticism remains for good reason in parts owing to the many assumptions and variability of modelling choices. To investigate the accuracy of CFD, Drs. Steinman and Loth launched the gAneurysm CFD Challenge 2012h, and concluded that pressure drop due to stenosis was reasonably well predicted among the vast majority of the participants1. Dr. Janiga followed up in 2013 and assessed whether CFD modellers could predict the ruptured aneurysm and rupture point of two cases2, 3. Drs. Kono and Valen-Sendstad launched the Aneurysm CFD Challenge 2015 to address variabilities of segmentations and prediction of rupture status between CFD groups and clinicians (manuscript under preparation). Although the organizers tried to address clinically relevant issues in these challenges, not all of the results may be directly helpful in clinical settings. Improvement in the design of the challenge so that the results have a direct clinical application has been an issue.

We are therefore happy to announce the launch of the International Flow Diverter CFD Challenge 2016, which asks whether occlusion/thrombosis could be predicted by CFD. Flow diverter (FD) stents are used for treatments of intracranial aneurysms. It is not easy for clinicians to predict thrombosis and delayed rupture after FD placement. There are two questions we wish to answer in the current challenge: (i) could CFD predict thrombosis? (ii) would CFD results change cliniciansf prediction?

In this challenge, we will provide participants STL data of three cerebral aneurysms that were treated by FD, and ask them to predict whether each aneurysm will be occluded/thrombosed or not after FD placement. The deadline of the data submission is October 31, 2016.

We plan to disclose the results at a workshop at the ICS (Interdisciplinary Cerebrovascular Symposium), at Kobe in Japan, in November 26-27, 2016.

If you wish to participate in this challenge, please e-mail us at vyr01450@gmail.com (Kenichi Kono). I (Kenichi Kono) will provide you the instruction and STL data via e-mail (total ~6MB).

We look forward to your contribution in this challenge and sharing our experience for future clinical use of CFD!

Best regards,

Kenichi Kono1 (chief director of this challenge)
Masaaki Shojima2, Makoto Ota3

Nobuyuki Sakai4 (organizer of the ICS 2016, and providing clinical data of this challenge)
Assistant Professor at Department of Neurosurgery, Showa Univ. Fujigaoka Hospital, 1-30, Aoba-ku, Yokohama, Kanagawa, 227-8501, Japan
(2)   Associate Professor of Biomedical Flow Dynamics Lab. Creative Flow Research Div. Institute of Fluid Science, Tohoku University. 2-1-1 Katahira Aoba-ku Sendai Miyagi, 980-8577, Japan
(3)   Lecturer at Department of Neurosurgery, the University of Tokyo Hospital 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
(4)   Director, Department of Neurosurgery, KCGH Comprehensive Stroke Center Kobe City Medical Center General Hospital 2-1-1 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan

Contact e-mail address: vvyr01450@gmail.com (Kenichi Kono)

Web site address of the challenge: www.cfdchallenge2015.com
(Because Kenichi Kono has continued to use the paid web site address of the CFD challenge 2015, the address of the CFD challenge 2016 is the same as the previous one.)

Disclosure: We declare no conflict of interests on this challenge.


1.          Steinman DA, Hoi Y, Fahy P, Morris L, Walsh MT, et al.: Variability of computational fluid dynamics solutions for pressure and flow in a giant aneurysm: the ASME 2012 Summer Bioengineering Conference CFD Challenge. J Biomech Eng. 2013;135(2):021016. doi: 10.1115/1.4023382.

2.          Janiga G, Berg P, Sugiyama S, Kono K, Steinman DA: The Computational Fluid Dynamics Rupture Challenge 2013?Phase I: prediction of rupture status in intracranial aneurysms. AJNR Am J Neuroradiol. 2015;36(3):530-6. doi: 10.3174/ajnr.A4157.

3.          Berg P, Roloff C, Beuing O, Voss S, Sugiyama S, et al.: The Computational Fluid Dynamics Rupture Challenge 2013--Phase II: Variability of Hemodynamic Simulations in Two Intracranial Aneurysms. J Biomech Eng. 2015; 137(12):121008. doi: 10.1115/1.4031794.