Technology and Health Care 16 (2008) 119–128 119 IOS Press Comparison of velocity patterns in an AComA aneurysm measured with 2D phase contrast MRI and simulated with CFD Christof Karmonik a,b,* , Richard Klucznik a and Goetz Benndorf a a Department of Radiology, The Methodist Hospital Research Institute, Houston, TX, USA b Weill Medical College of Cornell University, New York, NY, USA Received 19 September 2007 Revised /Accepted 10 December 2007 Abstract. Objective: Computational Fluid Dynamic (CFD) is increasingly being used for modeling hemodynamics in intracra- nial aneurysms. While CFD techniques are well established, need for validation of the results remains. By quantifying features in velocity patterns measured with 2D phase contrast magnetic resonance (pcMRI) in vivo and simulated with CFD, the role of pcMRI for providing reference data for the CFD simulation is explored. Methods: Unsteady CFD simulations were performed with inflow boundary conditions obtained from 2D pcMRI measure- ments of an aneurysm of the anterior communication artery. Intra-aneurysmal velocity profiles were recorded with 2D pcMRI and calculated with CFD. Relative areas of positive and negative velocity were calculated in these profiles for maximum and minimum inflow. Results: Areas of positive and of negative velocity similar in shape were found in the velocity profiles obtained with both methods. Relative difference in size of the relative areas for the whole cardiac cycle ranged from 1%–25% (average 12%). Conclusion: 2D pcMRI is able to record velocity profiles in an aneurysm of the anterior commuting artery in vivo. These velocity profiles can serve as reference data for validation of CFD simulations. Further studies are needed to explore the role of pcMRI in the context of CFD simulations. Keywords: Cerebral aneurysms, hemodynamics, computational fluid dynamics, phase contrast magnetic resonance imaging 1. Introduction The rupture of a cerebral aneurysm is a serious clinical event with poor prognosis leading to a mortality of 45–75% [3,27,43] and cognitive impairment occurs in 46% of the surviving patients [16,34]. While only a small percentage of cerebral aneurysm rupture (8–10/100,000 per year [37,39,42]), risk of treatment complications is in the order of 3–11% [55]. To reduce risk to the patient as well as health care costs, it would therefore be beneficial to identify those aneurysms with the highest risk for rupture. Although size of a cerebral aneurysm has been identified as risk factor for aneurysm rupture [22], there is no consensus of a critical value [44,46,53]. Geometric factors other than size as a possible indicator for aneurysm rupture including neck width, dome-neck ratio, height, ratio of diameter to height, ratio of * Corresponding author: Christof Karmonik, 6565 Fannin MB1-002, Houston, TX 77030, USA. Tel.: +1 713 441 1583; Fax: +1 713 441 4660; E-mail: ckarmonik@tmhs.org. 0928-7329/08/$17.00  2008 – IOS Press and the authors. All rights reserved