Electronic Posters: Cardiovascular

Thursday 13:30-15:30 Computer 37

13:30 3708. Vortex Core Detection and Visualization Using 4D Flow-Sensitive MRI

Aurelien F. Stalder^1,2, Alex Frydrychowicz³, Andreas Harloff⁴, Qi Yang¹, Jelena Bock², Juergen Hennig², Kuncheng Cheng Li¹, Michael Markl<sup>2

1</sup>Dept. of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China; ²Dept. of Diagnostic Radiology - Medical Physics, University Hospital, Freiburg, Germany; ³Dept. of Radiology, University of Wisconsin-Madison, Freiburg, Germany; ⁴Dept. of Neurology, University Hospital, Freiburg, Germany

4D flow-sensitive MRI was used with 3D flow visualization techniques and a vortex core detection algorithm to detect patterns of swirling flow in the aorta, the carotid arteries as well as intracranial arteries in volunteers and patients. While aneurysms presented strong vortex cores, weaker vortex cores were identified in the healthy aortic arch and the healthy internal carotid artery. The vortex core detection provided a fast and simple way to detect locations of swirling flow within 4D flow-sensitive MRI datasets.

14:00 3709. Age Relation of Aortic Wall Compliance in Marfan Syndrome: Evaluation with Velocity-Encoded MRI

Jos J.M. Westenberg¹, Arthur J.H.A. Scholte², Zuzana Vaskova³, Rob J. van der Geest¹, Maarten Groenink⁴, Gerda Labadie¹, Pieter J. van den Boogaard¹, Teodora R. Radonic⁴, Yvonne Hilhorst-Hofstee⁵, Lucia J.M. Kroft¹, Albert de Roos¹, Johan H.C. Reiber<sup>1

1</sup>Radiology, Leiden University Medical Center, Leiden, Zuid-Holland, Netherlands; ²Cardiology, Leiden University Medical Center; ³Radiology, St. Anne's University Hospital, Brno, Czech Republic; ⁴Cardiology, Academic Medical Center, Amsterdam, Netherlands; ⁵Clinical Genetics, Leiden University Medical Center

The purpose of this study is to describe age relation of aortic wall compliance, expressed in Pulse Wave Velocity, Distensibility and Stiffness Index, with Velocity-Encoded MRI in Marfan syndrome. Twenty-five patients with Marfan syndrome and twenty-five age-matched healthy volunteers are examined and measures for compliance are compared. In Marfan, the Pulse Wave Velocity is generally increased in the aortic arch, distal aorta and total aorta. Distensibility is decreased. Only the Stiffness Index is not statistically significantly different. Age-related change in compliance is best expressed in increasing Pulse Wave Velocity.

14:30 3710. Aortic Compliance Evaluation: Comparison of Time Delay Algorithms

Yi Wang¹, Edwin Estrada¹, Jianping Zhang<sup>2

1</sup>Research and Education, St. Francis Hospital, Roslyn, NY, United States; ²Applied Mathematics and Statistics, State University of New York, Stony Brook, NY, United States

Aortic pulse wave velocity (PWV), a measurement of the flow pulse traveling along aorta as a surrogate for aortic compliance, can be assessed using a single breath-hold through-plane phase contrast imaging technique. Accurate determination of the time delay between flows in ascending and descending aorta is critical in PWV assessment. Various approaches have been studied, including measuring the intervals between flow onset points, between maximal flow points, and between parallel upslopes after least squares fittings. We compared five automated approaches for time delay detection and evaluated their effects on aortic compliance and their relationship to age in 186 normal volunteers.

15:00 3711. Improved Simulation of 3D Flow Characteristics in a Pressure Controlled in Vitro Model System

Ramona Lorenz¹, Christoph Benk², Jelena Bock¹, Jan Korvink³, Michael Markl<sup>1

1</sup>Dept. of Diagnostic Radiology, University Hospital, Freiburg, Germany; ²Dept. of Cardiovascular Surgery, University Hospital, Freiburg, Germany; ³Dept. of Microsystems Technology, IMTEK, Freiburg, Germany

In-vitro model systems provide a useful tool for the systematic evaluation of hemodynamic changes associated with geometric vascular modifications. However, realistic in-vivo in-flow and boundary conditions are necessary for accurate flow simulations. This paper presents a novel approach for an in-vitro model setup which includes a pulsatile pump chamber in combination with flexible and monitored pressure control using an adjustable mock loop to simulate physiological pre- and after load conditions. In contrast to measurements without pressure control an improved generation of qualitative and quantitative flow characteristics compared to in-vivo flow conditions could be achieved.