Electronic Posters: Cardiovascular

Thursday 13:30-15:30 Computer 31

13:30 3612. The Patho-Physiological Sensitivity of Cardiac MR Elastography: Preliminary Results.

Thomas Elgeti¹, Mark Beling², Dieter Klatt¹, Sebastian Papazoglou¹, Sebastian Hirsch¹, Kerstin Riek¹, Bernd Hamm¹, Jürgen Braun³, Ingolf Sack<sup>1

1</sup>Institut für Radiologie, Charité Universitätsmedizin , Berlin, Germany; ²Klinik und Poliklinik für Kardiologie, Charité Universitätsmedizin , Berlin, Germany; ³Institut für Medizinische Informatik und Biometrie, Charité Universitätsmedizin , Berlin, Germany

MR Elastography (MRE) is capable to directly measure tissue stiffness. This is particularly interesting for cardiac applications, since the cardiac shear modulus changes over the cardiac cycle. It is known, that increasing myocardial stiffness yields decrease of wave amplitudes in MRE. Therefore, left ventricular shear wave amplitudes were measured in 11 healthy volunteers and 11 patients with relaxation abnormalities. It is observed, that shear wave amplitudes are significantly lower in the left ventricle of patients. This result indicates the sensitivity of amplitude-based cardiac MRE to identify increased myocardial stiffness.

14:00 3613. Relationship Between Mitral Velocity and Mitral Flow Time-Profiles During Ventricular Filling

June Cheng-Baron¹, Jessica M. Scott², Ben T. Esch², Mark J. Haykowsky², John V. Tyberg³, Richard B. Thompson<sup>1

1</sup>Biomedical Engineering, University of Alberta, Edmonton, AB, Canada; ²Physical Therapy, University of Alberta, Edmonton, AB, Canada; ³Cardiac Sciences, University of Calgary, Calgary, AB, Canada

It has been shown that blood velocity waveforms measured at the conventional mitral leaflet tips location do not match mitral flow waveforms. In this study we quantify the relationship between velocity profiles at several points along the inflow path and volumetric flow, illustrating the dependence of commonly derived diastolic parameters (E/A ratio, deceleration time) on the measurement approach. Velocity profiles and derived parameters vary significantly over small (1 cm) intervals and are distinct from flow profiles. Velocity-time curves above the conventional leaflet tip location (in the atrium) are less susceptible to measurement error and are most similar to flow curves.

14:30 3614. Cine DENSE and Manganese-Enhanced Cardiac MRI Demonstrate That ENOS Does Not Play a Determining Role in Modulating the Effects of ß-Adrenergic Stimulation

Moriel H. Vandsburger¹, Brent A. French¹, Xiaodong Zhong^1,2, Christopher M. Kramer¹, Frederick H. Epstein<sup>1

1</sup>University of Virginia, Charlottesville, VA, United States; ²MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, United States

Dynamic manganese-enhanced MRI and cine DENSE MRI can be used to probe calcium flux and contractile function in vivo in the mouse heart. Using these methods, we sought to elucidate the role of endothelial nitric oxide synthase (eNOS) in modulating calcium flux and contractile function. Counter to the prevailing opinion, which suggests that eNOS inhibits basal calcium flux, we found that eNOS does not play a role in modulating either calcium flux or contractile function at baseline, during β-adrenergic stimulation, or during muscarinic inhibition of β-adrenergic stimulation.

15:00 3615. Adaptive Method for Black Blood Cardiac Imaging in End-Systolic Rest Improves Visualization of the Right Ventricular Wall

Brice Fernandez^1,2, Julien Oster^2,3, Maelene Lohezic^1,2, Damien Mandry^2,4, Olivier Pietquin, ^2,5, Pierre-André Vuissoz^2,3, Jacques Felblinger<sup>2,3

1</sup>Global Applied Science Lab., GE Healthcare, Nancy, France; ²IADI lab., Nancy-Université, Nancy, France; ³U947, INSERM, Nancy, France; ⁴Departement of Radiology, CHU Nancy, Nancy, France; ⁵IMS Research Group, Supelec, Metz, France

Conventional Double Inversion Recovery Fast Spin Echo (DIR-FSE) sequence provides detailed anatomical information in cardiac MRI. However, the preparation time required to cancel blood signal is too long to acquire DIR-FSE during the end-systolic rest. To overcome this constraint, two methods are described. The first one relies on the assumption that the RR intervals are constant whereas the second method is based on an adaptive RR interval prediction algorithm. These approaches were evaluated on 14 healthy volunteers; results demonstrated the robustness of the adaptive method with a better delineation of the right ventricle wall than with the conventional DIR-FSE.