Electronic Posters: Cardiovascular

Tuesday 13:30-15:30 Computer 29

13:30 3572. Measuring the Myocardial Angular Information Through the Radial Tagging

Abbas Nasiraei Moghaddam¹, J. Paul Finn<sup>1

1</sup>Radiology, UCLA, Los Angeles, CA, United States

The angular information of the left ventricle, including the twist, shear and circumferential strain, are of fundamental importance to quantify the regional or global myocardial function . Radial tagging facilitates the measurement of this information . In particular when the density of radial taglines are sufficiently high, it was theoretically shown that the circumferential strain can be measured directly from the K-Space data . In this study we present the application of the circumferential encoding method on the actual cardiac MR images which are tightly tagged in the radial direction using our newly developed sequence. We also show the transmural differences in rotational motion of the left ventricle using these images.

14:00 3573. High Spatio-Temporal Fidelity Nongated Cardiac MRI with a 3 Second Patient-Adaptive Scan

Behzad Sharif¹, John Andrew Derbyshire², Yoram Bresler<sup>1

1</sup>Electrical and Computer Engineering, Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, United States; ²Translational Medicine Branch, NHLBI, National Institutes of Health, Bethesda, MD, United States

Patient-Adaptive Reconstruction and Acquisition Dynamic Imaging with Sensitivity Encoding (PARADISE), is a highly accelerated non-gated dynamic imaging scheme that enables artifact-free imaging while providing performance guarantees on achievable SNR and spatio-temporal resolution. In addition to parallel imaging, the method gains acceleration from a sparse physiologically-driven spectral support model (in x-y-f space); hence it is doubly accelerated and adaptive. In this work, we present a modification of the PARADISE method that enables high spatio-temporal fidelity nongated 2D cine imaging with short scan times (3 seconds per slice). The method uses prospective adjustments to the x-y-f-space support to accommodate short scan times.

14:30 3574. Prolonged Right Ventricular Post-Systolic Isovolumic Period in Pulmonary Arterial Hypertension: A Reflection of Diastolic Dysfunction?

Gert Jan Mauritz¹, J. Tim Marcus¹, Nico Westerhof¹, Pieter E. Postmus¹, Anton Vonk Noordegraaf<sup>1

1</sup>VU University Medical Center, Amsterdam, Netherlands

In PAH a prolonged time interval between pulmonary valve closure and tricuspid valve opening is observed. This period is assumed to measure a prolonged right ventricular (RV) relaxation, and to reflect diastolic dysfunction. In this study it was shown that this period is the consequence of a prolonged contraction of the RV free wall which continues after pulmonary valve closure causing a post-systolic contraction. In contrast the RV isovolumic relaxation period is not increased. Therefore, in clinical practice the isovolumic period between pulmonary valve closure and tricuspid valve opening is not a real measure of diastolic dysfunction in PAH patients.

15:00 3575. The Impact of Myosin Heavy Chain Isoforms on Contractile Behavior of the Heart

Yong Chen^1,2, Julian E. Stelzer³, Xin Yu<sup>1,2

1</sup>Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; ²Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, United States; ³Department of Physiology and Biophysics, Case Western Reserve University

In the present study, we evaluated the impact of shift in myosin heavy chain (MHC) isoforms on in vivo ventricular function in thyroid-deficient rats. Our results show that increased expression of β-MHC not only reduced the magnitude of peak systolic strain and torsion, but also altered the timing when the myocardium reached peak systole, leading to deteriorated cardiac function in hypothyroid rat hearts.