Electronic Posters: Cardiovascular

Wednesday 13:30-15:30 Computer 39

13:30 3736. Cardiac Diffusion MR Microscopy of Rabbit Heart

Min Sig Hwang¹, Katja Odening², Ohad Ziv², Bum-Rak Choi², Gideon Koren², John R. Forder<sup>1

1</sup>McKnight Brain Institute, University of Florida, Gainesville, FL, United States; ²Cardiovascular Research Center, Rhode Island Hospital Alert Medical School of Brown University, Providence, RI, United States

In this study, we explored the potential of microscopic high angular resolution diffusion imaging (MHARDI) achieving a cellular level spatial resolution as a non-invasive tool that is sensitive to subtle changes in the heterogeneous microstructure and arrangement of the cardiac tissues. Diffusion tensor images and tensor invariants acquired with two diffusion sensitizing factors were investigated. Our results suggest that MHARDI with an optimized b-value and resolution may be a powerful tool for non-invasive monitoring of electro-mechanical property and its well-coordinated function.

14:00 3737. Automated Segmentation of Left Ventricle in Cine Cardiac MR Images: Experience from a Large Study

YingLi Lu¹, Perry Radau¹, Kim A. Connelly^1,2, Alexander Dick³, Graham A. Wright<sup>1

1</sup>Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; ²Cardiology, St Michael's Hospital, Toronto, ON, Canada; ³Cardiology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Purpose of this study is to develop a fully automatic left ventricle segmentation method from cine short-axis MR images and evaluate it on a large data set of 147 subjects grouped by pathology. Advantages of this method include that it: 1) does not require manually drawn contours; 2) provides not only endocardial and epicardial contours, but also papillary muscles and trabeculations¡¯ contours; 3) introduces a roundness measure that automatically locates the left ventricle; 4) simplifies the epicardial contour segmentation by mapping the pixels from Cartesian to approximately polar coordinates.

14:30 3738. Three-Dimensional Myocardial Tissue Tracking and Strain Calculation for Volumetric Cine DENSE Data

Xiaodong Zhong^1,2, Bruce S. Spottiswoode³, Craig H. Meyer^2,4, Frederick H. Epstein<sup>2,4

1</sup>MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, United States; ²Biomedical Engineering, University of Virginia, Charlottesville, VA, United States; ³MRC/UCT Medical Imaging Research Unit, University of Cape Town, Cape Town, Western Cape, South Africa; ⁴Radiology, University of Virginia, Charlottesville, VA, United States

This abstract introduces novel automatic algorithms for myocardial tissue tracking and strain calculation for three-dimensional (3D) cine DENSE data. Specifically, scattered data interpolation using radial basis functions (RBF) was developed for Lagrangian tissue tracking. Also, a finite-strain based algorithm was developed to calculate the deformation gradient tensor and the Lagrangian strain tensor. The algorithms were performed on 3D cine DENSE data from five healthy volunteers to obtain 3D Lagrangian displacement and strain fields. The 3D myocardial mechanics, including normal strains, twist and torsion, were consistent with previous results from myocardial tagging in healthy volunteers.

15:00 3739. Towards Non-Invasive Automatic Detection of Cardiac Pathology by Strain and Rotation Analysis

Hans C. van Assen¹, Luc M.J. Florack², Frank F.J. Simonis¹, Jos J.M. Westenberg³, Gustav J. Strijkers¹, Bart M. ter Haar Romeny<sup>1

1</sup>Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Noord Brabant, Netherlands; ²Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Noord Brabant, Netherlands; ³Radiology, Leiden University Medical Center, Leiden, Netherlands

This paper describes a novel image processing method for automated detection of cardiac pathology. It entails tagging analysis by means of an optical flow approach. Tag fading is overcome by exploitation of tag phase - retrieved by Gabor filtering - instead of tag brightness.

The method yields both the motion field and its first order derivative structure, necessary to calculate strain and rotation. Calculation of these derived parameters thus becomes straightforward. High-resolution in-slice cardiac strain and rotation are presented for four volunteers and a patient, and clearly show deviations for a patient with known small infarctions and wall motion abnormalities.