**Acknowledgement**

374 Practical Applications in Biomedical Engineering

ventricle.

scaling in mice and humans.

Christakis Constantinides

*University of Cyprus, Nicosia, Cyprus*

*Laboratory of Physiology and Biomedical Imaging (LBI),* 

*Department of Mechanical and Manufacturing Engineering, School of Engineering,* 

**Author details** 

can identify modal components of shape variability and disseminate components of global mechanical motion. Such atlases can be population-based instead of single-subject based and can serve as a powerful reference tool for morphological and functional inter-strain mouse studies, complementary to current ongoing efforts for image-based phenotyping that target the cardiovascular system. Based on constructed morphometric maps and atlases using principal component analysis in C57BL/6J, it is found that in probabilistic atlases, a gradient of probability exists for both strains in longitudinal locations from base to apex. Based on the statistical atlases, differences in size (49.8%), apical direction (15.6%), basal ventricular blood pool size (13.2%), and papillary muscle shape and position (17.2%) account for the most significant modes of shape variability for the left ventricle of the C57BL/6J mice. Correspondingly, for DBA mice, differences in left ventricular size and direction (67.4%), basal size (15.7%), and position of papillary muscles (16.8%) account for significant variability. These data reason in favor of existing variability in the apical location in both strains, a direct consequence of the heart's effort to re-establish the position of the apex in a consistent manner at end-diastole. Additionally, higher variability exists in DBA mice in the location of the papillary muscles, as well as in the epicardial areas of the left

On the forefront of direct, high-field acquisitions using RF technologies with mouse cardiac MRI, the commercially available birdcage outperforms cylindrical spiral multi-turn surface coils in relative signal-to-ratio (SNR) by a factor of 3–5 times as assessed by experimental measurements, simulations, and experiments in free space, and under phantom and animal loading conditions. Nevertheless, quantitative comparison of the performance of the two spiral coil geometries in anterior, lateral, inferior, and septal regions of the murine heart yield maximum mean percentage rSNR increases to the order of 27–167% post-mortem (cylindrical compared to flat coil), values that are by far higher than previous designs of

Such hardware improvements, in association with fast radial pulse sequence acquisitions, may also lead to quantification of global and regional functional parameters in various mouse strains. While morphological differences appear only to relate to increased papillary muscle variability in the DBA/2J mice, nevertheless interstrain cardiac hemodynamics, based on dynamic cardiac MRI acquisitions, do not exhibit significant differences for neither the LV nor RV in C57BL/6J or DBA/2J mice. Comparative to previous reports of global functional indices [Bucholz 2010], similar mouse and human results were also observed. The work supports the validity of the hypothesis of functional

surface coils and comparable to receiver phased array performance.

I would like to thank Professors G. A. Johnson, G. Truskey, L. Hedlund, and Dr. E. Bucholz, Mr. G. Cofer, and Mr. J. Cook at Duke University, Drs. R. Balaban and A. Koretsky, and Mr. D. Despres and Dr. M. Lizak at the National Institutes of Health, Prof. D. Rueckert at Imperial College, London, Professor BA Janssen at Maastricht Cardiovascular Institute, and my fellows and students Dr. D. Perperidis, Mr. N. Aristocleous, Mr. R. Mean, Mr. S. Gkagkarelis, and Mr. S. Angeli at the University of Cyprus. I am indebted to the help and support from Remcom Inc. I am also grateful for the availability of the Image Registration Toolkit used under License from IXICO Ltd and to Dr. E. Treiber from Bruker Biospin for the provision of the cardiac MR images.

I would also like to acknowledge grant support from the Research Promotion Foundation (RPF) under grants RPF/TEXNOLOGY/MHXAN/0609(BE)/05, RPF/STOXOS/0302/02, and RPF/PROSVASI/0302/01.
