Technical notes

Comprehensive Cardiovascular magnetic resonance of myocardial mechanics in mice using three-dimensional cine DENSE

Xiaodong Zhong¹, Lauren B Gibberman², Bruce S Spottiswoode³, Andrew D Gilliam⁴, Craig H Meyer^2,5, Brent A French⁵ and Frederick H Epstein^2,5*

• * Corresponding author: Frederick H Epstein fhe6b@virginia.edu

Author Affiliations

¹ MR R&D Collaborations, Siemens Healthcare, Atlanta, USA

² Radiology Department, University of Virginia, Charlottesville, USA

³ MRC/UCT Medical Imaging Research Unit, University of Cape Town, Cape Town, South Africa

⁴ R&D Department, A.D. Gilliam Consulting, Providence, USA

⁵ Biomedical Engineering Department, University of Virginia, Charlottesville, USA

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Journal of Cardiovascular Magnetic Resonance 2011, 13:83 doi:10.1186/1532-429X-13-83

Published: 30 December 2011

Abstract

Background

Quantitative noninvasive imaging of myocardial mechanics in mice enables studies of the roles of individual genes in cardiac function. We sought to develop comprehensive three-dimensional methods for imaging myocardial mechanics in mice.

Methods

A 3D cine DENSE pulse sequence was implemented on a 7T small-bore scanner. The sequence used three-point phase cycling for artifact suppression and a stack-of-spirals k-space trajectory for efficient data acquisition. A semi-automatic 2D method was adapted for 3D image segmentation, and automated 3D methods to calculate strain, twist, and torsion were employed. A scan protocol that covered the majority of the left ventricle in a scan time of less than 25 minutes was developed, and seven healthy C57Bl/6 mice were studied.

Results

Using these methods, multiphase normal and shear strains were measured, as were myocardial twist and torsion. Peak end-systolic values for the normal strains at the mid-ventricular level were 0.29 ± 0.17, -0.13 ± 0.03, and -0.18 ± 0.14 for E_rr, E_cc, and E_ll, respectively. Peak end-systolic values for the shear strains were 0.00 ± 0.08, 0.04 ± 0.12, and 0.03 ± 0.07 for E_rc, E_rl, and E_cl, respectively. The peak end-systolic normalized torsion was 5.6 ± 0.9°.

Conclusions

Using a 3D cine DENSE sequence tailored for cardiac imaging in mice at 7 T, a comprehensive assessment of 3D myocardial mechanics can be achieved with a scan time of less than 25 minutes and an image analysis time of approximately 1 hour.