|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1Department of Biomedical Engineering, Duke University, and 2Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina; 3Department of Surgery, University of California, San Francisco, and 4Veterans Affairs Medical Center, San Francisco, California; and 5Department of Bioengineering, University of Utah, Salt Lake City, Utah
Submitted 16 March 2007 ; accepted in final form 28 June 2007
The orientation of MRI-measured diffusion tensor in the myocardium has been directly correlated to the tissue fiber direction and widely characterized. However, the scalar anisotropy indexes have mostly been assumed to be uniform throughout the myocardial wall. The present study examines the fractional anisotropy (FA) as a function of transmural depth and circumferential and longitudinal locations in the normal sheep cardiac left ventricle. Results indicate that FA remains relatively constant from the epicardium to the midwall and then decreases (25.7%) steadily toward the endocardium. The decrease of FA corresponds to 7.9% and 12.9% increases in the secondary and tertiary diffusion tensor diffusivities, respectively. The transmural location of the FA transition coincides with the location where myocardial fibers run exactly circumferentially. There is also a significant difference in the midwall-endocardium FA slope between the septum and the posterior or lateral left ventricular free wall. These findings are consistent with the cellular microstructure from histological studies of the myocardium and suggest a role for MR diffusion tensor imaging in characterization of not only fiber orientation but, also, other tissue parameters, such as the extracellular volume fraction.
fractional anisotropy; left ventricle; extracellular volume fraction; cardiac electrophysiology and biomechanics
This article has been cited by other articles:
![]() |
M.-T. Wu, M.-Y. M. Su, Y.-L. Huang, K.-R. Chiou, P. Yang, H.-B. Pan, T. G. Reese, V. J. Wedeen, and W.-Y. I. Tseng Sequential Changes of Myocardial Microstructure in Patients Postmyocardial Infarction by Diffusion-Tensor Cardiac MR: Correlation With Left Ventricular Structure and Function Circ Cardiovasc Imaging, January 1, 2009; 2(1): 32 - 40. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |