Mapping myocardial structure-function relations with cardiac diffusion and strain MRI

The myocardial structure-function relation is the key to understand the functional design of the ventricular myocardium. While the function of myocardial fibers has been extensively studied, the recently observed laminar organization (sheets) of myocardial fibers is not well understood. This thesis establishes noninvasive MRI methods, registered cardiac diffusion and strain MRI, to acquire information about myocardial sheet structure and myocardial strain under identical in vivo conditions, and thus defines the functional role of myocardial sheets. This methodology solves limitations of existing methods that require postmortem dissection, and can be applied to living humans at multiple time horizons in the cardiac cycle. To establish valid MRI methods to map myocardial structure, we present a new method for diffusion MRI in the beating heart that is insensitive to cardiac motion and strain. Using phantom and in vivo validations, we demonstrate that this method addresses the problem of motion sensitivity of diffusion MRI in the beating heart. We also map myocardial sheet and fiber structure during systole in normal humans and find evidence that sheet architecture undergoes remarkable changes during contraction. To establish valid MR methods to quantify myocardial strain, we present a new 3D phase contrast strain imaging using single-shot 3D EPI. Compared to previous phase contrast 3D strain methods, the new method realizes potential sensitivity of phase contrast EPI. It significantly improves image quality regarding noise and artifact, requires much shorter acquisition time, and can be quickly and automatically processed without operator supervision. Following validation using a strain phantom,

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Nuclear Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Dou, Jiangang, 1972-

Advisor dc:contributor.advisor

• Van J. Wedeen.

• Nuclear Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/30008

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/30008