Abstract
An imaging method for the rapid reconstruction of fiber orientation
throughout the cardiac ventricles is described. In this method, gradient-recalled
acquisition in the steady-state (GRASS) imaging is used to measure
ventricular geometry in formaldehyde-fixed hearts at high spatial
resolution. Diffusion-tensor magnetic resonance imaging (DTMRI)
is then used to estimate fiber orientation as the principle eigenvector
of the diffusion tensor measured at each image voxel in these same
hearts. DTMRI-based estimates of fiber orientation in formaldehyde-fixed
tissue are shown to agree closely with those measured using histological
techniques, and evidence is presented suggesting that diffusion tensor
tertiary eigenvectors may specify the orientation of ventricular
laminar sheets. Using a semiautomated software tool called HEARTWORKS,
a set of smooth contours approximating the epicardial and endocardial
boundaries in each GRASS short-axis section are estimated. These
contours are then interconnected to form a volumetric model of the
cardiac ventricles. DTMRI-based estimates of fiber orientation
are interpolated into these volumetric models, yielding reconstructions
of cardiac ventricular fiber orientation based on at least an order
of magnitude more sampling points than can be obtained using manual
reconstruction methods.
- 11144678
- anatomic,
- animals,
- biomedical
- calcium
- cardiovascular,
- channel,
- comparative
- computer
- contraction,
- diffusion,
- electrophysiology,
- endocardium,
- engineering,
- fibers,
- function,
- gov't,
- heart
- humans,
- imaging,
- magnetic
- male,
- models,
- muscle
- myocardial
- non-u.s.
- of
- p.h.s.,
- pericardium,
- rabbits,
- receptor
- release
- reproducibility
- research
- resonance
- results,
- reticulum,
- ryanodine
- sarcoplasmic
- signaling,
- simulation,
- study,
- support,
- u.s.
- ventricles,
- ventricular
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