Snake Tracking and Dense Deformations
from Tagged Cardiac Images
Amir A. Amini, Rupert W. Curwen,
R. Todd Constable, and John C. Gore
Departments of Diagnostic Radiology, Electrical Engineering,
and Applied Physics
New Haven, CT 06510
MRI is unique in its ability to non-invasively
and selectively alter tissue magnetization, and
create grid patterns on a soft, deforming body
such as the heart muscle.
We track motion of myocardial tag lines with
energy-minimizing B-spline snakes.
Oriented tag templates are first constructed by simulating
the MR imaging process. The templates are subsequently
correlated with the image data, giving rise to an
energy landscape, which is optimized over with
Tracking the valleys of the energy landscape
with snakes allows
of MR tag deformations due to tissue motion.
Tissue deformation parameters corresponding
to strain, vorticity, and compression/expansion of
myocardial regions are also derived. The latter two
quantities are computed from a modified thin-plate spline
reconstruction of a dense motion field.