Right ventricular midwall surface motion and deformation using
magnetic resonance tagging.
Young, Alistair A., Zahi A. Fayad, Leon Axel.
Department of Physiology, School of Medicine, University of
Auckland, Private Bag 92019, Auckland, New Zealand, Department of
Radiology, University of Pennsylvania, Philadelphia PA 19104-6086,
Department of Bioengineering, University of Pennsylvania,
Philadelphia PA 19104
APStracts 3:0171H, 1996.
We describe a method for reconstructing the 3D motion and deformation
of the midwall surface of the right ventricular free wall (RVFW)
using magnetic resonance tissue tagging. Tag points were defined
where the tag stripes intersected the midwall contour and were
tracked through systole in both short and long axis images. A finite
element model of the midwall surface of the RVFW was constructed to
fit the midwall shape at end-diastole. The model was then deformed to
each subsequent frame by fitting the tag displacements and midwall
contour locations. The method was applied to two human studies: a
normal subject and a patient with right ventricular hypertrophy. The
root mean squared error between model tag planes and tracked tag
points was 0.70 mm for the normal heart (180 points) and 0.67 mm for
the hypertrophic heart (52 points), both less than the image pixel
size of approximately 1.0 mm. The differences in contraction patterns
were visualized between the two studies. We conclude that this method
allows accurate, non-invasive measurement of in vivo RVFW
deformation.
Received 5 July 1995; accepted in final form 11 April 1996.
APS Manuscript Number H607-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96