1 research outputs found
Translational Motion Compensation for Soft Tissue Velocity Images
Purpose: Advancements in MRI Tissue Phase Velocity Mapping (TPM) allow for
the acquisition of higher quality velocity cardiac images providing better
assessment of regional myocardial deformation for accurate disease diagnosis,
pre-operative planning and post-operative patient surveillance. Translation of
TPM velocities from the scanner's reference coordinate system to the regional
cardiac coordinate system requires decoupling of translational motion and
motion due to myocardial deformation. Despite existing techniques for
respiratory motion compensation in TPM, there is still a remaining
translational velocity component due to the global motion of the beating heart.
To compensate for translational motion in cardiac TPM, we propose an
image-processing method, which we have evaluated on synthetic data and applied
on in vivo TPM data. Methods: Translational motion is estimated from a suitable
region of velocities automatically defined in the left-ventricular volume. The
region is generated by dilating the medial axis of myocardial masks in each
slice and the translational velocity is estimated by integration in this
region. The method was evaluated on synthetic data and in vivo data corrupted
with a translational velocity component (200% of the maximum measured
velocity). Accuracy and robustness were examined and the method was applied on
10 in vivo datasets. Results: The results from synthetic and in vivo corrupted
data show excellent performance with an estimation error less than 0.3% and
high robustness in both cases. The effectiveness of the method is confirmed
with visual observation of results from the 10 datasets. Conclusion: The
proposed method is accurate and suitable for translational motion correction of
the left ventricular velocity fields. The current method for translational
motion compensation could be applied to any annular contracting (tissue)
structure