Twist measurement of the left ventricle through radial tagging
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KeywordsCircumferential Strain Endocardial Border Systolic Strain Deformation Gradient Tensor Proper Threshold
Assessment of left ventricular twist is of fundamental importance in evaluating cardiac pump function. The recently developed radial tagging method provides new insights into cardiac rotational motion and has facilitated quantifying LV twist. Herein, we suggest a method to simply obtain twist of radially tagged LV, directly in the image domain.
Short axis radially tagged images were acquired at apical and basal levels in 6 healthy subjects.
Contouring LV epicardial and endocardial borders is the only user interaction in the twist extraction process. Applying a proper threshold algorithm over the masked images results in binary images containing easily detectable tags. We tracked the mean position of tags over the cardiac cycle and utilized their spatial coordinates to calculate rotation by the deformation gradient tensor method. By calculating the rotation angle of apical and basal LV sections, we extract twist, as the difference of apical and basal rotation.
The values of peak twist and peak twist time
Peak twist time (percantage of cardiac cycle)
Peak twist value (degree)
The proposed method takes advantages of novel radial tagging and is fast and reliable to quantify LV twist, providing additional insight into cardiac contractile function. As derived quantities, other related indices such as torsion, twisting rate and untwisting rate can be calculated.
Images were obtained through DCVI section at UCLA.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.