Construction of a two-parameter empirical model of left ventricle wall motion using cardiac tagged magnetic resonance imaging data

View/ Open
Issue Date
2012-10-24Author
Shi, Jack J.
Alenezy, Mohammed D.
Smirnova, Irina V.
Bilgen, Mehmet
Publisher
BioMed Central
Type
Article
Article Version
Scholarly/refereed, publisher version
Rights
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.
Metadata
Show full item recordAbstract
Background
A one-parameter model was previously proposed to characterize the short axis motion of the LV wall at the mid-ventricle level. The single parameter of this model was associated with the radial contraction of myocardium, but more comprehensive model was needed to account for the rotation at the apex and base levels. The current study developed such model and demonstrated its merits and limitations with examples. Materials and methods
The hearts of five healthy individuals were visualized using cardiac tagged magnetic resonance imaging (tMRI) covering the contraction and relaxation phases. Based on the characteristics of the overall dynamics of the LV wall, its motion was represented by a combination of two components - radial and rotational. Each component was represented by a transformation matrix with a time-dependent variable α or β. Image preprocessing step and model fitting algorithm were described and applied to estimate the temporal profiles of α and β within a cardiac cycle at the apex, mid-ventricle and base levels. During this process, the tagged lines of the acquired images served as landmark reference for comparing against the model prediction of the motion. Qualitative and quantitative analyses were performed for testing the performance of the model and thus its validation. Results
The α and β estimates exhibited similarities in values and temporal trends once they were scaled by the radius of the epicardium (repi)and plotted against the time scaled by the period of the cardiac cycle (Tcardiac) of each heart measured during the data acquisition. α/repi peaked at about Δt/Tcardiac=0.4 and with values 0.34, 0.4 and 0.3 for the apex, mid-ventricle and base level, respectively. β/repi similarly maximized in amplitude at about Δt/Tcardiac=0.4, but read 0.2 for the apex and - 0.08 for the base level. The difference indicated that the apex twisted more than the base. Conclusion
It is feasible to empirically model the spatial and temporal evolution of the LV wall motion using a two-parameter formulation in conjunction with tMRI-based visualization of the LV wall in the transverse planes of the apex, mid-ventricle and base. In healthy hearts, the analytical model will potentially allow deriving biomechanical entities, such as strain, strain rate or torsion, which are typically used as diagnostic, prognostic or predictive markers of cardiovascular diseases including diabetes.
Collections
Citation
Shi, Jack J, Mohammed Alenezy, Irina V Smirnova, and Mehmet Bilgen. 2012. “Construction of a Two-Parameter Empirical Model of Left Ventricle Wall Motion Using Cardiac Tagged Magnetic Resonance Imaging Data.” Biomedical Engineering Online 11:79. http://dx.doi.org/10.1186/1475-925X-11-79.
Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.
We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.
Except where otherwise noted, this item's license is described as: 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.