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- Selskog, Pernilla, et al.
(författare)
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Kinematics of the Heart : Finite Element and 3D Time-Resolved Phase Contrast Magnetic resonance Imaging
- 2002
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Ingår i: Proceedings of 9th Workshop on The Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields.
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Konferensbidrag (refereegranskat)abstract
- The complex three-dimensional structure of the heart muscle (myocardium) has anisotropic, non-linear and time-dependent mechanical properties. During the cardiac cycle, the myocardium undergoes large elastic deformations as a consequence of the active muscle contraction along the muscle fibers and their relaxation, respectively. A four-dimensional (4D) description (three spatial dimensions + time) of the mechanical properties of the myocardium would be of interest in the assessment of myocardial function. Time-resolved 3D phase contrast MRI makes it possible to quantify all three velocity components, which is necessary to as accurately as possible describe the velocities in the heart. The velocity data may be used for investigation of the deformation of the heart and calculation of strain in the myocardial wall. We present a method for estimation of myocardial kinematics using finite elements and 3D time-resolved phase contrast MRI.
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| 3. |
- Selskog, Pernilla, 1975-, et al.
(författare)
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Kinematics of the heart : strain-rate imaging from time-resolved three-dimensional phase contrast MRI
- 2002
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Ingår i: IEEE Transactions on Medical Imaging. - 0278-0062 .- 1558-254X. ; 21:9, s. 1105-1109
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Tidskriftsartikel (refereegranskat)abstract
- A four-dimensional mapping (three spatial dimensions + time) of myocardial strain-rate would help to describe the mechanical properties of the myocardium, which affect important physiological factors such as the pumping performance of the ventricles. Strain-rate represents the local instantaneous deformation of the myocardium and can be calculated from the spatial gradients of the velocity field. Strain-rate has previously been calculated using one-dimensional (ultrasound) or two-dimensional (2-D) magnetic resonance imaging techniques. However, this assumes that myocardial motion only occurs in one direction or in one plane, respectively. This paper presents a method for calculation of the time-resolved three-dimensional (3-D) strain-rate tensor using velocity vector information in a 3-D spatial grid during the whole cardiac cycle. The strain-rate tensor provides full information of both magnitude and direction of the instantaneous deformation of the myocardium. A method for visualization of the full 3-D tensor is also suggested. The tensors are visualized using ellipsoids, which display the principal directions of strain-rate and the ratio between strain-rate magnitude in each direction. The presented method reveals the principal strain-rate directions without a priori knowledge of myocardial motion directions.
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