This paper presents a virtual tagging framework for measuring, as well as visualising, myocardial deformation using magnetic resonance (MR) velocity imaging. Tagging grids are allocated artificially according to the deformation gradient with varying shapes and densities. The control points are then deformed such that the difference between the induced deformation velocity and that of actually measured MR data is minimum. A full three-dimensional implementation of the technique combined with the mass conservation constraint is provided. Numerical considerations of applying the proposed framework and different optimization strategies have been investigated with both simulated and phantom experiments. The accuracy of the technique in terms of following material deformation is compared with that of conventional tagging technique. Index Terms-Finite-element analysis, magnetic resonance (MR) tagging, mass conservation, myocardial deformation, myocardial velocity mapping, strain analysis.

This paper introduces a novel approach to deformation modeling based on partial-least-squares-regression and its application to the registration of first-pass magnetic resonance perfusion image sequences. The method relies on the extraction of intrinsic correlations between the latent factors of both the input and output signals for deriving a simple yet accurate deformation model. The strength of the technique has been demonstrated with both numerically simulated data sets and a myocardial perfusion study which involves nine patients with known coronary artery disease. The method represents a step forward for the commonly used principal component analysis for salient motion feature extraction. The proposed technique should be applicable to studies that involve deformation prediction such as motion adaptive radiotherapy and imaging, where the deformation of the target organ can be predicted from externally measurable signals.

本文应用数字图像测量系统．对砼试件在成形早期最初26小时的变形场进行了非接触的定量测量，得到了砼成形早期收缩应变随时间变化的曲线。整个测量过程简便直接，表明数字图像测量方法完全可用来对砼结构的位移场进行非接触的精密测量，在配备了相应的光学观察仪器后，也可用来测量一般的应变场，从而特为土建结构的定量测试提供新的有力手段。