Estimation of images and nonrigid deformations in gated emission CT
Estimation of images and nonrigid deformations in gated emission CT
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DOI：
10.1109/tmi.2006.879323
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发表时间：
2006-09-01
影响因子：
10.6
通讯作者：
Sun, Jing
中科院分区：
文献类型：
--
作者：
Mair, B. A.;Gilland, David R.;Sun, Jing
在本文中，我们提出并测试了一种新的迭代算法，以同时估计门控心脏发射断层扫描中完整心动周期的非刚性运动矢量场和发射图像。我们将心肌建模为弹性材料，其运动不会产生大量应变。因此，我们的方法基于最小化目标函数，该目标函数由最大似然图像重建项的负对数、应变能的标准生物力学模型以及确保帧之间强度一致性测量的图像匹配项组成。使用四维 (4-D) NCAT 模型的数据获得模拟。这些数据模拟了典型门控心肌灌注 SPECT 研究中的真实噪声水平。我们表明，与后平滑 4-D 最大似然方法获得的图像相比，我们的同步算法生成的图像具有改进的空间分辨率特性和噪声特性。模拟还证明了与使用独立重建图像的运动估计相比，运动估计得到了改进。
In this paper, we propose and test a new iterative algorithm to simultaneously estimate the nonrigid motion vector fields and the emission images for a complete cardiac cycle in gated cardiac emission tomography. We model the myocardium as an elastic material whose motion does not generate large amounts of strain. As a result, our method is based on minimizing an objective function consisting of the negative logarithm of a maximum likelihood image reconstruction term, the standard biomechanical model of strain energy, and an image matching term that ensures a measure of agreement of intensities between frames. Simulations are obtained using data for the four-dimensional (4-D) NCAT phantom. The data models realistic noise levels in a typical gated myocardial perfusion SPECT study. We show that our simultaneous algorithm produces images with improved spatial resolution characteristics and noise properties compared with those obtained from postsmoothed 4-D maximum likelihood methods. The simulations also demonstrate improved motion estimates over motion estimation using independently reconstructed images.