Morgan V L, Pickens D R, Hartmann S L, Price R R
Department of Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2675, USA.
Magn Reson Med. 2001 Sep;46(3):510-4. doi: 10.1002/mrm.1221.
This study discusses the development of a computer-generated phantom to compare the effects of image realignment programs on functional MRI (fMRI) pixel activation. The phantom is a whole-head MRI volume with added random noise, activation, and motion. It allows simulation of realistic head motions with controlled areas of activation. Without motion, the phantom shows the effects of realignment on motion-free data sets. Prior to realignment, the phantom illustrates some activation corruption due to motion. Finally, three widely used realignment packages are examined. The results showed that the most accurate algorithms are able to increase specificity through accurate realignment while maintaining sensitivity through effective resampling techniques. In fact, accurate realignment alone is not a powerful indicator of the most effective algorithm in terms of true activation.
本研究探讨了一种计算机生成的体模的开发，以比较图像重新对齐程序对功能磁共振成像（fMRI）像素激活的影响。该体模是一个添加了随机噪声、激活和运动的全脑MRI容积。它允许模拟具有可控激活区域的真实头部运动。在没有运动的情况下，该体模显示了重新对齐对无运动数据集的影响。在重新对齐之前，该体模说明了由于运动导致的一些激活破坏。最后，研究了三种广泛使用的重新对齐软件包。结果表明，最精确的算法能够通过精确的重新对齐提高特异性，同时通过有效的重采样技术保持敏感性。事实上，就真正的激活而言，仅精确的重新对齐并不是最有效算法的有力指标。
