Glover G H, Li T Q, Ress D
Department of Radiology, Stanford University School of Medicine, Center for Advanced MR Technology at Stanford, Stanford, California, USA.
Magn Reson Med. 2000 Jul;44(1):162-7. doi: 10.1002/1522-2594(200007)44:1<162::aid-mrm23>3.0.co;2-e.
Respiration effects and cardiac pulsatility can induce signal modulations in functional MR image time series that increase noise and degrade the statistical significance of activation signals. A simple image-based correction method is described that does not have the limitations of k-space methods that preclude high spatial frequency correction. Low-order Fourier series are fit to the image data based on time of each image acquisition relative to the phase of the cardiac and respiratory cycles, monitored using a photoplethysmograph and pneumatic belt, respectively. The RETROICOR method is demonstrated using resting-state experiments on three subjects and compared with the k-space method. The method is found to perform well for both respiration- and cardiac-induced noise without imposing spatial filtering on the correction. Magn Reson Med 44:162-167, 2000.
呼吸效应和心脏搏动可在功能磁共振成像时间序列中诱发信号调制，从而增加噪声并降低激活信号的统计显著性。本文描述了一种基于图像的简单校正方法，该方法不存在妨碍高频空间校正的k空间方法的局限性。基于每次图像采集相对于心脏和呼吸周期相位的时间，利用低阶傅里叶级数拟合图像数据，分别使用光电容积描记器和气动带进行监测。通过对三名受试者进行静息状态实验验证了RETROICOR方法，并与k空间方法进行了比较。结果发现该方法在处理呼吸和心脏诱发的噪声方面表现良好，且在校正过程中无需进行空间滤波。《磁共振医学》44:162 - 167, 2000年。
