Lee C C, Grimm R C, Manduca A, Felmlee J P, Ehman R L, Riederer S J, Jack C R
Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Magn Reson Med. 1998 Feb;39(2):234-43. doi: 10.1002/mrm.1910390210.
Global head motion occurring between successive image acquisitions during a functional MRI time series can corrupt the signal of physiologic brain activation, potentially invalidating interpretation of the final activation map from that particular fMRI time series. By approximating the head as a rigid body, multiaxial global head motion can be decomposed into orthogonal linear and rotational components. This paper describes a method using orbital navigator echoes to provide prospective correction for both through-plane and in-plane inter-image head rotation in functional MRI. The dynamic detection and correction of rotation can be performed in <100 ms. Phantom experiments demonstrate accurate correction of rotational motion over a range of +/-0.36 degrees to +/-12 degrees. Imaging studies in volunteers document the feasibility of real-time prospective correction of rotational motion in vivo. Using a modified receiver operating characteristic method, motion-corrected functional MRI sensorimotor studies incorporating deliberate head rotations are shown to be superior to functional MRI time series acquired under similar conditions but without motion correction.
在功能磁共振成像（fMRI）时间序列的连续图像采集之间发生的整体头部运动，可能会破坏生理性脑激活信号，从而可能使来自该特定fMRI时间序列的最终激活图的解释无效。通过将头部近似为刚体，多轴整体头部运动可以分解为正交的线性和旋转分量。本文描述了一种使用轨道导航回波对功能磁共振成像中图像间的平面内和平面外头部旋转进行前瞻性校正的方法。旋转的动态检测和校正可以在不到100毫秒的时间内完成。模型实验证明，在+/-0.36度至+/-12度的范围内，旋转运动能够得到准确校正。对志愿者的成像研究证明了在体内实时前瞻性校正旋转运动的可行性。使用改良的接受者操作特征方法，结合故意头部旋转的运动校正功能磁共振成像感觉运动研究显示，优于在类似条件下但未进行运动校正所采集的功能磁共振成像时间序列。
