Bandettini P A, Jesmanowicz A, Wong E C, Hyde J S
Biophysics Research Institute, Medical College of Wisconsin, Milwaukee 53226.
Magn Reson Med. 1993 Aug;30(2):161-73. doi: 10.1002/mrm.1910300204.
Image processing strategies for functional magnetic resonance imaging (FMRI) data sets acquired using a gradient-recalled echo-planar imaging sequence are considered. The analysis is carried out using the mathematics of vector spaces. Data sets consisting of N sequential images of the same slice of brain tissue are analyzed in the time-domain and also, after Fourier transformation, in the frequency domain. A technique for thresholding is introduced that uses the shape of the response in a pixel compared with the shape of a reference waveform as the decision criterion. A method is presented to eliminate drifts in data that arise from subject movement. The methods are applied to experimental FMRI data from the motor-cortex and compared with more conventional image-subtraction methods. Several finger motion paradigms are considered in the context of the various image processing strategies. The most effective method for image processing involves thresholding by shape as characterized by the correlation coefficient of the data with respect to a reference waveform followed by formation of a cross-correlation image. Emphasis is placed not only on image formation, but also on the use of signal processing techniques to characterize the temporal response of the brain to the paradigm.
考虑了使用梯度回波平面成像序列采集的功能磁共振成像（FMRI）数据集的图像处理策略。使用向量空间数学进行分析。对由同一脑组织切片的N个连续图像组成的数据集在时域进行分析，并且在傅里叶变换后在频域进行分析。引入了一种阈值处理技术，该技术将像素中响应的形状与参考波形的形状进行比较，以此作为决策标准。提出了一种消除因受试者运动而产生的数据漂移的方法。这些方法应用于来自运动皮层的实验性FMRI数据，并与更传统的图像减法方法进行比较。在各种图像处理策略的背景下考虑了几种手指运动范式。最有效的图像处理方法包括通过形状进行阈值处理，该形状由数据相对于参考波形的相关系数表征，然后形成互相关图像。不仅强调图像形成，还强调使用信号处理技术来表征大脑对该范式的时间响应。
