Hamilton C A, Elster A D, Ulmer J L
Department of Radiology, Bowman Gray School of Medicine, Winston-Salem, NC 27157-1022.
Radiology. 1994 Oct;193(1):276-9. doi: 10.1148/radiology.193.1.8090908.
At conventional magnetic resonance imaging, the number of phase-encoding steps is often chosen to be less than the number of readout samples, resulting in reduced spatial resolution in the phase-encoding direction. Signal averaging improves the signal-to-noise ratio of the image but does not affect this asymmetry in resolution. By swapping the phase- and frequency-encoding directions between excitations and averaging the resultant data sets ("crisscross" imaging), equal spatial resolution can be obtained in both principal directions. Increased spatial resolution can be obtained with this method with no increase in imaging time, and the method can potentially be applied in echo-planar and three-dimensional Fourier transform imaging.
在传统磁共振成像中，相位编码步骤的数量通常选择少于读出样本的数量，这导致在相位编码方向上空间分辨率降低。信号平均提高了图像的信噪比，但不影响这种分辨率的不对称性。通过在激发之间交换相位和频率编码方向并对所得数据集进行平均（“交叉”成像），可以在两个主要方向上获得相等的空间分辨率。使用这种方法可以在不增加成像时间的情况下提高空间分辨率，并且该方法有可能应用于回波平面成像和三维傅里叶变换成像。
