Moriguchi Hisamoto, Dale Brian M, Lewin Jonathan S, Duerk Jeffrey L
Department of Radiology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44106, USA.
Magn Reson Med. 2003 Sep;50(3):643-8. doi: 10.1002/mrm.10570.
One primary disadvantage of spiral imaging is blurring artifact due to off-resonance effects. The conventional frequency segmented off-resonance correction method that is performed over the entire image is computationally intense due to the large number of fast Fourier transforms (FFTs) required. Here, a new fast off-resonance correction method, block regional off-resonance correction (BRORC), is presented. In this method, off-resonance correction proceeds block-by-block through the reconstructed image with FFTs performed on matrices that are smaller than the full image matrix. The BRORC algorithm is typically several times more computationally efficient than the conventional off-resonance correction algorithm. Additional computational reductions can be expected for the BRORC if only specific image regions require deblurring. The newly proposed off-resonance correction method offers significant speed advantages and equivalent image quality when compared to conventional off-resonance correction methods.
螺旋成像的一个主要缺点是由于失谐效应导致的模糊伪影。在整个图像上执行的传统频率分段失谐校正方法，由于需要大量快速傅里叶变换（FFT），计算量很大。在此，提出了一种新的快速失谐校正方法，即块区域失谐校正（BRORC）。在该方法中，失谐校正通过对小于完整图像矩阵的矩阵执行FFT，逐块地对重建图像进行。BRORC算法的计算效率通常比传统失谐校正算法高几倍。如果仅特定图像区域需要去模糊，则BRORC有望进一步减少计算量。与传统失谐校正方法相比，新提出的失谐校正方法具有显著的速度优势和相当的图像质量。
