Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.
Magn Reson Med. 2012 Apr;67(4):1167-72. doi: 10.1002/mrm.23086. Epub 2011 Jul 14.
Hardware constraints, scanning time limitations, patient movement, and signal-to-noise ratio (SNR) considerations, restrict the slice-selection and the in-plane resolutions of MRI differently, generally resulting in anisotropic voxels. This nonuniform sampling can be problematic, especially in image segmentation and clinical examination. To alleviate this, the acquisition is divided into (two or) three separate scans, with higher in-plane resolutions and thick slices, yet orthogonal slice-selection directions. In this work, a noniterative wavelet-based approach for combining the three orthogonal scans is adopted, and its advantages compared with other existing methods, such as Fourier techniques, are discussed, including the consideration of the actual pulse response of the MRI scanner, and its lower computational complexity. Experimental results are shown on simulated and real 7 T MRI data.
硬件限制、扫描时间限制、患者运动以及信噪比（SNR）等因素对 MRI 的层面选择和平面分辨率有不同的限制，通常会导致各向异性体素。这种非均匀采样可能会带来问题，尤其是在图像分割和临床检查中。为了解决这个问题，采集可以分为（两个或）三个单独的扫描，具有更高的平面分辨率和较厚的层面，但层面选择方向是正交的。在这项工作中，采用了一种基于非迭代小波的方法来组合这三个正交扫描，讨论了它与其他现有方法（如傅里叶技术）相比的优势，包括考虑 MRI 扫描仪的实际脉冲响应及其较低的计算复杂度。实验结果显示在模拟和真实的 7T MRI 数据上。
