Institute of Information and Control, Hangzhou Dianzi University, Hangzhou, Zhejiang, People's Republic of China.
Magn Reson Med. 2013 Dec;70(6):1674-81. doi: 10.1002/mrm.24605. Epub 2013 Jan 30.
To enhance the fast imaging technique of skipped phase encoding (PE) and edge deghosting (SPEED) for more general sampling options, and thus more flexibility in implementations and applications.
SPEED uses skipped PE steps to accelerate MRI scan. Previously, the PE skip size was chosen from prime numbers only. This restriction has been relaxed in this study to allow choice of any integers rather than merely prime numbers. Various sampling patterns were studied under all possible combinations of PE skip size and PE shifts. A criterion based on the rank values of ghost phasor matrices was introduced to evaluate SPEED reconstruction.
The reconstruction quality was found to correlate with the rank value of the ghost phasor matrix and the skipped PE size N. A low-rank value indicates a singular matrix that causes failure of the SPEED reconstruction. Composite numbers combined with appropriately chosen PE shifts yielded satisfactory reconstruction results.
With properly chosen PE shifts, it was found that any integers, including both prime numbers and composite numbers, could be used as PE skip size for SPEED. This finding allows much more flexible data acquisition options that may lead to more freedom in practical implementations and applications.
为了增强跳过相位编码（PE）和边缘去鬼影（SPEED）的快速成像技术，以实现更广泛的采样选项，从而在实施和应用中具有更大的灵活性。
SPEED 使用跳过的 PE 步骤来加速 MRI 扫描。以前，PE 跳过的大小只能从质数中选择。在这项研究中，放宽了这一限制，允许选择任何整数，而不仅仅是质数。在 PE 跳过大小和 PE 移位的所有可能组合下，研究了各种采样模式。引入了基于鬼影相量矩阵的秩值的准则来评估 SPEED 重建。
重建质量与鬼影相量矩阵的秩值和跳过的 PE 大小 N 相关。低秩值表示奇异矩阵，导致 SPEED 重建失败。组合数与适当选择的 PE 移位相结合，产生了令人满意的重建结果。
通过适当选择 PE 移位，可以发现任何整数，包括质数和复合数，都可以用作 SPEED 的 PE 跳过大小。这一发现允许更灵活的数据采集选项，从而在实际实施和应用中具有更大的自由度。
