Spielman D M, Pauly J M
Department of Radiology, Stanford University, California 94305-5488, USA.
Magn Reson Med. 1995 Oct;34(4):580-5. doi: 10.1002/mrm.1910340414.
Spiral imaging has a number of advantages for ultrafast data acquisition. However, implementation on high-field small-bore systems requires carefully addressing the issues of inhomogeneity-induced blurring and gradient hardware constraints. In this paper, spiral imaging on a 40-cm-bore 4.7T CSI Omega System (Bruker Instruments) is discussed. A constant-voltage gradient waveform design algorithm is developed to reduce readout times as well as minimize waveform distortions due to gradient amplifier nonlinearities. Residual errors are then measured and taken into account in the image reconstruction procedure. Multiple spiral interleaves as well as a multifrequency reconstruction algorithm are used to decrease blurring of off-resonance spins. Both phantom and in vivo images demonstrate the performance of the resulting pulse sequences.
螺旋成像在超快速数据采集方面具有诸多优势。然而，在高场小口径系统上实现需要仔细解决由不均匀性引起的模糊和梯度硬件限制等问题。本文讨论了在40厘米口径的4.7T CSI Omega系统（布鲁克仪器公司）上的螺旋成像。开发了一种恒压梯度波形设计算法，以减少读出时间，并使由于梯度放大器非线性导致的波形失真最小化。然后测量残余误差并在图像重建过程中加以考虑。使用多个螺旋交错以及多频重建算法来减少失谐自旋的模糊。体模和体内图像均展示了所得脉冲序列的性能。
