Institute of Applied Physics, University of Tsukuba.
Magn Reson Med Sci. 2018 Apr 10;17(2):174-183. doi: 10.2463/mrms.tn.2016-0049. Epub 2017 Mar 27.
Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans.
使用非屏蔽和自屏蔽梯度线圈，为 9.4T 垂直标准孔径（54mm）超导磁体开发了螺旋 MRI 序列。使用自屏蔽梯度线圈获得了具有 64 次激发扫描的清晰螺旋图像，但使用非屏蔽梯度线圈获得的螺旋扫描图像存在严重的阴影伪影。通过使用我们基于涡流场测量开发的参考扫描的相位校正技术，成功校正了这种阴影伪影。因此，我们得出结论，如果使用参考扫描进行相位校正，则即使使用非屏蔽梯度线圈也可以安装螺旋成像序列。
