Henningsson Markus, Carlhäll Carl-Johan
Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
Magn Reson Med. 2020 Dec;84(6):3308-3315. doi: 10.1002/mrm.28334. Epub 2020 May 27.
Late gadolinium enhancement (LGE) of the left atrium is susceptible to artifacts arising from the right pulmonary veins, caused by inflowing blood tagged by the navigator restore pulse. The purpose of this study was to evaluate a new method to reduce the inflow artifact using an adaptive flip-angle restore pulse.
A low-restore angle reduces the inflow artifact but may lead to a poor navigator SNR. The proposed approach aims to determine the patient-specific restore angle, which optimizes the trade-off between inflow artifacts and navigator SNR. Three-dimensional LGE with adaptive navigator restore (3D LGE ) was implemented by incrementing the flip angle of the restore pulse from a starting value of 0°, based on the navigator normalized cross-correlation. Magnetic resonance imaging experiments were performed on a 1.5T scanner. The value of 3D LGE was compared with 3D LGE with a constant 180° restore pulse (3D LGE ) in 22 patients with heart diseases. The values of 3D LGE and 3D LGE were compared in terms of pulmonary vein blood signal relative to reference blood in the descending aorta (PV ) and visual scoring to determine level of motion artifacts using a 4-point scale (1 = severe artifacts; 4 = no artifacts).
The value of PV was significantly lower for 3D LGE than for 3D LGE (1.16 ± 0.23 vs. 1.59 ± 0.29, P < .001). Furthermore, visual scoring of the motion artifacts yielded no difference (P = .78).
Adaptively adjusting the navigator restore flip angle based on the navigator normalized cross-correlation reduces the 3D LGE inflow artifact without affecting image quality or the scan time.
左心房延迟钆增强（LGE）易受右肺静脉产生的伪影影响，这些伪影由导航恢复脉冲标记的流入血液引起。本研究的目的是评估一种使用自适应翻转角恢复脉冲减少流入伪影的新方法。
低恢复角可减少流入伪影，但可能导致导航器信噪比不佳。所提出的方法旨在确定患者特异性恢复角，以优化流入伪影与导航器信噪比之间的权衡。基于导航器归一化互相关，通过将恢复脉冲的翻转角从0°的起始值增加来实施具有自适应导航器恢复的三维LGE（3D LGE）。在1.5T扫描仪上进行磁共振成像实验。在22例心脏病患者中，将3D LGE的值与具有恒定180°恢复脉冲的3D LGE（3D LGE）进行比较。根据相对于降主动脉中参考血液的肺静脉血液信号（PV）以及使用4分制（1 =严重伪影；4 =无伪影）的运动伪影视觉评分来比较3D LGE和3D LGE的值。
3D LGE的PV值显著低于3D LGE（1.16±0.23对1.59±0.29；P <.001）。此外，运动伪影的视觉评分无差异（P = 0.78）。
基于导航器归一化互相关自适应调整导航器恢复翻转角可减少三维LGE流入伪影，而不影响图像质量或扫描时间。
