Electrical and Electronic Engineering, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo 315100, China.
Sir Peter Mansfield Magnetic Imaging Center, University of Nottingham, Nottingham NG7 2RD, UK.
Sensors (Basel). 2022 Apr 24;22(9):3270. doi: 10.3390/s22093270.
Compared with hyperpolarized noble gas MRI, oxygen-enhanced lung imaging is a cost-effective approach to investigate lung function. In this study, we investigated the feasibility of free-breathing phase-resolved oxygen-enhanced pulmonary MRI based on a 3D stack-of-stars ultra-short echo time (UTE) sequence. We conducted both computer simulation and in vivo experiments and calculated percent signal enhancement maps of four different respiratory phases on four healthy volunteers from the end of expiration to the end of inspiration. The phantom experiment was implemented to verify simulation results. The respiratory phase was segmented based on the extracted respiratory signal and sliding window reconstruction, providing phase-resolved pulmonary MRI. Demons registration algorithm was applied to compensate for respiratory motion. The mean percent signal enhancement of the average phase increases from anterior to posterior region, matching previous literature. More details of pulmonary tissues were observed on post-oxygen inhalation images through the phase-resolved technique. Phase-resolved UTE pulmonary MRI shows the potential as a valuable method for oxygen-enhanced MRI that enables the investigation of lung ventilation on middle states of the respiratory cycle.
与超极化惰性气体 MRI 相比，氧增强肺部成像是一种具有成本效益的方法，可以用于研究肺功能。在这项研究中，我们研究了基于三维星形叠层超短回波时间 (UTE) 序列的自由呼吸相位分辨氧增强肺部 MRI 的可行性。我们进行了计算机模拟和体内实验，并从呼气末到吸气末计算了四名健康志愿者的四个不同呼吸相位的信号增强百分比图。通过提取呼吸信号和滑动窗口重建，对体模实验进行了分段，提供了相位分辨肺部 MRI。应用 Demons 配准算法来补偿呼吸运动。平均相位的平均信号增强百分比从前向后区域增加，与之前的文献一致。通过相位分辨技术，在吸氧后图像上可以观察到更多的肺部组织细节。相位分辨 UTE 肺部 MRI 有望成为一种有价值的氧增强 MRI 方法，可用于研究呼吸周期中中间状态的肺通气。
