Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.
Magn Reson Med. 2018 Apr;79(4):2297-2305. doi: 10.1002/mrm.26891. Epub 2017 Aug 30.
Magnetic resonance imaging is a promising alternative to computed tomography for lung imaging. However, organ motion and poor signal-to-noise ratio, arising from short T2*, impair image quality. To alleviate these issues, a new retrospective gating method was implemented and tested with an ultra-short echo time sequence.
A 3D double-echo ultra-short echo time sequence was used to acquire data during free breathing in ten healthy adult subjects. A self-gating method was used to reconstruct respiratory motion suppressed expiratory and inspiratory images. These images were objectively compared to uncorrected data sets using quantitative end-points (pulmonary vessel sharpness, lung-liver interface definition, signal-to-noise ratio). The method was preliminarily tested in two cystic fibrosis patients who underwent computed tomography.
Vessel sharpness in expiratory ultra-short echo time data sets with second echo motion detection was significantly higher (13% relative increase) than in uncorrected images while the opposite was observed in inspiratory images. The method was successfully applied in patients and some findings (e.g., hypointense areas) were similar to those from computed tomography.
Free breathing ultra-short echo time was successfully implemented, allowing flexible image reconstruction of two different respiratory states. Objective improvements in image quality were obtained with the new method and initial feasibility in a clinical setting was demonstrated. Magn Reson Med 79:2297-2305, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
磁共振成像是一种很有前途的肺部成像替代方法，与计算机断层扫描相比。然而，器官运动和较差的信噪比，由于短 T2*，会影响图像质量。为了解决这些问题，我们采用了一种新的回顾性门控方法，并使用超短回波时间序列进行了测试。
使用三维双回波超短回波时间序列在 10 名健康成年受试者的自由呼吸期间采集数据。采用自门控方法重建呼吸运动抑制的呼气和吸气图像。使用定量终点（肺血管锐利度、肺肝界面定义、信噪比）客观比较校正前后数据集。该方法初步应用于两名囊性纤维化患者，他们接受了计算机断层扫描。
在使用第二回波运动检测的呼气超短回波时间数据集，血管锐利度明显更高（13%的相对增加），而在吸气图像中则相反。该方法在患者中成功应用，并且一些发现（例如，低信号区域）与计算机断层扫描相似。
自由呼吸超短回波时间序列成功实现，允许灵活重建两种不同的呼吸状态。新方法获得了图像质量的客观改善，并在临床环境中初步证明了可行性。磁共振医学 79:2297-2305, 2018。© 2017 国际磁共振学会。
