Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland.
Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
Magn Reson Med. 2017 Sep;78(3):1059-1069. doi: 10.1002/mrm.26503. Epub 2016 Oct 23.
To introduce a reproducible, nonenhanced 1H MRI method for rapid in vivo functional assessment of the whole lung at 1.5 Tesla (T).
At different respiratory volumes, the pulmonary signal of ultra-fast steady-state free precession (ufSSFP) follows an adapted sponge model, characterized by a respiratory index α. From the model, α reflects local ventilation-related information, is virtually independent from the lung density and thus from the inspiratory phase and breathing amplitude. Respiratory α-mapping is evaluated for healthy volunteers and patients with obstructive lung disease from a set of five consecutive 3D ultra-fast steady-state free precession (ufSSFP) scans performed in breath-hold and at different inspiratory volumes. For the patients, α-maps were compared with CT, dynamic contrast-enhanced MRI (DCE-MRI), and Fourier decomposition (FD).
In healthy volunteers, respiratory α-maps showed good reproducibility and were homogeneous on iso-gravitational planes, but showed a gravity-dependent respiratory gradient. In patients with obstructive pulmonary disease, the functional impairment observed in respiratory α-maps was associated with emphysematous regions present on CT images, perfusion defects observable on DCE-MRI, and impairments visualized on FD ventilation and perfusion maps.
Respiratory α-mapping derived from multivolumetric ufSSFP provides insights into functional lung impairment and may serve as a reproducible and normative measure for clinical studies. Magn Reson Med 78:1059-1069, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
介绍一种在 1.5T 场强下可重复、无需增强的 1H MRI 方法，用于快速进行活体全肺功能评估。
在不同呼吸容量下，超快速稳态自由进动（ufSSFP）的肺信号遵循适应性海绵模型，其特征在于呼吸指数α。从该模型可知，α反映了局部通气相关信息，与肺密度（进而与吸气相和呼吸幅度）几乎无关。对健康志愿者和阻塞性肺疾病患者进行了 5 次连续 3D 超快速稳态自由进动（ufSSFP）扫描的呼吸α映射评估，这些扫描均在屏气状态和不同吸气容量下进行。对于患者，将 α 映射与 CT、动态对比增强 MRI（DCE-MRI）和傅里叶分解（FD）进行了比较。
在健康志愿者中，呼吸α映射具有良好的可重复性，在等重平面上具有均一性，但表现出与重力相关的呼吸梯度。在阻塞性肺病患者中，呼吸α映射中观察到的功能障碍与 CT 图像上存在的肺气肿区域、DCE-MRI 上可见的灌注缺损以及 FD 通气和灌注映射上的功能障碍相关。
多容积 ufSSFP 衍生的呼吸α映射可深入了解功能受损的肺部，并可作为临床研究中的一种可重复的、规范性的测量方法。磁共振医学杂志 78:1059-1069, 2017。© 2016 国际磁共振学会。
