Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Sci Rep. 2018 May 9;8(1):7310. doi: 10.1038/s41598-018-25713-0.
Many forms of lung disease manifest themselves as pathological changes in the transport of gas to the circulatory system, yet the difficulty of imaging this process remains a central obstacle to the comprehensive diagnosis of lung disorders. Using hyperpolarized xenon-129 as a surrogate marker for oxygen, we derived the temporal dynamics of gas transport from the ratio of two lung images obtained with different timing parameters. Additionally, by monitoring changes in the total hyperpolarized xenon signal intensity in the left side of the heart induced by depletion of xenon signal in the alveolar airspaces of interest, we quantified the contributions of selected lung volumes to the total pulmonary gas transport. In a rabbit model, we found that it takes at least 200 ms for xenon gas to enter the lung tissue and travel the distance from the airspaces to the heart. Additionally, our method shows that both lungs contribute fairly equally to the gas transport in healthy rabbits, but that this ratio changes in a rabbit model of acid aspiration. These results suggest that hyperpolarized xenon-129 MRI may improve our ability to measure pulmonary gas transport and detect associated pathological changes.
许多形式的肺部疾病表现为气体向循环系统输送的病理变化，但由于成像这一过程具有难度，肺部疾病的全面诊断仍然存在着核心障碍。我们使用氙-129 作为氧的替代标记物，从利用不同时间参数获取的两幅肺部图像的比率中推导出气体输送的时间动态。此外，通过监测感兴趣的肺泡气空间中氙信号耗竭引起的左心总极化氙信号强度的变化，我们量化了选定肺容积对总肺气体输送的贡献。在兔模型中，我们发现氙气进入肺部组织并从气腔到达心脏的距离至少需要 200 毫秒。此外，我们的方法表明，健康兔的气体输送过程中，左右两肺的贡献相当，但在酸吸入兔模型中，这种比例会发生变化。这些结果表明，极化氙-129 MRI 可能会提高我们测量肺气体输送和检测相关病理变化的能力。
