Advances in functional and structural imaging of the human lung using proton MRI.
Advances in functional and structural imaging of the human lung using proton MRI.
复制标题
使用质子 MRI 进行人肺功能和结构成像的进展。
DOI：
10.1002/nbm.3156
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发表时间：
2014
影响因子：
2.9
通讯作者：
Hopkins,SusanR
中科院分区：
文献类型：
--
作者：
Miller,GWilson;Mugler3rd,JohnP;Sá,RuiC;Altes,TalissaA;Prisk,GKim;Hopkins,SusanR
质子肺磁共振成像领域正在多个战线上取得进展。在功能成像领域，现在可以使用动脉自旋标记(ASL)和氧气增强成像技术来分别以标准测量单位来量化区域的血流和通气量。通过将这些技术结合到一次扫描中，还可以量化局部通风/灌流比，这是肺内气体交换效率的最重要决定因素。为了展示精确和有意义的肺功能测量的潜力，该技术被用于研究健康受试者的通风、灌流和通风/灌流比的重力梯度，得到与预期的区域变化一致的定量结果。这种技术也可以应用于时间域，为研究肺功能的时间动力学提供新的工具。时间ASL测量显示，暴露在低氧环境下的健康受试者肺血流的时空异质性增加，这表明对诸如缺氧性肺血管收缩等主动控制机制的敏感性，并说明为了全面检查控制肺功能的因素，有必要考虑时间和空间的变异性。在结构成像领域，可以结合超短回波时间射线空间采集、超快稳态自由进动和基于成像的横隔膜触发等脉冲序列技术来克服与肺部质子磁共振相关的重大挑战，从而在临床合理的扫描时间内获得高质量的全肺三维成像。使用这些技术的健康和囊性纤维化受试者的图像显示了非对比剂肺血管造影术和呼吸道疾病的详细描述的巨大希望。虽然还有进一步优化的机会，但这种结构肺成像的方法已经准备好用于临床测试。版权所有©2014 John Wiley&Sons，Ltd.
The field of proton lung MRI is advancing on a variety of fronts. In the realm of functional imaging, it is now possible to use arterial spin labeling (ASL) and oxygen‐enhanced imaging techniques to quantify regional perfusion and ventilation, respectively, in standard units of measurement. By combining these techniques into a single scan, it is also possible to quantify the local ventilation–perfusion ratio, which is the most important determinant of gas‐exchange efficiency in the lung. To demonstrate potential for accurate and meaningful measurements of lung function, this technique was used to study gravitational gradients of ventilation, perfusion, and ventilation–perfusion ratio in healthy subjects, yielding quantitative results consistent with expected regional variations.Such techniques can also be applied in the time domain, providing new tools for studying temporal dynamics of lung function. Temporal ASL measurements showed increased spatial–temporal heterogeneity of pulmonary blood flow in healthy subjects exposed to hypoxia, suggesting sensitivity to active control mechanisms such as hypoxic pulmonary vasoconstriction, and illustrating that to fully examine the factors that govern lung function it is necessary to consider temporal as well as spatial variability. Further development to increase spatial coverage and improve robustness would enhance the clinical applicability of these new functional imaging tools.In the realm of structural imaging, pulse sequence techniques such as ultrashort echo‐time radialk‐space acquisition, ultrafast steady‐state free precession, and imaging‐based diaphragm triggering can be combined to overcome the significant challenges associated with proton MRI in the lung, enabling high‐quality three‐dimensional imaging of the whole lung in a clinically reasonable scan time. Images of healthy and cystic fibrosis subjects using these techniques demonstrate substantial promise for non‐contrast pulmonary angiography and detailed depiction of airway disease. Although there is opportunity for further optimization, such approaches to structural lung imaging are ready for clinical testing. Copyright © 2014 John Wiley & Sons, Ltd.