Cleveland Zackary I, Pavlovskaya Galina E, Stupic Karl F, Wooten Jan B, Repine John E, Meersmann Thomas
Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
Magn Reson Imaging. 2008 Feb;26(2):270-8. doi: 10.1016/j.mri.2007.06.009. Epub 2007 Sep 10.
Despite the importance of the tobacco smoke particulate matter in the lungs to the etiology of pulmonary disease in cigarette smokers, little is currently known about the spatial distribution of particle deposition or the persistence of the resulting deposits in humans, and no satisfactory technique currently exists to directly observe tobacco smoke condensate in airways. In this proof-of-principle work, hyperpolarized (hp) 83Kr MRI and NMR spectroscopy are introduced as probes for tobacco smoke deposition in porous media. A reduction in the hp-83Kr longitudinal (T1) relaxation of up to 95% under near-ambient humidity, pressure and temperature conditions was observed when the krypton gas was brought into contact with surfaces that had been exposed to cigarette smoke. This smoke-induced acceleration of the 83Kr self-relaxation was observed for model glass surfaces that, in some experiments, were coated with bovine lung surfactant extract. However, a similar effect was not observed with hp-(129)Xe indicating that the 83Kr sensitivity to smoke deposition was not caused by paramagnetic species but rather by quadrupolar relaxation due to high adsorption affinity for the smoke deposits. The 83Kr T1 differences between smoke-treated and untreated surfaces were sufficient to produce a strong contrast in variable flip angle FLASH hp-83Kr MRI, suggesting that hp-83Kr may be a promising contrast agent for in vivo pulmonary MRI.
尽管香烟烟雾中的颗粒物在肺部对吸烟者肺部疾病的病因具有重要意义，但目前对于颗粒沉积的空间分布或人体中沉积颗粒的持久性知之甚少，并且目前不存在直接观察气道中烟草烟雾冷凝物的令人满意的技术。在这项原理验证工作中，引入了超极化（hp）83Kr磁共振成像（MRI）和核磁共振光谱作为多孔介质中烟草烟雾沉积的探针。当氪气与暴露于香烟烟雾的表面接触时，在接近环境湿度、压力和温度条件下，观察到hp-83Kr纵向（T1）弛豫降低高达95%。在一些实验中，对于涂有牛肺表面活性剂提取物的模型玻璃表面，观察到这种烟雾诱导的83Kr自弛豫加速。然而，使用hp-（129）Xe未观察到类似效果，这表明83Kr对烟雾沉积的敏感性不是由顺磁性物质引起的，而是由对烟雾沉积物的高吸附亲和力导致的四极弛豫引起的。烟雾处理表面和未处理表面之间的83Kr T1差异足以在可变翻转角快速低角度激发hp-83Kr MRI中产生强烈对比，这表明hp-83Kr可能是一种有前途的用于体内肺部MRI的造影剂。
