Musch G, Venegas J G
Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Minerva Anestesiol. 2006 Jun;72(6):363-7.
Regional pulmonary perfusion and ventilation can be assessed by imaging, with positron emission tomography (PET), the pulmonary kinetics of [13N]nitrogen (13N2). Because of its low solubility in blood and tissues, 13N2 infused intravenously in saline solution evolves into the alveolar airspace at first pass, where it accumulates in proportion to regional perfusion during a short apnea. In contrast, infused 13N2 is not retained in non-aerated regions, which do not exchange gas. Robust estimates of regional perfusion and shunt are obtained by modeling the pulmonary kinetics of 13N2 infused as a bolus during a short apnea. Regional ventilation is measured by modeling the washout of 13N2 after breathing is resumed. Regional gas content and dead space ventilation can be measured with inhalation of 13N2. Application of this novel functional imaging technique can further the understanding of the pathophysiology of a variety of pulmonary processes. This review briefly describes the methodological aspects of PET imaging of regional perfusion and ventilation and then focuses on insights in the pathophysiology of acute lung injury and asthma that have been gained by imaging the pulmonary kinetics of 13N2 with PET.
可通过成像技术，即正电子发射断层扫描（PET），对[13N]氮（13N2）的肺动力学进行评估，从而测定局部肺灌注和通气情况。由于13N2在血液和组织中的溶解度较低，静脉注射到盐溶液中的13N2在首次通过时会进入肺泡腔，在短暂屏气期间，它会根据局部灌注比例在肺泡腔中蓄积。相比之下，注入的13N2不会滞留在不进行气体交换的非通气区域。通过对短时间屏气期间静脉推注13N2的肺动力学进行建模，可获得局部灌注和分流的可靠估计值。通过对恢复呼吸后13N2的洗脱过程进行建模来测量局部通气。吸入13N2可测量局部气体含量和无效腔通气。应用这种新型功能成像技术有助于进一步了解各种肺部疾病的病理生理学。本文综述简要介绍了PET成像评估局部灌注和通气的方法学方面，然后重点阐述了通过PET对13N2的肺动力学进行成像所获得的关于急性肺损伤和哮喘病理生理学的见解。
