Department of Anesthesiology and Intensive Care, Karolinska University Hospital Solna, Stockholm, Sweden.
J Appl Physiol (1985). 2012 Jul;113(2):340-52. doi: 10.1152/japplphysiol.00173.2012. Epub 2012 May 17.
Several methods allow regional gas exchange to be inferred from imaging of regional ventilation and perfusion (V/Q) ratios. Each method measures slightly different aspects of gas exchange and has inherent advantages and drawbacks that are reviewed. Single photon emission computed tomography can provide regional measure of ventilation and perfusion from which regional V/Q ratios can be derived. PET methods using inhaled or intravenously administered nitrogen-13 provide imaging of both regional blood flow, shunt, and ventilation. Electric impedance tomography has recently been refined to allow simultaneous measurements of both regional ventilation and blood flow. MRI methods utilizing hyperpolarized helium-3 or xenon-129 are currently being refined and have been used to estimate local PaO(2) in both humans and animals. Microsphere methods are included in this review as they provide measurements of regional ventilation and perfusion in animals. One of their advantages is their greater spatial resolution than most imaging methods and the ability to use them as gold standards against which new imaging methods can be tested. In general, the reviewed methods differ in characteristics such as spatial resolution, possibility of repeated measurements, radiation exposure, availability, expensiveness, and their current stage of development.
几种方法可用于从区域性通气和灌注（V/Q）比值的成像中推断区域性气体交换。每种方法都测量气体交换的略微不同方面，具有内在的优点和缺点，对此进行了综述。单光子发射计算机断层扫描（SPECT）可提供区域性通气和灌注的测量值，从中可以得出区域性 V/Q 比值。使用吸入或静脉内给予的氮-13 的正电子发射断层扫描（PET）方法可提供区域性血流、分流和通气的成像。电阻抗断层扫描（EIT）最近已经得到改进，可同时测量区域性通气和血流。利用超极化氦-3 或氙-129 的 MRI 方法正在改进中，并已用于估计人和动物的局部 PaO2。微球方法也包括在本综述中，因为它们可提供动物的区域性通气和灌注的测量值。它们的优点之一是空间分辨率高于大多数成像方法，并且能够将其用作新成像方法的金标准进行测试。一般来说，所综述的方法在空间分辨率、重复测量的可能性、辐射暴露、可用性、昂贵程度以及当前的开发阶段等方面存在差异。
