Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, Virginia, USA.
Clin Radiol. 2012 Jan;67(1):69-77. doi: 10.1016/j.crad.2010.12.021. Epub 2011 Nov 8.
Dual-energy (DE) pulmonary blood volume (PBV) computed tomography (CT) has recently become available on clinical CT systems. The underlying physical principle of DECT is the fact that the photoelectric effect is strongly dependent on the CT energies resulting in different degrees of x-ray attenuation for different materials at different energy levels. DECT thus enables the characterization and quantification of iodine within tissues via imaging at different x-ray energies and analysis of attenuation differences. Technical approaches to DECT include dual-source scanners acquiring two scans with different energy levels simultaneously, and single-source CT scanners using sandwich detectors or rapid voltage switching. DE PBV CT enables the creation of iodine maps of the pulmonary parenchyma. Experience to date shows that these studies can provide additional physiological information in patients with acute or chronic pulmonary embolism beyond the pure morphological assessment a standard CT pulmonary angiography (CTPA) provides. It appears also to be promising for the evaluation of patients with obstructive airways disease. This article reviews the physics and technical aspects of DE PBV CT as well as the appearance of normal and abnormal lung tissue on these studies. Special consideration is given to pitfalls and artefacts.
双能量（DE）肺部血容量（PBV）计算机断层扫描（CT）最近已在临床 CT 系统上应用。DECT 的基本物理原理是光电效应强烈依赖于 CT 能量，导致不同材料在不同能级下具有不同程度的 X 射线衰减。因此，DECT 可以通过不同 X 射线能量的成像以及衰减差异的分析来对组织内的碘进行特征描述和定量。DECT 的技术方法包括同时采集两种不同能级的双源扫描仪、使用夹层探测器或快速电压切换的单源 CT 扫描仪。DE PBV CT 可创建肺实质的碘图。迄今为止的经验表明，这些研究除了标准 CT 肺动脉造影（CTPA）提供的纯形态评估外，还可以为急性或慢性肺栓塞患者提供额外的生理信息。它似乎对评估阻塞性气道疾病的患者也很有前途。本文综述了 DE PBV CT 的物理和技术方面，以及这些研究中正常和异常肺组织的表现。特别关注了陷阱和伪影。
