Kyoyama Hiroyuki, Hirata Yusuke, Kikuchi Satoshi, Sakai Kosuke, Saito Yuriko, Mikami Shintaro, Moriyama Gaku, Yanagita Hisami, Watanabe Wataru, Otani Katharina, Honda Norinari, Uematsu Kazutsugu
Department of Pulmonary Medicine Department of Radiology, Saitama Medical Center, Saitama Medical University, Saitama Research and Collaborations Department, Siemens Healthcare KK, Tokyo, Japan.
Medicine (Baltimore). 2017 Jan;96(3):e5937. doi: 10.1097/MD.0000000000005937.
Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected pulmonary function. Xenon images obtained with xenon-enhanced CT using a single-breath-hold technique can qualitatively depict pulmonary ventilation. A larger study comprising only COPD patients should be conducted, as xenon-enhanced CT is expected to be a promising technique for the management of COPD.
氙增强双能量计算机断层扫描（氙增强CT）可提供肺部通气图，这可能有助于评估肺部的结构和功能异常。在氙气洗脱过程中，氙增强CT一直采用多次屏气技术进行。我们最近开发了一种采用单次屏气技术的氙增强CT来评估通气情况。我们试图评估采用单次屏气技术的氙增强CT是否与肺功能测试（PFT）结果相关。26例患者，包括11例慢性阻塞性肺疾病（COPD）患者，接受了氙增强CT和PFT检查。其中3例COPD患者在支气管扩张剂治疗前后接受了氙增强CT检查。在单次肺活量吸入氙氧混合气体后屏气期间，通过双源CT获取氙CT图像。通过三物质分解进行图像后处理生成传统CT图像和氙增强图像。氙图像上的低衰减区域在21例中与传统CT上的低衰减区域匹配，但在5例中与正常衰减区域匹配。氙图像的亨氏单位（HU）直方图的体积分别与肺活量（VC）和肺总量（TLC）呈中度和高度相关（r = 0.68和0.85）。直方图的均值和众数与VC呈弱相关（r = 0.39和0.38），与1秒用力呼气量（FEV1）呈中度相关（r = 0.59和0.56），与FEV1与FVC的比值呈弱相关（r = 0.46和0.42），与FEV1与其预测值的比值呈中度相关（r = 0.64和0.60）。2例COPD患者在使用支气管扩张剂使FEV1改善后，直方图的众数和体积增加。吸入氙气未引起不良反应。采用单次屏气技术的氙增强CT显示了在薄层CT上无法检测到的功能异常。氙图像的HU直方图的众数、均值和体积反映了肺功能。采用单次屏气技术的氙增强CT获得的氙图像可以定性地描绘肺通气情况。由于氙增强CT有望成为一种用于COPD管理的有前景的技术，因此应开展一项仅纳入COPD患者的更大规模研究。
