From the *Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich; †Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany; ‡Department of Medical Radiation Physics, Lund University, Lund, Sweden; §Department of Radiology, University of Tübingen, Tübingen; and ∥Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Member of the German Center for Lung Research, Helmholtz Zentrum Munich, Neuherberg, Germany.
Invest Radiol. 2014 Oct;49(10):653-8. doi: 10.1097/RLI.0000000000000067.
The purpose of this study was to assess whether the recently developed method of grating-based x-ray dark-field radiography can improve the diagnosis of pulmonary emphysema in vivo.
Pulmonary emphysema was induced in female C57BL/6N mice using endotracheal instillation of porcine pancreatic elastase and confirmed by in vivo pulmonary function tests, histopathology, and quantitative morphometry. The mice were anesthetized but breathing freely during imaging. Experiments were performed using a prototype small-animal x-ray dark-field scanner that was operated at 35 kilovolt (peak) with an exposure time of 5 seconds for each of the 10 grating steps. Images were compared visually. For quantitative comparison of signal characteristics, regions of interest were placed in the upper, middle, and lower zones of each lung. Receiver-operating-characteristic statistics were performed to compare the effectiveness of transmission and dark-field signal intensities and the combined parameter "normalized scatter" to differentiate between healthy and emphysematous lungs.
A clear visual difference between healthy and emphysematous mice was found for the dark-field images. Quantitative measurements of x-ray dark-field signal and normalized scatter were significantly different between the mice with pulmonary emphysema and the control mice and showed good agreement with pulmonary function tests and quantitative histology. The normalized scatter showed a significantly higher discriminatory power (area under the receiver-operating-characteristic curve [AUC], 0.99) than dark-field (AUC, 0.90; P = 0.01) or transmission signal (AUC, 0.69; P < 0.001) alone did, allowing for an excellent discrimination of healthy and emphysematous lung regions.
In a murine model, x-ray dark-field radiography is technically feasible in vivo and represents a substantial improvement over conventional transmission-based x-ray imaging for the diagnosis of pulmonary emphysema.
本研究旨在评估基于光栅的 X 射线暗场射线照相术的最新方法是否可以改善体内肺气肿的诊断。
通过气管内滴注猪胰弹性蛋白酶在雌性 C57BL/6N 小鼠中诱导肺气肿，并通过体内肺功能测试、组织病理学和定量形态计量学进行确认。在成像过程中，小鼠在麻醉但自主呼吸的情况下进行。实验使用原型小动物 X 射线暗场扫描仪进行，该扫描仪在 35 千伏（峰值）下运行，每个光栅步骤的曝光时间为 5 秒。通过视觉比较图像。为了对信号特征进行定量比较，在每个肺的上、中、下区域放置感兴趣区域。进行接收器操作特征统计，以比较传输和暗场信号强度以及组合参数“归一化散射”的有效性，以区分健康和肺气肿的肺。
发现健康和肺气肿小鼠的暗场图像之间存在明显的视觉差异。X 射线暗场信号和归一化散射的定量测量在患有肺气肿的小鼠和对照小鼠之间有明显差异，并且与肺功能测试和定量组织学具有良好的一致性。归一化散射显示出明显更高的区分能力（接收器操作特征曲线下面积[AUC]，0.99），而暗场（AUC，0.90；P=0.01）或传输信号（AUC，0.69；P<0.001）单独使用，允许对健康和肺气肿的肺区域进行出色的区分。
在小鼠模型中，X 射线暗场射线照相术在体内技术上是可行的，并且在诊断肺气肿方面与传统的基于传输的 X 射线成像相比有了实质性的改进。
