Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
Department of Radiology, University of Colorado School of Medicine, Aurora, Colorado.
Int J Radiat Oncol Biol Phys. 2014 May 1;89(1):199-205. doi: 10.1016/j.ijrobp.2014.01.009.
Four-dimensional computed tomography (4DCT) ventilation imaging provides lung function information for lung cancer patients undergoing radiation therapy. Before 4DCT-ventilation can be implemented clinically it needs to be validated against an established imaging modality. The purpose of this work was to compare 4DCT-ventilation to nuclear medicine ventilation, using clinically relevant global metrics and radiologist observations.
Fifteen lung cancer patients with 16 sets of 4DCT and nuclear medicine ventilation-perfusion (VQ) images were used for the study. The VQ-ventilation images were acquired in planar mode using Tc-99m-labeled diethylenetriamine-pentaacetic acid aerosol inhalation. 4DCT data, spatial registration, and a density-change-based model were used to compute a 4DCT-based ventilation map for each patient. The percent ventilation was calculated in each lung and each lung third for both the 4DCT and VQ-ventilation scans. A nuclear medicine radiologist assessed the VQ and 4DCT scans for the presence of ventilation defects. The VQ and 4DCT-based images were compared using regional percent ventilation and radiologist clinical observations.
Individual patient examples demonstrate good qualitative agreement between the 4DCT and VQ-ventilation scans. The correlation coefficients were 0.68 and 0.45, using the percent ventilation in each individual lung and lung third, respectively. Using radiologist-noted presence of ventilation defects and receiver operating characteristic analysis, the sensitivity, specificity, and accuracy of the 4DCT-ventilation were 90%, 64%, and 81%, respectively.
The current work compared 4DCT with VQ-based ventilation using clinically relevant global metrics and radiologist observations. We found good agreement between the radiologist's assessment of the 4DCT and VQ-ventilation images as well as the percent ventilation in each lung. The agreement lessened when the data were analyzed on a regional level. Our study presents an important step for the integration of 4DCT-ventilation into thoracic clinical practice.
四维计算机断层扫描（4DCT）通气成像是为接受放射治疗的肺癌患者提供肺功能信息。在 4DCT-通气能够在临床上实施之前，需要用一种已建立的成像方式对其进行验证。本研究的目的是通过使用临床相关的全局指标和放射科医生的观察来比较 4DCT-通气和核医学通气。
本研究使用了 15 例肺癌患者的 16 组 4DCT 和核医学通气灌注（VQ）图像。VQ-通气图像是使用 Tc-99m 标记的二乙三胺五乙酸气溶胶吸入在平面模式下采集的。4DCT 数据、空间配准和基于密度变化的模型用于计算每位患者的 4DCT 通气图。计算了 4DCT 和 VQ-通气扫描中每个肺和每个肺段的通气百分比。核医学放射科医生评估了 VQ 和 4DCT 扫描中通气缺陷的存在。使用区域通气百分比和放射科医生的临床观察比较了 VQ 和 4DCT 基图像。
个别患者的例子显示 4DCT 和 VQ-通气扫描之间具有良好的定性一致性。使用每个单独的肺和肺段的通气百分比，相关系数分别为 0.68 和 0.45。使用放射科医生指出的通气缺陷的存在和接收者操作特性分析，4DCT-通气的灵敏度、特异性和准确性分别为 90%、64%和 81%。
本研究使用临床相关的全局指标和放射科医生的观察比较了 4DCT 与基于 VQ 的通气。我们发现放射科医生对 4DCT 和 VQ-通气图像的评估以及每个肺的通气百分比之间具有良好的一致性。当数据在区域水平上进行分析时，一致性会降低。我们的研究为将 4DCT-通气整合到胸部临床实践中迈出了重要的一步。
