Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
Int J Radiat Oncol Biol Phys. 2019 Mar 1;103(3):738-746. doi: 10.1016/j.ijrobp.2018.10.024. Epub 2018 Oct 26.
Patients with esophageal cancer treated with chemoradiation and surgery can develop pulmonary complications. Four-dimensional computed tomography-ventilation (4DCT-ventilation) is a developing imaging modality that uses 4DCT data to calculate lung ventilation. 4DCT-ventilation has been studied in the lung-cancer population but has yet to be extended to patients with esophageal cancer. The purpose of this study was to characterize 4DCT-ventilation-based spatial lung function for patients with esophageal cancer.
Thirty-five patients with esophageal cancer who underwent 4DCT scans participated in the study. A 4DCT-ventilation map was calculated using the patient's 4DCT imaging and a density change-based algorithm. To assess each patient's ventilation profile, radiologist interpretations and quantitative metrics were used. A radiologist interpreted the 4DCT-ventilation images for lobar-based defects and gravity-dependent atelectasis. The 4DCT-ventilation maps were reduced to single metrics intended to reflect the degree of ventilation heterogeneity. The quantitative metrics included the coefficient of variation and metrics based on the ventilation in each lung and each lung third (superior-inferior ventilation [Vent-SI] and anteroposterior ventilation). The functional profile of patients with esophageal cancer was characterized and compared (using the Mann-Whitney test) for cohorts based on thoracic comorbidities and radiologist-identified defects.
Radiologist observations revealed that 26% of patients with esophageal cancer had lobar-based defects and 46% had gravity-dependent atelectasis. The baseline values were 0.52 ± 0.20 (mean ± SD), 11.2 ± 12.5, and 72.5 ± 14.6 for the coefficient of variation, the ventilation ratio of right to left lung, and Vent-SI metrics, respectively. The Vent-SI values were significantly different between patients with and without thoracic comorbidities (P = .05), and the anteroposterior ventilation metric was able to delineate patients with and without gravity-dependent atelectasis (P < .01).
Our data demonstrate that approximately 30% of patients with esophageal cancer have significant ventilation heterogeneities. The current work uses radiologist observations and quantitative metrics to characterize 4DCT ventilation-based lung function for patients with esophageal cancer and presents data that can be used for future applications of 4DCT-ventilation to reduce thoracic toxicity for patients with esophageal cancer.
接受放化疗和手术治疗的食管癌患者可能会发生肺部并发症。四维计算机断层扫描-通气（4DCT-ventilation）是一种新兴的成像方式，它利用 4DCT 数据来计算肺通气。4DCT-ventilation 已在肺癌患者中进行了研究，但尚未扩展到食管癌患者。本研究的目的是描述食管癌患者基于 4DCT-ventilation 的空间肺功能。
35 例接受 4DCT 扫描的食管癌患者参与了本研究。使用患者的 4DCT 成像和基于密度变化的算法计算 4DCT-ventilation 图。为了评估每位患者的通气情况，使用放射科医生的解释和定量指标。放射科医生对 4DCT-ventilation 图像进行了基于叶的缺陷和重力依赖性肺不张的解释。将 4DCT-ventilation 图简化为单个指标，旨在反映通气异质性的程度。定量指标包括变异系数以及基于每个肺和每个肺三分之一（上下通气[Vent-SI]和前后通气）的通气指标。通过 Mann-Whitney 检验，根据胸部合并症和放射科医生识别的缺陷，对食管癌患者的功能谱进行了特征描述和比较。
放射科医生的观察结果显示，26%的食管癌患者存在叶状缺陷，46%的患者存在重力依赖性肺不张。基线值分别为变异系数为 0.52±0.20（均值±标准差）、右肺与左肺通气比为 11.2±12.5、Vent-SI 指标为 72.5±14.6。有和没有胸部合并症的患者之间的 Vent-SI 值有显著差异（P=0.05），前后通气指标能够区分有和没有重力依赖性肺不张的患者（P<0.01）。
我们的数据表明，约 30%的食管癌患者存在显著的通气异质性。目前的工作使用放射科医生的观察结果和定量指标来描述食管癌患者基于 4DCT-ventilation 的肺功能，并提供了可用于未来应用 4DCT-ventilation 以降低食管癌患者胸部毒性的相关数据。
