Kuang Pingding, Ding Xinfa, Xu Jingjing, Zhou Qijing, Zhang Minming
Department of Radiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China.
Zhejiang Da Xue Xue Bao Yi Xue Ban. 2017 May 25;46(5):511-516. doi: 10.3785/j.issn.1008-9292.2017.10.10.
To assess the diagnostic value of dual energy CT for lymph node metastasis in patients with non-small cell lung cancer (NSCLC).
Forty NSCLC patients, including 15 cases of squamous cell carcinoma and 25 cases of adenocarcinoma, underwent dual energy CT examination in pre-contrast and venous phase contrast scans, then the CT attenuation value of the lung cancer lesions and 85 mediastinal enlarged lymph nodes (the short diameter ≥ 5 mm, 53 metastatic and 32 non-metastatic) were measured at different energy levels (40-190 keV, spacing 10 keV) in venous phase contrast. CT spectral curves of the lung cancer lesions, hilus pulmonis and mediastinal enlarged lymph nodes were produced automatically, through comparing their CT spectral curves slope to judge whether or not the lymph nodes were metastatic. Receiver operating characteristic (ROC) curve was used to evaluate the efficiency of CT spectral curve in diagnosis of lymph node metastasis.
The CT spectral curves slopes of the lung cancer, metastatic lymph nodes and non-metastatic lymph nodes were 1.10±0.11, 1.08±0.07 and 1.54±0.17, respectively. There was no significant difference in curve slope between metastatic lymph nodes and lung cancer (=-1.32,>0.05); while there was significant difference between non-metastatic lymph nodes and lung cancer (=-2.58,<0.05). The CT spectral curve slope ratios of metastatic and non-metastatic lymph nodes to lung cancer were 0.98±0.05 and 1.40±0.12, respectively (=-2.86,<0.05). ROC curve showed that taking CT spectral curve slope ratio of 1.15 as cut-off value for the diagnosis of metastatic lymph nodes, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 81.1%, 87.5%, 91.5%, 73.7% and 83.5%, respectively.
Dual energy CT is of value in improving the diagnostic accuracy of lymph node metastasis in NSCLC patients before treatment.
评估双能CT对非小细胞肺癌（NSCLC）患者淋巴结转移的诊断价值。
40例NSCLC患者，其中鳞状细胞癌15例，腺癌25例，行双能CT平扫及静脉期增强扫描，测量静脉期增强扫描不同能量水平（40 - 190 keV，间隔10 keV）下肺癌病灶及85个纵隔肿大淋巴结（短径≥5 mm，其中转移淋巴结53个，非转移淋巴结32个）的CT衰减值。自动生成肺癌病灶、肺门及纵隔肿大淋巴结的CT光谱曲线，通过比较其CT光谱曲线斜率判断淋巴结是否转移。采用受试者操作特征（ROC）曲线评估CT光谱曲线诊断淋巴结转移的效能。
肺癌、转移淋巴结及非转移淋巴结的CT光谱曲线斜率分别为1.10±0.11、1.08±0.07和1.54±0.17。转移淋巴结与肺癌的曲线斜率差异无统计学意义（=-1.32，>0.05）；而非转移淋巴结与肺癌的曲线斜率差异有统计学意义（=-2.58，<0.05）。转移淋巴结及非转移淋巴结与肺癌的CT光谱曲线斜率比值分别为0.98±0.05和1.40±0.12（=-2.86，<0.05）。ROC曲线显示，以CT光谱曲线斜率比值1.15为诊断转移淋巴结的截断值，其灵敏度、特异度、阳性预测值、阴性预测值及准确度分别为81.1%、87.5%、91.5%、73.7%和83.5%。
双能CT对提高NSCLC患者治疗前淋巴结转移的诊断准确性具有重要价值。
