双能CT诊断颈部中央区甲状腺乳头状癌小淋巴结转移

Dual energy CT in diagnosis of central cervical metastatic lymph nodes in patients with papillary thyroid cancer

目的探讨双能量CT对甲状腺乳头状癌在颈部中央区小淋巴结转移的诊断价值。方法回顾性分析经病理证实为甲状腺乳头状癌且术前接受双能量CT增强扫描的43例患者资料。比较甲状腺乳头状癌转移淋巴结组及非甲状腺乳头状癌转移淋巴结组淋巴结的短径、动脉期及静脉期碘浓度、标准化碘浓度(NIC)、能谱曲线斜率。绘制ROC曲线,分析应用碘浓度及NIC对甲状腺癌转移淋巴结的诊断效能。结果 43例患者共119枚淋巴结,其中转移淋巴结55枚、非转移淋巴结64枚。2组淋巴结短径差异有统计学意义(t=-2.20,P=0.03)。动脉期转移淋巴结组及非转移淋巴结组碘浓度分别为(2.93±1.62)mg/ml及(2.17±1.09)mg/ml,NIC分别为0.33±0.21及0.19±0.12,曲线斜率分别为0.79±0.43及0.63±0.37。静脉期甲状腺乳头状癌转移淋巴结组及非甲状腺乳头状癌转移淋巴结组碘浓度分别为(2.68±1.54)mg/ml及(2.17±1.01)mg/ml,NIC分别为0.51±0.18及0.43±0.15,曲线斜率分别为0.54±0.42及0.62±0.39。2组间动脉期及静脉期碘浓度、NIC、动脉期曲线斜率差异均有统计学意义(P均<0.05)。ROC曲线分析显示,动脉期碘浓度、NIC诊断甲状腺癌转移淋巴结的曲线下面积(AUC)分别为0.62、0.73,静脉期碘浓度、NIC分别为0.61、0.63。结论双能CT动脉期及静脉期碘浓度、NIC及动脉期曲线斜率在不同性质的中央区小淋巴结间存在差异,双能量CT有助于鉴别中央区转移及非转移小淋巴结。

Objective To investigate the diagnostic value of dual energy CT for small central cervical metastatic lymph nodes in patients with papillary thyroid cancer. Methods The data of 43 patients with thyroid papillary carcinoma con- firmed by pathology were retrospectively analyzed. All of the patients underwent dual energy CT scan before operation. The short diameter, iodine concentration and normalized iodine concentration （NIC） of enhanced arterial and venous phases and the slope of the energy spectrum curve were analyzed between metastatic central cervical lymph nodes and non-meta- static lymph nodes. ROC curve was used to analyze the diagnosis efficacy of iodine concentration and NIC for metastatic lymph nodes of thyroid carcinoma. Results Totally there were 119 lymph nodes in 43 patients included 55 thyroid papillary carcinoma metastasis lymph nodes （metastasis group） and 64 non-metastatic lymph nodes （non-metastasis group）. There was significant differences of the mean short diameter of the lymph nodes between the two groupos （t= -2.20, P= 0.03）. In arterial phase, the average iodine concentration of metastasis group and non-metastasis group were （2.93± 1.62）mg/ml and （2.17±1.09）mg/ml; the NIC were 0. 33-±0. 21 and 0. 19±0.12; and the slope of the energy spectrum curve were 0.79±0.43 and 0.63±0.37 respectively. In venous phase, the average iodine concentration of metastasis group and non- metastasis group were （2.68±1.54）mg/ml and （2.17±1.01）mg/ml; the NIC were 0.51±0.18 and 0.43±0.15; the slope of the energy spectrum curve were 0.54±0. 42 and 0. 62±0. 39 respectively. The iodine concentration and NIC in both phases and the slope of spectrum curve in arterial phase had statistical differences between the metastasis and non-me- tastasis groups （all P〈0.05）. ROC curve showed that the area under the curve （AUC） of iodine concentration and NIC in the diagnosis of metastatic lymph nodes were 0.62 and 0.73 in arterial phase, respectively. And the AUC of iodine concen- tration and NIC were 0.61 and 0.63 in venous phase, respectively. Conclusion There are differences of iodine concentra- tion, NIC in arterial and venous phases and curve slope in arterial phase of dual energy between malignant and benign cen- tral cervical lymph nodes in thyroid papillary carcinoma. Dual energy CT technology is helpful in identifying of metastatic from non-metastatic small central cervical lymph nodes.