双能量CT碘图定量参数联合形态学征象预测甲状腺微小乳头状癌颈部中央区淋巴结转移的价值

目的 探讨双能量CT碘图定量参数联合形态学征象预测甲状腺微小乳头状癌（PTMC）颈部中央区淋巴结转移（CLNM）的价值。 方法 回顾性分析2020年1至12月就诊于昆明医科大学第三附属医院云南省肿瘤医院的经术后组织病理学检查诊断为PTMC且行中央区淋巴结清扫的165例患者的临床资料和影像资料，其中，男性51例、女性114例，年龄22~69（47.8±13.9）岁，根据组织病理学检查结果将患者分为CLNM组和无CLNM组。对病灶进行形态学征象评价，包括多发病灶、病灶长径、形态不规则、微钙化、甲状腺边缘接触、增强扫描后边界模糊。测量术前行双能量CT扫描动、静脉期PTMC病灶的碘浓度（IC）及CT值，计算动、静脉期病灶的标准化碘浓度（NIC）和标准化CT值（NCT值）。采用独立样本t检验比较CLNM组与无CLNM组患者动、静脉期病灶的IC、NIC以及CT值、NCT值间的差异；采用χ2检验比较CLNM组与无CLNM组患者病灶的形态学征象。绘制单因素分析中差异有统计学意义的形态学征象及双能量CT碘图定量参数的受试者工作特征（ROC）曲线，计算曲线下面积（AUC），并采用二元逐步Logistic回归得到双能量CT碘图定量参数与形态学征象的联合预测系数。 结果 形态学征象方面，CLNM组与无CLNM组患者在多发病灶、病灶长径、形态不规则、甲状腺边缘接触间的差异均有统计学意义（χ2=7.298~12.422，均P<0.01），且甲状腺边缘接触诊断颈部CLNM的效能最高（AUC=0.695）。双能量CT碘图定量参数方面，CLNM组患者原发灶动、静脉期的NIC和NCT值均高于无CLNM组，且差异有统计学意义（0.36±0.02对0.32±0.03、0.70±0.11对0.59±0.10、0.43±0.06对0.37±0.07、0.81±0.08对0.75±0.12，t=4.248~8.301，均P<0.01）。且动脉期NIC诊断颈部CLNM的效能最高（AUC=0.822），最佳临界值为0.36。双能量CT碘图定量参数联合形态学征象诊断颈部CLNM的效能最高，AUC=0.908，灵敏度为86.70%、特异度为75.10%。甲状腺边缘接触是颈部CLNM的独立危险因素。 结论 双能量CT碘图定量参数联合形态学征象对术前预测PTMC颈部CLNM具有重要的临床价值。

Value of the quantitative parameters of dual-energy CT iodine map combined with morphological signs in predicting the cervical central lymph node metastasis of papillary thyroid microcarcinoma

Objective To explore the value of the quantitative parameters of dual-energy CT iodine map combined with morphological signs in predicting cervical central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC). Methods Clinical and imaging data of 165 patients with PTMC diagnosed by postoperative histopathology and who underwent central lymph node dissection in Yunnan Cancer Hospital, the Third Affiliated Hospital of Kunming Medical University from January 2020 to December 2020 were retrospectively analyzed. The cohort included 51 males and 114 females, aged 22–69 (47.8±13.9) years old. The patients were divided into the CLNM and non-CLNM groups according to the histopathological results. Morphological signs of the lesions, including multiple lesions, long diameter, irregular shape, microcalcification, thyroid edge contact, and blurred boundary after enhanced scanning, were evaluated. The iodine concentration (IC) and CT value of the PTMC lesions in the arteriovenous phase were measured by dual-energy CT scanning before the operation. The normalized IC (NIC) and normalized CT (NCT) value of the lesions in the arteriovenous phase were calculated. Independent sample t-test was used to compare the IC, NIC, CT, and NCT values of the arteriovenous lesions between the two groups. χ2 test was used to compare the morphological signs of lesions between the two groups. A receiver operator characteristic curve (ROC) was drawn for the morphological signs and quantitative parameters of the dual-energy CT iodine map with statistically significant differences in univariate analysis, and the area under curve (AUC) was calculated. Binary stepwise logistic regression was used to obtain the joint prediction coefficient of the quantitative parameters and the morphological signs. Results Significant differences were found in the multiple lesions, lesion diameter, irregular shape, and thyroid edge contact between the two groups (χ2=7.298–12.422, all P<0.01), and thyroid edge contact had the highest diagnostic efficiency for cervical CLNM(AUC=0.695). The NIC and NCT values of the CLNM group were higher than those of the non-CLNM group in the arteriovenous phase, and the differences were statistically significant (0.36±0.02 vs. 0.32±0.03, 0.70±0.11 vs. 0.59±0.10, 0.43±0.06 vs. 0.37±0.07, 0.81±0.08 vs. 0.75±0.12; t=4.248–8.301, all P<0.01). The NIC in the arterial phase had the highest diagnostic efficiency for cervical CLNM(AUC=0.822), and the optimal cut-off value was 0.36. The quantitative parameters of the dual-energy CT iodine map combined with the morphological signs had the highest diagnostic efficiency for cervical CLNM, with AUC of 0.908, sensitivity of 86.70%, and specificity of 75.10%. Thyroid edge contact was an independent risk factor for cervical CLNM. Conclusion The quantitative parameters of dual-energy CT iodine map combined with the morphological signs exhibited important clinical value in predicting cervical CLNM of patients with PTMC before an operation.