双源CT双能量技术鉴别甲状腺良恶性结节的临床应用研究

目的 探讨双源CT能量成像在鉴别甲状腺良恶性结节中的临床应用价值.方法 收集91例经双源CT双能量扫描的甲状腺结节患者,获得单能量40~190 keV图像及碘图,计算线性融合图像与各单能量图像对比噪声比(CNR),测量动静脉期良恶性结节各单能量图像CT值、碘图正常甲状腺、结节、同层面颈动脉碘浓度值,绘制良恶性结节CT值衰减趋势图,计算曲线斜率、正常甲状腺与甲状腺结节内碘浓度差异(ICD)、碘浓度差异比(ICDNR)、标准化碘浓度比(NIC),采用配对样本t检验并绘制受试者工作特征(ROC)曲线比较上述定量参数值诊断恶性结节效能.结果 动、静脉期甲状腺结节在不同能量水平下CNR均有统计学差异(P<0.0001),动脉期最佳CNR在70 keV为11.61±1.71,静脉期最佳CNR在60 keV为10.55±1.09;良恶性结节动脉期单能谱曲线斜率(λ)分别为1.66±0.48,3.31±1.33,ICD分别为(2.83±1.23)mg/mL,(2.10±0.98)mg/mL,ICDNR分别为0.50±0.23,0.38±0.27,差异均有统计学意义(F=-89.43,4.036,2.791,P均<0.05),λ恶性结节大于良性,ICD及ICDNR良性结节大于恶性;静脉期曲线斜率分别为3.85±2.47,1.24±1.26,NIC分别为0.57±0.32,0.39±0.13,差异有统计学意义(F=8.651,4.893,P均<0.05),均良性结节大于恶性;动脉期ICDNR曲线下面积(AUC)最大为0.913,诊断敏感度为100%,特异度为87.5%.结论 动、静脉期分别采用70 keV及60 keV单能量图像可提高甲状腺结节检出率,能量相关定量参数值对良恶性结节鉴别诊断有较大临床应用价值.

Clinical application of dual energy scanning technology with dual-source CT in differentiating benign from malignant thyroid nodules

Objective To evaluate the clinical value of dual-source CT energy imaging in the differential diagnosis of benign and malignant thyroid nodules.Methods Total 91 cases with thyroid nodules were included in this study.Dual-energy CT scan were performed to obtain single images and iodine map with energy 40-190 keV.The linear image fusion with a single energy image contrast to noise ratio (CNR)was calculated,and arteriovenous value of benign and malignant nodules on each single energy CT image,iodine FIG on normal thyroid nodules,and the same level of carotid iodine concentration were measured.CT attenuation values trends of benign and malignant nodules were drawed,The slope of the curve,iodine concentration difference (ICD)within the normal thyroid and thyroid nodules iodine concentration difference ratio (ICDNR),and standardized iodine concentration ratio (NIC)were calculated.Paired samples t-test and the ROC curve comparing the quantitative parameters for diagnosis of malignant nodules were performed.Results The CNR of thyroid nodule during AP and VP were statistically significant (P<0.0001),the best CNR was in 70 keV (11.61±1.71) during AP,and 60 keV (10.55±1.09)during VP.The slopes of monochromatic images in benign and malignant nodules during AP were (1.66±0.48)and (3.31±1.33),the ICDs were (2.83±1.23)mg/mL and (2.10±0.98)mg/mL,ICDNRs were (0.50±0.23) and (0.38±0.27),respectively ,the differences were statistically significant (F=-89.43,4.036,2.791,P<0.05),and the slope for the malignant was greater than the benign nodules,while the ICD and ICDNR of the benign were greater than the malignant nodules. The slopes of monochromatic images in benign and malignant nodules during VP were (3.85±2.47)and (1.24±1.26),the NICs were (0.57±0.32)and (0.39±0.13),respectively,the differences were statistically significant (F=8.651,4.893,P<0.05),both in benign nodules were greater than that in the malignant nodules.The largest area under the curve(AUC)was 0.913 of the ICDNR during AP,the sensitivity was 100%,the specificity was 87.5%.Conclusion Virtual monochromatic images of 70 keV during AP and60 keV during VP improve detection rate of the thyroid nodule signifcantly.Quantitative parameters associate with energy can increase the efficiency and accuracy for differentiating thyroidbenign from malignant nodules.