双能量CT定量参数预测乳腺浸润性导管癌Ki-67表达的可行性探讨

The Feasibility of Using Dual-energy CT Quantitative Parameters for Predicting the Expression of Ki-67 in Breast Invasive Ductal Carcinoma

目的探讨浸润性乳腺癌的双能量CT动、静脉期的定量参数与肿瘤Ki-67表达指数的关系。方法回顾性收集术前行双能量CT能谱双期增强扫描、术后病理确诊为浸润性乳腺癌的患者33例,以Ki-67表达指数14%为界将患者分为高表达组和低表达组。测量两组动脉期和静脉期病灶和同层面降主动脉的碘浓度(IC),计算相对碘浓度(SIC);测量双期病灶在40和70keV的CT值,计算能谱曲线斜率(λ),采用独立样本t检验或者Mann-Whitney U检验(不满足正态分布)来比较高、低Ki-67表达组的动静脉两期定量参数(IC、SIC、λ)的差异。使用受试者操作特征(receiver operator characteristic,ROC)曲线来评估增强两期参数对高低Ki-67的鉴别效能。采用Pearson相关性分析定量参数与Ki-67表达指数值高低的相关性。结果Ki-67高表达组在动静脉两期中的IC值、SIC值及能谱曲线斜率λ均大于Ki-67低表达组,P<0.05。动脉期IC值、SIC值及能谱曲线斜率λ对Ki-67表达高低组的鉴别效能为0.678、0.752、0.711,静脉期三个参数的鉴别效能为0.752、0.822、0.736。浸润性乳腺癌患者动、静脉期IC、SIC与曲线斜率λ与Ki67的高低存在正相关,其中动脉期IC、SIC与Ki67值相关性最高,分别为0.685、0.648。结论浸润性乳腺癌的双能量CT定量参数与其Ki-67表达指数水平有关。

Objective To analyze the relationship between quantitative parameters of dual-energy CT and tumor Ki-67 expression index in arterial and venous phase of invasive breast cancer.Methods 33 patients,who underwent preoperative dual-energy CT energy spectrum dual-phase enhancement and were diagnosed with invasive breast cancer by postoperative pathology,were retrospectively collected.A Ki-67 expression index of 14%was used to divide the patients into high or low expression groups,measuring the their arterial and venous phase lesions and iodine concentration at the same level descending aorta,calculate relative iodine concentration;CT values at 40 and 70 keV were measured for two-stage lesions,the slope of the energy spectrum curve was calculated,and the independent samples t-test or Mann-Whitney U test(which did not satisfy the normal distribution)was used to compare the differences in quantitative parameters between the high and low Ki-67-expressing groups for both arterial and venous stages.Receiver operator characteristic(ROC)curves were used to assess the discrimination efficacy of the enhanced two-phase parameters for discriminating high and low Ki-67.Pearson correlation analysis was used to evaluate the correlation between quantitative parameters and high and low Ki-67 expression index values.Results The IC values,SIC values and slope of energy spectrumλwere greater in the high Ki-67 expression group than those in the low Ki-67 expression group in both arterial and venous stages,P<0.05.The discriminatory efficacy of IC values,SIC values and slope of energy spectrumλin the arterial stage was 0.678,0.752 and 0.711,respectively.While the discriminatory efficacy of the three parameters in the venous stage was 0.752,0.822 and 0.736,respectively.The level of Ki67 is positively correlated with the IC and SIC of the arterial and venous stage,and with the slope of the curveλin patients with invasive breast cancer.The highest correlation,0.685 or 0.648,was observed between Ki67 level and IC or SIC,respectively.Conclusion The quantitative parameters of dual-energy CT are related to the Ki-67 expression levels in invasive breast cancer.