IVIM多参数预测乳腺癌免疫组化指标表达的可行性研究

目的基于扩散加权成像(diffusion weighted imaging,DWI)和体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion-weighted imaging,IVIM-DWI)技术,探究乳腺癌表观扩散系数(apparent diffusion coefficient,ADC)值和IVIM-DWI多参数值(D值、D*值、f值)与乳腺癌免疫组化指标(ER、PR、HER-2和Ki-67)不同表达情况之间是否具有统计学差异。材料与方法前瞻性搜集怀疑为乳腺癌的患者,术前进行MRI评估,并进行IVIM-DWI成像,利用单指数DWI模型测量ADC值,利用双指数IVIM模型对多b值DWI进行后处理,通过后处理工作站获得IVIM各参数值:D值、D*值及f值。追踪所有手术病人病理结果,最终入组经病理确诊的乳腺癌患者共51例。采用SPSS 19.0统计软件进行数据分析,探究乳腺癌ADC值和IVIM-DWI多参数值(D值、D*值、f值)与乳腺癌免疫组化指标(ER、PR、HER-2和Ki-67)不同表达情况之间是否具有统计学差异,采用独立样本t检验或U检验。结果 51例乳腺癌患者共55个病灶。其中ER阳性、PR阳性、HER-2阳性及Ki-67高表达分别为45个、40个、14个、36个病灶。经统计学分析发现以Ki-67表达百分比为14%为阈值,Ki-67高表达组与低表达组的D平均值差异有统计学意义(P=0.046),D*和f平均值差异无统计学意义;55个乳腺癌病灶中,ER、PR、HER-2阴性组和阳性组的D、D*及f平均值差异均无统计学意义(P0.05);ER、PR、HER-2阳性组与阴性组及Ki-67高表达组与低表达组的ADC平均值差异均无统计学意义(P0.05)。结论乳腺癌Ki-67高低表达组的IVIM-DWI定量参数D值存在统计学差异,提示了通过非侵入性的影像学检查方法预测Ki-67表达情况的潜能。

The feasibility of intravoxel incoherent motion to indicate immunohistochemical characteristics in breast cancer

Objective:To explore the difference in apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) parameters (D, D*, and f) of breast cancer regarding the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and antigen identified by monoclonal antibody Ki-67.Materials and Methods:Patients suspected to be suffering from breast cancer and had undergone preoperative breast MRI with intravoxel incoherent motion diffusion-weighted imaging in our institution between November 2015 and February 2016 were included in this study. All MR imaging examinations were performed on a 3.0 T MRI scanner (Philips, Ingenia). The ADC values were calculated from DW images at all b-values, assuming monoexponential signal shape. IVIM parameters (D, D*, and f) were obtained using multi-b-value DWI with a biexponential curve fitting. ADC and IVIM parameters (D, D*, and f) of patients with different ER, PR, HER-2, or Ki-67 expression were compared to explore the relationships between MRI and immunohistochemical findings of patients with breast cancer.Results:Fifty-five breast cancer lesions (51 patients) with positive pathologic results were included in our study. Of the 55 lesions, the amount of ER positive, PR positive, HER-2 positive, and Ki-67 high-expression lesions were 45, 40, 14, and 36, respectively. Mean D values in the Ki-67 high-expression group were significantly lower than those in the Ki-67 low-expression group (0.80±0.16 vs 0.88±0.14,P=0.046), while no signiifcant differences were showed in ADC, D*, and f value between the two groups. No statistical signiifcance was reached regarding the difference in mean ADC value or IVIM parameters (D, D*, and f) between the groups with different ER, PR, or HER-2 expression.Conclusions:Statistical difference in D value of IVIM parameters was found between the two groups with different Ki-67 expression in breast carcinoma. This may indicate the potential to provide a surrogate measure of Ki-67 expression through noninvasive imaging tools.