乳腺癌磁共振表观扩散系数与Ki-67表达的相关性

目的:探讨乳腺癌磁共振表观扩散系数(apparent diffusion coefficient,ADC)与Ki-67表达的相关性。方法:回顾性分析120例经手术证实的乳腺癌术前扩散加权成像(diffusion weighted imaging,DWI)的磁共振影像(b=0、800、1 000 s/mm~2),并测量其ADC值,分析ADC值与Ki-67指数的相关性。根据Ki-67指数的不同分为A组(低Ki-67组,n=60)和B组(高Ki-67组,n=60),比较两组间的ADC值并采用受试者工作特征(receiver operating characteristics,ROC)曲线分析ADC值鉴别诊断价值。结果:乳腺癌测量的ADC值与Ki-67指数明显负相关(r_(b值800)=-0.587,r_(b值1 000)=-0.63,P0.000 1)。相同b值下,B组的平均ADC值明显小于A组(P0.000 1)。b值为1 000 s/mm~2时的平均ADC值小于同组b值800 s/mm~2的平均ADC值。当b值为800、1 000 s/mm~2时,分别以ADC值1 954.00、1 521.00(10~(-6) mm~2/s)为临界值,鉴别诊断A、B组乳腺癌的ROC曲线下面积分别为0.91、0.94,敏感度分别为73.30%、83.00%,特异度分别为95.00%、91.70%。结论:MRI ADC值与乳腺癌Ki-67指数表达明显相关,值得进一步研究以应用于临床指导乳腺癌术前诊治。

Correlation between MRI apparent diffusion coefficient value and Ki-67 index in patients with breast cancer

Objective: To explore the relationship between MRI apparent diffusion coefficient (ADC) value and Ki-67 index in patients with breast cancer. Methods: The preoperative MRI diffusion weighted imaging (DWI) images (b=0, 800, 1000 s/mm²) of 120 patients with surgically confirmed breast cancer were retrospectively analyzed, and the ADC values were measured. The correlation between the ADC value and Ki-67 index was analyzed. According to the different Ki-67 index, they were divided into group A (low Ki-67 group, n=60) and group B (high Ki-67 group, n=60). ADC values between the two groups were compared and the identification ability of ADC value was analyzed by receiver operating characteristics (ROC) curve. Results: The ADC value of breast cancer was negatively correlated with Ki-67 index (r_{b value 800}=-0.587, r_{b value 1 000}=-0.63, P<0.000 1). Under the same B value, the average ADC value of group B was significantly lower than that of group A (P<0.000 1). When b value was 1 000 s/mm², the average ADC value was lower than that of 800 s/mm² in the same group. When the b value was 800 or 1 000 s/mm², using 1 954.00 or 1 521.00 (10^-6 s/mm²) as the critical ADC values respectively, the area under the ROC curve for differential diagnosis of breast cancer in group A and B was 0.91 or 0.94, respectively. The sensitivity was 73.30% or 83.00%, and the specificity was 95.00% or 91.70%, respectively. Conclusions: ADC value has an important predictive value for the expression of Ki-67 index in patients with breast cancer.