磁共振扩散加权成像的表观扩散系数与胃癌Ki-67表达及分化程度的关系

Associations of apparent diffusion coefficient value from MR diffusion-weighted imaging with Ki-67 expression and differentiation grade in gastric cancer

目的探讨磁共振扩散加权成像（DWI）的表观扩散系数（ADC）与胃癌Ki-67表达及分化程度的关系。 方法回顾性分析苏州大学附属常熟医院2013年9月至2015年2月间的68例胃癌患者的影像及病理资料。采用免疫组织化学方法检测胃癌组织中Ki-67表达情况，计算Ki-67标记指数（LI），并据此分为低Ki-67组（Ki-67 LI 〈 50%）和高Ki-67组（Ki-67 LI ≥ 50%）。分析DWI的ADC值与胃癌Ki-67 LI及分化程度之间的关系。 结果低Ki-67组患者肿瘤的平均ADC值明显高于高Ki-67组[（0.977±0.100）× 10-3 mm2/s比（0.859±0.064）× 10-3 mm2/s，P= 0.000]；肿瘤平均ADC值与Ki-67 LI呈负相关（r=-0.685 ，P= 0.000）。高分化腺癌、中分化腺癌、低分化腺癌与印戒细胞癌的ADC值分别为（1.124±0.080）× 10-3 mm2/s、（0.950±0.064）× 10-3 mm2/s、（0.899±0.091）× 10-3 mm2/s和（0.894±0.081）× 10-3 mm2/s，4组间的差异有统计学意义（F= 11.405，P= 0.000），其中高分化腺癌组明显高于另3组（均P= 0.000）。 结论ADC值与胃癌的Ki-67表达及分化程度有关，有望作为无创性生物学指标辅助判断胃癌的增殖程度和组织学分化程度。

ObjectiveTo examine the associations of apparent diffusion coefficient （ADC）value from MR diffusion-weighted imaging （DWI）with Ki-67 expression and differentiation grade in gastric cancer. MethodsImages and pathologic data of 68 gastric cancer patients between September 2013 and February 2015 in Affiliated Changshu Hospital of Soochow University were analyzed retrospectively. The expression of Ki-67 antigen in cancer tissue sample was determined by immunohistochemistry. Ki-67 labeling index （LI）was calculated to divide the cases into low Ki-67 group （Ki-67 LI 〈 50%）and high Ki-67 group （Ki-67 LI ≥50%）. Associations of ADC value with differentiation grade and Ki-67 LI were examined. ResultsMean ADC value of low Ki-67 LI group was significantly higher than that of high Ki-67 LI group [（0.977±0.100）× 10-3 mm2/s vs. （0.859±0.064）× 10-3 mm2/s, P = 0.000]. The ADC value was negatively correlated with Ki-67 LI （r = -0.685, P= 0.000）. Mean ADC value of well differentiated adenocarcinoma, moderately differentiated adenocarcinoma, poorly differentiated adenocarcinoma, and signet-ring cell carcinoma was （1.124±0.080）× 10-3 mm2/s, （0.950±0.064）× 10-3 mm2/s, （0.899±0.091）× 10-3 mm2/s, and （0.894±0.081）× 10-3 mm2/s respectively. Difference of ADC value among differentiation grades was significantly different （F = 11.405, P = 0.000）. Difference of ADC value between well differentiated adenocarcinoma and non-well differentiated adenocarcinoma was significantly different （P = 0.000）. ConclusionADC value is associated with differentiation grade and Ki-67 LI of gastric cancer, which may be used as a noninvasive predictor for evaluating the proliferation and differentiation grade of gastric cancer.