直肠腺癌扩散峰度成像定量参数与Ki-67表达的相关性研究

  目的  探讨直肠腺癌扩散峰度成像(DKI)定量参数与Ki-67表达的相关性。  方法  选取广东省中医院2019年1月—2020年6月收治的术前未接受新辅助化疗行高分辨率MRI、扩散加权成像(DWI, b=0、1 000 s/mm2)及DKI(b=0、600、1 000、2 000 s/mm2)检查的43例直肠腺癌患者, 测量病灶相应的平均扩散峰度(MK)、平均扩散系数(MD)及表观扩散系数(ADC), 按Ki-67表达将其分为低表达组(Ki-67指数≤25%)和高表达组(Ki-67指数＞25%), 比较2组间MK、MD及ADC有无差异, 用Spearman相关法评价各定量参数与Ki-67表达的相关性, 并通过受试者工作特征曲线(ROC)来确定各参数鉴别诊断直肠腺癌Ki-67低表达与高表达的效能。  结果  直肠腺癌Ki-67低表达组与高表达组的MK、ADC分别为0.88(0.81, 0.94) vs. 1.22(1.06, 1.34);1.20(1.12, 1.30)×10-3 mm2/s vs. 1.10(0.94, 1.15)×10-3 mm2/s], 差异有统计学意义(均P＜0.01), 2组间MD1.20(1.12, 1.30)×10-3 mm2/s vs.1.20(1.10, 1.30)×10-3 mm2/s]比较差异无统计学意义(P>0.05)。MK与Ki-67表达呈正相关(r=0.523, P＜0.001), ADC与Ki-67表达呈负相关(r=-0.467, P＜0.01)。MK的曲线下面积(AUC=0.906)较ADC、MD的更大, 以MK=0.96为诊断阈值时, 敏感性为96.77%, 特异性为75.00%。  结论  MK、ADC与Ki-67表达相关, 均可间接评估直肠腺癌肿瘤细胞的增殖情况, 但MK在诊断效能方面优于ADC, 能更好地反映直肠腺癌的侵袭性和分子生物学特性。 

Relationship between the quantitative parameters of diffusion kurtosis imaging and the Ki-67 expression level in rectal adenocarcinoma

Objective To explore the relationship between quantitative parameters of diffusion kurtosis imaging(DKI)and the molecular markers Ki-67 in patients with rectal adenocarcinoma.Methods A total of 43 patients with rectal adenocarcinoma who underwent surgery and did not receive chemoradiotherapy were selected in this retrospective study.The image data included high-resolution MRI,conventional diffusion-weighted imaging and DKI,Mean kurtosis(MK),mean diffusivity(MD)and apparent diffusion coefficient(ADC)were calculated.The patients were divided into the low-Ki-67 group(Ki-67≤25%)and high-Ki-67 group(Ki-67>25%)on the basis of the Ki-67 level.The difference of each parameter between the two groups was compared.Spearman correlation analysis was applied to confirm the correlation between each parameter value and Ki-67 expression level.The receiver operating characteristic(ROC)curve was used to evaluate the diagnostic efficacy of each parameter.Results In the high-Ki-67 group,MK and MD were significantly different compared with those in the low-Ki-67 group0.88(0.81,0.94)vs.1.22(1.06,1.34),P<0.01;1.20(1.12,1.30)×10^-3mm²/s vs.1.10(0.94,1.15)×10^-3mm²/s,P<0.01].However,MD showed no difference between the two groups1.20(1.12,1.30)×10^-3mm²/s vs.1.20(1.10,1.30)×10^-3mm²/s,P>0.05].MK showed a positive association with the Ki-67 expression level(r=0.523,P<0.001),whereas ADC showed a negative association with the Ki-67 expression level(r=-0.467,P<0.01).Compared with MD and ADC,MK showed relatively higher area under the ROC curve of 0.906,sensitivity of 0.97 and specificity of 0.75.Conclusion MK and ADC are related to Ki-67 expression,which can indirectly evaluate the proliferation of rectal adenocarcinoma cells.However,MK is superior to ADC in diagnosis efficiency,and can better reflect the invasion and molecular biological characteristics of rectal adenocarcinoma.