扩散峰度成像与直肠腺癌分期及组织病理学分级的相关性研究

Correlation Between Diffusion Kurtosis Imaging and TN Stage, Histological Differentiation Grade of Rectal Adenocarcinoma

目的探讨扩散峰度成像(DKI)与直肠腺癌分期及组织病理学分级的相关性。方法搜集术前行高分辨率MRI、常规DWI(b=0,1000 s/mm2)及DKI(b=0,600,1000,2000 s/mm2)检查的59例直肠腺癌患者,采用美国癌症联合委员会(AJCC)第八版结直肠腺癌分期标准对患者进行术后T、N分期,采用结直肠肿瘤WHO分类的组织病理学分级标准,以腺管结构形成的百分率对患者进行术后分级,并比较平均扩散峰度(MK)、平均扩散系数(MD)及表观扩散系数(ADC)在不同TN分期及高、低级别直肠腺癌间的差异,通过受试者工作特征曲线(ROC)来确定各定量参数的诊断效能,Spearman相关分析用于评估各定量参数与直肠腺癌WHO组织病理学分级的相关性。结果MK值随着直肠腺癌TN分期及WHO分级的增加而增高,差异有统计学意义(P<0.05);N0期直肠腺癌的MD值明显高于N1-2期(P<0.05);不同T分期及WHO分级间直肠腺癌的MD值差异无统计学意义(P>0.05);不同TN分期及WHO分级间直肠腺癌的ADC值差异无统计学意义(P>0.05)。MK值较MD值、ADC值具有更大的曲线下面积(AUC),为0.82,以1.11为诊断阈值时,敏感度为60.0%,特异度为94.9%。MK值与直肠腺癌WHO组织病理学分级呈正相关(r=0.53,P<0.001),MD值、ADC值与直肠腺癌WHO组织病理学分级间未见明显相关性(P>0.05)。结论MK值可以作为鉴别直肠腺癌术前TN分期及组织病理学分级的一个参考指标,DKI模型对高、低级别直肠腺癌的诊断效能优于传统DWI。

Objective To explore the correlation between diffusion kurtosis imaging(DKI)-derived parameters and TN stage,histological differentiation grade for rectal adenocarcinoma.Methods 59 patients with rectal adenocarcinoma who underwent surgery were selected in this retrospective study.The image data included high resolution MRI(HR-MRI),conventional diffusion weighted imaging(DWI)and DKI.Pathologic staging was performed by pathologists according to the American Joint Committee on Cancer eighth TNM classification.Tumors are classified as grade 1(G1),grade 2(G2),or grade 3(G3)according to WHO grading criteria.Relationships between the quantitative parameters and tumor pathology indexes including histological differentiation grade,tumor TN stage were assessed.The receiver operating characteristic(ROC)curve was used to evaluate the diagnostic efficacy of each parameter.Spearman correlation analysis was applied to confirm the correlation between each parameter value and WHO grading criteria of rectal adenocarcinoma.Results The MK values increased with the increase of TN staging and WHO classification of rectal adenocarcinoma,and the difference was statistically significant(P<0.05).The MD values were significantly higher in N0 stage group than in N1-2 stage group(P<0.05).There was no significant difference in MD values between different T classification and WHO grade(P>0.05).There was no significant difference in ADC values between different TN classifications and WHO grade(P>0.05).MK values showed relatively higher AUC compared with MD and ADC values in differentiating high and low grade tumors with the area under the ROC curve(AUC)of 0.82,sensitivity of 0.60 and specificity of 0.949.MK value showed a positive association with rectal adenocarcinoma WHO grade(r=0.53,P<0.001).There were no significant correlation between MD,ADC value and rectal adenocarcinoma WHO grade(P>0.05).Conclusion MK value derived from DKI demonstrated a higher correlation with histologic grades compared with MD and ADC value.