DKI直方图预测局部进展期直肠癌患者预后的临床价值

The clinical value of DKI histogram parameter metrics predicting survival in patients with locally advanced rectal cancer

目的:探讨弥散峰度成像(diffusion kurtosis imaging,DKI)直方图对局部进展期直肠癌(locally advanced rectal cancer,LARC)新辅助放化疗(neoadjuvant chemoradiation therapy,NCRT)预后的预测价值。方法:回顾并收集2015年1月—2017年12月于复旦大学附属肿瘤医院诊治的61例LARC患者,所有患者经NCRT后行直肠癌根治术。患者NCRT前1周内行包括DKI序列在内的直肠磁共振成像(magnetic resonance imaging,MRI)检查。评估NCRT前MRI表现:mrT分期、mrN分期、mr直肠系膜筋膜(mesorectal fascia,MRF)情况、mr系膜内血管侵犯(extramural vascular invasion,EMVI)情况、肿瘤位置及长度。记录NCRT前癌胚抗原(carcinoembryonic antigen,CEA)及糖类抗原(carbohydrate antigen,CA)19-9水平,术后评估肿瘤退缩分级(tumor regression grade,TRG)、神经侵犯(perineural invasion,PNI)及淋巴血管侵犯(lymphovascular invasion,LVI)情况。由1名放射科医生分割出NCRT前肿瘤全体积,随后生成K、D直方图及相应参数。Cox风险回归模型分析影响总生存期(overall survival,OS)的独立预后因素。结果:NCRT前D_(Skewness)能预测患者OS状态,其最佳诊断界值0.588,曲线下面积(area under curve,AUC)为0.678(P=0.044)。单因素分析显示NCRT前mrEMVI(+)[HR=9.796(2.623~36.580),P=0.001]、mrMRF(+)[HR=7.140(1.929~26.429),P=0.003]、CA19-9(+)[HR=5.111(1.634~15.993),P=0.006]、NCRT前D_(Skewness)高组[HR=4.054(1.043~22.888),P=0.044]及术后病理PNI(+)[HR=6.021(1.206~30.053),P=0.029]与较差OS相关。经多因素分析得出NCRT前mrEMVI(+)[HR=12.163(2.714~54.514),P=0.001]、CA19-9(+)[HR=5.032(1.440~17.577),P=0.011]、NCRT前D_(Skewness)高组[HR=13.518(2.000~91.378),P=0.008]是预后的独立危险因素。结论:NCRT前DKI直方图参数D_(Skewness)可作为LARC患者的OS预测因子,提示DKI直方图可预测LARC患者生存。

Objective:To determine histogram analysis of diffusion kurtosis imaging(DKI)in evaluating the prognostic factors for a locally advanced rectal cancer(LARC)treated with neoadjuvant chemoradiation therapy(NCRT).Methods:A total of 61 patients with rectal cancer were retrospectively collected and followed in Fudan University Shanghai Cancer Center between January 2015 and December 2017.All patients received NCRT followed by total mesorectal excision.The enrolled patients were examined using pretreatment magnetic resonance imaging(MRI)within 1week before NCRT.Pretreatment T stage,N stage,mesorectal fascia(MRF),extramural vascular invasion(EMVI),tumor location and length,pretreatment carcinoembryonic antigen(CEA)and carbohydrate antigen(CA)19-9 levels were recorded.Tumor response,perineural invasion(PNI)and lymphovascular invasion(LVI)were evaluated.Whole tumor volume of interest(VOI)was obtained by semi-automatic segmentation method in pretreatment MRI.Then,K and D histograms and corresponding parameters were calculated.The predictor of OS was analyzed by using Cox proportional hazards model.Results:Pretreatment D_(Skewness)predicted patients OS status with an optimal diagnostic cut-off value of 0.588 and an area under curve(AUC)of 0.678(P=0.044).The mrEMVI(+)[HR=9.796(2.623-36.580),P=0.001],mrMRF(+)[HR=7.140(1.929-26.429),P=0.003],CA19-9(+)[HR=5.111(1.634-15.993),P=0.006],high pretreatment D_(Skewness)[HR=4.054(1.043-22.888),P=0.044]and PNI(+)[HR=6.021(1.206-30.053),P=0.029)could be associated with worse OS in univariate analysis.Multivariate analysis identified the mrEMVI(+)[HR=12.163(2.714-54.514),P=0.001],CA19-9(+)[HR=5.032(1.440-17.577),P=0.011]and high pretreatment D_(Skewness)[HR=13.518(2.000-91.378),P=0.008]were independent risk predictors for worse OS.Conclusion:Pretreatment D_(Skewness)can be as a predictor for OS in LARC patients.DKI histogram can be used to predict survival of LARC patients.