逐层匀场技术弥散加权成像评价膀胱癌

Diffusion-weighted imaging with integrated slice-by-slice shimming for evaluation of bladder cancer

目的对比基于逐层匀场技术弥散加权成像(iShim-DWI)与常规弥散加权成像(DWI)图像质量,评估iShim-DWI对膀胱癌的应用价值。方法回顾性分析70例经手术病理证实的膀胱癌患者,依据TNM分期将其分为肌层浸润性膀胱癌(MIBC)组(n=34)和非肌层浸润性膀胱癌(NMIBC)组(n=36),根据术后病理分级分为低级别尿路上皮癌组(n=38)和高级别尿路上皮癌组(n=32)。观察常规DWI和iShim-DWI图像质量的差异。测量iShim-DWI病灶表观弥散系数(ADC),比较NMIBC组与MIBC组、高、低级别尿路上皮癌组ADC差异。以受试者工作特征(ROC)曲线评估ADC鉴别膀胱癌肌层浸润及高、低级别膀胱癌和T2WI、传统DWI及iShim-DWI诊断膀胱癌肌层浸润的效能。结果2名医师对iShim-DWI图像的主观评分均高于传统DWI(P均<0.01)。NMIBC组ADC[1.12(1.06,1.18)×10^(-3)mm^(2)/s]大于MIBC组[0.81(0.75,0.83)×10^(-3)mm^(2)/s,Z=-6.79,P<0.01],ADC鉴别MIBC与NMIBC的AUC为0.97;低级别尿路上皮癌组ADC[1.13(1.06,1.17)×10^(-3)mm^(2)/s]大于高级别尿路上皮癌组[0.80(0.74,0.82)×10^(-3)mm^(2)/s,Z=-6.79,P<0.01],AUC为0.99。基于T2WI+常规DWI诊断膀胱癌肌层浸润的AUC均低于T2WI+iShim-DWI(P均<0.05)。结论iShim-DWI有助于评估膀胱癌病理分级及肌层浸润,且图像质量优于常规DWI。

Objective To compare the image quality of diffusion-weighted imaging based on integrated slice-by-slice shimming technique(iShim-DWI)and conventional diffusion-weighted imaging(DWI),and to evaluate the value of iShim-DWI for bladder cancer.Methods Data of 70 patients with post-surgery pathology confirmed bladder cancer were retrospectively analyzed.The patients were divided into muscular invasive bladder cancer(MIBC)group(n=34)and non-muscular invasive bladder cancer(NMIBC)group(n=36)as well as low-grade urothelial carcinoma group(n=38)and high-grade urothelial carcinoma group(n=32)according to TNM stages and post operation pathological findings,respectively.The image quality of conventional DWI and iShim-DWI were scored and compared.The apparent diffusion coefficients(ADC)were measured on iShim-DWI,and ADC were compared between NMIBC group and MIBC group,also between high and low grade urothelial carcinoma group.Receiver operating characteristic(ROC)curves were drawn to evaluate the efficacy of ADC for differentiating muscular invasions and grades of bladder cancer,and the diagnostic efficacy of muscular invasion of bladder cancer was compared between T2WI+traditional DWI and T2WI+iShim-DWI,then the corresponding areas under the curves(AUC)were calculated.Results The subjective scores of iShim-DWI were higher than those of traditional DWI images(both P<0.01).ADC of NMIBC group(1.12[1.06,1.18]×10^(-3)mm^(2)/s)was higher than that of MIBC group(0.81[0.75,0.83]×10^(-3)mm^(2)/s,Z=-6.79,P<0.01),and AUC of ADC for differentiating MIBC and NMIBC was 0.97.ADC of low-grade urothelial carcinoma group(1.13[1.06,1.17]×10^(-3)mm^(2)/s)was higher than that of high-grade urothelial carcinoma group(0.80[0.74,0.82]×10^(-3)mm^(2)/s,Z=-6.79,P<0.01),and AUC of ADC in judging low and high-grade urothelial carcinoma was 0.99.AUC of assessing muscular invasion of bladder cancer based on T2WI+conventional DWI was lower than that of T2WI+iShim-DWI(both P<0.05).Conclusion IShim-DWI was helpful to evaluation of pathological grade and muscular infiltration of bladder cancer with image quality better than traditional DWI.