磁共振扩散加权成像对胰腺癌的诊断价值探讨

Study on diagnostic value of DWI in pancreatic carcinoma

目的探讨磁共振扩散加权成像(DWI)及表观扩散系数(ADC)对胰腺癌的诊断价值。方法回顾性研究该院2009年5月至2010年11月行腹部常规磁共振成像(MRI)、DWI及增强扫描的37例胰腺癌患者(胰腺癌组)的影像学资料,其中胰头癌28例,胰腺颈部癌3例,胰腺体尾部癌6例。对照组32例为同期接受上腹部检查患者(临床、影像学及实验室检查均排除胰腺病变)。采用Philips1.5 T或3.0 T超导型磁共振扫描仪行常规MRI及DWI扫描,分析胰腺癌的DWI影像学表现;测量胰腺癌、癌周组织及正常胰腺ADC值,并进行单因素方差分析;绘制受试者工作特征(ROC)曲线,确定最佳诊断阈值,判断其诊断价值,计算ADC诊断胰腺癌的灵敏度、特异性及准确度。结果 37例患者胰腺癌组织在DWI序列上呈高信号。胰腺癌、癌周组织及正常胰腺组织平均ADC值分别为(1.470±0.188)×10-3、(1.571±0.175)×10-3、(1.683±0.169)×10-3mm2/s,三者ADC值比较,差异有统计学意义(F=12.207,P<0.01)。最佳阈值(ADC=1.503×10-3 mm2/s)诊断胰腺癌的灵敏度为78.38%,特异性为87.50%。ROC曲线下面积为0.817,具有中等诊断价值。结论胰腺癌组织在DWI序列上呈高信号。胰腺癌组织与正常组织的平均ADC值差异明显,测量ADC值有助于胰腺癌的诊断。

Objective To analyze the diagnostic value of magnetic resonance diffusion-weighted imaging （DWI） and ap parent diffusion coefficient（ADC） in pancreatic carcinoma. Methods The imaging data in 37 patients with pancreatic carcinoma undergoing routine MRI,DWI and enhancement scanning in our hospital from May 2009 to November 2010 were retrospectively analyzed,including 28 cases of pancreatic head carcinoma,3 cases of pancreatic neck carcinoma and 6 cases of pancreatic body and tail carcinoma. Contemporaneous 32 patients with upper abdominal examination （excluding pancreatic diseases by clinical, imaging and laboratory detection） were selected as the control group. The Philips 1.5 T or 3.0 T superconduction MR scanner was adopted to conduct routine MRI and DWI scanning for analyzing the DWI imaging manifestations of pancreatic carcinoma;The ADC values of pancreatic carcinoma,pericancerous tissue and normal pancreas were measured and analyzed by using the one way Anova. The receiver operating characteristic（ROC） curve was drawn to determine the best diagnostic threshold,then their diagnos-tic value was judged,and the sensitivity,specificity and accuracy of ADC for diagnosing pancreatic carcinoma were calculated. Results All 37 cases of pancreatic carcinoma tissue displayed hyperintensity signal on DWI sequence. The mean ADC values of cancer,pericancerous tissue and normal pancreas were（1.470±0.188）×10-3,（1.571±0.175）×10-3,（1.683±0.169）×10-3 mm2/s re-spectively,showing statistical different among them（F=12.207,P〈0.01）. The sensitivity and specificity of the best diagnostic threshold（ADC=1.503×10-3 mm2/s） for diagnosing pancreatic carcinoma were 78.38%and 87.50%respectively. The area under the ROC curve was 0.817,which had the middle diagnostic value. Conclusion Pancreatic carcinoma tissue displays hyperinten-sity signal on DWI sequence. There is obvious difference in average ADC value between pancreatic carcinoma tissue and normal pancreatic tissue. So the measure of ADC may contribute to diagnose pancreatic carcinoma.