弥散加权成像对急性胰腺炎的诊断价值

目的探讨弥散加权成像(DWI)检查对急性胰腺炎的诊断价值。方法对21例急性胰腺炎患者及50例正常对照组进行常规MRI、DWI检查,测量DWI图像上胰腺及肝脏的信号强度,计算胰腺与肝脏的相对信号强度比(SIR),并测量胰腺的ADC值。结果常规DWI(b=500)正常胰腺的平均ADC值为(1.39±0.47)×10-3mm2/s,急性胰腺炎的平均ADC值为(1.03±0.32)×10-3mm2/s,急性胰腺炎的ADC值较正常胰腺低,两者差异具有统计学意义(t=-3.163,P<0.01)。DWI上急性胰腺炎患者胰腺的信号强度明显高于肝脏(SIR=2.63),正常对照组胰腺度信号强度与肝脏相似或稍高(SIR=1.64)。ROC曲线分析显示,常规DWI序列的曲线下面积0.831,当诊断界值SIR>2.02时灵敏度为72%,特异度为87.5%,Youden指数0.595。结论 DWI结合常规MRI检查可提高急性胰腺炎的检出率。

Diagnostic Value of Diffusion Weighted Imaging in Acute Pancreatitis

Objective To assess the diagnostic value of diffusion weighted imaging(DWI) in acute pancreatitis.Method Routine MRI and DWI were undertaken in 21 cases of acute pancreatitis and 50 cases of normal controls.The ADC value and the signal intensity of pancreas and liver were measured by DWI.The signal intensity ratio(SIR) of pancreas and liver was calculated.Results ADC value(b=500) in acute pancreatitis group(1.03±0.32)×10-3mm2/s] was less than that in the control group(1.39±0.47)×10-3mm2/s],there was a statistical difference(t=-3.163,P<0.01).In DWI,the signal intensity of pancreas in acute pancreatitis group was obviously higher than that of liver(SIR=2.63);the signal intensity of pancreas was similar or slighterly higher than that of liver in the control group(SIR=1.64).In ROC analysis of SIR,the AUC was 0.831 in routine DWI,when the cut off level SIR was >2.02,the sensitivity was 72% and the specificity was 87.5%,the Youden index was 0.595.Conclusions DWI combined with routine MRI can improve the sensitivity and accuracy in the diagnosis of acute pancreatitis.