不同b值磁共振弥散加权像对胰腺癌与局灶性胰腺炎的鉴别诊断

目的探讨不同b值磁共振弥散加权像影像特征对局灶性性胰腺炎(Focal Pancreatitis,FP)与胰腺导管腺癌(Pancreatic Ductal Adenocarcinoma,PDA)的鉴别诊断价值。方法对37名PDA和28例FP患者进行D WI扫描,选取b值为0、400和800s/mm^2。两名磁共振诊断医师采用双盲法观察并比较6 5名患者不同b值磁共振弥散加权像影像特征。结果磁共振DWI诊断PDA的主要特征为胰管扩张(χ~2=10.481,P=0.001)、胰管中断(χ~2=1 3.094,P=0.000)及胰腺萎缩(χ~2=6.029,P=0.014),其中胰管中断对PDA的诊断敏感性、特异性及准确度分别为54.1%、89.3%及69.2%;诊断FP的主要特征是荚膜缘征和穿管征,其中荚膜缘征对局灶性胰腺炎的诊断敏感性、特异性及准确度分别为78.6%,100%和90.8%(χ~2=4 3.945,P=0.000)。FP和PDA病灶与周围正常胰腺分界无明显差异性(χ~2=2.652,P=0.103):但与FP相比,位于胰尾部PDA边缘清晰,两者具有明显差异性(χ~2=8.647,P=0.003)。结论不同b值弥散加权像相结合能够鉴别诊断FP与PDA。

Differential Diagnosis of PDA and FP with Different B-value DWI

Objective To investigate the differential diagnostic value of diffusion-weighted magnetic resonance imaging(DWI) with different b values in focalpancreatitis(FP) and pancreatic ductal adenocarcinoma(PDA). Methods 37 patients with PDA and 28 patients with FP were scanned by DWI with the b value of 0, 400 and 800 s/mm2. Two magnetic resonance diagnosticians observed and compared the imaging features of pancreatic lesions in 65 patients by double-blind method. Results The main features of PDA on DWI were pancreatic duct dilatation(χ~2=10.481, P=0.001), pancreatic duct cut-off(χ~2=13.094, P=0.000) and pancreatic atrophy(χ~2=6.029, P=0.014). The diagnostic sensitivity, specificity and accuracy of pancreatic duct cut-off for PDA were 54.1%、89.3% and 69.2% respectively. The main features of FP on DWI were capsule rim signand Ductpenetrating sign, in which the existence of capsule-rim sign had the highest predominance odds ratio in predicting FP. Its sensitivity, specificity and accuracy in the diagnosis of FP were 78.6%, 100% and 90.8%, respectively(χ~2=43.945, P=0.000).There was no significant difference between edges of PDA and FP(χ~2=2.652, P=0.103). However, compared with FP, the edge of PDA located at the tail of pancreas was clear, and there was significant difference between them(χ~2=8.647, P=0.003). Conclusion Diffusion weighted images with different b values can differentiate FP from PDA.