磁共振扩散加权成像在胰腺囊性病变中的鉴别诊断价值

MR diffusion weighted imaging in the differential diagnosis of cystic lesions of the pancreas

目的 评价磁共振扩散加权成像（DWI）在胰腺囊性病变中的鉴别诊断价值.方法 收集经临床和（或）病理证实的34例胰腺囊性病变,包括非肿瘤性病变的假性囊肿11例、单纯囊肿5例,肿瘤性病变的浆液性囊腺瘤6例、黏液性囊腺瘤10例、黏液性囊腺癌2例.34例均行常规MRI平扫及动态增强、DWI（b值0,600 s/mm2）扫描,记录病变DWI信号特点,测量病变及毗邻胰腺实质表观扩散系数（ADC）值,计算病变-胰腺实质ADC值比（ADCR）.采用受试者工作特征（ROC）曲线评价病灶ADC值及ADCR的诊断价值.结果 16例非肿瘤性囊性病变组中2例DWI上呈稍高信号,14例呈等信号,18例肿瘤性囊性病变组中17例呈高或稍高信号,l例呈等信号,两组差异具有统计学意义（P ＜0.001）.非肿瘤性、肿瘤性囊性病变的ADC值分别为（3.30 ±0.30）×10-3、（2.74±0.34）×10-3mm2/s;ADCR分别为1.85 ±0.20、1.31 ±0.21,差异均具有统计学意义（P值均＜0.001）.ADC值及ADCR诊断胰腺肿瘤性囊性病变的ROC曲线下面积分别为0.94±0.04、0.98±0.02.ADC值以3.105×10-3 mm2/s为阈值,诊断肿瘤性囊性病变的敏感性为81.3％,特异性为94.4％,ADCR值以1.525为阈值,诊断肿瘤性囊性病变的敏感性为100％,特异性为88.9％.结论 DWI在胰腺囊性病变的诊断与鉴别诊断中具有重要价值,可作为常规MRI的重要补充.

Objective To evaluate the value of diffusion-weighted imaging （DWI） in the differential diagnosis of cystic pancreatic lesions.Methods Thirty-four cystic pancreatic lesions confirmed clinically or pathologically were collected,including 11 case of non-neoplastic pseudocyst,5 cases of simple cyst,6 cases of serous cystadenoma,10 cases of mucinous cystadenoma and 2 cases of mucinous cystadenocarcinoma.All the patients underwent routine serial MR and echo-planar DW imaging examination of the pancreas with b values of 0 and 600 s/mm2.The appearances of signal intensity of DWI with all cysts were recorded.ADC maps were reconstructed,and the ratio of the cysts and cyst-to-pancreas ADC （ADCR） were calculated.The receiver operating characteristic （ROC） curves were constructed to evaluate the diagnostic value of ADC and ADCR.Results Among all the 16 non-neoplastic cysts,2 cysts were slightly hyperintense in DWI,and 14 cysts were isointense.Among all the 18 neoplastic cysts,17 cysts appeared slightly hyperintense or hyperintense in DWI,and 1 cyst was isointense.The difference between the two groups was statistically significant （P 〈 0.001）.The ADC values of non-neoplastic and neoplastic cysts were （3.30 ± 0.30） × 10-3,（2.74 ± 0.34） × 10-3 mm2/s ; and the ADCR values of non-neoplastic and neoplastic cysts were 1.85 ± 0.20,1.31 ± 0.21,the difference between the two groups was statistically significant （P 〈 0.001）.The areas under the ROC curves of ADC and ADCR diagnosing neoplastic cysts were 0.94 ± 0.04,0.98 ± 0.02,respectively.An ADC of 3.105 × 10-3 mm2/s showed 81.3% sensitivity and 94.4% specificity for predicting neoplastic cysts.An ADCR of 1.525 showed 100% sensitivity and 88.9% specificity for predicting neoplastic cysts.Conclusions Diffusion-weighted imaging is of importance in the diagnosis and differential diagnosis of pancreatic cysts,and can be applied as a complementary tool for routine MRI.