采用MR弹性成像评价正常胰腺及鉴别胰腺占位性病变的价值

MR elastography of pancreatic masses：preliminary results

目的 探讨MR弹性成像（MRE）评价正常胰腺、鉴别胰腺占位性病变的价值.方法 回顾性搜集经手术病理证实的62例胰腺病变患者（病变组）,并招募健康志愿者20名（对照组）.病变组62例中,实性肿瘤57例（恶性39例、良性18例）,囊性肿瘤5例.所有受试者均行腹部低频（40 Hz）3.0 T MRE检查.测量胰腺肿瘤和正常胰腺组织的弹性值,并对两者采用Mann-Whitney U检验进行比较.采用ROC评价弹性值鉴别胰腺肿瘤的效能.结果 弹性图对病灶的总体检出率（敏感度）为91.9%（57/62）,误诊率（假阳性率）5.0%（1/20）,漏诊率（假阴性率）为8.1%（5/62）.对照组和病变组的弹性值[中位数（上、下四分位数）]分别为1.18（1.15,1.30）和2.43（1.94,3.64）kPa,差异有统计学意义（Z值为-5.967,P〈0.01）.以弹性值≥1.36 kPa区分正常胰腺与胰腺肿块的ROC下面积为0.946,诊断敏感度和特异度分别为93.6%和100.0%;以弹性值≥2.17 kPa鉴别良、恶性实性占位性病变的敏感度和特异度分别为82.1%和83.3%.结论 MRE有助于区分正常胰腺及胰腺占位性病变,并对鉴别胰腺良、恶性病变有一定价值.

Objective To investigate the feasibility of spin-echo echo-planar imaging（SE-EPI） of magnetic resonance elastography （MRE） for the diagnosis of pancreatic mass and to evaluate the difference of stiffness value in different pancreatic mass. Methods In a retrospective study, MRE was performed in 20 healthy volunteer （control group） and 62 patients with surgery-proved pancreatic masses, including pancreatic cystadenoma in 5 cases and solid masses of pancreas in 57 cases （39 with malignant mass and 18 with benign mass） using 3.0 T MRE. The differences of stiffness between two groups were evaluated using non-parametric Mann-Whitney U test. ROC was used to assess the diagnostic ability of elastogram for the detection of pancreatic masses, and to evaluate MRE-determined stiffness for the differentiation of masses from healthy pancreas, and malignancy from benign solid masses. Results The total detection rate of elastogram was 91.9%（57/62）,with false positive rate of 5.0%（1/20） and false negative rate of 8.1%（5/62）. The median stiffness value in the control group vs patient group were 1.18 kPa （interquantile range：1.15 to 1.30） kPa and 2.43 kPa （interquantile range：1.94 to 3.64 kPa） respectively, with statistically significant differences （Z=-5.967,P〈0.01）. The sensitivity and specificity of stiffness （≥1.36 kPa） to differentiate pancreatic mass from healthy pancreas was 93.6%and 100.0%, respectively, and to differentiate benign and malignant solid masses （≥2.17 kPa） was 82.1%and 83.3%, respectively. Conclusion MRE is a promising method in detecting and distinguishing different pancreatic masses.