胰腺神经内分泌肿瘤MRI表现在术前分级中的应用价值

Value of magnetic resonance imaging features in the grading of pancreatic neuroendocrine neoplasms

目的:探讨胰腺神经内分泌肿瘤(PNENs)MRI特征在肿瘤术前分级评估中的应用价值。方法:将99例(共114个病灶)术前行MRI检查的PNENs患者纳入本研究。根据WHO 2010年标准对114个肿瘤进行病理分级,其中G1级69个、G2级38个、G3级7个。分析病灶的主要MRI特征,包括位置、最大径、边界、、强化方式、以及有无囊变、胰管扩张、胰周血管或脏器侵犯和肝转移等。采用χ~2检验、Kruskal-Wallis秩和检验和方差分析等方法对不同病理分级PNENs的MRI表现进行比较。结果:边界不清、囊变、胰周血管或脏器侵犯、胰管扩张、肝转移、低-低型强化(动脉期及门脉期)等特征在高级别尤其是G3级PNENs中更常见,G1和G2级在强化方式上多表现为持续性高强化。在边界不清楚、最大径≥3cm、胰周血管或脏器侵犯、肝转移和低-低型强化方式这5项特征中具有任意两个以上特征时,鉴别G3级与G1～G2级PNENs的敏感度和特异度为100%和87%。具有边界清楚、最大径≤2cm、无胰周血管/脏器侵犯、无肝转移和高-高型强化方式这5个特征中的四个及以上特征时,鉴别G1级与G2～G3级PNENs的敏感度及特异度分别为91%和49%。结论:不同病理分级的PNENs的MRI特征有一定差异,MRI检查有助于PNENs的术前诊断。

Objective:To explore the application value of MRI features in the grading of pancreatic neuroendocrine neoplasms(PNENs)before surgery.Methods:A total of 99 patients(114 lesions)with PNEN who underwent preoperative MR scan were included from January 1st 2012 to December 30th 2016.All cases were confirmed as PNENs by post-operative pathology.The 114 tumors was graded as G1(n=69),G2(n=38)and G3(n=7)based on the 2010 WHO classification criteria.MR imaging features of the tumors included location,size,boundary,cystic degeneration,enhancement patterns,dilatation of pancreatic duct,invasion of peri-pancreatic vessels or organs and liver metastasis.Statistical analysis methods includingχ2 test,Kruskal-Wallis test,variance analysis,were used to compare the difference of MRI features among the tumors with different grades.Results:Ill-defined boun-dary,cystic degeneration,peri-pancreatic invasion,bile duct dilatation,liver metastasis,hypo-intensity in both arterial and portal phases(named low-low enhancement pattern)were more commonly seen in higher grade of PNENs,especially in G3.When at least two of the five features(ill-defined boundary,size≥3cm,invasion of vessel or organs,liver metastasis,low-low enhancement pattern)were used as criteria,sensitivity and specificity of differentiating G3 PNENs from G1 and G2 PNENs were 100%and 87%respectively.When at least four of the five criteria(well-defined boundary,size≤2cm,no invasion of vessel or organs,no liver metastasis,high-high enhancement pattern)were used,sensitivity and specificity of differentiating G1 PNENs from G2 and G3 PNENs were 91%and 49%respectively.Most G1 and G2 PNETs were characterized by persistent enhancement.Conclusion:MR imaging features vary with different grades of PNENs.MRI examination is helpful for preoperative diagnosis of pancreatic neuroendocrine neoplasms.