胰腺神经内分泌瘤的MRI征象对术前病理分级的应用价值

Application Value of MRI Signs in Preoperative Pathological Classification of Pancreatic Neuroendocrine Tumors

目的:探讨MRI对于胰腺神经内分泌瘤术前病理分级的应用价值。方法:回顾性分析38例胰腺神经内分泌瘤(pancreatic neuroendocrine tumors,PNETs)患者的MRI增强及弥散加权成像(diffusion-weighted imaging,DWI)图像,所有患者术后病理按照2018 IARC/WHO共同分类框架标准进行分级,包括G1-3级。分析病灶的主要影像学征象包括:瘤体位置、有无囊变坏死、瘤径、肿瘤形态是否规则、肿瘤边界是否清晰、有无主胰管扩张、有无转移、强化方式及表观扩散系数(apparent diffusion coefficient,ADC)值。等级资料采用Kruskal-Wallis秩和检验方法进行分析;计量资料采用t检验对比分析。结果:38例PNETs中G1级4例、G2级20例、G3级14例。MRI图像一般特征对比提示瘤体位置(P=0.002)、瘤径(P=0.010)、瘤体形态及边缘(P<0.001)、转移(P<0.001)在G1-2级与G3级组间差异有统计学意义;G1-2与G3级PNETs间的MRI强化方式差异有统计学意义(P<0.05);功能参数ADC值G1与G2组间差异无统计学意义(P=0.237),G1-2与G3级间存在统计学差异(P=0.030)。结论:MRI及DWI检查对于PNETs术前分级具有指导价值。瘤径大、瘤体形态不规则、边界模糊、伴有转移、延迟期低信号及ADC值低均有助于高级别PNETs的诊断。

Objective:To investigate the application value of MRI signs in preoperative pathological classification of pancreatic neuroendocrine tumors(PNETs).Methods:We analyzed MRI enhancement and diffusion-weighted imaging(DWI)images of 38 patients which were confirmed as PNETs.Postoperative pathological results of all patients were graded(1-3)according to A common classification framework for neuroendocrine neoplasms:an International Agency for Research on Cancer(IARC)and World Health Organization(WHO)expert consensus proposal.Signs of the lesion including location,diameter,morphology and margin of the tumor,incidences of cystic necrosis,main pancreatic duct dilatation and metastasis,as well as enhancement methods and apparent diffusion coefficient(ADC)values.Ranked data were analyzed using Kruskal-Wallis rank sum test;measurement data were analyzed by the t-test.Results:Among the 38 PNETs patiens,4 cases were in G1,20 cases in G2,and 14 cases in G3.There were statistically significant differences between G1-2 and G3 patients in tumor location(P=0.002),tumor diameter(P=0.010),tumor morphology(P<0.001),tumor margin(P<0.001),enhancement methods(P<0.05)and the incidence of metastasis(P<0.001).There was statistically significant difference between G1-2 and G3 patients in the ADC value(P=0.030),and there was not between G1 and G2 patients(P=0.237).Conclusion:MRI and DWI are instructive for preoperative classification of PNETs.Large tumor diameter,irregular tumor morphology,blurred margins,incidence of metastasis,low signal in the delayed phase,and low ADC value all contribute to the diagnosis of high-grade PNETs.