CT征象对胃肠间质瘤恶性程度预测的诊断价值

目的:探讨CT征象与胃肠间质瘤(gastrointestinal stromal tumors,GIST)恶性程度的相关性。方法:回顾性分析36例手术病理证实的胃肠道间质瘤的CT表现,对照病理组织学分级,主要观察病变的发病部位、大小、形态、生长方式、密度、强化程度、周围有无淋巴结转移、邻近器官有无受侵、有无远处转移灶等方面。结果:36例GIST肿块大小不一,肿块大小与恶性程度密切相关(P<0.05)。病灶形态与恶性程度无统计学差异(P=0.870)。肿块生长方式与恶性程度无统计学差异(P=0.601)。肿瘤强化程度与恶性程度关系见表3,无明显统计学差异(P>0.05)。本组资料出现"牛眼征"(肿块明显不均匀强化,缺血和坏死部分呈低密度,其余实质呈高密度增强)的交界组50%、恶性组83%。肿瘤强化方式与恶性程度差异有统计学意义(P<0.05)。2例网膜肿块与周围组织粘连分界不清。有3例肝内转移,1例腹腔广泛种植转移;36例均未见淋巴结转移表现。结论:肿块的部位、大小、密度、牛眼征,强化方式单因素分析均有统计学意义;肿块的形态、边缘、强化程度和生长方式对胃肠间质瘤恶性程度评估无统计学意义。通过逐步回归分析肿块大小对胃肠间质瘤良恶性判断最有特异性,且肿块直径大于5cm并出现"牛眼征"时,可明确的诊断为恶性GIST。

CT findings for the prediction of malignancy in gastrointestinal stromal tumors

Objective:To evaluate spiral CT features of gastric stromal tumors and the value for the prediction of malignancy in gastrointestinal stromal tumors.Methods:Plain and enhanced spiral CT scan were performed in 36 patients with gastric stromal tumors which were proved by operation and pathology.Two radiologists retrospectively reviewed the CT findings with the consensus in terms of lesion size,contour,tumor growth pattern,enhancing pattern,degree of enhancement,mesenteric fat infiltration,ulceration,direct invasion to adjacent organ,and distant metastasis.Results:Size,presence of an ulcer,mesenteric fat infiltration,direct organ invasion,and metastasis were more frequently observed during univariate analysis in tumors with a high mitoticrate(P< 0.05).With stepwise logistic regression analysis,the size was the only significant predictor of a high mitotic rate.Conclusion:Although the presence of bull eye sign,site,mesenteric fat infiltration,enhancing pattern,direct organ invasion,and metastasis are more frequently observed in tumors with a high mitotic rate.No CT feature,other than size,was found to have predictive value with respect to malignant gastrointestinal stromal tumor.