胰岛细胞瘤的MRI诊断——着重探讨3D Gd-DTPA动态增强MRI的应用

MRI Diagnosis of Pancreatic Islet Cell Tumors——Stressing the Applications of 3D Gd - DTPA Dynamic Enhanced MR Imaging

目的:分析胰岛细胞瘤的MRI表现,着重探讨3D Gd-DTPA动态增强MRI的应用。材料和方法:13例经手术病理证实的胰岛细胞瘤,3例男性,10例女性;年龄29～79岁,平均53.4±19.0岁。回顾性分析胰岛细胞瘤的MRI表现,比较MRI T_1加权(in phase)、GRE脂肪抑制T_1加权、T_2加权和Gd-DTPA GRE 3D动态增强四个序列对病灶的显示情况。结果:13例中,12例(92.3％)在MRI上共发现14个病灶,其中2例有两个病灶。病灶分布:胰头21.4％,胰体28.6％,胰尾50.0％。病灶最大径1.0～4.3cm,平均2.6±1.1cm。14个病灶中,在T-1加权同相位图像上,71.4％的病灶为低信号,28.6％为等信号;在脂肪抑制T_1加权,78.6％的病灶为低信号,21.4％为等信号;在T_2WI上,71.4％的病灶为高信号,28.6％为等信号;在Gd-DTPA增强后动脉期,71.4％的病灶明显强化,14.3％的病灶中等强化,14.3％为轻微强化。57.1％的病灶表现为均匀强化,28.6％为不均匀强化,14.3％为环状强化。四个序列对病灶的显示差异无统计意义(p>0.05)。结论:多数胰岛细胞瘤T_1WI上表现为低信号、T_2WI表现为高信号、Gd-DTPA增强MRI动脉期明显强化。3D增强MRI对病灶的显示与T_1WI和T_2WI相似,但3D增强MRI可显示病灶的血供。

Purpose: To study the MR imaging appearances of pancreatic islet cell tumors,stressing the applications of 3D Gd - DTPA dynamic enhanced MR imaging. Materials and Methods: Thirteen patients with pancreatic islet cell tumors confirmed by surgery and pathology were included in this study.Those were three men and ten women aged 29-79 years(mean 53.4 ± 19.0 years). The appearances of MR imaging of the tumors were studied, retrospectively, to compare the difference for the demonstration of the tumors among T1 weighteddn phase) with and without fat suppression, T2 weighted and post Gd - DTPA 3D dynamic MR imaging series. Results:In the thirteen patients, 12 patients(92.3%) had 14 lesions of pancreas on MR images, and 2 patients had 2 lesions, respectively. 21.4% of islet cell tumors were in the head of pancreas, 28.6% in the body and 50.0% in the tail.The maximal diameter of the tumors ranged from 1.0cm to 4.3cm(mean 2.6cm) .Of the 14 lesions, 71.4% of the lesions showed hypointensity and 28.6% iso - intensity on T1 WI (in phase); 78.6 % hypointensity and 21.4% isointensity on fat suppressed T1 WI; 71.4% hyperintensity and 28.6% isointensity on T2WI.On the arterial phase MR images after Gd - DTPA, 71.4% of the tumors showed intense enhancement, 14.3% moderate enhancement and 14.3% mild enhancement. 57.1% of the tumors had homogeneous enhancement, 28.6% heterogeneous enhancement and 14.3% ring enhancement. No significant difference for the demonstration of the lesions can be found among the four MRI series (p > 0.05) . Conclusion: Most islet cell tumors of the pancreas are hypointen-sity on T1 WI, hyperintensity on T2 WI and intense enhancement on the arterial phase images after Gd -DTPA.The demonstration of the lesions by enhanced MR imaging is similar to that by T1WI or T2WI, while the enhanced MRI can depict the angiogenesis of the tumors.