动态增强磁共振成像对胰腺癌及胰腺内分泌肿瘤的诊断价值探讨

Value of dynamic enhanced magnetic resonance in diagnosis of pancreatic carcinoma and endocrine tumors

目的评价动态磁共振增强扫描对胰腺癌及胰腺内分泌肿瘤的诊断价值。方法对术前均行磁共振平扫和动态增强扫描的22例胰腺癌和9例胰腺内分泌肿瘤的MR表现进行对照分析。结果22例胰腺癌(4例未见肿块),在FS-T1WI上呈低信号11例,略低信号6例,等信号1例;在FS-T2WI上呈高信号5例,稍高信号7例,等信号5例,略低信号1例,其中13例信号不均。动态增强后动脉期均未见明显强化;胰期和门静脉期强化明显,呈等信号5例,略低信号10例,低信号3例;其中5例小胰腺癌4例为等信号,1例为略低信号。在延迟期强化程度下降。9例胰腺内分泌肿瘤(1例未见肿块),在FS-T1WI上低信号5例,略低信号3例;在FS-T2WI上高信号2例,较高信号4例,等信号2例。增强动脉期2例中度强化,6例均未见明显强化;在胰期和门静脉期强化明显,瘤体呈等信号2例,略低信号1例,较高信号5例,6例瘤体周边薄壁环形强化。结论动态MRI增强对两种病变鉴别有一定价值:(1)胰腺癌可有不同程度强化,其最大强化程度不超过正常胰腺组织;(2)胰腺内分泌肿瘤多数可有较明显强化,其最大强化程度可超过正常胰腺组织,瘤体周边薄壁环形高密度强化为本病特征性表现。

Objective To explore the value of dynamic enhanced magnetic resonance （MR） in diagnosis of pancreatic carcinoma and endocrine tumors. Methods Twenty-two patients with pancreatic carcinoma and 9 patients with pancreatic endocrine tumors underwent routine MR scanning and dynamic contrast enhanced MR examination before they underwent operation. Results No tumor image was seen in 4 of the 22 patients with pancreatic carcinoma by routine MR scanning. Fat-saturated T1 -weighted imaging （FS- T1 WI） showed that 11 of them were hyposignal, 6 slightly hyposignal, and 1 isosignal; and fat- saturated T2-weighted imaging （FS- T2 WI ） showed that 5 were hypersignal, 7 slightly hypersignal, 5 isosignal, 1 slightly hyposignal, and 13 with heterogeneous signals. After dynamic MR imaging no tumor was enhanced in the arterial phase （AP） ; and all the tumors were obviously enhanced during the pancreatic phase （PP） and portal venous phase （PVP）, 5 of which showed isosignal intensity, 10 slightly hyposignal intensity, and 3 hyposignal intensity. Four of the 5 cases with small pancreatic carcinoma were demonstrated as isosignal and one was slightly hyposignal. During the delayed enhancement phase （DEP） the signal intensity of the tumors became slightly weaker. No tumor image was seen in 14 of the 9 patients with pancreatic endocrine tumors by routine MR scanning. FS- T1 WI showed that 5 of them were hyposignal, and 3 slightly hyposignal ; and FS- T2 WI showed that 2 were hypersignal, 4 slightly hyposignal, and 2 isosignal. After dynamic MR imaging 2 cases were moderately enhanced and 6 cases mildly enhanced during AP, and all pancreatic endocrine tumors were obviously enhanced during PP and PVP, with isosignal intensity in 2 cases, slightly hyposignal intensity in 1 case, and slightly hypersignal intensity in 5 cases. Peritumor thin- walled enhancement was seen in 6 cases. Conclusion Dynamic enhanced MR has a certain value in the diagnosis of pancreatic carcinoma and endocrine tumors. Pancreatic carcinoma shows various enhanced forms by dynamic enhanced magnetic resonance, the degree of the greatest enhanced form not surpassing that of normal pancreatic tissue. Pancreatic endocrine carcinoma shows obvious enhanced forms by dynamic enhanced magnetic resonance, the degree of the greatest enhanced form surpassing that of normal pancreatic tissue. Peritumor thin-walled enhancement is a characteristic feature of pancreatic endocrine carcinoma.