非功能性胰岛细胞瘤螺旋CT表现与鉴别诊断

Spiral CT Diagnosis and Differentiation of Non-Functioning Islet Cell Tumor

目的:探讨螺旋CT在非功能性胰岛细胞瘤诊断和鉴别诊断中的价值.方法:回顾性分析经手术病理证实的5例非功能性胰岛细胞瘤的螺旋CT表现.采用平扫和双期(动脉期和门静脉期)增强扫描,动脉期、门静脉期扫描延迟时间分别为25 s、70 s.结果:5例肿瘤中位于胰头2例、胰体1例、胰尾2例,平均直径7.6 cm(4.5～12.6 cm).实体性肿瘤(n=2)平扫呈稍低密度,囊性者(n=3)囊壁及壁结节(实性成份)呈等或稍低密度,有囊壁钙化者2例.增强扫描示实性者动脉期明显强化,门静脉期中度～明显强化;囊性者动脉期囊壁、壁结节呈中度～明显强化,门静脉期轻度～中度强化,囊性部分在增强扫描前后均呈低密度.5例均不伴有胆总管和胰管扩张.结论:实性非功能性胰岛细胞瘤螺旋CT增强扫描表现有一定特征性;囊性者缺乏特征性改变,需与囊腺瘤(癌)、胰腺癌囊变、胰腺实性假乳头状瘤、胰腺假性囊肿及胰腺结核等鉴别.

Objective：To evaluate spiral CT scanning in the diagnosis and differentiation of non-functioning islet cell tumor （NFICT）. Methods：CT features of five patients with surgically and pathologically proved NFICT were retrospectively analyzed. The CT findings were investigateld by using pre-contrast and contrast scanning （including arterial and portal venous phase） with 10mm thickness and 1.0 pitch. The contrast-enhanced study started in 25s and 70s after initiation of injection of the contrast medium with a volume of 60～80ml at the rate of 2.5ml/s. Results：The average diameter of the NFICT was 7.6cm （4.5～12.6cm）. The tumor localized in the pancreatic head in 2 cases,in the pancreatic body in 1 case, and in the pancreatic tail in 2 cases. On pre-contrast imaging the solid tumors （n=2） showed mild hypodensity; the cystic walls and mural nodules of the cystic tumor （n=3） showed isodensity or mild hypodensity, the cystic walls exhibited calcification in 2 cases. The solid tumors showed marked enhancement during arterial phase, moderate to marked enhancement during portal venous phase. The cystic walls and mural nodules showed moderate to marked enhancement during arterial phase,mild to moderate enhancement during portal venous phase. The cystic portions appeared hypodensity on both pre- and post- contrast views. There was no associated dilatation of the common bile duct or pancreatic duct. Conclusion： The spiral CT characteristic findings of solid NFICT might be of great value for the diagnosis, there was no spiral CT characteristic findings in the cystic NFICT. The cystic NFICT should be differentiated from cyst-adenoma, cyst caninoma, solid-pseudo- papillary tumors of the pancreas （SPTP）, pseudo-cyst of the pancres, pancreatic tuberculosis and cystic degeneration of pancreatic carcinoma.