兔VX2肝癌MRI征象与病理对照研究

目的探讨新西兰兔VX2肝癌MRI征象的病理学基础。方法移植法建立新西兰兔VX2肝癌模型20只共32个瘤灶。模型建立后2~4周,全部兔肝癌模型行肝脏MRI平扫,10只兔肝癌模型(包括15个瘤灶)加做MRI增强扫描。MRI检查完成后,留取肿瘤最大横截面标本,行VX2肝癌MRI征象与病理学对照研究。结果种植瘤成活率为100%。T2WI 6个瘤灶呈均匀稍高信号,其余26个瘤灶显示特征性瘤内异常信号,其中"结中结征"5个瘤灶、"靶环征"7个瘤灶、"点彩征"14个瘤灶。对照研究证实此种瘤内异常信号病理基础为不同结构类型的坏死肿瘤组织。增强后肿瘤环形强化,轻微强化6个瘤灶,中等程度强化7个瘤灶,明显强化2个瘤灶,光镜下轻微强化者强化肿瘤组织有大量点状坏死区,明显强化者瘤内血窦明显扩张。结论MRT2WI可评价坏死肿瘤组织结构类型,兔VX2肝癌肿瘤强化程度与肿瘤内血窦扩张程度及瘤内点状坏死数量有关。

Comparative Study on MRI Features and Pathology of Rabbit VX2 Hepatic Carcinoma

Objective To investigate the pathologic bases of MRI manifestations of rabbit VX2 hepatic carcinoma.Methods 32 foci of hepatic carcinoma models in 20 rabbits VX2 were set up by implantation.Plain MR examinations in all rabbits and contrast-enhanced MR scan in 10 rabbits(15 foci) were performed 2~4 weeks after implantation.The largest transverse section specimens of all the tumors were obtained for imaging-pathology comparative study after MR scan.Results All the 32 tumors were detectable on both T1WI and T2WI.The size of the tumors ranged from 0.5 to 3.5 cm in diameter.6 foci showed homogeneous slight hyperintense on T2WI,the other 26 showed characteristic intratumoral signal intensity on T2WI,including "nodule in nodule"sign in 5 foci,"target"sign in 7 foci,and "dot and color"sign in 14 foci.The characteristic intratumoral signal showed on T2WI were pathologically testified as necrotic tumor tissue of different structures.All the 15 tumors with contrast-enhanced scan appeared annular enhancement in different degrees,slight enhancement in 6,medium enhancement in 7 and obvious enhancement in 2.The sinusoidlike vascular space between tumor cells were significantly dilated in the obvious enhancement cases,and there were many spots of necrosis in the slight enhancement tumors under microscope.Conclusion The tectology of intratumoral necrosis can be evaluated by T2WI.Enhanced degree after administration of contrast agent in the hepatic cancer in rabbit model is associated with dilating degrees of sinusoidlike vascular space and number of dotted necrosis of tumors.