中文摘要：

目的探讨兔肝VX2瘤MR灌注成像（PWI）动态变化的病理机制，以及PWI在评价肝脏肿瘤血管生成中的应用价值。方法建立15只兔肝VX2瘤模型，随机分成A、B、C3组，每组5只，分别在肿瘤种植成功后16、28d和45d对肿瘤进行PWI，随后处死荷瘤兔，并对瘤标本行免疫组化微血管密度（MVD）检测及H—E染色。PWI采用信号强度一时间曲线的最大信号下降斜率（SRSmax）作为定量指标，分析肿瘤SRSmax与MVD的相关性，并分析肿瘤PWI表现与病理特征的关系。结果除C组肿瘤周边区与瘤旁肝实质MVD计数的差异无统计学意义外（P〉0．05），余各组内VX2瘤中央区、周边区及瘤旁肝实质的SRSmax、MVD的差异有统计学意义（P〈0．05）。肿瘤的SRSmax与MVD呈正相关（r=0．731，P=0．002）。3组之间肿瘤的SRSmax、MVD的差异有统计学意义（P〈0．05），A组的SRSmax、MVD明显高于C组（P〈0．05）。结论兔肝VX2瘤PWI表现与其病理特征相符，PWI可用于评价肝脏肿瘤的血管生成状况。

英文摘要：

Objective To study the pathological mechanism of the dynamic appearnces on MR perfusion weighted imaging （ PWI） in rabbit hepatic VX2 carcinoma,and to evaluate the value of PWI in detecting liver tumor angiogenesis. Methods 15 New Zealand white rabbits with VX2 carcinoma were divided randomly into 3 groups{ group A,group B and group C） ,5 animals per group. PWI was performed in days 16,28 and 45 respectively after tumor implantation in all animals, then the rabbits were killed and immunohistochemical staining for mierovessel density（ MVD） and hematoxylin -eosin staining were conducted on representative pathological sections in tumor center,tumor border and paratumor parenchyma. Maximal signal reduction slope （SRSmax） of the signal intensity versus time curves were created as quantitative variable. The correlation between SRSmax and MVD was studied in tumor model, and the findings of PWI were compared with that of pathology. Results Except for no significant difference in MVD between tumor border and paratumor parenchyma in group C,there were all significant difference in both SRSmax and MVD in the other groups （P 〈 0.05 ）. There was a positive correlation between SRSmax and MVD in 15 rabbit hepatic VX2 carcinomas （ r = 0. 731, P = 0.002 ）. The difference was significant in SRSmax （ F = 6. 352, P = 0.013 ） and MVD （X^2 =9. 260 ,P =0. 010 ） of tumor border in 3 groups of tumors,and there was significant difference between group A and group C（ P 〈 0.05 ）. Conclusion The findings of VX2 carcinomas on PWI are matched with pathological characteristics,and PWI can be used in evaluating the liver tumor angiogenesis.