兔VX2肝癌模型的MR扩散加权成像与肿瘤恶性程度的相关性

Correlation between MR diffusion weighted imaging with malignant degree of rabbit liver VX2 tumor models

目的探讨不同时间点兔VX2种植性肝癌模型肿瘤实性部分的表观扩散系数（ADC）值与细胞密度和增殖细胞核抗原标记指数（PCNA—LI）的相关性。方法将成功建立模型的38只实验兔随机分为两组，每组均为19只，分别在种植后第14天和21天行DWI检查，并对全部肿瘤标本行HE及PCNA染色。结果（1）第21天肿瘤实性部分的ADC值（×10^-3mm2／s）均低于第14天（0．77±0．19vs1．00±0．24，P=0．007）；（2）第21天肿瘤实性部分的细胞密度和PCNA—LI均高于第14天（63％±7％vs43％±10％，P=0．011；80％±11％vs56％±8％，P=0．008）；（3）两个时间点肿瘤实性部分的ADC值均与其细胞密度和PCNA—LI呈负相关（r=-0．695，P=0．000；r=-0．698，P=0．000）。结论在影响兔VX2种植性肝癌模型肿瘤实性部分ADC值的因素中，细胞密度可能起关键作用，而肿瘤的恶性程度与其细胞密度、PCNA—LI密切相关，通过测量肿瘤实性部分的ADC值，有可能为在体推测肿瘤恶性程度提供新的方法。

Objective To investigate the correlation between NR diffusion weighted imaging with cellularity and PCNA-LI of rabbit liver VX2 tumor models in different periods. Methods 38 successful implanted rabbits were assigned randomly into 2 equal groups and were performed MR DWI in different periods （14 and 21 d） after implantation respectively. Specimens of all tumors were stained with HE and PCNA-LI after MR examination. Results （ 1 ） The ADC value （ × 10^-3 mm2/s） in surrounding solid components of liver VX2 tumors in the group of 21 d was lower than that of the group of 14 d （0. 77 ±0. 19 vs 1.00 ± 0. 24, P = 0. 007） ; （2） the cellularity and PCNA-LI in surrounding solid components of liver VX2 tumors in the group of 21 d were higher than those of the group of 14 d respectively （63% ±7% vs 43%± 10%, P = 0. 011 ; 80% ± 11% vs 56% ± 8% , P = 0. 008 ） ; （ 3 ） there were negative correlation between ADC value and cellularity, PCNA-LI of the solid components of the tumors （ r = - 0. 695, P = 0. 000 ; r = - 0. 698, P = 0. 000）. Conclusion The cellularity may be the most important factor that affects ADC value in solid components of liver VX2 tumors. Since the degree of malignancy is closely connected with cellularity and PCNA labeling index, ADC value measurement may be a new method which could predict the degree of malignancies in vivo.