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

To investigate the correlation between MR diffusion weighted imaging with cellularity and PCNA-LI of rabbit liver VX2 tumor models in different periods.

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.

(1) The ADC value (x 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).

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.