The experimental study of MR perfusion weighted imaging in rabbit models of hepatic VX2 tumors after high intensity focused ultrasound / 中华放射学杂志

ABSTRACT

Objective To discuss the imaging technology and characteristic of perfusion-weighted imaging in rabbit models of hepatic VX2 tumors. Methods Twenty-eight New Zealand rabbits were implanted in liver with VX2 tumor by tissue block. After routine scans were performed on 1.5 T MR scanner, 28 New Zealand white rabbits with VX2 carcinoma were divided randomly into treatment group and control group. Treatment group was divided randomly into group A, group B and group C, 7 animals per group. Perfusion weighted imaging(PWI) was performed in day 14, 25 and 35, respectively, after tumor implantation in all animals. Select the regions of interest (ROI) of the VX2 tumor center, tumor border and pars-tumor parenchyma. Maximal signal reduction slope ( SRSmax ) of the signal intensity versus time curves were created as quantitative variable, and the parameters were calculated and compared in all groups. Results Maximal signal reduction slope ( SRSmax ) of the signal intensity versus time curves were studied in 4 groups, 23 VX2 rabbits,7,5 and 6 in group A , B and C, respectively. The SRSmax of tumor center were ( 12. 6 ± 3.4), ( 9. 8 ± 2. 6 ) and ( 1.0 ± 0. 4 ), the difference was significant ( F = 10. 855, P < 0. 05 ). The SRSmax of tumor border were(48. 3 ± 2.4), (46. 2 ± 1.5 ) and (43. 6 ± 1.8 ) ( P > 0. 05 ). The SRSmax of para-tumor parenchyma were ( 14.4 ± 3.0 ), ( 12. 2 ± 1. 4 ) and ( 14. 8 ± 5.0 ) ( P > 0. 05 ). The difference was significant in different ROI in treatment groups( F value was 7. 435,8. 625 and 12. 595, respectively, P < 0. 05 ). Conclusion PWI can be used in evaluating the liver tumor angiogenesis and angio-degeneration with the treatment of HIFU. It will be possible for qualitative analysis of rabbit models of hepatic VX2 tumors by different treatments.