Correlation Studies Between CT Perfusion Parameters And MVD Before And After Radiotherapy Of Rabbit VX2 Tumor Model In Common Bile Duct

PurposeWe intend to establish a rabbit model of implanting VX2 tumor in the common bile duct. Using the model, we will observe the change of CT perfusion parameters and the change of MVD before and after radiotherapy, investigate the correlative relation between CT perfusion parameters and the MVD, then investigate the applicative value of CT perfusion imaging on assessment of tumor radiotherapy effect.MethodsThirty healthy Newzland White rabbits offered by Experiment Animal Center of China Medical University, weight(2.5±0.5)kg. VX2 cell were provided by the Department of Radiology of the First Affiliated Hospital of China Medical University. VX2 tumor was implanted in the rabbit common bile duct by operation. The first CT perfusion was applied to rabbits when tumor grew to 1-2cm.The rabbits were divided into two grorps at random. Treated group rabbits were performed to 3DCRT(three-dimensional conformal radiotherapy) one days after the first CT perfusion, then performed conventional CT plain scan and perfusion scan after radiotherapy. Control group rabbits were performed CT perfusion one week later, without radiotherapy. Rabbits were humanely sacrificed less than 1 hour after CT perfusion scanning. The tumors and circumambient tissure were excised in 10% formalin for 1 or 2 weeks and embedded in paraffin. Axial sections(4μm) of the tumors were obtained. The tumors were stained with HE(hematoxylin and eosin)and CD34 immunohistochemical stains, and MVD was measured by anti-CD34. Then, CTP parameters between 2 groups were determined whether they were correlated with MVD using Pearsonos correlation coefficient. ResultsThere were no significant differences of the CTP(Computed tomography perfusion) parametric values of the first CT perfusion between the treatment group and the control group. The values of BF, BV, and PS of the VX2 tumors in treated group were noticeable decreased after radiotherapy. But, there were no significant differences of the above parametric values in the control group. CT perfusion parameters such as BF, BV and PS measured one week after radiotherapy in treatment group was obviously lower than that in control group without radiotherapy, P< 0.01. The value of MVD in non-treatment group was 38±6, while the value of MVD measured one week after radiotherapy in treatment group was 20±3. The value of MVD in the two groups was different with statistical significance, P＜0.01.ConclusionWe could use BF, BV as an index corresponding to MVD to evaluate capillary angiogenesis of tumor in vivo.