鼠骨肉瘤CT灌注成像研究

CT perfusion study of the rat osteosarcoma

目的利用鼠骨肉瘤模型,观察各CT灌注参数、最大强化速率(MER)与肿瘤微血管密度(MVD)的关系;分析鼠骨肉瘤外周区与中央区各CT灌注参数、MER、MVD之间有无差异。方法Wistar大鼠30只,采用大鼠骨肉瘤细胞系UMR106,接种于大鼠股骨远端或胫骨近端的骨髓腔中。CT灌注检查:用CT自动高压注射器经大鼠尾静脉注射非离子型碘对比剂欧乃派克(300 mgI/ml),总量为1.5～2.0 ml,注射速度0.5 ml/s。电影采集,2 mm层厚,1次扫描4层,扫描速度1 s/周,扫描时间50 s,共得到200幅图像。CT灌注检查后,将鼠处死,取肿瘤标本行HE及免疫组织化学检查,免疫组织化学检查用SP法,用单克隆抗CD34抗体标记血管,用Weidner技术计算肿瘤MVD。结果肿瘤BF、BV的平均值分别为100.09 ml·min^(-1)·100 g^(-1)、10.81 ml·100 g^(-1),均高于正常肌肉组织(BF、BV平均值分别为60.45 ml·min^(-1)·100 g^(-1)、1.89 ml·100 g^(-1))。肿瘤的BF、BV和MER与肿瘤的MVD均呈正线性相关,即肿瘤的MVD越高,相应的BF、BV和MER也就越高。肿瘤外周区与中央区的BF、BV、MVD之间有显著性差异(P<0.05)。结论本研究显示鼠骨肉瘤的BF、BV均与MVD呈正线性相关,CT灌注成像可用于活体无创性地评价骨肿瘤的微血管生成,可以详细全面提供骨肿瘤医生制定手术计划所需要的骨肿瘤的性质和血供情况的信息。

Objective On the rat osteosarcoma model： To observe the relationship between the CT perfusion parameters, the maximal enhancement rate （MER） and the microvessel （MVD） of the tumors; To compare the difference of the CT perfusion parameters, MER and MVD between the rim and the center of the rat osteosarcoma. Methods 30 Wistar rats were used in this experiment. Rat osteosarcoma cell line named UMR106 was injected into the distal femoral or proximal tibia bone marrow cavity of the rats. The CT scans were performed on the grafted osteosarcoma model., the nonionic contrast agent （Ultravist 300） were injected through the tail vein by an injection pump with 1.5-2.0 ml dosage at rate of 0.5 ml/s. Cine acquisition, 2 mm slice thickness （4 slices per rotation）, 1 s per 360 revolution, total scan time 50 s. 200 images were acquired. The rats were sacrificed after the CT examination, and the tumors of the rats were taken out for normal HE and immunohistochemistry staining, The SP method was used for the immunohistochemistry staining. The anti-CD34 monoclonal antibodies were used to mark microvessels. The MVD of the tumors were calculated using Weidner technique. Results Quantitive study shows that the mean values of BF and BV were 100.09 ml · min^-1 · 100 g^-1 and 10.81 ml · min^-1 · 100 g^-1 which were much higher than those of normal muscle tissues which were 60.45 ml · min^-1 · 100 g^-1 , 1.89ml · min^-1 · 100 g^-1 respectfully. There were positive linear correlation between the tumor MVD and tumor BF, BV and MER. The results demonstrated that the bigger the MVD of the tumor, the higher the BF, BV and MER. The difference between BF,BV and MVD in rim and center part of the tumors had statistically significance（P〈0. 05）. Conclusion This study has demonstrated that there was positive correlation between BF, BV and the MVD of the rat osteosarcoma and osteolytic bone tumors. CT perfusion imaging was feasible for evaluation of microvessel angiogenesis of bone tumors in vivo. The CT perfusion imaging had much superiority： convenient to perform, safe, less time consume and cheap. Information about the nature and blood supply of tumors is important in presurgical planning and CT perfusion is feasible and safe for what bone tumor surgeons required.