动态增强MRI评价去势兔骨质疏松腰椎骨髓灌注:与BMD和MVD对照研究

Lumbar Spine Bone Marrow Perfusion in Osteoporosis Rabbit with ynamic Contrast Enhancement MRI:Correlation with BMD and MVD

目的用MR动态增强观察去势兔骨质疏松腰椎的骨髓灌注变化,并与骨密度(BMD)、免疫组织化学对照。材料与方法新西兰大白兔22只,随机分为2组(实验组12只,对照组10只)。双侧卵巢切除术后3、5、7个月分别行动态增强MRI和双能X线吸收测量法(DEXA)检测腰椎骨髓灌注的最大增强百分比(Emax)、增强斜率(ES)和BMD,并与组织的微血管密度(MVD)对照。结果双侧卵巢切除去势法(OVX)组兔在术后7个月时腰椎BMD与对照组相比明显降低(P<0.05)。术后3个月和5个月两组间腰椎的Emax和ES值均无明显差异(P>0.05);术后第7个月OVX组腰椎的灌注较对照组明显下降,Emax和ES值均明显降低(P<0.05);对照组腰椎骨髓MVD计数平均为67.58±11.6;而OVX组的MVD计数为39.32±9.54,明显少于对照组(P<0.05)。OVX组兔术后7个月腰椎动态增强MRI的Emax、ES和组织的MVD呈正相关(r分别为0.866和0.771,P<0.05);Emax、ES和腰椎BMD之间亦有明显的正相关性(r分别为0.714和0.820,P<0.05)。结论去势兔骨质疏松后腰椎骨髓的血液灌注明显下降,免疫组织化学显示骨质疏松后骨髓组织的MVD明显减少。动态增强MRI能提供骨质疏松后骨髓的血供信息,其指标Emax和ES与BMD和组织MVD均有很好的相关性,提示血管减少导致血供下降也是骨质疏松发生机制之一,对于骨质疏松的诊断和治疗有一定的指导意义。

Objective To assess lumbar spine bone marrow blood perfusion in osteoporosis rabbit using dynamic contrast enhancement（DCE-MRI）and correlate with bone mineral density（BMD） and microvessel density（MVD）.Materials and Methods 22 New Zealand white rabbits were randomly divided into 2 groups,including experimental group（n=12） and control group（n=10）.Bilateral ovariectomies（OVX） were applized in experimental group.DCE-MRI,DEXA and immunohistochemistry exam were respectively performed in both groups in 3,5,7 months after OVX.Vertebral maximum percentage of enhancement（Emax）,enhancement slope（ES）,BMD and MVD were measured.Results BMD of lumber spine in OVX group in postoperative was obviously decreased in 7 months after OVX compared to control group（P〈0.05）.In postoperative 3 and 5m lumber spine bone marrow Emax and ES had no difference between two groups（P〈0.05）,however the significant difference were found in postoperative 7m（P〈0.05）,Emax and ES were significantly decreased in OVX group.MVD of vertebral marrow was 67.58±11.6 in control group and 39.32±9.54 in OVX group,which were significant difference between them（P〈0.05）.Vertebral marrow Emax and ES were significant positive correlation with BMD and MVD in 7m OVX group（r=0.714,0.820,0.866 and 0.771,P〈0.05）.Conclusion Lumbar spine bone marrow perfusion is significantly decreased in osteoporosis rabbit,and vertebral MVD is also obviously reduced.DCE-MRI can provide more information about osteoporosis blood perfusion.Emax and ES are significant correlation with BMD and MVD,which suggest mechanism in the pathogenesis of OP and is helpful to diagnosis and treatment of OP.