骨内微血管和骨的同步三维显像及定量评价

Quantification and 3-D reconstruction of bone and intraosseous vessels

[目的]评价基于显微CT(Micro-CT)骨内微血管造影进行骨内微血管显影和三维重建在缺血性股骨头坏死(osteonecrosis of femoral head,ONFH)研究中的应用价值,实现在三维空间内同时定量评价骨显微结构及骨矿物量和骨内微血管。[方法]采用局部液氮冷冻和射频加热交替的方法建立鸸鹋塌陷性股骨头坏死动物模型,右侧为手术侧,左侧为对照侧。术后定期进行核磁检查,证实造模成功后自鸸鹋腹主动脉注入亚纳米级硫酸钡明胶混悬液进行下肢血管造影,取下肢股骨标本进行Micro-CT扫描,通过软件进行骨内微血管的二维及三维重建,同时结合Micro-CT骨显微结构研究,并将标本常规HE染色进行组织学检查。[结果]在术后12周证实出现股骨头塌陷,至16周16只动物出现股骨头塌陷。Micro-CT图像骨小梁结构及骨内血管显示清晰,与对照侧相比鸸鹋股骨头坏死塌陷后股骨头部的骨小梁厚度、骨体积分数增加,骨矿物量及骨小梁间距减小,血管体积分数减小,且差异均具有统计学意义。[结论]以亚纳米级硫酸钡作为造影剂,Micro-CT骨内微血管造影可以在不破坏骨标本的基础下清晰的显示骨内微血管,不干扰影像及组织学检查,并实现骨内微血管与骨显微结构及矿物量同时定量评价;在股骨头坏死的研究中具有重要价值,可以用于股骨头坏死造模评估、骨坏死和修复机制及治疗评价的研究。

[Objective] To investigate the efficacy of Micro-CT intraosseous microangiography used in research about osteonecrosis of femoral head,provide a three-dimensional evaluation protocol of characteristic intraosseous changes which would be useful for elucidating the mechanism of osteonecrosis in humans as well as for developing preventive and therapeutic strategies. [Method]Emu model of osteonecrosis was established by focal alternate freezing with liquid nitrogen and heating with radiofrequency.After surgery,hip MRI were performed to help in verifying the model.Before the emus were sacrificed,barium sulfate was infused to lower extremity for studying patterns of blood vessel distribution.The femoral samples were scanned by micro-computed tomography（Micro-CT） and evaluated histologically. [Result]Femoral head collapse was verified at 12 weeks.The vessel distribution density was improved remarkably at the proximal region of the femur except for the necrotic zone.Compared with contra lateral intact femoral head,the features of collapsed femoral heads,bone mineral density,trabecular separation,vessel volume fraction decreased significantly,trabecular thickness and bone volume fraction increased significantly. [Conclusion]Micro-CT images showed clear bone trabecular structure and clear vessel distribution through the contrast medium.The microangiography is useful for elucidating the mechanism of osteonecrosis in humans as well as for developing preventive and therapeutic strategies.