正常骨骺的动态钆增强MRI研究

目的 运用动态钆增强MRI技术,评价正常骨骺软骨、生长板软骨、海绵状骨松质、干骺端等不同解剖区域的血液供应特征.材料与方法 10只2周大的健康乳猪,共20个股骨远端.采用GE 1.5 T磁共振扫描仪,作钆增强动态MRI,即运用时间分辨率为3 s的扰相梯度回波(SPGR)技术,在静脉注射钆之前、注射过程之中及之后连续扫描,全部成像时间为4 min多钟.计算在动态钆增强MRI上骨骺及干骺端各个解剖区域在不同时间的增强率,并与相应组织学发现作对照研究.结果 生长板软骨的增强率比骨骺软骨的增强率有明显增高(P＜0.001);与各解剖区域的增强率相比,海绵状骨松质的增强率最高(P＜0.001);与生长板和海绵状骨松质相比,骨骺软骨的强化最慢(P＜0.001),而生长板与海绵状骨松质强化快慢之间差异无统计学意义(P＞0.1).组织学研究所显示的生长板软骨、骨骺软骨、干骺端等不同解剖区域的血管密度分布特征与相应部位的增强率及强化快慢所提示的血供状态基本相吻合.结论 动态钆增强MRI能够显示骨骺不同解剖区域的血液灌注特征.

The Study of Dynamic Gadolinium-enhanced MR Imaging in Normal Growth Cartilage

Objective To evaluate the blood perfusion of epiphysis, physis, spongiosa and metaphysis in normal growth skeletons by using dynamic gadolinium-enhanced MR imaging.Materials and Methods 10 piglets(2 weeks old )were selected,including 20 distal femurs. All piglets were performed with 1.5T GE scanner. For dynamic gadolinium enhanced imaging, spoiled gradient-recalled echo images with a temporal resolution of 3.0s was used before, during and after the injection of gadolinium, and a total of 96 images were obtained. The histological samples were examined after scanning. Enhancement ratios of the various anatomic regions on MRI were evaluated and compared with histological findings.Results The enhancement ratio of physeal cartilage was greater than that of epiphyseal cartilage (P<0.001). The enhancement ratio of metaphyseal spongiosa was greatest compared to those of other anatomic regions (P<0.001). The epiphyseal cartilage enhanced most slowly, compared to physis and spongiosa (P<0.001). There was no significant difference in enhancement ratio between physeal cartilage and metaphyseal spongiosa (P>0.1) Dynamic enhancement on MR imaging coincided with histological results of the locations and concentrations of blood vessels in physis, epiphyses, spongiosa and metaphyses.Conclusion Dynamic gadolinium-enhanced MR imaging can demonstrate the perfusion features in the various anatomic regions of epiphysis.