正常乳猪骨骺及干骺端骨髓的增强MR成像研究

Gadolinium-enhanced MR imaging in developing epiphysis of normal piglets:an experimental study

目的 :探讨正常乳猪骨骺及干骺端骨髓的增强MR表现特征及不同年龄阶段的骨髓转化特征。方法 :8头乳猪 ,分别在出生 2、4、6和 8周的时间对双侧股骨近段及远段进行增强前后T1WIMR扫描 ,分析不同时间骨骺二次骨化中心骨髓和干骺端骨髓增强MR表现特征及增强率的变化 ,并与相应组织学发现进行对照研究。结果 :干骺端骨髓和骨骺二次骨化中心周边骨髓为含有丰富血管的红骨髓 ,增强后呈显著强化 ,且干骺端增强率较骨骺骨髓更高 ,但随年龄增长 ,两者的增强率均逐渐减低。骨干中央和二次骨化中心中央为黄骨髓 ,强化不明显。结论 :Gd DTPA增强在干骺端红骨髓与二次骨化中心周边红骨髓比在骨骺二次骨化中心中央区域黄骨髓强化更明显 ,其强化程度随年龄的增长逐渐减弱。

Objective:To define normal epiphyseal and metaphyseal marrow on Gadolinium (Gd)-enhanced MR.Methods:We studied Gd-enhanced MR appearance of epiphyseal and metaphyseal marrow in 20 proximal and distal femoral ends of 10 healthy piglets.In 8 of them,the enhancement ratio of epiphyseal and metaphyseal marrow with different weeks-old piglets were analysed.The correlation study of MRI characteristics with histologic finding was performed.Results:The metaphysis and the periphery of the secondary center of ossification were red marrow.They showed marked enhancement on T 1WI.Enhancement ratio declined in both regions with age.The central regions of secondary ossification center and diaphysis were yellow marrow and showed no definite enhancement of T 1WI.Conclusion:Metaphysis (red marrow) and periphery of the secondary ossification center (red marrow) are enhanced more intensely than the central regions of secondary ossification center (yellow marrow).The enhancements decline in the both regions with age.