兔超早期激素性股骨头坏死的病理和影像学对比研究

A Comparative Study of Pathological and Imageological Changes in Pre-early Steroid-induced Femoral Head Osteonecrosis of Rabbits

目的研究兔超早期激素性股骨头坏死病理及影像学表现,以探索超早期诊断方法。材料和方法42只新西兰大耳白兔随机分成两组:实验组28只,于臀肌注射甲基泼尼松龙20mg/kg,共3次,每次间隔24小时。对照组14只,于实验组相同时间点用同样方法注射等量生理盐水。在造模后第2、3、4、5、6、7、8周分别对实验组随机4只兔、对照组随机2只兔进行DR、CT、MRI检查及病理学观察。结果所有动物股骨头DR、CT、常规MRI检查及大体病理均无异常改变;实验组造模3周后股骨头磁共振成像STIR序列开始出现点片状高信号。造模后2周开始实验组股骨头出现异常病理改变,主要表现为空骨陷窝增多,骨髓脂肪细胞肥大,血窦出血。结论通过肌肉注射激素制作兔超早期股骨头坏死模型操作简单,成功率高;磁共振成像STIR序列是超早期诊断股骨头坏死的敏感检查方法。

Objective To study the pathological changes and imageological findings of pre- early femoral head osteonecrosis in rabbits,in order to explore the diagnostic method. Materials and Methods Thirty New Zealand white adult rabbits were randomly divided into contral group （n= 10） and experimental group （n=20）. The rabbits were injected intra- muscularly with 20mg/kg of methylprednisolone acetate for 3 days or saline in experimen- tal group and contral group respectively. X-ray, CT, MRI and pathology were performed on femoral heads of two groups animals at the time of 2,3,4,5,6,7,8 weeks. Results The imageological examination demonstrated that plan-film and CT had no significant findings. However, MR imaging with STIR sequences showed high spot signal during 3 to 8 weeks. Histopathological findings revealed that the fat cells of the marrow cavity enlarged： empty bone lacunac clearly increased,and the blood sinus hemorrhage at 2 weeks after steroid injection.At the time of 3, 4, 5, 6, 7, 8 weeks, the necrosis areas became larger and the fat cells proliferated and hypertrophied, and the numbers of empty bone lacunae increased. Conclusion The inject intramuscularly with methylprednisolone acetate method is simple operation and high success rate. MR imaging with STIR sequences is a high sensitive means of diagnosing pre-early osteonecrosis of the femoral head.