乳猪股骨头骨骺早期缺血与恢复的增强磁共振成像

目的确定Gadolinium（GD）增强磁共振成像（magnetic resonance imaging，MRI）能够检出早期股骨头骨骺缺血及恢复的变化。方法20例2～3周龄乳猪，分为正常对照组10例，缺血模型组10例。缺血模型组10例，将双侧髋关节固定成为极度屈髋屈膝外展位，在持续固定3-6h内对10例乳猪的20个股骨头进行动态GD增强MRI扫描，后解除固定自由行走，1d和／或7d后再次进行MRI扫描。观察此过程中股骨头增强MRI的表现特征，并与组织学发现相对照。结果在GD增强MRI，可见14个股骨头的骨骺软骨表现为不强化或弱强化的局部缺血征象，自由行走1d后10个股骨头完全恢复正常血供，7d后剩余4个也完全恢复正常血供。结论增强MRI能够检出因极度髋关节屈曲外展所致的乳猪股骨头骨骺早期缺血及恢复的变化。

Manifestation hyperabduction-induced early reversible ischemia of the capital femoral epiphysis and its reversal in piglets on Gadolinium enhanced MRI

Objective To demonstrate whether Gadolinium-enhanced MRI can detect early reversible ischemia of the capital femoral epiphysis caused by hip hyperabduction in piglets. Methods Ten 2- to 3-week-old piglets were placed in maximal bilateral hip abduction bilaterally. Between 3 and 8 hours of consistent hyperabduction, dynamic gadolinium-enhanced MRI was performed in 20 femoral heads of 10 piglets. After MRI study, the piglets were allowed to ambulate freely for 1 or 7 days and re-imaged. Enhanced-MRI characteristics of epiphyseal and physeal cartilage and the secondary center of ossification were evaluated. And comparison between MRI appearances and histological findings was made. Results On Gadolinium-enhanced MRI, decreased or absent enhancement was seen in 14 cartilaginous epiphyses of all 20 femoral heads. Reperfusion was completed in 10 of 14 femoral heads after one day of ambulation and in the rest 4 after 7 days of ambulation. Conclusions Gadolinium-enhanced MRI can identify early ischemia and its reversal of the capital femoral epiphysis induced by hip hyperabdudion.