股骨头骨骺早期缺血的动态Gadolinium增强MRI研究

目的 比较动态Gadolinium(Gd)增强和常规Gd增强MR技术在早期缺血的股骨头骨骺中的灌注差异,并观察骨骺血管闭塞时生长板的血供.方法 28只2周龄乳猪,共56个髋关节,雄性12只,雌性16只;体重5～7 kg,平均6 kg;随机分为A、B、C、D组,每组7只.将A、B组乳猪的双髋关节极度外展固定30 min后,对A组行动态Gd增强FSPGR序列扫描,对B组行常规Gd增强SE T1WI序列扫描;行双髋关节外展体位的血管造影.之后让乳猪自由活动1 d,再采用双髋关节自然平放体位重复MR扫描.C、D组分别是A、B组的对照,即MR扫描前及扫描中双髋关节保持自然平放,C组行动态Gd增强扫描,D组行常规Gd增强扫描.最后将乳猪处死行组织学观察.结果 动态Gd增强MRI示:A组股骨头不同组织(除干骺端外)的强化率(ER)和强化速度(ES)均明显小于C组;A组生长板的ER和ES均小于干骺端,而C组生长板与干骺端的ER和ES值均无明显差异.常规Gd增强MRI示:B组股骨头各部分的ER与D组比较无明显下降.结论 对早期股骨头骨骺缺血的检测,动态Gd增强MRI技术比常规Gd增强SE T1WI技术更敏感.当骨骺血管闭塞时,生长板的血液灌注可能来自于干骺端.

Dynamic Gadolinium-enhanced MRI in early ischaemia of the proximal femoral epiphysis

Objective To investigate the perfusion difference of early ischaemia of the proximal femoral epiphysis by MRI between with dynamic Gadolinium (Gd)-enhanced technique and conventional Gd-enhanced technique, respectively, and to observe the contribution of metaphyseal vascularity to physeal per-fusion in epiphyseal vascular occlusion. Methods Fifty-six hips of 28 two-week-old piglets were studied. All piglets were randomly divided into four groups (group A, B, C and D), with 7 in each. In group A and B, MR1 was performed bilaterally on the hips in persistent hyperabduction for 30 min. The piglets of group A underwent dynamic Gd-enhanced FSPGR MR scan, and those of group B did Gd-enhanced SE T1WI MR scan. The piglets of group C underwent dynamic Gd-enhaneed FSPGR MR scan, and those of group D did Gd-enhanced SE T1WI MR scan respectively without hyperabduction. Results On dynamic Gd-euhanced MRI, the enhancement ratio (ER) and enhancement speed (ES) of various region of interest (ROI) (except the metaphysis) in group A were significantly lower than those in group C. However, on conventional Gd-en-hanced SE T1WI, no significant decrease in the ER of each ROI in group B was found, compared with the ER in group D. In group A, the ER and ES of the physis were less than those of metaphysis on dynamic Gd-enhanced MRI; however, in group C, the ER and ES of the physis were similar to those of metaphysis. Con-clusion Dynamic Gd-enhanced MRI has an advantage in the detection of early epiphyseal ischaemia, com-pared with conventional Gd-enhanced SE T1WI. Metaphyseal vessels might play an important role in physeal perfusion with epiphyseal vascular occlusion.