正常生长软骨MR表现特征和横向弛豫时间测定实验研究

目的观察骨骺软骨和生长板软骨的T2弛豫时间差异.方法 12头出生2周的乳猪,扫描双侧股骨远端骨骺,范围包括二次骨化中心骨质、周围骺软骨、生长板软骨、干骺端.将MR所显示的各层微细解剖结构的信号特征与相应组织学构造进行比较对照.运用多层面、多回波、自旋回波MR序列对8头乳猪进行T2弛豫时间测量.结果 MRI显示了二次骨化中心骨髓和干骺端之间的5种不同的微细解剖结构,包括:①二次骨化中心临时钙化带;②二次骨化中心生长板;③骨骺软骨;④生长板;⑤临时钙化带.与骨骺软骨相比,股骨生长板软骨的T2值有显著延长(P<0.05).结论 MRI能够鉴别骨骺软骨和生长板软骨.

MR imaging characteristics and transverse relaxation time measurements in growth cartilage: experimental study

Objective To determine MR signal characteristics of growth cartilage and identify the difference in transverse relaxation times between vivo physeal and epiphyseal cartilage. Methods Total 24 distal femora of twelve 2 week-old piglets were imaged at 1.5 Tesla GE MR scanner. Comparison of signal intensity seen on MR images was made with architecture shown in corresponding histologic sections. T2 values were measured in 8 piglets by means of multiecho spin-echo sequences. Results MR imaging delineated 5 regions between the secondary ossification center and the metaphysis corresponding histologically to zone of provisional calcification of secondary ossification center, physis of the secondary ossification center, epiphyseal cartilage, physis and zone of provisional calcification. T2 value in the physeal cartilage was much longer than that in the epiphyseal cartilage ( P <0.05). Conclusion MRI findings differentiate the regions of growth cartilage. T2 is longer in physeal than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycans.