正常乳猪生长软骨:MR表现特征与组织学发现的相关性对照和横向及纵向弛豫时间测定

目的 :明确正常生长软骨的MR信号特征及与组织学发现的相关性 ,检测乳猪骨骺软骨和生长板软骨T1和T2弛豫时间的不同。方法 :12例出生仅 2周的乳猪 ,用 1.5TeslaGEMR仪对双侧股骨远端和胫骨近端骨骺进行扫描 ,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序列进行T2弛豫时间测量 ,运用反转恢复系列进行T1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 ,它们分别为 :①二次骨化中心的临时钙化带 ;②二次骨化中心的生长板 ;③骨骺软骨 ;④生长板 ;⑤临时钙化带。股骨生长板软骨的T2 和T1值与骨骺软骨相比有显著延长 ,两者之间的差异有显著性意义 (P <0 .0 5 )。结论 :MRI能够鉴别骨骺软骨和生长板软骨。生长板和骨骺软骨T2 和T1值的不同主要是因为软骨基质内水分子被蛋白粘多糖束缚的状态不同所致

Growth Cartilage of Piglet:Correlation between MRI Characteristics and Histologic Findings and Measurements of T1 and T2 Relaxation Time

Objective: To determine the correlation between MR signal characteristics and histologic findings of growth cartilage and identify the difference in transverse and longitudinal relaxation time between in vivo physeal and epiphyseal cartilage. Methods: Twenty-four knees including distal femora and proximal tibia of 12 2-week-old piglets were imaged at 1.5 Tesla GE MR scanner. The comparison between signal intensity on MRI and architecture in corresponding histologic sections was made. T 2 and T 1 values were measured by means of multiecho spin-echo sequences and by using inversion-recovery-series, respectively. Results: MRI delineated five different regions between the metaphysis and 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, main physis and main zone of provisional calcification. Both T 2 and T 1 values in the physeal cartilage were much longer than those in the epiphyseal cartilage (P<0.05). Conclusion: MRI findings differentiate the different zones of growth cartilage and correlate with histologic findings. T 2 and T 1 are longer in physeal cartilage than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycan.