Growth Cartilage of Piglet: Correlation between MRI Characteristics and Histologic Findings and Measurements of T_1 and T_2 Relaxation Time

摘要

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 pro-teoglycan.