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.