Pre- and postcontrast T1 and T2 mapping of patellar cartilage in young adults with recurrent patellar dislocation

PurposeTo examine the cartilage quality in young adults with recurrent patellar dislocation in childhood using different magnetic resonance imaging parameters. MethodsSixteen young adults with unilateral recurrent patellar dislocation were investigated 5 y (mean, 8.5 y) after the first dislocation. Pre- and postcontrast T1 and precontrast T2 relaxation times were analyzed in four superficial and four deep patellar cartilage regions of both knees. Two hours after intravenous injection of 0.2 mM/kg Gd-DTPA(2-), postcontrast T1 [T1(Gd)] and R1 [1/T1 (precontrast)-1/T1 (postcontrast)] were analyzed in the regions. Muscle performance and patient-reported outcome were evaluated. ResultsWhen comparing the injured side with the noninjured side, differences were seen in the superficial half but not the deep half of the cartilage. T1(Gd) was shorter in the central part, whereas T2 was shorter in the periphery of the patellar cartilage (P<0.05). R1 demonstrated similar differences between healthy and diseased cartilage as T1(Gd) alone. The knee function was not correlated to the degenerative changes. ConclusionThe short T1(Gd) centrally indicates degenerative cartilage changes consistent with loss of glycosaminoglycans. Precontrast and R1 calculations may be excluded in clinical dGEMRIC, which simplifies the procedure. A decrease in T2 may be a very early sign of joint pathology but warrants further investigation. Magn Reson Med 74:1363-1369, 2015. (c) 2014 Wiley Periodicals, Inc.