Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and morphologic MRI of cartilage in the long-term follow-up after Legg-Calvé-Perthes disease (LCPD)

Introduction: The purpose of the present study was to evaluate the feasibility of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the detection of cartilage changes versus morphologic imaging in the long-term course of Legg-Calvé-Perthes disease (LCPD). Methods: A total of 31 hips in 26 patients (mean age, 30.0years; range, 18-54years) who were diagnosed with LCPD in childhood were included. Twenty-one radiographically normal contralateral hips served as controls. dGEMRIC indices of femoral and acetabular cartilage in the weight-bearing zone. Cartilage morphology was classified on radial PD-weighted images according to the modified Outerbridge classification. Results: Mean dGEMRIC values of cartilage were significantly lower in hips after LCPD than in the radiographically normal contralateral hips (513±100 ms vs. 579±103 ms; P=0.026). In 24 out of 31 LCPD hips and in 4 out of 21 radiographically normal contralateral hips, morphological cartilage changes were noted. Analysis of variance analysis revealed a significant influence of Outerbridge grading on decreased T1-values (P=0.031). Conclusion: Our results suggest that dGEMRIC at 1.5 T is suitable to assess cartilage quality changes in the long-term follow-up after LCPD. The evaluation of biochemical cartilage quality with dGEMRIC may provide additional information about early cartilage changes occurring without visible alterations of cartilage morphology.