Radial dGEMRIC in developmental dysplasia of the hip and in femoroacetabular impingement: preliminary results.

OBJECTIVE

To assess the pattern of cartilage damage in symptomatic cases of developmental dysplasia of the hip (DDH) and of femoroacetabular impingement (FAI) with a novel three-dimensional (3D) delayed Gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC) technique.

METHODS

After clinical diagnosis with conventional radiographs, two consecutive series of each 20 patients with DDH or FAI were assessed with 3D dGEMRIC. Radial T1 maps were reconstructed and region of interest analysis of the central and peripheral cartilage was carried out.

RESULTS

The dGEMRIC index was mean 531 ± 92.7 (391-729) ms in DDH and 551 ± 95.7 (372-694) ms in FAI, respectively (P=0.507). Subgroup analysis showed higher T1 in the weight-bearing areas and significantly higher values in the central areas (DDH P<0.0001, N=11; FAI P=0.036, N=14) of the acetabulum in pre-arthritic cases (dGEMRIC index>500 ms) both in DDH and FAI. A breakdown of this distribution was found both in DDH and FAI cases with dGEMRIC index<500 ms. Pearson correlation analysis demonstrated the dGEMRIC index had a poor predictive value for the anterior-superior quadrant of the hip joint in FAI (r=0.482, P=0.031, r(2)=0.233).

CONCLUSION

Radial dGEMRIC allows for the assessment of cartilage damage in the entire hip; different patterns of T1 distribution are found in DDH and FAI at progressed stages. The assessment of the anterior-superior quadrant of the acetabulum can be considered a fundamental advantage of the 3D dGEMRIC protocol.