Evaluation of radial distribution of cartilage degeneration and necessity of pre-contrast measurements using radial dGEMRIC in adults with acetabular dysplasia

Abstract

Background: The purpose of the present study was to investigate the radial distribution patterns of cartilage degeneration in dysplastic hips at different stages of secondary osteoarthritis (OA) by using radial delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), and to assess whether pre-contrast measurements are necessary. Methods. Thirty-five hips in 21 subjects (mean age SD, 27.6 10.8 years) with acetabular dysplasia (lateral CE angle < 25°) were studied. Severity of OA was assessed on radiographs using Tönnis grading. Pre- (T1pre) and post-contrast T1 (T1Gd) values were measured at 7 sub-regions on radial reformatted slices acquired from a 3-dimensional (3D) T1 mapping sequence using a 1.5 T MR scanner. Values of radial T1pre, T1Gd and R1 (1/T1Gd - 1/T1pre) of subgroups with different severity of OA were compared to those of the subgroup without OA using nonparametric tests, and bivariate linear Pearson correlations between radial T1Gd and R1 were analyzed for each subgroup. Results: Compared to the subgroup without OA, the subgroup with mild OA was observed with a significant decrease in T1 Gd in the anterosuperior to superior sub-regions (mean, 476 ∼ 507 ms, p = 0.026 ∼ 0.042) and a significant increase in R1 in the anterosuperior to superoposterior and posterior sub-regions (mean, 0.93 ∼ 1.37 s-1, p = 0.012 ∼ 0.042). The subgroup with moderate to severe OA was observed with a significant overall decrease in T1Gd (mean, 404 ∼ 452 ms, p = 0.001 ∼ 0.020) and an increase in R1 (mean, 1.17 ∼1.69 s-1, p = 0.001 ∼ 0.020). High correlations were observed between radial T1Gd and R1 for all subgroups (r = 0.869 ∼ 0.944, p < 0.001). Conclusions: Radial dGEMRIC without pre-contrast measurements is useful for evaluating different patterns of cartilage degeneration in the entire hip joint of patients with hip dysplasia, particularly for those in early stages of secondary OA. © 2012 Xu et al.; licensee BioMed Central Ltd.