ABSTRACT
BACKGROUND: Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. METHODS: Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. RESULTS: Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = -0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. CONCLUSIONS: The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis.
Subject(s)
Cartilage, Articular/diagnostic imaging , Femoracetabular Impingement/complications , Osteoarthritis, Hip/diagnostic imaging , Osteoarthritis, Hip/etiology , Adult , Aged , Cartilage, Articular/pathology , Contrast Media , Disease Progression , Early Diagnosis , Female , Femoracetabular Impingement/diagnostic imaging , Follow-Up Studies , Gadolinium , Hip Joint/diagnostic imaging , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Osteoarthritis, Hip/pathology , Prognosis , Prospective Studies , RadiographyABSTRACT
OBJECTIVE: To measure the variability of T1ρ relaxation times using CubeQuant, T2 relaxation times using quantitative double echo in steady state (DESS), and normalized sodium signals using 3D cones sodium magnetic resonance imaging (MRI) of knee cartilage in vivo at 3 T. DESIGN: Eight healthy subjects were scanned at 3 T at baseline, 1 day, 5 months, and 1 year. Ten regions of interest (ROIs) of knee cartilage were segmented in the medial and lateral compartments of each subject's knee. T1ρ and T2 relaxation times and normalized sodium signals were measured and the root-mean-square coefficient of variation (CVRMS) was calculated. Intra-subject variability was measured over short, moderate and long-term, as well as intra-observer and inter-observer variability. RESULTS: The average intra-subject CVRMS measurements over short, moderate, and long-term time periods were 4.6%, 6.1%, and 6.0% for the T1ρ measurements, 6.4%, 9.3%, and 10.7% for the T2 measurements and 11.3%, 11.6%, and 12.9% for the sodium measurements, respectively. The average CVRMS measurements for intra-observer and inter-observer segmentation were 3.8% and 5.7% for the T1ρ measurements, 4.7% and 6.7% for the T2 measurements, and 8.1% and 11.4% for the sodium measurements, respectively. CONCLUSIONS: These CVRMS measurements are substantially lower than previously measured changes expected in patients with advanced osteoarthritis compared to healthy volunteers, suggesting that CubeQuant T1ρ, quantitative DESS T2 and 3D cones sodium measurements are sufficiently sensitive for in vivo cartilage studies.
