OBJECTIVE: To evaluate the usefulness of combining static and kinematic magnetic resonance imaging in the evaluation of the femoropatellar joint. MATERIALS AND METHODS: Twenty healthy volunteers (40 knees) and 23 patients (43 knees) were submitted to both static and kinematic magnetic resonance imaging on a 1.5 tesla whole-body magnetic resonance scanner. The knees were positioned at 30º flexion with the quadrature knee coil at the inner end of the examination table. The patellar translation was evaluated by measurements of bisect offset, lateral patellar displacement and patellar tilt angle. The nonparametric Wilcoxon test was utilized for statistical analysis of data resulting from the static and kinematic studies in both groups. Nonparametric Mann-Whitney test was utilized in the comparison between healthy volunteers and patients. RESULTS: Statistical analysis demonstrated significant differences (p < 0.05) between static and kinematic magnetic resonance imaging for the three parameters evaluated in both groups. Among the patients the differences between static and kinematic measurements were greater than those found in the volunteers, at 30° and 20° flexion, with bisect offset and lateral patellar displacement. CONCLUSION: Static and kinematic magnetic resonance imaging, when performed in association, demonstrated that the lateral forces being exerted on the patella are higher at a knee flexion at the range between 20° and 30°, particularly in individuals symptomatic for femoropatellar instability.

Keywords: Knee, Knee joint, Patella, Patellofemoral pain syndrome, Magnetic resonance imaging, Biomechanics, Chondromalacia patellae

OBJECTIVE: To compare the performance of low-field-strength and high-field-strength magnetic resonance imaging equipments for evaluation of the patella articular cartilage. MATERIALS AND METHODS: The study was developed using GRE 2D, GRE 3D, FSE T2, STIR sequences (low-field) and TSE T2 SPIR sequence. Each sequence has been separately analyzed for evaluation of the cartilage without knowledge of other sequences results or any patients data; the lesion was assigned a grade from 0 to 3 and had its location defined. Agreement and disagreement results were analyzed by Kappa and McNemar tests. RESULTS: Medial facet has presented low agreement index and disagreements showed to be significantly overestimated. Lateral facet has presented a reasonable agreement index and disagreement index was not significant. Medial ridge has presented a reasonable agreement index and disagreement index has showed to be underestimated. CONCLUSION: The STIR sequence versus TSE T2 SPIR sequence has presented the higher agreement index. High grade lesions are better characterized by low-field-strength magnetic resonance imaging equipment sequences. Areas of increased signal intensity make difficult the study of the patella medial facet cartilage in low-field-strength equipment.

Keywords: Magnetic resonance imaging, Skeletal - appendicular, Knee, Comparative study, Equipments, Imaging sequences

OBJECTIVE: To assess the usefulness of MRI as a diagnostic method in patients with rheumatoid arthritis, and to evaluate the frequency of changes in the hip in symptomatic and asymptomatic patients. MATERIALS AND METHODS: Forty patients (17 symptomatic and 23 asymptomatic) were evaluated by 1.5 T magnetic resonance imaging (MRI) after intravenous contrast media injection. MRI findings were divided in inflammatory, degenerative, combined (inflammatory and degenerative) and extra-articular changes. RESULTS: The most frequent findings seen were degenerative and extra-articular changes (22.5% each). Inflammatory changes were seen in only five (12.5%) symptomatic patients, four of them with degenerative findings associated (10%). CONCLUSION: The use of MRI of the hip allowed the evaluation of the main articular abnormalities seen in patients with rheumatoid arthritis. The most frequent findings were degenerative and extra-articular changes. Inflammatory findings were seen in only five patients, four of them with degenerative changes associated.

Keywords: Magnetic resonance imaging, Hip, Rheumatoid arthritis, Adult