Structured reporting template for radial mr arthrography in femoroacetabular impingement: Inter-reader agreement and reproducibility.

OBJECTIVE: To develop, implement, and validate a standardized structured reporting template for radial MR arthrography in Femoroacetabular impingement (FAI) and to assess its inter-reader agreement for key diagnostic parameters. METHODS: A structured reporting template was developed based on key FAI imaging biomarkers. For validation, two musculoskeletal radiologists independently applied the template to a pre-existing cohort of 122 patients with suspected FAI who underwent hip arthroscopy. Using only radial sequences, they assessed the FAI morphotype (cam, pincer, mixed), labral tear location (clock-face), and cartilage lesion zone. Inter-reader agreement was quantified using Cohen's kappa (κ) with 95 % confidence intervals. RESULTS: The application of the structured template demonstrated excellent inter-reader agreement for key parameters. Agreement was excellent for FAI morphotype classification (κ = 0.89; 95 % CI: 0.84-0.93) and cartilage lesion detection (κ = 0.83; 95 % CI: 0.78-0.88), and near-perfect for labral tear localization (κ = 0.97; 95 % CI: 0.93-0.99). Labral tears were present in 80.3 % of patients, with 65.6 % localized to the anterosuperior quadrant (1-2o'clock). CONCLUSION: The structured reporting template for radial MRA in FAI demonstrates high inter-reader reproducibility across key diagnostic domains, supporting consistent communication of FAI-related morphologic and soft-tissue findings.