Reliability and Validation of the WB-MRI Radiological Score in CRMO

Inclusion Criteria: * Patients with a diagnosis of CRMO according to the international Bristol clinical and radiologic criteria, followed at the Pediatric Rheumatology Clinic of the Pediatric Unit, IRCCS AOU Bologna, Sant'Orsola Hospital; * Age under 18 years at the time of CRMO diagnosis; * At least one WB-MRI performed as part of routine clinical follow-up between January 2015 and the start date of the study; * Availability of complete clinical documentation (including reports, radiologic images, and clinical information) sufficient to apply both the WB-MRI score and the PedCNO score; * Obtain informed consent. Exclusion Criteria: \- Alternative diagnoses accounting for the bone lesions (e.g., infections, neoplasms).