MR-HIFU Treatment of Painful Osteoid Osteoma

Inclusion Criteria: * Age ≤30 years. * Diagnosis of OO: All patients diagnosed with painful OO based on characteristic clinical history of pain relieved with NSAID medications AND confirmatory imaging findings characteristic of OO on CT and/or MRI scans. * Location of OO: eligible lesions must be located in a bone with acoustic accessibility and within the normal safety margins of MR-HIFU, as specified in the instructions for use. * Prior therapy: Patients with prior unsuccessful treatments including CT-RFA and/or surgical resection are eligible for enrollment. * Patients \< 18 years old must be accompanied by a legal guardian at the time of recruitment. * Laboratory: * Complete Blood Count (CBC) values within acceptable range for safe administration of anesthesia. Hemoglobin \> 9 g/dL. * PT, PTT and INR \< 1.5 x ULN (including patients on prophylactic anticoagulation) * Basic metabolic panel (BMP) and/or Complete metabolic panel (CMP) values within acceptable range for safe administration of anesthesia. * Adequate renal function: Age-adjusted normal serum creatinine (see table below) OR a creatinine clearance ≥60 mL/min/1.73 m2 for safe contrast administration * Adequate pulmonary function: Defined as no dyspnea at rest, and a pulse oximetry \>94% on room air. Exclusion Criteria: * Diagnosis of bone lesion other than OO in the judgement of the Principal Investigator. * Clinically significant unrelated systemic illness, such as serious infections, hepatic, renal…