Safety and Feasibility of MR-Guided High Intensity Focused Ultrasound (MR-HIFU) Ablation of Osteoid Osteoma in Children

Inclusion Criteria: * Diagnosis: * All patients with a clinical suspicion of OO based on presence of typical symptoms of localized nocturnal pain that is relieved by NSAIDs and unrelated to trauma or activity. * Typical imaging findings on CT and/or MRI. Plain radiographs and bone scans may be obtained by referring physicians and are helpful for confirming the clinical diagnosis but cannot be substituted for a CT or MRI. * Non-contrast enhanced or contrast enhanced CT studies are acceptable. * Contrast enhanced MRI studies should be performed. * Tissue biopsy is not required * Tumor location: * Target lesions can be located in any peripheral bone with acoustic accessibility. * Target lesions may be intracortical or juxtacortical in location. * Target lesions must be reachable within the normal safety margins of HIFU as specified in the instructions for use. * Prior therapy: ●Patients with prior unsuccessful surgical resection or RFA are eligible for enrollment. * Laboratory : * Hemoglobin \> 9 g/dL * Platelet count ≥75,000/µL (may receive transfusions) * Normal PT, PTT and INR \< 1.5 x ULN (including patients on prophylactic anticoagulation) * Renal function: Age-adjusted normal serum creatinine (table in protocol) 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 if there is clinical indication for determination. Exc…