title: MR-guided focused ultrasound (MRgFUS) ablation for the treatment of nonspinal osteoid osteoma: a prospective multicenter evaluation.
abstract: BACKGROUND
  Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel imaging-guided surgical technique that allows the performance of noninvasive and radiation-free ablation. Presently, computed tomography (CT)-guided radiofrequency ablation, a minimally invasive percutaneous technique, is the standard for treating symptomatic osteoid osteomas. The purpose of this study was to evaluate the use of MRgFUS ablation for the treatment of nonspinal osteoid osteomas in terms of technical success, complications, and clinical success through one year of follow-up.
  
  
  METHODS
  In this prospective multicenter study, thirty consecutive patients with a nonspinal osteoid osteoma were enrolled between May 2010 and April 2012 at three different university centers; twenty-nine of the patients were treated with use of MRgFUS. Lesions had been previously diagnosed on the basis of imaging, including dynamic contrast-enhanced MR. The mean number of sonications and energy deposition were determined. Technical success was evaluated through an assessment of complications immediately after treatment. Clinical success was determined on the basis of pain reduction as measured with a visual analog scale (VAS), recurrence, and long-term complications through twelve months.
  
  
  RESULTS
  Technical success of MRgFUS was observed for all twenty-nine patients. The mean number of sonications (and standard deviation) was 7 ± 3, and the mean delivered acoustic energy was 1180 ± 736 J. At the twelve-month follow-up, complete clinical success was observed in twenty-six (90%) of the twenty-nine patients (95% confidence interval [CI] = 84 to 95; mean VAS, 0 ± 0 points). Partial success was observed in three (10%) of the twenty-nine patients (95% CI = 5 to 16; mean VAS score, 5 ± 0 points); two of these patients subsequently underwent CT-guided radiofrequency ablation, and one underwent open surgery. Pain score values showed a significant reduction (p < 0.001) between baseline (mean VAS score, 8 ± 1 points) and post treatment (mean VAS score, 1 ± 2 points). No complications were observed.
  
  
  CONCLUSIONS
  MRgFUS may be an effective and safe alternative approach in the treatment of nonspinal osteoid osteoma. A complete clinical success rate of 90% was demonstrated without adverse events. MRgFUS is totally noninvasive and eliminates radiation exposure.
authors.affiliation: Departments of Radiological, Oncological and Pathological Sciences (D.G., A.N., M.M., and C.C.), and Orthopedics and Traumatology (O.M.), Sapienza University of Rome, V.le Regina Elena 324, Rome, Italy 00161. E-mail address for D. Geiger: danielgeigermd@g.
authors.forename: D
authors.initials: D
authors.lastname: Geiger
authors.affiliation: Departments of Radiological, Oncological and Pathological Sciences (D.G., A.N., M.M., and C.C.), and Orthopedics and Traumatology (O.M.), Sapienza University of Rome, V.le Regina Elena 324, Rome, Italy 00161. E-mail address for D. Geiger: danielgeigermd@g.
authors.forename: A
authors.initials: A
authors.lastname: Napoli
authors.affiliation: Department of Radiology, University of L'Aquila, S. Salvatore Hospital, Coppito, L'Aquila, Italy 67100.
authors.forename: A
authors.initials: A
authors.lastname: Conchiglia
authors.affiliation: Department of Radiology, University of L'Aquila, S. Salvatore Hospital, Coppito, L'Aquila, Italy 67100.
authors.forename: L M
authors.initials: LM
authors.lastname: Gregori
authors.affiliation: Department of Radiology, University of L'Aquila, S. Salvatore Hospital, Coppito, L'Aquila, Italy 67100.
authors.forename: F
authors.initials: F
authors.lastname: Arrigoni
authors.affiliation: Department of Radiology, Istituto Ortopedico Rizzoli, University of Bologna, Via Pupilli 1, Bologna, Italy 40136.
authors.forename: A
authors.initials: A
authors.lastname: Bazzocchi
authors.affiliation: Department of Radiology, Istituto Ortopedico Rizzoli, University of Bologna, Via Pupilli 1, Bologna, Italy 40136.
authors.forename: M
authors.initials: M
authors.lastname: Busacca
authors.affiliation: Departments of Radiological, Oncological and Pathological Sciences (D.G., A.N., M.M., and C.C.), and Orthopedics and Traumatology (O.M.), Sapienza University of Rome, V.le Regina Elena 324, Rome, Italy 00161. E-mail address for D. Geiger: danielgeigermd@g.
authors.forename: O
authors.initials: O
authors.lastname: Moreschini
authors.affiliation: Departments of Radiological, Oncological and Pathological Sciences (D.G., A.N., M.M., and C.C.), and Orthopedics and Traumatology (O.M.), Sapienza University of Rome, V.le Regina Elena 324, Rome, Italy 00161. E-mail address for D. Geiger: danielgeigermd@g.
authors.forename: M
authors.initials: M
authors.lastname: Mastantuono
authors.affiliation: Department of Radiology, Istituto Ortopedico Rizzoli, University of Bologna, Via Pupilli 1, Bologna, Italy 40136.
authors.forename: U
authors.initials: U
authors.lastname: Albisinni
authors.affiliation: Department of Radiology, University of L'Aquila, S. Salvatore Hospital, Coppito, L'Aquila, Italy 67100.
authors.forename: C
authors.initials: C
authors.lastname: Masciocchi
authors.affiliation: Departments of Radiological, Oncological and Pathological Sciences (D.G., A.N., M.M., and C.C.), and Orthopedics and Traumatology (O.M.), Sapienza University of Rome, V.le Regina Elena 324, Rome, Italy 00161. E-mail address for D. Geiger: danielgeigermd@g.
authors.forename: C
authors.initials: C
authors.lastname: Catalano
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000628:therapy*; D002648:Child; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000517:prevention & control; D009364:Neoplasm Recurrence, Local / Q000209:etiology; D010017:Osteoma, Osteoid / Q000628:therapy*; D010147:Pain Measurement; D011446:Prospective Studies; D016896:Treatment Outcome; D055815:Young Adult