title: Microwave ablation of osteoid osteomas using dynamic MR imaging for early treatment assessment: preliminary experience.
abstract: OBJECTIVE
  To evaluate the efficacy of microwave ablation for osteoid osteomas by using dynamic contrast-enhanced magnetic resonance (MR) imaging in early treatment assessment.
  
  
  METHODS
  Ten patients (two female, eight male; mean age, 28 y; range, 16-47 y) presenting with osteoid osteomas were treated between June 2010 and December 2012 with the use of computed tomography (CT)-guided microwave ablation. Osteoid osteomas were found at the femoral neck (n = 4), tibia (n = 3), calcaneus (n = 1), navicular bone (n = 1), and dorsal rib (n = 1). Dynamic contrast-enhanced MR imaging at 3.0 T was performed 1 day before microwave ablation and again after ablation. The procedure was considered successful if the signal intensity (SI) of the lesion on MR imaging decreased by at least 50% and the patient was pain-free within 1 week of intervention.
  
  
  RESULTS
  All patients were pain-free within 1 week after microwave ablation and remained so during the 6 months of follow-up. No major or minor complications developed. On average, SI of the lesions decreased by 75% (range, 55.5%-89.1%) after treatment. The difference in lesion SI before versus after ablation was significant by t test (P < .0001; confidence interval, 120.26-174.96) and Wilcoxon test (P = .0020).
  
  
  CONCLUSIONS
  Microwave ablation treatment of osteoid osteoma was highly successful, without any complications observed. Dynamic contrast-enhanced MR imaging is a useful tool for diagnosing osteoid osteoma and evaluating treatment.
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany. Electronic address: michael.kostrzewa@umm.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Kostrzewa
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Patricius
authors.initials: P
authors.lastname: Diezler
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Michaely
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Rathmann
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Ulrike I
authors.initials: UI
authors.lastname: Attenberger
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
authors.forename: Steffen J
authors.initials: SJ
authors.lastname: Diehl
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008872:Microwaves / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D010017:Osteoma, Osteoid / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D010149:Postoperative Pain / Q000209:etiology; D011237:Predictive Value of Tests; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: 3D; NSAID; PG; RF; SI; TWIST; nonsteroidal antiinflammatory drug; prostaglandin; radiofrequency; signal intensity; three-dimensional; time-resolved imaging with stochastic trajectories