title: Peritumoral edema in osteoid osteoma on magnetic resonance imaging.
abstract: OBJECTIVE
  To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient's age, duration of symptoms, or location of the lesion.
  
  
  METHODS
  All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient's age, duration of symptoms, and location of lesions were evaluated by Pearson's correlation coefficient and analysis of variance.
  
  
  RESULTS
  Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient's age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions.
  
  
  CONCLUSIONS
  Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema.
authors.affiliation: Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ehara
authors.forename: D I
authors.initials: DI
authors.lastname: Rosenthal
authors.forename: J
authors.initials: J
authors.lastname: Aoki
authors.forename: K
authors.initials: K
authors.lastname: Fukuda
authors.forename: H
authors.initials: H
authors.lastname: Sugimoto
authors.forename: H
authors.initials: H
authors.lastname: Mizutani
authors.forename: K
authors.initials: K
authors.lastname: Okada
authors.forename: M
authors.initials: M
authors.lastname: Hatori
authors.forename: M
authors.initials: M
authors.lastname: Abe
mesh_terms: D000293:Adolescent; D001853:Bone Marrow / Q000473:pathology; D001859:Bone Neoplasms / Q000473:pathology*; D004487:Edema / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010017:Osteoma, Osteoid / Q000473:pathology*