Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Objective. To determine whether there is a relationship between the peritum oral edema caused by osteoid osteoma seen on magnetic resonance (MR) imagin g and the patient's age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, du ration 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-weighte d MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two maske d observers. The relationships between the patient's age, duration of sympt oms, and location of lesions were evaluated by Pearson's correlation coeffi cient and analysis of variance. Results. Twenty-seven cases met the inclusion criteria. The observer agreem ent on grading was good. Patients of 15 years of age or younger had signifi cantly higher grades than patients older than 15 years. There was a moderat e negative linear correlation between the patient's age and peritumoral ede ma. No significant relationship was identified between edema and the durati on of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema.