An analysis of the imaging features and diagnostic value of osteoid osteoma on DR, CT, and MRI.

OBJECTIVE: To compare the diagnostic value of digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI) in osteoid osteoma (OO). MATERIALS AND METHODS: A retrospective analysis was performed on imaging data of 99 patients with pathologically confirmed OO (84 underwent DR, 86 underwent CT, and 36 underwent MRI). Detection rates of lesion features and diagnostic concordance rates for DR, CT, and MRI were calculated; intergroup comparisons were conducted using Fisher's exact test. RESULTS: Among 99 OO patients, 74.7% were male (mean age, 15.41 ± 9.98 years). The proximal femur was the most common site (42.4%). For imaging features, CT showed detection rates of 100, 91.9, and 89.5% for the nidus, bone sclerosis, and intranidal calcification, respectively all higher than those of DR (52.4, 69.0, 16.7%) and MRI (44.4, 58.3, 55.6%). MRI achieved an 83.3% detection rate for perilesional bone marrow edema. All 23 intra-articular OOs were accompanied by joint effusion and synovitis. Diagnostic concordance rate comparison revealed that CT's overall rate was significantly higher than that of DR and MRI (p < 0.001). CONCLUSION: CT provides the best visualization of the OO nidus, surrounding bone sclerosis, and intranidal calcifications, with the highest diagnostic accuracy, making it the optimal imaging modality. MRI has a distinct advantage in edema detection, aiding in the assessment of intra-articular lesion activity.