To explore the clinical value of CT-guided radiofrequency ablation (RFA) and imaging follow-up for patients with osteoid osteoma.

Thirty-seven patients with osteoid osteomas were selected. Their tumors occurred mainly in the femur and tibia (16/37, 13/37) with local pain aggravated at night in 32 of the cases. They were treated with CT-guided RFA. One week, 1 month and 3 months after the surgery, CT and MRI examinations were conducted to observe the density of the ablated area, any density (signal) changes and the recovery of adjacent tissues. A visual analogue scale (VAS) was used to assess the perceived pain of the patients.

All of the patients went through the operation successfully and resumed unrestricted normal activity within 2 d to 1 week without complications. Field CT showed a low density of bone defects one month after the ablation, with the bone defect narrowing and peripheral thickened reactive bone thinning slightly 2 months later. One week after the RFA treatment the MRI′s T₂WI signal was lower than before the treatment and the T₁WI signal was low. One month after the RFA the T₂WI high signal of 20 of the patients (54.1%) had decreased and the T₁WI low signal had narrowed compared to one week after the operation. The signals of the other 17 cases (45.9%) had returned to normal. Three months after the operation the T₂WI high signal of 10 of the 20 patients (27%) had decreased further and their T₁WI low signal had also narrowed further compared to one month after the operation, with a total of 27 then normal. After the operation, the average VAS score decreased significantly compared to before the operation.

CT-guided RFA is a safe and effective minimally invasive method for the treatment of osteoid osteoma. Dynamic imaging is very useful for assessing the therapeutic effect in the short term.

Osteomas; Catheter ablation; Punctures; Diagnostic imaging