Contrast-enhanced MRI predicts local recurrence of osteoid osteoma after radiofrequency ablation
- AH Mahnken MD MBA MME; P Bruners MD; H Delbrück MD; RW Günther MD; C Plumhans MD.
- Conflict of interest: There is no conflict of interest to report.
Professor Andreas H Mahnken, Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany.
Osteoid osteoma is a painful benign tumour, which is commonly treated by radiofrequency ablation (RFA). The goal of this study is to assess the value of contrast-enhanced magnetic resonance imaging (MRI) for predicting clinical success after RFA of osteoid osteoma.
Twenty consecutive patients (14 male, 6 female; mean age 23.3 ± 13.4 years) suffering from osteoid osteoma underwent unenhanced and contrast-enhanced T1-weighted MRI the day after RFA. Post-interventional contrast enhancement of the nidus was analyzed by comparing signal-to-noise ratios (SNR) of the nidus before and after contrast administration. The SNR between pre- and post-contrast scans was computed.
There were no significant differences in SNR between pre- and post-contrast scans in the area of ablation (P = 0.1583), while the SNR exceeded one in four patients, indicating residual contrast enhancement. In three of these patients clinical symptoms recurred, requiring re-ablation, while one patient remained free from symptoms during follow-up. In patients with a pre- and post-contrast SNR of ≤1.18 no local recurrence was observed.
Contrast enhancement on T1-weighted MRI imaging seems to be predictive of clinically unsuccessful RFA in osteoid osteoma. Patients with a SNR increase of ≥20% after contrast administration might be considered for re-ablation to avoid symptomatic tumour recurrence.