Treatment-related alterations of imaging findings in osteoid osteoma after percutaneous radiofrequency ablation.
OBJECTIVES
We aimed to report the long-term outcomes of osteoid osteoma patients and to determine CT and dynamic contrast-enhanced MR imaging characteristics of radiofrequency ablation (RFA) treatment related changes of osteoid osteoma between follow-up periods.


MATERIALS AND METHODS
Thirty patients (seven female, 23 male) who underwent CT-guided RFA of osteoid osteoma were included. Follow-up imaging examinations were divided into two subgroups; first (1-3 months) and second (> 6 months) periods. Nidus size, calcification, cortical thickening, maximum signal intensity (SImax), time of SImax (Tmax), slope of signal intensity-time (SIT) curves were noted. CT and dynamic MR imaging findings were compared between follow-up periods.


RESULTS
Clinical success rate was 100%. The mean of OO nidi size was 5.85 ± 1.98 mm before treatment. There was a significant difference for OO nidi sizes between pretreatment and second follow-up period examinations (p = 0.002). SImax and slope of SIT curves of all patients (100%) showed decrease on follow-up MRIs. There was a significant decrease for SImax values between pretreatment and second follow-up period. There was a significant decrease for slope of SIT curves between pretreatment and both follow-up periods.


CONCLUSIONS
RFA is an effective and safe treatment choice for osteoid osteomas. On follow-up imaging, slope of SIT curve and Tmax have the most important positive predictive value for long-term outcomes and single dynamic contrast-enhanced MRI within first 3 months after treatment may be sufficient for symptom-free patients.
['Erbaş|Gonca|G|', 'Şendur|Halit Nahit|HN|', 'Kiliç|Hüseyin Koray|HK|', 'Cindil|Emetullah|E|', 'Öner|Ali Yusuf|AY|', 'Tokgöz|Nil|N|', 'Ilgit|Erhan Turgut|ET|']
D000293:Adolescent D000328:Adult D001859:Bone Neoplasms D001842:Bone and Bones D017115:Catheter Ablation D002648:Child D002675:Child, Preschool D003287:Contrast Media D005260:Female D006801:Humans D007089:Image Enhancement D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D010017:Osteoma, Osteoid D015203:Reproducibility of Results D012189:Retrospective Studies D014057:Tomography, X-Ray Computed D016896:Treatment Outcome D055815:Young Adult
Osteoid osteoma Radiofrequency ablation Follow-up Computed tomography Magnetic resonance imaging