Imaging-derived risk score predicts pain recurrence in osteoid osteoma patients undergoing radiofrequency ablation

Pain recurrence following regular radiofrequency ablation (RFA) in osteoid osteoma (OO) remains incompletely understood, yet impacts quality of life.

To detect predictive imaging parameters in OO with symptomatic recurrence.

This retrospective, monocentric study included 122 OO patients [median age 19 (16; 27) years, male 78%] January 2010 to May 2024, which underwent T1-weighted dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) (3T) before CT-guided RFA. Pain recurrence was defined as visual analogue scale increase >4/10 occurring >2 weeks post-intervention (22 (18%) patients). Nidus was categorized intra-/extracortical. DCE-MRI relative/maximum (relative) enhancement (M(R)E) (%), time to peak (TTP) (s), wash-in/out rate (s^-1), brevity of enhancement (s) were compared by Wilcoxon rank-sum test. Hazard ratios (HR), multivariate cox proportional hazard regression, receiver operating characteristics and Bayesian were performed.

Extracortical nidus occurred more frequently in patients with recurrence (14%) compared to intracortical nidus (5%, p < 0.001). Patients with recurrence had lower MRE [median, 327.2 (IQR, 227.5-393.6)% vs 386.1 (261, 511.6)%; p = 0.038], higher TTP [47.1 (34.5-59.5) vs 32.3 (24.7-46.7); p = 0.002], lower wash-in rate [38.9 (0-107.5) vs. 83.7(30.5-159.7); p = 0.028]. ME [HR 0.2 (95% CI: 0.06, 0.04); p < 0.001], MRE [HR 0.3 (0.1,1); p = 0.042], TTP [HR 6 (1.4, 25.4); p = 0.016], wash-in rate [HR 0.1(0.02, 0.8); p = 0.03] were predictors of recurrence. Extracortical nidus [HR 6.5 (2.1, 19.7); p < 0.001] was predictive. In extracortical nidus-subgroup recurrence probability ≥55% occurred with TTP >40 s, MRE <300%.

Imaging-based risk stratification enables personalized treatment approaches for osteoid osteoma patients, who may benefit from alternative ablation protocols such as extended ablation time, higher temperatures.