Objective:To discuss the possible factors leading to the discrepancy of ablation efficacy through analyzing MRI performances.Methods:Patients with uterine fibroids of the reproductive age were selected

who had no reproductive requirements

were diagnosed by the MRI and had the typical clinical symptoms under ultrasound-guided focused ultrasound ablation in the out-patient department.Enhanced MRI was used to assess the efficacy immediately after ablation

and the ablation efficacy differences of different locations

sizes

types and T2WI signal intensity were compared.Results:Seventy-four patients with seventy-six submucosal fibroids were enrolled in the study from October 2006 to October 2008.All the patients completed the treatment successfully

and there were no significant complications.The median myoma volume was 98.22 cm3 pre-operation;the non-enhancer region volume was 82.81 cm3 measured in the enhanced MRI after treatment.Myoma volume ablation rate was(76.88±16.28)%.The efficacy in the different locations

sizes and types compared

there was no significant difference(P> 0.05)

but statistically significant difference was found in signal intensity of MRI T2WI(P <0.05):fibroids of low signal intensity had the highest volume of ablation proportion.Conclusion:Uterine fibroids of low signal intensity in the MRI T2WI are easier to achieve the desired ablation efficacy

which might be used as an indicator to predict the ablation efficacy.