Synopsis:  Transcutaneous MR-guided High  Focus Ultrasound  (HIFUS)  ablation  of

uterine  fibroids  was  performed  in  38  symptomatic  women  scheduled  for

hysterectomy.  Accurate  targeting  of  the  ultrasound  beam  and  assessment  of  heat

generation were achieved by real-time MRI monitoring. The aim of the present study

was to determine the safety, feasibility and clinical efficacy of this novel non-invasive

alternative  to  hysterectomy.  This  outpatient  procedure  was  well  tolerated  by  all

women, with only 3 women  subsequently undergoing  their  scheduled hysterectomy.

The  treated  fibroids  demonstrated  a  statistically  significant  reduction  in  size  on

follow-up  MRI,  and  the  majority  of  women  reported  an  improvement  in  their

symptoms.

Objective:  Thermal ablation of uterine fibroids using HIFUS (High intensity focused

ultrasound) under MR-guidance was evaluated for feasibility and clinical efficacy. 

Materials and Methods:  38 women with symptomatic uterine fibroids of 5-10 cm

were included in this study under Helsinki criteria.  Women underwent diagnostic ultrasound and MR studies previous to treatment. MRguided  HIFUS thermal ablations at energies of 1400-3600J were performed. Followup  MR studies at 1 month (for the first 25 women) and at 3-6 months were performed. Clinical examinations were performed monthly after treatment. 

Results: Results from the first 25 women are now available. 28 fibroids were treated

in 25 women. Mean fibroid volume was 250ml. Mean ablated volume was 30ml and

mean non-perfused volume after ablation was 70ml. At follow-up MRI, mean fibroid

volume decreased to 88% of pretreatment volume at 1 month (p<0.001), and to 83.2%

at 3-6 months (p<0.005). There was a statistically significant correlation between the

ablated volume and the reduction in fibroid volume. 16/25 women reported clinical

improvement in their fibroid-related symptoms. None of the women experienced any

significant adverse side effect after the procedure or during the follow-up period. 

Conclusions: Non-invasive thermal ablation of uterine fibroids by MR-guided

HIFUS induced a significant regression in mean fibroid size and caused clinical

improvement in a majority of women at 3-6m after therapy. The correlation between

the ablated volume and the reduction in fibroid volume suggests that larger coagulated

volumes will result in even better results.