Young-Sun Kim MD, Presenter: Nothing to Disclose

Hyunchul Rhim MD, PhD, Abstract Co-Author: Nothing to Disclose

Hyo Keun Lim MD, Abstract Co-Author: Research grant, Koninklijke Philips Electronics NV

Duk-Soo Bae, Abstract Co-Author: Nothing to Disclose

Byoung-Gie Kim, Abstract Co-Author: Nothing to Disclose

Jeong-Won Lee, Abstract Co-Author: Nothing to Disclose

Tae-Joong Kim, Abstract Co-Author: Nothing to Disclose

Chelhun Choi, Abstract Co-Author: Nothing to Disclose

Volumetric MR-HIFU ablation technique has been recently developed to overcome a low time efficiency of conventional method. The purpose of our study was to assess early clinical outcomes of volumetric MR-HIFU ablation for the treatment of uterine fibroids focused on learning curve and treatment speed.

From Aug 2009 to Mar 2011, we treated 53 symptomatic uterine fibroids (volume 341±257 [33.5-1184]mL) in 43 women (mean age 43.7) with volumetric MR-HIFU ablation. We assessed procedure time, NPV (non-perfused volume), complication and learning curve (in terms of treatment speed [NPV/treatment time]). We also evaluated which factors (BMI, fibroid volume, T2 signal ratio of fibroid to skeletal muscle, presence of scar, before or after learning curve) significantly affect treatment speed by multivariate analysis.

Technical success was achieved in 42 cases (98.7%). MR room time was 216.0±40.6min and treatment time from 1st to last sonication was 131.5±55.9min. Sonication duration for mean 35.2 sonications (4/8/12/16mm-0.3/6.3/15.5/13.2) was 28.0±15.4min. NPV at immediate MR was 178.9±147.3mL which was 57.4±25.5% of fibroid volume (~20% n=5, 20~50% n=11, 50~80% n=25, 80%~ n=12). Treatment speed was 81.8±48.0 (1.0-179.0)mL/hr. There were 6 minor complications (14.0%; thermal injury of abdominal wall muscle n=3, 1st degree skin burn n=1, self-limiting numbness on right shin n=1, cystitis n=1). Learning curve showed a plateau starting from the 16th case, and there were significant differences in both NPV/fibroid volume (39.8±20.0% vs. 65.7±18.4%, p=0.003) and NPV/treatment time (50.6±35.7mL/hr vs. 96.0±45.8mL/hr, p<0.001) between before and after learning curve. Multivariate analysis showed large fibroid volume (B=0.108, p<0.001), low T2 signal ratio (B=-7.236, p=0.009) and after learning curve (B=42.405, p<0.001) significantly increased treatment speed.

Volumetric MR-HIFU ablation is an effective and safe modality for the treatment of uterine fibroids, of which treatment speed increases when treating large or dark fibroid. After getting learning curve, treatment speed as well as therapeutic result is significantly improved.

The new volumetric MR-HIFU ablation technique can be effectively and safely used for the treatment of symptomatic uterine fibroids within acceptable range of procedure time.

Kim, Y, Rhim, H, Lim, H, Bae, D, Kim, B, Lee, J, Kim, T, Choi, C, Volumetric MR-HIFU (Magnetic Resonance Imaging-guided High-intensity Focused Ultrasound) Ablation for the Treatment of Symptomatic Uterine Fibroids: Analysis Focused on Learning Curve and Treatment Speed.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010698.html