title: Volumetric MR-guided high-intensity focused ultrasound ablation with a one-layer strategy to treat large uterine fibroids: initial clinical outcomes.
abstract: OBJECTIVE
  To evaluate initial clinical outcomes of volumetric magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU) ablation by using a one-layer strategy to treat large (>10 cm in diameter) uterine fibroids, with investigation of the correlation between effectiveness of the one-layer strategy and dynamic contrast material-enhanced (DCE) MR parameters.
  
  
  METHODS
  Institutional review board approval and informed consent were obtained. Twenty-seven women (mean age, 44.5 years) with 27 large uterine fibroids (mean diameter, 11.3 cm ± 1.4 [standard deviation] [range, 10.1-16.0 cm]; fibroid volume, 502.5 mL ± 214.3 [range, 253.8-1184.0 mL]) underwent volumetric MR-guided HIFU ablation with a one-layer strategy. (All treatment cells were placed in one coronal plane at a depth of half to anterior two-thirds of the anteroposterior dimension of fibroids.) Treatment time, immediate nonperfused volume (NPV), and effectiveness of a one-layer strategy (ratio of immediate NPV to total volume of treatment cells planned) correlating with baseline DCE MR parameters (volume transfer constant [K(trans)], fractional extravascular extracellular space, and fractional blood plasma volume [Pearson correlation test]), complications, 3-month follow-up volumes, and symptom severity score (SSS) changes (paired t test) were assessed retrospectively.
  
  
  RESULTS
  All treatments showed technical success in one session (mean treatment time, 166.2 minutes ± 38.9). NPV was 301.3 mL ± 119.1, which was 64.2% ± 19.9 (<50%, n = 4; ≥ 50%, n = 23) of fibroid volume. Ratio of immediate NPV to total volume of treatment cells (1.79 ± 0.61) negatively correlated with DCE MR imaging K(trans) values (r = -0.426, P = .017). Minor complications occurred in five patients (18.5% [thermal injury of abdominal wall, n = 3; 30-day leg numbness, n = 1; cystitis, n = 1]). At 3-month follow-up (n = 18), mean SSS had decreased from 37.4 at baseline to 24.0 (P < .001), and volume reduction ratio was 0.64 ± 0.15 (P < .001).
  
  
  CONCLUSIONS
  Volumetric MR-guided HIFU ablation with a one-layer strategy is safe and effective for treatment of large uterine fibroids. Effectiveness of this strategy showed a significant negative correlation with K(trans) values at baseline DCE MR imaging.
authors.affiliation: High-Intensity Focused Ultrasound Center, Samsung Medical Center, Seoul, Korea.
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Jae-Hun
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: Hyo Keun
authors.initials: HK
authors.lastname: Lim
authors.forename: Bilgin
authors.initials: B
authors.lastname: Keserci
authors.forename: Duk-Soo
authors.initials: DS
authors.lastname: Bae
authors.forename: Byoung-Gie
authors.initials: BG
authors.lastname: Kim
authors.forename: Jeong-Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Tae-Joong
authors.initials: TJ
authors.lastname: Kim
authors.forename: Chel Hun
authors.initials: CH
authors.lastname: Choi
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006801:Humans; D007889:Leiomyoma / Q000473:pathology / Q000601:surgery*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D014594:Uterine Neoplasms / Q000473:pathology / Q000601:surgery*
chemical_list: D003287:Contrast Media