title: Diffusion-weighted imaging for prediction of volumetric response of leiomyomas following uterine artery embolization: a preliminary study.
abstract: OBJECTIVE
  To determine if pretreatment apparent diffusion coefficient (ADC) of leiomyomas could predict volumetric response (VR) following uterine artery embolization (UAE).
  
  
  METHODS
  We retrospectively studied 11 women who underwent pelvic MRI before and >120 days following UAE. MRI included conventional and diffusion weighted imaging sequences. Percentage change in leiomyoma volume was determined by multiplanar T2-weighted imaging. A Pearson correlation coefficient was calculated between leiomyoma VR following UAE and the following pre-embolization parameters: initial volume, relative enhancement, relative T2 signal intensity (SI) and ADC. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity and specificity of ADC for predicting volumetric response.
  
  
  RESULTS
  Twenty-eight leiomyomas were included with a mean interval from UAE to follow-up MRI of 207 days. The preprocedural volume of the leiomyomas ranged from 18 to 182 cm(3) (median 47 cm(3)). and ADC ranged from 0.37 to 1.71 mm(2)/s (mean 0.80 mm(2)/s). All leiomyomas were 100% necrotic following UAE. Leiomyoma VR following UAE was 48% ± 3.5%. with significant correlation between VR and ADC (r = 0.41; P = 0.017) but no correlation with initial leiomyoma volume, relative T2 SI, or relative enhancement. Using a threshold of 0.875 × 10(-3) mm(2)/s, ADC could predict > 50% VR with sensitivity and specificity of 70% and 83%, respectively.
  
  
  CONCLUSIONS
  Pre-UAE ADC of leiomyomas correlated significantly with percent VR following UAE. In contrast, no correlation was seen between VR post-UAE and conventional imaging findings. This suggests that VR following UAE depends on leiomyoma histology reflected in DWI rather than features revealed by conventional MRI.
authors.affiliation: NYU Langone Medical Center, Department of Radiology, New York, New York, USA. elizabeth.hecht@uphs.upenn.edu
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Hecht
authors.forename: Richard K G
authors.initials: RK
authors.lastname: Do
authors.forename: Stella K
authors.initials: SK
authors.lastname: Kang
authors.forename: Genevieve L
authors.initials: GL
authors.lastname: Bennett
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Timothy W I
authors.initials: TW
authors.lastname: Clark
mesh_terms: D000368:Aged; D004058:Diffusion; D004621:Embolization, Therapeutic / Q000009:adverse effects; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007889:Leiomyoma / Q000175:diagnosis* / Q000209:etiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009336:Necrosis; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055988:Uterine Artery / Q000473:pathology*; D055357:Uterine Artery Embolization / Q000009:adverse effects*