Quantitative Assessments of Uterine Fibroids pre and post Uterine Artery Embolization

Abstract

The objective of this study was to quantify fibroid microvascularity before and after uterine artery embolization (UAE) using contrast-enhanced ultrasound (CEUS) and superb microvascular imaging (SMI). To date 14 women scheduledfor UAE to treat their uterine fibroids have been enrolled in this ongoing IRB-approved study. Subjects underwent threeexaminations (day 0, 15 and 90 after UAE) using an Aplio i800 scanner (Canon Medical Systems) with a curvilinear array. Color Doppler (CDI), power Doppler (PDI), color and monochrome SMI (cSMI and mSMI) images of the uterine fibroids were acquired followed by CEUS. For the CEUS examination 2.0 mL of Lumason (Bracco, Milan, Italy) was administered IV. Images were analyzed using ImageJ (NIH, Bethesda, MD, USA) to quantify the fractional vascularity of the fibroids (FV; as % of enhanced pixels within the fibroid) and flow intensity (as mean brightness level of the enhanced pixels within the fibroid). The CEUS results were used as the reference standard, and compared to all modes. Results were analyzed using repeated measures (over days and flow modes) ANOVA tests. Results from 20 fibroids in 14 women are available with CEUS showing complete embolization for all but one patient. Quantitative analysis of the FV across imaging modes (CDI, PDI, cSMI and mSMI) and examination days showed statistically significant differences (p < 0.001) in agreement with the CEUS findings. Amongst the flow modes, mSMI showed the most difference (p=0.006), which could be due to the artifacts inherent in this imaging mode. Analyzing flow intensity resulted in no statistically significant differences between flow modes (p= 0.96). In conclusion, results indicate that CEUS and SMI pre and post UAE can accurately evaluate fibroid microvascularity and, thus, procedure outcomes benefiting patient care; albeit based on a small sample size.