Diffusion-weighted imaging properties of uterine fibroids pre- and post-uterine fibroid embolisation

• Change in ADC and contrast enhancement of uterine fibroids following UFE was studied.
• ADC of fibroids rises post-UFE. Previous studies assessing this change have conflicting results.
• ADC rise post-UFE is associated with degree of loss of contrast enhancement.
• ADC measurement using DWI is not yet a proven replacement for GBCA-enhanced MRI.

ObjectiveTo determine the change in apparent diffusion coefficient (ADC) of uterine fibroids following uterine fibroid embolisation (UFE), and if the ADC change correlates with either volume loss or degree of contrast enhancement post-UFE.Materials and methodsThis study was approved by our institutional review board with waiver of consent. The pelvic MRI examinations, including diffusion-weighted MRI (DWI) using 4 b-values, of 50 consecutive patients prior to and 6 months post-UFE were analyzed. The volume, ADC and amount of enhancement were calculated for each fibroid both pre- and post-UFE. The percent residual enhancement for each fibroid was categorized as either: no (0–1%) residual enhancement or residual (>1%) enhancement. Statistical analysis compared ADC, enhancement and volume for each fibroid pre- and post-UFE using paired t-tests and Pearson correlation coefficients.ResultsThe mean ADC of all (n = 88) fibroids pre-UFE was 1.30 ± 0.20 × 10−3 mm2/s, and increased to 1.68 ± 0.24 × 10−3 mm2/s post-UFE (p < 0.0001). Lower pre-UFE ADC correlated with greater ADC change post-UFE (r = −0.50; p < 0.0001). There was no correlation between ADC change and volume change post-UFE (r = 0.07; p = 0.59). However, fibroids with no residual enhancement post-UFE had larger ADC change than those with residual enhancement (p = 0.003).ConclusionThe ADC of fibroids rises post-UFE. ADC change post-UFE is associated with the degree of loss of enhancement and may therefore be valuable in predicting response to treatment in pre-procedural counseling.