Ineffectiveness of magnetic resonance imaging enhancement to predict fibroid volume reduction after uterine artery embolization.

Fibroid nonenhancement is considered a relative contraindication to uterine artery embolization (UAE) for symptomatic fibroids. This retrospective study assessed the impact of UAE on nonenhancing fibroids to determine imaging predictors of fibroid shrinkage. All women who underwent UAE for symptomatic fibroids between May 2009 and July 2014 and had follow-up magnetic resonance imaging 6 months after UAE were included. There were 59 fibroids (5 nonenhancing, 54 enhancing) among 18 women aged 40 to 53 (mean 46) years. All fibroids were assessed for size, position, and enhancement on subtraction and apparent diffusion constant (ADC) images. Enhancing fibroids had an average decrease in diameter of 19% ± 3%, not significantly different than nonenhancing fibroids, which decreased 23% ± 6% (P = 0.49). Multiple linear regression with percent change in fibroid diameter as the dependent variable and patient age, fibroid position, and pre-UAE fibroid diameter, enhancement, and ADC as independent variables showed that ADC (P = 0.04) and pre-UAE diameter (P = 0.03) were the only significant independent variables. In conclusion, pre-UAE size and ADC, but not contrast enhancement, predicted fibroid diameter reduction. Enhancing and nonenhancing fibroids had a similar size reduction after UAE. Nonenhancement should not be considered a contraindication to UAE.