Can measurement of apparent diffusion coefficient before treatment predict the response to uterine artery embolization for adenomyosis?

Objectives: To determine the usefulness of the apparent diffusion coefficient (ADC) in predicting response to uterine artery embolization (UAE) for symptomatic adenomyosis. Methods: A prospective study was performed on 25 patients who underwent diffusion-weighted (DW) magnetic resonance imaging (MRI) before UAE between June 2011 and December 2012. All patients underwent 3-month follow-up MRI after UAE using non-spherical polyvinyl alcohol (PVA) particles ranging from 150 to 500 μm. Quantitative measurement of the ADC was performed for each adenomyosis. Complete response and incomplete response were defined as ≥90 % or <90 %, respectively, of the non-perfusion area with adenomyosis at the follow-up MRI. The ADC values were compared between patients who achieved complete or incomplete response which was assessed according to the MRI findings after UAE. Results: Nineteen patients showed complete response, and six showed incomplete response. The ADC value ranged from 0.842 to 1.346 × 10^-3 mm²/s (mean 1.075 ± 0.117). The mean ADC was 1.043 ± 0.237 in the complete response group and 1.176 ± 0.429 in the incomplete response group (0.012). Using a threshold of <1.147 × 10^-3 mm²/s, the sensitivity and specificity of the ADC to predict success after UAE were 83.3 % and 84.2 %. Conclusion: The ADC of adenomyosis may potentially predict a successful response to UAE for adenomyosis. Key Points: • Pre-procedural MRI might help clinicians predict response of UAE in adenomyosis • ADC might help predict UAE outcomes in adenomyosis • MR predictors might be used to counsel patients with symptomatic adenomyosis