Diffusion-weighted imaging as a non-gadolinium alternative for immediate assessing nonperfused area of adenomyosis after magnetic resonance-guided focused ultrasound (MRgFUS) ablation: a potential technique but with slightly overestimate.

Background: It is a technical challenge to monitor ablation outcome during magnetic resonance-guided focused ultrasound (MRgFUS) treatment using non-gadolinium technique. The study aimed to investigate the value of diffusion-weighted imaging (DWI) for immediately assessing nonperfused area of adenomyosis after MRgFUS treatment. Methods: We retrospectively included patients with adenomyosis who underwent MRgFUS ablation and underwent both DWI (b=800 sec/mm Results: A total of 48 women with adenomyosis (mean age 39.6±4.9 years) were analyzed. Abnormal signals were observed in all 48 adenomyosis lesions on DWI images and could be categorized into 3 types: large area of central low-signal with complete (type 1) or incomplete (type 2) high-signal ring, or inhomogeneous high-signal areas without a ring sign (type 3). Intra- and interobserver intraclass correlation coefficients (ICCs) were 0.84 and 0.80, respectively, for categorizing the DWI signal types (both P<0.001). The DWI abnormal signals and nonperfused areas were essentially corresponding. ICCs were ranged from 0.85 to 0.91 for area measurements using DWI Conclusions: DWI can serve as a non-gadolinium technique for the initial evaluation of nonperfused area of adenomyosis after MRgFUS ablation. However, it is also important to note that DWI may slightly overestimate the nonperfused area.