Abstract: Objective To evaluate the correlation of magnetic resonance (MR) T2-weighted image (T2WI) signal characteristics of adenomyosis and the efficacy of high-intensity focused ultrasound (HIFU) ablation. Methods Based on the presence or absence of patchy hyperintense foci on preoperative MR T2WI, the patients with adenomyosis undergoing HIFU treatment were divided into homogeneous signal group and heterogeneous signal group, and the heterogeneous group was further divided into heterogeneous hypointense group and heterogeneous isointense group according to signal intensity of the lesions. The patients in heterogeneous signal group were matched with the patients in the homogeneous group at a 1:1 ratio using the propensity score matching, and similarly, the patients in the heterogeneous hypointense group were matched with those in the heterogeneous isointense group at a 1:1 ratio. The non-perfused volume ratio (NPVR) and relief of dysmenorrhea were used to assess the therapeutic efficacy in the 4 groups. Results A total of 299 patients were enrolled, who had a median preoperative dysmenorrhea score of 7.0 (6.0, 8.0) and a median NPVR of 53.5% (35.4, 70.1)%. After propensity score matching, the NPVR in homogeneous signal group was significantly higher than that in heterogeneous signal group [(60.3 ± 21.8)% vs (44.6±21.6)%, P<0.05]. At 3, 6 and 12 months after HIFU, dysmenorrhea relief rates were higher in homogeneous signal group than in heterogeneous signal group, and the difference was statistically significant at 12 months (91.1% vs 76.8%, P<0.05). The NPVR of heterogeneous hypointense group was higher than that of heterogeneous isointense group [(54.0±22.0) % vs (47.3±22.9) % , P<0.05]. At 6 months after HIFU, dysmenorrhea relief rate was significantly higher in heterogeneous hypointense group than in heterogeneous isointense group (91.5% vs 80.9%, P<0.05). Conclusion The signal characteristics of adenomyosis on T2WI are closely related with the outcome of HIFU ablation, and its efficacy is better for homogeneous than for hetero-geneous adenomyosis, and better for heterogeneous hypointense adenomyosis than for heterogeneous isointense adenomyosis.

Key words: adenomyosis; high-intensity focused ultrasound; magnetic resonance imaging; signal characteristics