Purpose: To evaluate a novel feedback-regulated volumetric sonication method in MR-guided HIFU treatment of symptomatic uterine fibroids.
Materials and Methods: 27 fibroids with an average volume of 124.9???139.8 cc in 18 women with symptomatic uterine fibroids were ablated using the new HIFU system Sonalleve (1.5?T MR system Achieva, Philips). 21 myomas in 13 women were reevaluated 6 months later. Standard (treatment) cells (TC) and feedback-regulated (feedback) cells (FC) with a diameter of 4, 8, 12, and 16?mm were used and compared concerning sonication success, diameter of?induced necrosis, and maximum achieved temperature. The non-perfused volume ratio (NPV related to myoma volume) was quantified. The fibroid volume was measured before, 1 month, and 6 months after therapy. Symptoms were quantified using a specific questionnaire (UFS-QoL).
Results: In total, 205 TC and 227 FC were applied. The NPV ratio was 23???15?% (2???55). The TC were slightly smaller than intended (?3.9???52?%; range, ?100???81), while the FC were 20.1???25.3?% bigger (p?=?0.02). Feedback mechanism is less diversifying in diameter (p?0.001). Overall, the FC correlate well with the planned treatment diameter (r?=?0.79), other than the TC (r?=?0.38). Six months after therapy, the fibroid volume was reduced by 45???21?% (5???100) (p?=?0.001). The symptoms decreased significantly (p?=?0.001). No serious adverse events were recorded.
Conclusion: Use of volumetric sonication leads to homogenous heating and sufficient necrosis. It is a safe and effective therapy for treating symptomatic uterine fibroids. Successful sonication of feedback cells leads to more contiguous necrosis in diameter and a less diversifying temperature.
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