MR-Guided HIFU Treatment of Symptomatic Uterine Fibroids Using Novel Feedback-Regulated Volumetric Ablation: Effectiveness and Clinical Practice

Abstract

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. Key Points: Citation Format:

Predictive Value of Quantitative Uterine Fibroid Perfusion Parameters From Contrast‐Enhanced Ultrasound for the Therapeutic Effect of High‐Intensity Focused Ultrasound Ablation

“…High‐intensity focused US has increasingly been used for treatment of uterine fibroids worldwide because of its excellent therapeutic efficacy in producing symptomatic relief . It has been revealed that HIFU has a therapeutic effect on uterine fibroids mainly by causing coagulation necrosis of targeted tissue, which was presented as a nonenhancement characteristic on enhanced MRI . Enhanced MRI was considered an important evaluation measure for the early therapeutic response of uterine fibroids to HIFU .…”

“…26,27 It has been revealed that HIFU has a therapeutic effect on uterine fibroids mainly by causing coagulation necrosis of targeted tissue, which was presented as a nonenhancement characteristic on enhanced MRI. 28,29 Enhanced MRI was considered an important evaluation measure for the early therapeutic response of uterine fibroids to HIFU. 18,30,31 The extent of the nonperfused volume or nonperfused volume ratio obtained from posttreatment enhanced MRI was significantly correlated with the treatment outcome for uterine fibroids.…”

MRI‐compatible breast/rib phantom for evaluating ultrasonic thermal exposures

“…The use of angular axis in robotic systems of MRgFUS is mandatory because ribs or other structures (for example nerves) can be avoided. Angular axis is also needed for the case of fibroid treatment using MRgFUS since during treatments targeting of the lumbar and sacral nerve was reported causing severe pain. Another problem reported during fibroids was bowel perforation, which can be eliminated with proper angulation of the FUS transducer.…”

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