Improving treatment efficacy of MR-HIFU fibroid ablation

Abstract

IMPROVING TREATMENT EFFICACY OF MR-HIFU FIBROID ABLATION

During the study period, MR-HIFU therapy for uterine fibroids was implemented in a non-academic hospital setting. The work carried out in this thesis focused on identifying and solving the main limitations of MR-HIFU fibroid ablation; (long-term) effectiveness, patient selection and treatment efficacy.

Part I – Treatment Effectiveness In chapter 2, the clinical outcomes after MR-HIFU fibroid ablation were reevaluated by excluding restricted treatment protocols. We showed that MR-HIFU treatments are more effective in alleviating fibroid-related symptoms and lower re-intervention rate when complete fibroid ablation is pursued. However, long-term data is lacking and there are no controlled, comparative trials available. Both should be subject of future research to define the role of MR-HIFU therapy in the management of uterine fibroids.

In chapter 3, long-term outcomes after MR-HIFU fibroid ablation were evaluated, primarily to assess the re-intervention rate. Restrictive versus unrestrictive treatment protocols were compared, the re-intervention rate significantly decreased in the unrestrictive treatment protocol group, emphasizing the need to aim for complete fibroid ablation during MR-HIFU therapy. Although the re-intervention rate did increase over time, no re-interventions were reported beyond 21 months follow-up in the unrestricted treatment protocol group.

Part II – Patient Selection In chapter 4, quantitative MRI was used to study various biological characteristics of uterine fibroids. In this explorative study, it was possible to distinguish different uterine fibroid tissue types. Therefore, quantitative MRI could be a useful tool to optimize patient selection for MR-HIFU and other fibroid treatment modalities. However, the results of this study must be linked to treatment outcome in future research.

Part III – Treatment Efficacy In chapter 5, it was demonstrated that the treatment efficacy of MR-HIFU increased by implementing our newly developed 3-step manipulation protocol. Results showed that the number of women eligible for the procedure increased and the number of treatment failures due to unsuccessful positioning of the fibroid decreased. Thus, implementation of the 3-step manipulation protocol led to less restricted screening guidelines and more gain during the MR-HIFU treatment.

In chapter 6, the use of DWI in monitoring the NPV without administrating a contrast agent was investigated. Visualization of the NPV with DWI was feasible and three distinct imaging patterns of the NPV on DWI were recognized. Importantly, a hyperintense rim on DWI (b-400,600,800) may indicate (near)complete fibroid ablation. In summary, DWI might be a promising tool for periprocedural monitoring of the NPV.