PhD defense Inez Verpalen

On Friday 16 April 2021, Inez Verpalen will defend her thesis entitled: “Improving Treatment Efficacy of MR-HIFU Fibroid Ablation”.


Magnetic-Resonance image guided-High Intensity Focused Ultrasound (MR-HIFU) is a completely non-invasive, relatively new treatment option. The rather technical procedure combines MRI with focusing ultrasound waves to ablate tissue and this technique can be used, among other applications, to treat women with symptomatic uterine fibroids.

Currently, women suffering from uterine fibroids are often treated by (hormonal) medication, or when insufficient or not desired, undergo more invasive treatments like hysterectomy or uterus artery embolization. MR-HIFU is seen as an attractive alternative for these more invasive treatment options since less complications are seen after treatment, recovery time is shorter and the treatment is uterus saving and therefor an option for women with a (future) pregnancy wish. However, some hurdles needed to be taken to improve the efficacy of the treatment that could lead to implementation of MR-HIFU in the Dutch clinical practice.

The work in this thesis focused on improving the treatment efficacy of MR-HIFU fibroid ablation. Study results showed that the implementation of unrestricted treatment protocols led to better long-term outcomes. Thus, complete ablation of the uterine fibroid results in greater symptom reduction and reduces the number of additional treatments during follow-up. Moreover, newly developed treatment protocols on how to modify uterine fibroid positioning decreased the number of treatment failures in our patient cohort. Furthermore, the treating radiologist is ‘blinded’ to the treatment result until the end of the therapy. Therefore, a method to visualize the ablated volume during the MR-HIFU procedure is desired. Diffusion Weighted Imaging (DWI) showed the potential to be a valuable clinical tool to monitor treatment progression of MR-HIFU fibroid ablation. Finally, not all patients with symptomatic uterine fibroids are suitable for MR-HIFU ablation because of the various biological characteristics of uterine fibroids. Patient selection is based on a pre-treatment MRI, but it is difficult to predict treatment success. Quantitative Magnetic Resonance Imaging (MRI) pre-treatment can be used to distinguish different types of uterine fibroids and might therefore be a useful tool to optimize patient selection for MR-HIFU and other fibroid treatment modalitie.