Oxytocin selectively reduces blood flow in uterine fibroids without an effect on myometrial blood flow: a dynamic contrast enhanced MRI evaluation

Abstract

Introduction: Uterine fibroids are the most common benign neoplasms in women. The administration of intravenous oxytocin is known to increase the efficacy of a non-invasive thermal ablation method (MR-HIFU) for treating fibroids. However, it is not known whether this phenomenon is caused by the effect of the oxytocin on the myometrium or the fibroid itself. The objective of this study was to evaluate the influence of oxytocin on the blood flow of fibroids, myometrium and skeletal muscle using a quantitative perfusion MRI technique. Materials and methods: 17 premenopausal women with fibroids considered to be treated with MR-HIFU and 11 women with no fibroids were enrolled in the study. An extended MRI protocol of the pelvis was acquired for each subject. Later another MRI scan was performed with continuous intravenous infusion of oxytocin. The effect of oxytocin was analyzed from quantitative perfusion imaging. The study was registered in clinicaltrials.gov NCT03937401. Results: Oxytocin decreased the blood flow of each fibroid; the median blood flow of fibroid was 39.9 ml/100 g tissue/min without and 3.5 mL/100 g/min with oxytocin (p 0.0001). Oxytocin did not affect the blood flow of the myometrium in either group. Oxytocin increased the blood flow of the skeletal muscle in both groups (p ¼ 0.04). Conclusion: Oxytocin is effective in decreasing the blood flow in fibroids while having minor or no effect on the blood flow of normal myometrium. Routine use of oxytocin in HIFU therapy may make the therapy suitable to a larger group of women in a safe manner.

Feasibility of apparent diffusion coefficient in predicting the technical outcome of MR-guided high-intensity focused ultrasound treatment of uterine fibroids – a comparison with the Funaki classification

“…One of the limitations of this study is the small number of Funaki type III and ADC type III fibroids. This is mostly attributable to the fact that Funaki type III fibroids are usually excluded in the selection process and are not treated with MRgHIFU and the number of subjects could not be increased due to the use of oxytocin infusion during MRgHIFU treatment which has been shown to increase the treatment efficiency [32] and decrease the blood flow to the fibroid [33]. Oxytocin infusion during the treatment would therefore interfere with our interpretation of the results and patients treated after the completion of this study cannot be included any longer.…”

Magnetic Resonance-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids—Efficiency Assessment with the Use of Dynamic Contrast-Enhanced Magnetic Resonance Imaging and the Potential Role of the Administration of Uterotonic Drugs

“…To the best of our knowledge no study on enhancement curves has been conducted so far. The data about the use of oxytocin or misoprostol in MR-HIFU are also recent [ 24 , 25 , 27 ]. Our study underlines the importance of vascular analysis when qualifying patients with UFs for MR-HIFU procedures.…”

“…However, this classification is still not optimal and several UFs subjected to MR-HIFU treatment did not react as expected, with resulting suboptimal NPV eventually found after the procedure [ 23 ]. In order to increase the success rate various uterotonic agents were proposed [ 24 , 25 , 26 , 27 ].…”

Feasibility of T2 relaxation time in predicting the technical outcome of MR-guided high-intensity focused ultrasound treatment of uterine fibroids

“…This is caused by the MRgHIFU treatment selection process where usually Funaki type III fibroids are excluded. The number of subjects could not be increased as we changed the treatment protocol to include an oxytocin infusion during the MRgHIFU treatment which has been shown to improve technical outcomes and significantly decrease the blood flow of the uterine fibroids [27,28]. Second, fifteen patients had screening MRI with different scanners which could have affected the Funaki classification results.…”