Magnetic Resonance-Guided High-Intensity Focused Ultrasound (MR-HIFU) in Treatment of Symptomatic Uterine Myomas

Effects of high-intensity focused ultrasound combined with levonorgestrel-releasing intrauterine system on patients with adenomyosis

It is very important to treat adenomyosis which may cause infertility, menorrhagia, and dysmenorrhea for women at the reproductive age. High-intensity focused ultrasound (HIFU) is effective in destroying target tumor tissues without damaging the path of the ultrasound beam and surrounding normal tissues. The levonorgestrel-releasing intrauterine system (LN-IUS) is a medical system which is inserted into the uterine to provide medicinal treatment for temporary control of the symptoms caused by adenomyosis. This study was to investigate the effect of HIFU combined with the LN-IUS on adenomyosis. In the HIFU treatment, the parameters of the ultrasound were transmission frequency 0.8 MHz and input power 50-400 W (350 ± 30), and the temperature in the target tissue under these conditions would reach 60-100 °C (85 °C ± 6.3 °C). Size reduction and blood flow signal decrease were used to assess the effect of combined treatment. In this study, 131 patients with adenomyosis treated with HIFU combined with LN-IUS were retrospectively enrolled. The clinical and follow-up data were analyzed. After treatment, the volume of the uterine lesion was significantly decreased with an effective rate of 72.1%, and the adenomyosis blood flow signals were significantly reduced, with an effective rate of 71.3%. At six months, the menstrual cycle was significantly (P < 0.05) decreased from 31.4 ± 3.5 days before treatment to 28.6 ± 1.9 days, the menstrual period was significantly shortened from 7.9 ± 1.2 days before HIFU to 6.5 ± 1.3 days, and the menstrual volume was significantly (P < 0.05) decreased from 100 to 49% ± 13%. The serum hemoglobin significantly (P < 0.05) increased from 90.8 ± 6.2 g/L before treatment to 121.6 ± 10.8 g/L at six months for patients with anemia. Among seventy-two (92.3%) patients who finished the six-month follow-up, sixty-five (90.3%) patients had the dysmenorrhea completely relieved, and the other seven (9.7%) patients had only slight dysmenorrhea which did not affect their daily life. Adverse events occurred in 24 (18.3%) patients without causing severe consequences, including skin burns in two (1.5%) patients, skin swelling in four (3.1%), mild lower abdominal pain and low fever in 15 (11.5%), and subcutaneous induration in three (2.3%). Six months after treatment, no other serious side effects occurred in any patients with follow-up. In conclusions, the use of high-intensity focused ultrasound combined with the levonorgestrel-releasing intrauterine system for the treatment of adenomyosis is safe and effective even though the long-term effect remains to be confirmed.

Low frequency nanobubble-enhanced ultrasound mechanotherapy for noninvasive cancer surgery

Scaling down the size of microbubble contrast agents to the nanometer level holds the promise for noninvasive cancer therapy. However, the small size of nanobubbles limits the obtained bioeffects as a result of ultrasound cavitation, when operating near the nanobubble resonance frequency. Here we show that coupled with low energy insonation at a frequency of 80 kHz, well below the resonance frequency of these agents, nanobubbles serve as noninvasive therapeutic warheads that trigger potent mechanical effects in tumors following a systemic injection. We demonstrate these capabilities in tissue mimicking phantoms, where a comparison of the acoustic response of micro- and nano-bubbles after insonation at a frequency of 250 or 80 kHz revealed that higher pressures were needed to implode the nanobubbles compared to microbubbles. Complete nanobubble destruction was achieved at a mechanical index of 2.6 for the 250 kHz insonation vs. 1.2 for the 80 kHz frequency. Thus, the 80 kHz insonation complies with safety regulations that recommend operation below a mechanical index of 1.9. In vitro in breast cancer tumor cells, the cell viability was reduced to 17.3 ± 1.7% of live cells. In vivo, in a breast cancer tumor mouse model, nanobubble tumor distribution and accumulation were evaluated by high frequency ultrasound imaging. Finally, nanobubble-mediated low frequency insonation of breast cancer tumors resulted in effective mechanical tumor ablation and tumor tissue fractionation. This approach provides a unique theranostic platform for safe, noninvasive and low energy tumor mechanotherapy.

Recognition of Biological Tissue Denaturation Based on Improved Multiscale Permutation Entropy and GK Fuzzy Clustering

Recognition of biological tissue denaturation is a vital work in high-intensity focused ultrasound (HIFU) therapy. Multiscale permutation entropy (MPE) is a nonlinear signal processing method for feature extraction, widely applied to the recognition of biological tissue denaturation. However, the typical MPE cannot derive a stable entropy due to intensity information loss during the coarse-graining process. For this problem, an improved multiscale permutation entropy (IMPE) is proposed in this work. IMPE is obtained through refining and reconstructing MPE. Compared with MPE, the IMPE overcomes the deficiency of amplitude information loss due to the coarse-graining process when computing signal complexity. Through the simulation of calculating MPE and IMPE from white Gaussian noise, it is found that the entropy derived by IMPE is more stable than that derived by MPE. The processing method based on IMPE feature extraction is applied to the experimental ultrasonic scattered echo signals in HIFU treatment. Support vector machine and Gustafson–Kessel fuzzy clustering based on MPE and IMPE feature extraction are also used for biological tissue denaturation classification and recognition. The results calculated from the different combination algorithms show that the recognition of biological tissue denaturation based on IMPE-GK clustering is more reliable with the accuracy of 95.5%.

Comparison of magnetic resonance-guided high-intensity focused ultrasound with uterine artery embolization for the treatment of uterine myoma: A systematic literature review and meta-analysis

OBJECTIVE

This study aimed to compare the outcomes of magnetic resonance-guided (MR-g) high-intensity focused ultrasound (HIFU) with uterine artery embolization (UAE) for the treatment of uterine myoma.

MATERIALS AND METHODS

A systematic literature review and meta-analysis was conducted using database searches of Medline, Cochrane, EMBASE, and Google Scholar. Articles were searched through March 25, 2020. Outcomes of interest were Symptom Severity Score (SSS), Health-related Quality of Life (HRQoL), re-intervention rate, and rate of adverse reactions in patients with uterine myoma.

RESULTS

Four studies were included with a total of 207 patients with uterine myomas who received MR-g HIFU and 201 who received UAE. UAE was associated with a greater reduction in SSS, improved HRQoL, and a significantly lower re-intervention rate compared with MR-g HIFU in 3 of 4 included studies. No significant differences were found in the incidence and severity of adverse events between treatment arms in one study, but differences were observed in the percentage of adverse reactions in another.

CONCLUSION

Published evidence suggests that the efficacy of MR-g HIFU may not be superior to that of UAE in the treatment of uterine myoma.

Vilaprisan, a New Selective Progesterone Receptor Modulator in Uterine Fibroid Pharmacotherapy-Will it Really be a Breakthrough?

BACKGROUND

Vilaprisan (VPR) is a new orally available selective progesterone receptor modulator (SPRM), with anti-proliferative activity against uterine fibroids (UFs). It definitively causes suppression of ovulation and inhibition of proliferation of endometrial, myometrial and UF cells.

PURPOSE

This review aims to summarize current knowledge on VPR from all studies, including clinical trials, conducted to date and to contextualize the potential role of VPR in future medical regimens for the treatment of UFs.

METHODS

We performed a literature search in PubMed US National Library of Medicine and Google Scholar databases. Both databases were extensively searched for all original and review articles/book chapters as well as congress abstracts published in English until July 2019. The use of VPR for UF therapy was identified by using the keywords: "uterine fibroids" and "vilaprisan".

RESULTS

In phase I and II clinical trials, VPR was shown to be effective in ameliorating UF-related clinical symptoms, especially abnormal or excessive uterine bleeding and in shrinking UFs. The tolerability of VPR is roughly similar to that of ulipristal acetate (UPA) and it tends to be more favorable than that of GnRH-agonists.

CONCLUSION

Presently, all trials examining the utility of VPR for the treatment of UF are halted; likely, due to the recently reported cases of hepato-toxicity with UPA, in addition to non reassuring toxicology results from preclinical long-term testing on rodents, carried out in parallel with late stage testing on humans. An accurate summary of robust data related to the safety of VPR is urgently needed to draw definitive conclusions on the future clinical development of this drug for UF therapy.

Magnetic resonance-guided high-intensity focused ultrasound of uterine fibroids: whole-tumor quantitative perfusion for prediction of immediate ablation response

Background

In magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) treatment of uterine fibroids, the immediate ablation response is significantly affected by blood perfusion. The variability of measurement for blood perfusion is critical due to the inherent non-uniformity of tumor perfusion and its dependence on reproducible region of interest (ROI) placement.

Purpose

To investigate the value of whole-tumor ROI (ROIwt) analysis for quantitative perfusion in predicting immediate ablation response of uterine fibroids in MR-HIFU.

Material and Methods

Thirty-one fibroids in 28 eligible patients were treated with MR-HIFU. Quantitative perfusion parameters (K^trans, K_ep, and V_p) derived from dynamic contrast-enhanced MRI were obtained before MR-HIFU treatment. The ROIwt and single-layer ROI (ROIsl) were used for quantitative perfusion analysis. T1 contrast-enhanced MRI immediately after MR-HIFU treatment was conducted to determine the non-perfused volume ratio (NPVR). Intraclass correlation coefficient (ICC) was used for consistency test. Spearman’s correlation and multivariate linear regression were used to investigate the predictors of the NPVR. Received operating characteristic (ROC) curve was used to test the predictive efficacy of quantitative perfusion parameter.

Results

The intra- and inter-observer ICC of the quantitative perfusion parameters from ROIwt were higher than those from ROIsl. Multivariate analysis showed that the K^trans of ROIwt was a predictor of the immediate ablation response. ROC analysis displayed that the AUC of K^trans of ROIwt is 0.817 in predicting the ablation response.

Conclusion

Pretreatment K^trans of ROIwt is more reliable and stable than that of ROIsl. It could be a predictor for the immediate ablation response of uterine fibroids in MR-HIFU.

Review of influential clinical factors in reducing the risk of unsuccessful MRI-guided HIFU treatment outcome of uterine fibroids

Magnetic resonance imaging-guided high-intensity focused ultrasound (MRI-guided HIFU) is an effective noninvasive treatment option for symptomatic uterine fibroids. However, tissue characteristics of uterine fibroids and technical limitations can limit the patient population that can benefit from this therapy. In this article, we present our literature review focusing on the influential clinical factors that might reduce the risk of an unsuccessful MRI-guided HIFU treatment outcome of uterine fibroids.

Au nanoparticle-coated, PLGA-based hybrid capsules for combined ultrasound imaging and HIFU therapy

A simple method to prepare AuNPs@PDA/PLGA hybrid capsules for combined ultrasound imaging and HIFU therapy was presented.