Efficacy and safety of ultrasound-guided high intensity focused ultrasound ablation of symptomatic uterine fibroids in Black women: a preliminary study

Multi-sequence magnetic resonance imaging radiomics combined with imaging features predicts the difficulty of HIFU treatment of uterine fibroids

To establish a multivariate linear regression model for predicting the difficulty of high-intensity focused ultrasound (HIFU) ablation of uterine fibroids based on multi-sequence magnetic resonance imaging radiomics features. A retrospective analysis was conducted on 218 patients with uterine fibroids who underwent HIFU treatment, including 178 cases from Yongchuan Hospital of Chongqing Medical University and 40 cases from the Second Affiliated Hospital of Chongqing Medical University (external validation set). Radiomics features were extracted and selected from magnetic resonance images, and potentially related imaging features were collected. The energy efficiency factor (EEF) was used as the dependent variable. Imaging models, radiomics models, and joint models were established using a stepwise approach. The model with the highest R2 value was selected for external validation. The R2 value of the combined model was 0.642, higher than that of other models. Spearman correlation analysis showed a correlation coefficient of R = 0.824 (P < 0.001) between predicted EEF and actual EEF. External validation yielded a correlation coefficient of R = 0.645 (P < 0.001). A model for predicting EEF has been developed, which is clinically important for predicting the difficulty of HIFU treatment of uterine fibroids.

A systematic review of the side effects of high-intensity focused ultrasound ablation of uterine fibroids

Background

A new intervention called high-intensity focused ultrasound (HIFU) targets fibroids with high-intensity ultrasound pulses using ultrasound probes. This noninvasive method, which can be carried out with either magnetic resonance imaging or ultrasound guidance, results in immediate coagulated necrosis within a clearly defined area a few millimeters in diameter.

Methods

This systematic review evaluated the safety of HIFU in the treatment of uterine fibroids regardless of site or size. We specifically aimed to determine the incidence of side effects that can occur during and after HIFU. We searched the PubMed, Scopus, ScienceDirect, and Mendeley archive using only the terms HIFU and fibroid. After identifying 1077 studies of different types from 2014 to March 2024, 300 studies were screened and 60 included.

Results

According to Society of Interventional Radiology guidelines, class A adverse events (AEs) showed no significant results, and individuals with these AEs required no treatment and had no long-term consequences. Similarly, there were no class B significant results. However, 3943 of 10,204 patients (38%) complained of lower abdominal pain after the procedure, a class B AE, which resolved by analgesics. Further, 153 of 24,700 patients (0.6%) had skin burns, blisters, or nodules, and these issues resolved with conservative treatment. Additionally, 74 of 23,741 patients (0.3%) had hematuria; 882 of 5970 patients (14.7%) had abnormal vaginal discharge; 414 of 23,449 (1.7%) had vaginal bleeding; and 267 of 7598 (3.5%) had leg paresthesia. Major AEs (class C and D) were almost nonexistent, and the incidence of death in our study was zero.

Conclusion

HIFU ablation of uterine fibroids is generally safe, causing mostly mild side effects and very few severe complications. The relative safety of HIFU compared to other minimally invasive techniques, such as uterine artery embolization, still needs further evaluation.

Efficacy and Safety of Ultrasound-Guided High-Intensity Focused Ultrasound Ablation in Women With Multiple Uterine Fibroids: An Exploratory Study

OBJECTIVE

The aim of the work described here was to explore the clinical efficacy and safety of ultrasound-guided high-intensity focused ultrasound (USg-HIFU) treatment in women with multiple fibroids and identify the characteristic parameters predicting USg-HIFU efficacy in multiple fibroids.

METHODS

From February 2021 to August 2022, 138 patients with multiple fibroids (group A comprising 125 patients with two to four fibroids and 13 patients with five or more fibroids) and 149 patients with solitary fibroids (group B) were included. HIFU treatment information, efficacy comparisons and adverse events were recorded. A nomogram model of the characteristic parameters used to predict the efficacy of USg-HIFU in multiple fibroids was established.

RESULTS

After USg-HIFU treatment, the statistical comparison of pre-operative versus post-operative symptom scores and fibroid volume in the two groups indicated obvious symptom relief and substantial shrinkage of fibroid volume (all p values <0.001). Nevertheless, group A required more energy and longer treatment and sonication times to achieve a 70% non-perfused volume (NPV) ratio, and had a lower energy efficiency factor than group B (all p values <0.05). No severe complications were observed in either group. The nomogram model included fibroid volume, fibroid location and signal intensity on T2-weighted imaging (T2WI). The area under the receiver operating characteristic curve and the accuracy of the model were 0.698 and 0.686, respectively.

CONCLUSION

USg-HIFU appears to be an effective and safe treatment option for multiple fibroids. Knowledge of the fibroid volume, location and signal intensity on T2WI may help determine the efficacy of USg-HIFU in multiple fibroids.

Deep-Learning-Based High-Intensity Focused Ultrasound Lesion Segmentation in Multi-Wavelength Photoacoustic Imaging

Photoacoustic (PA) imaging can be used to monitor high-intensity focused ultrasound (HIFU) therapies because ablation changes the optical absorption spectrum of the tissue, and this change can be detected with PA imaging. Multi-wavelength photoacoustic (MWPA) imaging makes this change easier to detect by repeating PA imaging at multiple optical wavelengths and sampling the optical absorption spectrum more thoroughly. Real-time pixel-wise classification in MWPA imaging can assist clinicians in monitoring HIFU lesion formation and will be a crucial milestone towards full HIFU therapy automation based on artificial intelligence. In this paper, we present a deep-learning-based approach to segment HIFU lesions in MWPA images. Ex vivo bovine tissue is ablated with HIFU and imaged via MWPA imaging. The acquired MWPA images are then used to train and test a convolutional neural network (CNN) for lesion segmentation. Traditional machine learning algorithms are also trained and tested to compare with the CNN, and the results show that the performance of the CNN significantly exceeds traditional machine learning algorithms. Feature selection is conducted to reduce the number of wavelengths to facilitate real-time implementation while retaining good segmentation performance. This study demonstrates the feasibility and high performance of the deep-learning-based lesion segmentation method in MWPA imaging to monitor HIFU lesion formation and the potential to implement this method in real time.

Factors influencing USgHIFU ablation for adenomyosis with NPVR ≥ 50

OBJECTIVE

To investigate the influencing factors of ultrasound-guided HIFU (USgHIFU) ablation for adenomyosis with a non-perfused volume ratio (NPVR)≥50%.

METHODS

A total of 299 patients with adenomyosis who underwent USgHIFU ablation were enrolled. Quantitative signal intensity (SI) analysis was performed on T2WI and dynamic enhancement type. The energy efficiency factor (EEF) was defined as the ultrasound energy delivered for ablating 1 mm³ of tissue. NPVR ≥ 50% was used as the criterion for technical success. Adverse effects and complications were recorded. Logistic regression analyses of variables were conducted to identify the factors affecting NPVR ≥ 50%.

RESULTS

The median NPVR was 53.5% (34.7%). There were 159 cases in the NPVR ≥ 50% group and 140 cases in the NPVR < 50% group. The EEF in NPVR < 50.0% group was significantly higher than that in NPVR ≥ 50% group (p < 0.05). The incidence of intraoperative adverse effects and postoperative adverse events in the NPVR < 50% group were higher than those in the NPVR ≥ 50% group (p < 0.05 for both). Logistic regression analysis showed that abdominal wall thickness, SI difference on T2WI between adenomyosis and rectus abdominis, and enhancement type on T1WI were protective factors for NPVR ≥ 50% (p < 0.05), while the history of childbirth was an independent risk factor (p < 0.001).

CONCLUSIONS

Compared with NPVR < 50%, NPVR ≥ 50% did not increase the intraprocedural and postprocedural adverse reactions. The possibility of NPVR ≥ 50% was higher in patients with thinner abdominal walls, showed slight enhancement of adenomyosis on T1WI, with a history of childbirth, or in whom the SI difference on T2WI between adenomyosis and rectus abdominis was more minor.

Stability testing of gadoteridol and gadobenate dimeglumine formulations under exposure to high-intensity focused ultrasound

OBJECTIVE

Contrast-enhanced MRI could be useful to guide high-intensity focused ultrasound treatment (HIFU), but the effects of HIFU on gadolinium-based agents is not known. Here, we tested in vitro the stability of gadoteridol and gadobenate dimeglumine, two widely used MR contrast agents, after exposure to HIFU at power levels typically applied in the clinical practice.

METHODS

0.5 M (gadoteridol and gadobenate dimeglumine) and diluted formulations (1:10 gadoteridol in saline) were exposed to different HIFU sequences. Unexposed and exposed solutions were characterized by high-performance liquid chromatography in terms of concentration of gadolinium complex, free gadolinium and free ligand.

RESULTS

Gadoteridol formulation after treatment showed concentrations of the complex not significantly different from control. Free Gd and/or free ligand concentrations in the order of 0.002/0.004% w/w, were observed occasionally without significant correlation with intensity and duration of exposure to HIFU. Gadobenate dimeglumine formulation after treatment showed complex assay content values, by-products (0.24-0.26%) and free BOPTA levels (0.07%) comparable to control sample within the experimental error.

CONCLUSION

In the range of conditions explored, HIFU exposure did not induce significant dissociations of gadoteridol and gadobenate dimeglumine, nor a detectable increase in the concentration of free species.

ADVANCES IN KNOWLEDGE

Our study strengthens the hypothesis that gadolinium-based contrast agents are stable during HIFU treatment for body applications (e.g. thermal ablation of uterine fibroids).

Tips and Details for Successful Robotic Myomectomy: Single-Center Experience with the First 125 Cases

With the continuous development of minimally invasive and precise surgical techniques, laparoscopic myomectomy has become a mainstream surgical method due to its aesthetic outcomes and rapid postoperative recovery. However, during laparoscopic myomectomy, clinicians often encounter unfavorable factors, such as limited vision, inaccurate suturing, difficulty in removing tumors, and susceptibility to fatigue in the operating position. In recent years, robot-assisted surgery has been widely used in gynecology. The advantages of this technique, such as a three-dimensional surgical view, reducing the surgeon’s tremor, and the seven degrees of freedom of the robotic arms, compensate for the defects in laparoscopic surgery. The Department of Gynecology in our hospital has accumulated a wealth of experience since robot-assisted surgery was first carried out in 2017. In this article, the surgical skills of the robotic myomectomy process are described in detail.

Should Ultrasound-Guided High Frequency Focused Ultrasound Be Considered as an Alternative Non-Surgical Treatment of Uterine Fibroids in Non-Asiatic Countries? An Opinion Paper

Minimally invasive interventions for myomata treatment have gained acceptance due to the possibility of preserving fertility with reduced trauma induced by laparotomy as way of entrance. There are insufficient data regarding outcomes of high intensity focused ultrasound (HIFU) in non-Asiatic women. Therefore, we revised the available evidence to present an expert opinion that could support physicians, patients and policy-makers for considering this approach in other populations. We revisited systematic reviews, randomized controlled trials and cohort studies from January 2018 to August 2021 using PubMed and Google scholar, regarding short and long term outcomes after ablation with focused ultrasound waves. In total, 33 studies, including 114,810 adult patients showed that outcomes of this approach depend on several parameters directly related with resistance to thermal ablation, especially fibroid size and vascularization. Two studies report satisfactory outcomes in Afro-American women. In accordance to the technique used, fibroid volume reduction showed to be higher in fibroids <300 cm3 after ultrasound guided HIFU than after MRI guided. Compared to myomectomy and uterine artery embolization, HIFU seems to have shorter hospital stay, higher pregnancy rates and similar adverse events rates, with skin burn being the most reported. Symptoms and quality of life improvement is similar to myomectomy but lower than embolization, however reintervention rate is higher after HIFU. Lacks evidence about long-term sarcoma risk after ablation. Available evidence shows that HIFU can be considered as a uterine sparing treatment for women of different ethnicities suffering of uterine myomatosis, especially for those wishing to preserve their fertility.

The effect of ultrasound-guided high-intensity focused ultrasound treatment for cesarean scar pregnancy on ovarian reserve

OBJECTIVE

The aim of this study was to evaluate changes in anti-Müllerian hormone (AMH) levels after ultrasound-guided high-intensity focused ultrasound (USgHIFU) treatment of cesarean scar pregnancy (CSP).

METHODS

A retrospective case series study was conducted in the Affiliated Hospital of North Sichuan Medical College. Thirty-two women with cesarean scar pregnancy who met the inclusion criteria were enrolled in the study between January 2018 and December 2019. All patients underwent USgHIFU treatment with or without suction curettage. Intraoperative blood loss in suction curettage and hysteroscopy procedures, time to return of β-human chorionic gonadotropin (β-hCG) to normal levels, and time to recovery of normal menstruation were recorded. AMH levels before and 3 months after HIFU treatment were compared to determine whether USgHIFU treatment affected ovarian reserve.

RESULTS

AMH levels before and 3 months after HIFU ablation were 1.87 ± 1.19 ng/ml and 1.90 ± 1.17 ng/ml, respectively. There was no significant difference in AMH levels between the two-time points (p > .05). The median volume of intraoperative blood loss was 20 ml, the median time for the serum β-hCG level to return to normal was 35.5 days, and the median time of menstruation recovery was 39 days.

CONCLUSIONS

USgHIFU treatment for CSP was effective and safe without affecting ovarian reserve.

A comparative analysis of pregnancy outcomes of patients with uterine fibroids after high intensity focused ultrasound ablation and laparoscopic myomectomy: a retrospective study

PURPOSE

The aim of this study was to retrospectively compare and analyze pregnancy outcomes of patients with uterine fibroids after high intensity focused ultrasound (HIFU) ablation and laparoscopic myomectomy (LM).

MATERIALS AND METHODS

The study group consisted of 346 patients with uterine fibroids who wished to conceive, in which 152 patients received HIFU ablation treatment (HIFU group) and 194 patients received LM treatment (LM group). The parents' baseline characters were recorded and the pregnancy outcomes were evaluated in a median follow-up time of 42 months (range: 16 ∼ 81) after the treatment, and the differences of the two groups were compared.

RESULTS

Patients with uterine fibroids in HIFU group had a significant shorter pregnancy interval than that in LM group (10 months VS. 13 months, p < .05). No significant differences were observed in pregnancy rate, miscarriage rate, live birth rate, natural pregnancy rate, cesarean section rate, and perinatal complications rate between the HIFU group and the LM group (p > .05). When stratified by age, infertility history, fibroid types, fibroid numbers, and fibroid sizes, there was no statistically significant difference in pregnancy rate between the HIFU group and the LM group (p > .05).

CONCLUSIONS

Based on the results from this study, both HIFU and LM can be safely used to treat patients who wish to conceive. The pregnancy outcomes of post-HIFU are similar to that of post-LM.

Focused Ultrasound (FUS) for Chronic Pain Management: Approved and Potential Applications

Chronic pain is one of the leading causes of disability and disease burden worldwide, accounting for a prevalence between 6.9% and 10% in the general population. Pharmacotherapy alone results ineffective in about 70-60% of patients in terms of a satisfactory degree of pain relief. Focused ultrasound is a promising tool for chronic pain management, being approved for thalamotomy in chronic neuropathic pain and for bone metastases-related pain treatment. FUS is a noninvasive technique for neuromodulation and for tissue ablation that can be applied to several tissues. Transcranial FUS (tFUS) can lead to opposite biological effects, depending on stimulation parameters: from reversible neural activity facilitation or suppression (low-intensity, low-frequency ultrasound, LILFUS) to irreversible tissue ablation (high-intensity focused ultrasounds, HIFU). HIFU is approved for thalamotomy in neuropathic pain at the central nervous system level and for the treatment of facet joint osteoarthritis at the peripheral level. Potential applications include HIFU at the spinal cord level for selected cases of refractory chronic neuropathic pain, knee osteoarthritis, sacroiliac joint disease, intervertebral disc nucleolysis, phantom limb, and ablation of peripheral nerves. FUS at nonablative dosage, LILFUS, has potential reversible and tissue-selective effects. FUS applications at nonablative doses currently are at a research stage. The main potential applications include targeted drug and gene delivery through the Blood-Brain Barrier, assessment of pain thresholds and study of pain, and reversible peripheral nerve conduction block. The aim of the present review is to describe the approved and potential applications of the focused ultrasound technology in the field of chronic pain management.

Contrast-Enhanced Ultrasound for Monitoring Non-surgical Treatments of Uterine Fibroids: A Systematic Review

Non-surgical treatment options for uterine fibroids are uterine artery embolization (UAE), high-intensity focused ultrasound ablation (HIFUA), and percutaneous microwave ablation (PMWA). Magnetic resonance imaging (MRI) is the reference standard imaging method before and after these procedures. Contrast-enhanced ultrasound (CEUS) has been studied as an alternative to MRI for evaluating the fibroids' characteristics and responses to non-surgical treatments. PubMed, Ovid MEDLINE and Scopus databases were searched for literature published from January 2000 through June 7, 2020, that investigated the application of CEUS as an adjunct to monitor UAE, HIFUA or PMWA in human uterine fibroid treatments. Two independent reviewers analyzed 128 publications, out of which 17 were included. Based on this systematic review, CEUS provides detailed data about fibroid volume and vascularization prior, during and post UAE, and it helps determine the endpoint of the procedure. HIFUA with intra-procedural CEUS has faster volume shrinkage over a shorter time period with less needed energy and provides early detection of residual tissue after HIFUA. CEUS and contrast-enhanced MRI have sufficient agreement to be used interchangeably in the clinic to evaluate the therapeutic effect of PMWA and HIFUA on fibroids.

Uterine Myomas: Extravascular Treatment

Uterine fibroids are common benign tumors that affect the female reproductive tract. They are responsible for considerable morbidity and deterioration of life quality. The main advantages offered by mini invasive techniques are low grade of invasiveness and short times of hospitalization. The most diffuse technique is uterine artery embolization (UAE). Common concerns with UAE include postprocedural pain, postembolization syndrome, and risk of infection. Image-guided thermal ablation techniques like radiofrequency ablation, percutaneous microwave ablation, and imaging-guided high-intensity focused ultrasound were introduced to overcome the side effects related to UAE and surgery. The aim of this review is to briefly analyze the ablative procedures and their role in the management of symptomatic fibroids, and to describe the safety profile and outcomes of these modalities.

Outcomes of subsequent pregnancies in patients following treatment of cesarean scar pregnancy with high intensity focused ultrasound followed by ultrasound-guided dilation and curettage

Objective: To evaluate the outcomes of subsequent pregnancies in patients with a history of cesarean scar pregnancy (CSP) treated with high intensity focused ultrasound (HIFU) followed by ultrasound-guided dilation and curettage (USg-D&C). Methods: A retrospective analysis was performed on data collected from 154 patients with CSP who were treated by HIFU followed by USg-D&C in Suining Central Hospital between January 2015 and January 2018. Among them, 28 patients wanted to conceive following treatment. Baseline characteristics, treatment results, intraoperative hemorrhages during USg-D&C, post-curettage serum beta human chorionic gonadotropin (β-hCG) levels and vaginal bleeding were investigated. Subsequent pregnancy outcomes, including intervals between pregnancy and treatment of CSP, complications during pregnancy, and outcomes of newborns were evaluated. Results: All patients with CSP were successfully treated by HIFU combined with USg-D&C. Of the 28 CSP patients who intended to conceive after the treatment, 23 patients (82.14%) successfully conceived. The average interval between conception and HIFU treatment was 18.38 ± 10.04 months. Eighteen patients (78.26%) had an intrauterine pregnancy, in which 12 had delivery by cesarean section, 1 had an ongoing pregnancy, and 5 had an abortion in the first trimester. Among the other 5 women, 3 had tubal ectopic pregnancy and 2 had recurrent CSP. These five patients underwent laparoscopy within the first trimester. Conclusion: HIFU followed by USg-D&C is an effective and safe treatment for patients with CSP who wish to conceive. Prospective multi-center studies with larger sample sizes and longer follow-up periods are needed to compare this treatment with others.

Wedged gel pad for bowel manipulation during MR-guided high-intensity focused ultrasound therapy to treat uterine fibroids: a case report

Background

Magnetic resonance guided high-intensity focused ultrasound (MR-HIFU) therapy is not feasible in all patients with uterine fibroids because of limiting anatomical factors such as scar tissue, bowel loops or other obstacles in the sonication path. These may prevent the treatment or limit the treatment window, and therefore, also the volume where HIFU therapy can be delivered. Bowel loops present a particular problem because of bowel gas bubbles and hard particles which may cause reflection or absorption of ultrasound energy, potentially leading to thermal damage and even bowel perforation. Most commonly used techniques for bowel repositioning are bladder and/or rectum filling but these are not always sufficient to reposition the bowel loops. With more efficient bowel repositioning technique, the number of eligible patients for MR-HIFU treatment could be increased, and therapy efficacy be improved in cases where bowel loops limit the treatment window.

Case presentation

A wedged exterior gel pad was used in two patients presented with in total of four symptomatic fibroids undergoing MR-HIFU treatment when bladder and/or rectum filling was not sufficient to reposition the bowel loops. No severe adverse effects were observed in these cases. The non-perfused volume ratios (NPVs) immediately after treatment were 86% and 39% for the first patient, and 3% for the second patient.

Conclusions

Our preliminary experience suggests that the use of a wedged gel pad during MR-HIFU treatment could be an effective tool to manipulate the bowels in cases where the bladder and/or rectum filling is not sufficient to reposition the bowel loops. A wedged gel pad could also be used in other situations to achieve better treatment coverage to the uterine fibroid.

Factors affecting effects of ultrasound guided high intensity focused ultrasound for single uterine fibroids: a retrospective analysis

OBJECTIVE

To investigate factors affecting effects of ultrasound guided high intensity focused ultrasound (USgHIFU) in the treatment of single uterine fibroids (UFs) with different magnetic resonance imaging (MRI) features.

METHODS

A total of 207 patients with single symptomatic UFs who were treated with HIFU were retrospectively analyzed. All UFs were grouped according to MRI features, and factors affecting HIFU ablation were set as independent variables. Non-perfusion volume ratio (NPVR) and energy efficiency factor (EEF) were set as dependent variables to establish multiple linear regression models with a stepwise method.

RESULTS

All patients had successful HIFU treatment, with the mean NPVR of 74.7 ± 15.1% and the mean EEF of 7.4 ± 5.2 j/mm3. The NPVR was negatively correlated with transmural type of UFs, hyperintense on T2 weighted image (T2WI), enhancement type on T1 weighted image (T1WI), distance from UFs ventral side to skin and posterior location of UFs, but positively correlated with anterior location of UFs, hypointense on T2WI and anteverted uterus (uterine location). The EEF was negatively correlated with size, anterior location of UFs and hypointense on T2WI, but positively correlated with distance from UFs ventral side to skin, enhancement type on T1WI and transmural type of UFs. The UFs size and enhancement type on T1WI were the greatest factors affecting the ablation effect.

CONCLUSIONS

The effect of HIFU treatment for single UFs is affected by multiple factors, and the UFs of hypointense on T2WI, large size, mild enhancement on T1WI and anteverted uterus can be easily ablated with high ablation efficiency.