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

Prediction of non-perfusion volume ratio for uterine fibroids treated with ultrasound-guided high-intensity focused ultrasound based on MRI radiomics combined with clinical parameters

BACKGROUND

Prediction of non-perfusion volume ratio (NPVR) is critical in selecting patients with uterine fibroids who will potentially benefit from ultrasound-guided high-intensity focused ultrasound (HIFU) treatment, as it reduces the risk of treatment failure. The purpose of this study is to construct an optimal model for predicting NPVR based on T2-weighted magnetic resonance imaging (T2MRI) radiomics features combined with clinical parameters by machine learning.

MATERIALS AND METHODS

This retrospective study was conducted among 223 patients diagnosed with uterine fibroids from two centers. The patients from one center were allocated to a training cohort (n = 122) and an internal test cohort (n = 46), and the data from the other center (n = 55) was used as an external test cohort. The least absolute shrinkage and selection operator (LASSO) algorithm was employed for feature selection in the training cohort. The support vector machine (SVM) was adopted to construct a radiomics model, a clinical model, and a radiomics-clinical model for NPVR prediction, respectively. The area under the curve (AUC) and the decision curve analysis (DCA) were performed to evaluate the predictive validity and the clinical usefulness of the model, respectively.

RESULTS

A total of 851 radiomic features were extracted from T2MRI, of which seven radiomics features were screened for NPVR prediction-related radiomics features. The radiomics-clinical model combining radiomics features and clinical parameters showed the best predictive performance in both the internal (AUC = 0.824, 95% CI 0.693-0.954) and external (AUC = 0.773, 95% CI 0.647-0.902) test cohorts, and the DCA also suggested the radiomics-clinical model had the highest net benefit.

CONCLUSIONS

The radiomics-clinical model could be applied to the NPVR prediction of patients with uterine fibroids treated by HIFU to provide an objective and effective method for selecting potential patients who would benefit from the treatment mostly.

MRI parameters for predicting the effect of ultrasound-guided high-intensity focused ultrasound in the ablation of uterine fibroids

AIM

To study the value of magnetic resonance imaging (MRI) parameters in predicting the efficacy of ultrasonic ablation of fibroids.

MATERIALS AND METHODS

A total of 91 patients were divided into groups based on non-perfused volume (NPV) ratio and blood supply type. The preoperative MRI parameters were measured and analysed. A correlation analysis between the MRI parameters and the NPV ratio was performed. Receiver operating characteristic (ROC) curves were used to analyse and determine the cut-off value of MRI parameters to predict the ablation rate of fibroids.

RESULTS

The uterine fibroids group with an NPV ratio <80% and the group with an NPV ratio of ≥80% had significant differences in signal intensity (SI) at MRI T2-weighted imaging (WI), fibroid-to-rectus abdominis SI ratio (SIR) at T2WI, and blood supply type (p<0.05). There were no significant differences in fibroid volume, T2WI signal uniformity, and apparent diffusion coefficient (ADC) values. The ADC value and SI and SIR at MRI T2WI in the group with poor blood supply were lower than those in the group with a rich blood supply (p<0.05). SI at MRI T2WI correlated negatively with the NPV ratio. The cut-off values for SI and SIR at MRI T2WI of fibroids whose NPV ratio exceeds 80% were 220.58 and 1.315, respectively.

CONCLUSION

SI at MRI T2WI and blood supply type could be predictors of the efficacy of ablation. Ultrasonic ablation of fibroids with MRI T2WI hyperintensity and a rich blood supply had poor efficacy.

Occurrence of adverse events after magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) therapy in symptomatic uterine fibroids-a retrospective case-control study

OBJECTIVES

Our study aims at the comprehensive analysis of adverse events (AEs) in patients with symptomatic uterine fibroids (UFs) who underwent magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) in the last 6 years in one of the major Polish centers performing this type of therapy.

METHODS

The presented retrospective case-control study was conducted in the Department of Obstetrics and Gynecology, Pro-Familia Hospital, Rzeszów in cooperation with the Second Department of Obstetrics and Gynecology, Center of Postgraduate Medical Education, Warsaw. The study enrolled 372 women with symptomatic UFs who underwent MR-HIFU and reported AEs during or after the procedure. The occurrence of particular AEs was analyzed. Statistical comparison of two cohorts (patients with and without AEs) was conducted based on epidemiological factors, UF characteristics, fat layer thickness, the presence of abdominal scars and technical parameters of the procedure.

RESULTS

The overall mean occurrence rate of AEs was 8.9% (n = 33). No major AEs were reported. The only statistically significant risk factor of AEs was the treatment of type II UFs according to Funaki (OR 2.12, CI 95%, p = 0.043). Other investigated factors did not have a statistically significant influence on AE occurrence. Abdominal pain was the most common AE.

CONCLUSION

Our data showed that MR-HIFU seemed to be a safe procedure. The AE rate after the treatment is relatively low. According to the obtained data it seems that the occurrence of AEs does not depend on the technical parameters of the procedure and the volume, position and location of UFs. Further prospective, randomized studies and with long follow-up are necessary to confirm the final conclusions.

Post treatment and 3 month contrast enhanced MRI findings following HIFU of submucosal fibroids: a retrospective study

PURPOSE

This study used contrast-enhanced MRI (CE-MRI) examination to assess the efficacy of high-intensity focused ultrasound (HIFU) for submucosal fibroids.

METHODS

A total of 81 submucosal fibroids, including 33 cases of type 1, 29 cases of type 2, and 19 cases of type 2-5, treated by HIFU were retrospectively reviewed. CE-MRI was performed in all cases immediately after HIFU, the non-perfused volume ratio (NPVR) and the degree of endometrial impairment were recorded. Thereafter, CE-MRI was repeated in all cases after three months, and the change of fibroid volume shrinkage rate (FVSR), NPVR and the degree of endometrial impairment were recorded.

RESULTS

The immediate NPVR was 86.4 ± 19.3% in type 1, 90.0 ± 13.3% in type 2 and 90.3 ± 7.2% in type 2-5. Among 81 fibroids, grades 0, 1, 2 and 3 endometrial impairments were observed in 38.3%, 16.1%, 14.8% and 30.9%, respectively. Three months later, NPVR was 68.0 ± 36.4% in type 1, 74.3 ± 27.7% in type 2 and 85.0 ± 16.1% in type 2-5. Grades 0, 1, 2 and 3 endometrial impairments were observed in 64.2%, 23.5%, 9.9% and 2.4%.FVSR was 49.0 ± 1.3% in type 1, 39.6 ± 1.7% in type 2 and 37.2 ± 2.1% in type 2-5. The FVSR in submucosal fibroid type 1 was superior to type 2 and type 2-5 (p < 0.05). The NPVR of submucosal fibroids in type 2-5 were higher than type 1 (p < 0.05) .There was no difference among different types of submucosal fibroids in endometrial impairment (p > 0.05) three months after HIFU.

CONCLUSIONS

At three months after HIFU, FVSR was better for submucosal fibroid type 1 than for type 2 and type 2-5. And there was no difference in endometrial impairment among the different types of submucosal fibroid groups.

Efficacy and safety of HIFU in combination with TACE in unresectable pediatric HB: A randomized, controlled, single-center clinical trial

BACKGROUND

Hepatoblastoma (HB) is the most common liver tumor in children, and the main treatment for HB is currently surgery. Studies have shown that transcatheter arterial chemoembolization (TACE) combined with high intensity focused ultrasound (HIFU) has significant efficacy, but there are relatively few studies on TACE combined with HIFU in China.

OBJECTIVE

To investigate the effect of using HIFU combined with TACE on patients' liver function impairment and immune function in pediatric HB patients and to analyze the effectiveness and safety.

MATERIALS AND METHODS

The clinical data of 110 unresectable pediatric HB patients treated in our hospital from December 2019 to December 2021 were selected as the subjects and divided into 2 groups. The comparison group was treated with TACE, and the combination group was treated with HIFU on the basis of the comparison group. The differences in immune function, survival, treatment side effects and clinical efficacy between the 2 groups were observed.

RESULTS

In the combined group, the 1-year survival rate was 100%, the 3-year survival rate was 84.0%, the 5-year survival rate was 16.0%; while in comparison group, it was 82%, 16%, 0%, respectively. The ratio of CD4+/CD8+ in the combined group were significantly higher than in the comparison group after treatment (P < .05). Granulocytopenia, mucositis, thrombocytopenia, and cardiac and renal toxicity were significantly lower in the combined group than in the comparison group, and the effective rate of the combined group was 98.00% which was significantly higher than that of the control group (76.00%) (P < .05).

CONCLUSION

Comparative study of HB in children treated with HIFU combined with TACE is more effective, effectively improving the immune level of patients, significantly increasing the remission rate, which can improve the tumor necrosis and improve the survival quality of patients, and is a better choice for HB in children.

A narrative review on the application of high-intensity focused ultrasound for the treatment of occlusive and thrombotic arterial disease

Objectives

High-intensity focused ultrasound (HIFU) is a noninvasive therapeutic modality with a variety of applications. It is approved for the treatment of essential tremors, ablation of prostate, hepatic, breast, and uterine tumors. Although not approved for use in the treatment of atherosclerotic arterial disease, there is a growing body of evidence investigating applications of HIFU. Currently, percutaneous endovascular techniques are predominant for the treatment of arterial pathology; however, there are no endovascular techniques of HIFU available. This study aims to review the state of current evidence for the application of HIFU in atherosclerotic arterial disease.

Methods

All English-language articles evaluating the effect of HIFU on arterial occlusive and thrombotic disease until 2021 were reviewed. Both preclinical and human clinical studies were included. Study parameters such as animal or clinical model and outcomes were reviewed. In addition, details pertaining to settings on the HIFU device used were also reviewed.

Results

In preclinical models, atherosclerotic plaque progression was inhibited by HIFU, through decreases in oxidized low-density lipoprotein cholesterol and increases in macrophage apoptosis. Additionally, HIFU promotes angiogenesis in hindlimb ischemic models by the upregulation of angiogenic and antiapoptotic factors, with increased angiogenesis at higher line densities of HIFU. HIFU also promotes thrombolysis and conversely induces platelet activation at low frequencies and higher intensities. Various clinical studies have attempted to translate some of these properties and demonstrated positive clinical outcomes for arterial recanalization after thrombotic stroke, decreased atherosclerotic plaque burden in carotid arteries, increase in tissue perfusion and a decrease in diameter stenosis in patients with atherosclerotic arterial disease.

Conclusions

In current preclinical and clinical data, the safety and efficacy of HIFU shows great promise in the treatment of atherosclerotic arterial disease. Future focused studies are warranted to guide the refinement of HIFU settings for more widespread adoption of this technology.

Neurofibromatosis from Head to Toe: What the Radiologist Needs to Know

Neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2) are autosomal dominant inherited neurocutaneous disorders or phakomatoses secondary to mutations in the NF1 and NF2 tumor suppressor genes, respectively. Although they share a common name, NF1 and NF2 are distinct disorders with a wide range of multisystem manifestations that include benign and malignant tumors. Imaging plays an essential role in diagnosis, surveillance, and management of individuals with NF1 and NF2. Therefore, it is crucial for radiologists to be familiar with the imaging features of NF1 and NF2 to allow prompt diagnosis and appropriate management. Key manifestations of NF1 include café-au-lait macules, axillary or inguinal freckling, neurofibromas or plexiform neurofibromas, optic pathway gliomas, Lisch nodules, and osseous lesions such as sphenoid dysplasia, all of which are considered diagnostic features of NF1. Other manifestations include focal areas of signal intensity in the brain, low-grade gliomas, interstitial lung disease, various abdominopelvic neoplasms, scoliosis, and vascular dysplasia. The various NF1-associated abdominopelvic neoplasms can be categorized by their cellular origin: neurogenic neoplasms, interstitial cells of Cajal neoplasms, neuroendocrine neoplasms, and embryonal neoplasms. Malignant peripheral nerve sheath tumors and intracranial tumors are the leading contributors to mortality in NF1. Classic manifestations of NF2 include schwannomas, meningiomas, and ependymomas. However, NF2 may have shared cutaneous manifestations with NF1. Lifelong multidisciplinary management is critical for patients with either disease. The authors highlight the genetics and molecular pathogenesis, clinical and pathologic features, imaging manifestations, and multidisciplinary management and surveillance of NF1 and NF2. Online supplemental material is available for this article. ^©RSNA, 2022.

Predictive value of image indexes of B-mode and power Doppler sonography on the efficacy of high intensity focused ultrasound ablation for uterine fibroids

OBJECTIVE

To investigate the value of the image indexes of B-mode and power Doppler sonography in predicting the therapeutic efficacy of high intensity focused ultrasound (HIFU) ablation for uterine fibroids.

MATERIALS AND METHODS

Two hundred and three patients with a solitary uterine fibroid were enrolled in this study. Every patient underwent transvaginal sonography (TVS) and magnetic resonance imaging (MRI) before HIFU. The patients were divided into hypointense, isointense and hyperintense fibroid groups based on T2 weighted MR imaging characteristics, and ultrasonic image indexes of the fibroids in different groups were compared. Multiple linear regression analysis was used to evaluate the correlation between ultrasonic image indexes and energy efficiency factor (EEF), non-perfused volume (NPV) ratio of uterine fibroids.

RESULTS

Among them, 72 patients had a hypointense fibroid, 70 had an isointense fibroid and 61 had a hyperintense fibroid. Significant differences were observed in the ultrasound imaging gray scale value difference between the myometrium and uterine fibroids (GSmyo-fib), the ultrasound imaging gray scale value ratio of fibroids over the myometrium (GSfib/myo), and the ratio of power Doppler pixel area to fibroid area (PDPA/FA) among the three groups (p < 0.05). Linear regression analysis showed that the PDPA/FA and the location of fibroids were the factors affecting the NPV ratio, a model for predicting the NPV ratio was established.

CONCLUSIONS

A model with the PDPA/FA for NPV ratio could be used to predict the therapeutic efficacy of HIFU for fibroids.

A Modified Bowel Displacement Technique for Magnetic Resonance Imaging-Guided Focused Ultrasound Surgery in the Treatment of Uterine Fibroids and Adenomyosis

OBJECTIVE

The clinical application of magnetic resonance imaging-guided focused ultrasound (MRgFUS) surgery for treatment of symptomatic uterine fibroids is often limited because of the bowel between the abdominal wall and uterus. If bowels are in the pathway of sonication path, firstly filling the bladder, then filling the rectum, and emptying the bladder subsequently can be used to avoid them in recent research. The purpose of this study was to evaluate whether the modified bowel displacement technique (rectal filling first and then bladder filling, with or without subsequent bladder emptying) was feasible to create secure acoustic window.

METHODS

A total of 78 patients who had undergone MRgFUS treatment for uterine fibroids and adenomyosis from January 2020 to November 2020 were included in this retrospective study. Of the 78 patients, 19 patients were treated using a modified bowel displacement technique, whereas the rest of the patients did not require intestinal displacement. High-intensity focused ultrasound was performed using GE Sightec HDXT 1.5 Tesla MR and ExAblate high-intensity focused ultrasound system.

RESULTS

Of the 19 patients requiring bowel displacement techniques, 17 patients successfully completed MRgFUS surgery. Magnetic resonance imaging-guided focused ultrasound surgery was feasible in 4 patients after rectal filling, bladder filling, and subsequent bladder emptying. The others received ablation through the extended bladder because of bowel descending after emptying the bladder. The surgery caused no intestinal or uterine complications and no serious discomfort to the patient.

CONCLUSIONS

The modified bowel displacement technique was effective in displacing interposed bowels during MRgFUS treatment to create safe acoustic pathway for ablating uterine fibroids and adenomyosis.

Increased MR-guided high intensity focused ultrasound (MR-HIFU) sonication efficiency of uterine fibroids after carbetocin administration

Purpose

We investigated whether administration of the long-acting uterus stimulant carbetocin increased intra-subject sonication efficiency during Magnetic Resonance image guided High Intensity Focused Ultrasound (MR-HIFU) treatment of uterine fibroids.

Method

In this prospective cohort study, thirty women with symptomatic uterine fibroids undergoing MR-HIFU treatment were included between January 2018 and January 2019. Treatment started with three sonications on one side of the uterine fibroid. Subsequently, one ampoule of 1 mL carbetocin (100 µg/mL) was administered intravenously and treatment continued with three sonications on the other side of the uterine fibroid. We compared the intra-subject sonication efficiency, in terms of Energy Efficiency Factor (EEF), thermal dose volume and sonication time to ablate one cm3 of fibroid tissue, before and after carbetocin administration. Adverse events that occurred within 30 min after carbetocin administration were recorded.

Results

Sonication efficiency improved after carbetocin administration as indicated by a significant decrease in EEF and sonication time (p = 0.006 and p = 0.001 respectively), and a significant increase in thermal dose volume reached (p = <0.001). Five women (16.7%) experienced temporary tachycardia, one women in combination with headache, within 30 min after carbetocin administration.

Conclusion

Administration of the long-acting uterus stimulant carbetocin improved the MR-HIFU treatment intra-subject sonication efficiency in women with symptomatic uterine fibroids.

Physician Experience in Technical Success of Achieving NPVR ≥ 80% of High-Intensity Focused Ultrasound Ablation for Uterine Fibroids: A Multicenter Study

Objective

To evaluate the experience of the physician of the technical success in high-intensity focused ultrasound (HIFU) ablation of uterine fibroids with a nonperfused volume ratio (NPVR) of at least 80%.

Methods

Patients from a 20-center prospective study were enrolled in this study. In this study, among the 20 clinical centers, five centers had physician with >3 years of HIFU experience, and the other 15 centers initiated HIFU therapy <3 years, were defined as the experienced group and the inexperienced group, respectively. Technical success was defined as achieving NPVR ≥ 80% of uterine fibroids with no major complications and it was defined as the successful group; otherwise, it was defined as the unsuccessful group.

Results

A total of 1,352 patients were included at the age of 41.32 ± 5.08 years. The mean NPVR (87.48 ± 14.91%) was obtained in the inexperienced group (86.50 ± 15.76%) and in the experienced group (89.21 ± 13.12%), respectively. The multivariate analysis showed that the volume of uterus, location of fibroids, and physician experience were significantly correlated with technical success (p < 0.05). In the experienced group, 82.20% of uterine fibroids obtained NPVR ≥ 80%, compared with 75.32% in the inexperienced group, and the difference was significant (p = 0.003). The technical success rate of the experienced group was 82.00% which was higher than 75.20% of the inexperienced group (p = 0.004).

Conclusion

In technical success of achieving NPVR ≥ 80%, experience of the physician was positively correlated with technical success; NPVR and major complications for the inexperienced group were comparable to those of the experienced group from a clinical perspective; inexperienced physicians could reach NPVR ≥ 80% of sufficient ablation and were trustworthy in efficacy. Smaller uterus and fibroids of anterior wall were correlated with better technical success; experienced physicians still have better technical success when choosing patients with larger uterus, contributing to clinical decision-making and patient referral.

Exploring the Diagnostic Performance of Magnetic Resonance Imaging in Ultrasound-Guided High-Intensity Focused Ultrasound Ablation for Abdominal Wall Endometriosis

OBJECTIVE

This study aimed to explore the clinical value of magnetic resonance imaging (MRI) combined with ultrasound-guided high-intensity focused ultrasound (USg-HIFU) for the diagnosis and treatment of abdominal wall endometriosis (AWE).

METHODS

Magnetic resonance imaging was performed before and after USg-HIFU. Information on clinical characteristics of patients, MRI characteristics of lesions, and treatment outcomes were collected. Thirty AWE lesions in 29 patients were examined before HIFU treatment, while 27 patients were examined after treatment. The results of MRI and color doppler ultrasound before surgery, as well as the volume and the apparent diffusion coefficient (ADC) values of the lesions before and after USg-HIFU treatment were compared. We also observed the clinical symptoms remission, recurrence, and ablation rates of the lesions in follow-up after HIFU treatment.

RESULTS

The locations of the 30 AWE lesions were identified by MRI before USg-HIFU treatment. Their sizes appeared larger on MRI than ultrasound (P < 0.05). A total of 27 lesions were evaluated by MRI after USg-HIFU treatment, of which 92.6% (25/27) lesions were of high or slightly high signal intensity on T1-weighted images, and 77.8% (21/27) lesions were of mixed signal intensity on T2-weighted images. The mean ADC values of AWE lesions were 1.47 (1.20-1.59) × 10-3mm2/s and 1.86 (1.61-2.12) × 10-3mm2/s for pre-and post-HIFU treatment (P < 0.05). Patients with higher ablation rates (>50%) had a higher complete/partial remission rate than those with lower ablation rates (<50%), and had a lower recurrence rate (P < 0.05).

CONCLUSION

MRI is a useful tool for identifying the location, size, and concurrent changes of AWE before and after USg-HIFU treatment, which is beneficial for follow-up monitoring and defining treatment efficacy.

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.

Comparison of Dose and Effectiveness of a Single-Session Ultrasound-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids With Different Sizes

PURPOSE

This study aimed to compare the dose and effectiveness of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation of uterine fibroids with different sizes and explore the effect of uterine fibroid size on dose, which provided dose evaluation for clinicians in accordance with the size of uterine fibroids.

MATERIALS AND METHODS

A total of 1,000 patients with symptomatic uterine fibroids who received a single-session USgHIFU treatment were enrolled in this study. The size of fibroids was divided into seven groups: 3-4 cm, 4-5 cm, 5-6 cm, 6-7 cm, 7-8 cm, 8-9 cm, and 9-11 cm. The dose was expressed on the basis of the energy efficiency factor (EEF) as the energy required for ablation per unit volume of tissue, and the non-perfused volume ratio (NPVR) was used to assess the effect of HIFU ablation.

RESULTS

The median NPVR of 88.3% (IQR: 80.3%-94.8%) was obtained, and no significant difference was observed among the seven groups. The classification of T2-weighted image signal intensity fibroids in the 4-5 cm group was compared with that in the 6-7 cm and 8-9 cm groups, and the difference was significant (p < 0.05). However, the proportion of T2WI hyperintense signal fibroids had no significant difference among the seven groups (p > 0.05). The median EEF was 3.88 J/mm³, and a significant difference was observed among the seven groups of EEF (p < 0.05). The EEF of groups with a fibroid size less than 6 cm was more than double the EEF of groups with a fibroid size above 6 cm. In addition, the EEF of groups with a fibroid size of 4-5 cm and 3-4 cm was 3-4 times higher than those with a fibroid size above 7 cm (p < 0.05).

CONCLUSIONS

A single-session HIFU ablation for uterine fibroids of 3-11 cm can obtain an NPVR of more than 80%. The EEF decreased with the increase of the size of uterine fibroids. A fibroid size of 6.5 cm was considered as a clinical meaningful point affecting EEF.

MRI guided focused ultrasound (MRgFUS) treatment for uterine fibroids among women with and without abdominal scars

INTRODUCTION

MRI guided focused ultrasound (MRgFUS) is a noninvasive technique for treating uterine fibroids. The presence of abdominal scars can limit the number of women eligible for the procedure, due to absorbance of beam energy. The goals of this study were to assess the number of women that fit the procedure and to compare outcomes among women with or without abdominal scars.

MATERIAL AND METHODS

A prospective cohort study of all women that were interested in MRgFUS in a single University-Affiliated Hospital between November 2012 and December 2019. Rates of women that were referred to further screening, fulfilled selection criteria and underwent the procedure were compared between patients with or without abdominal scars. We evaluated the treatment parameters of the two groups and used linear regression model predict non-perfused volume (NPV) at the end of the process.

RESULTS

Out of 701 patients, 21.8% were suitable for MRgFUS. Women with scars had significant lower NPV compared with women without scars (60% versus 82.4%, p = 0.021). No serious adverse events were reported in both groups. Linear regression models showed that fibroids' volume, stopping the treatment due to severe pain and the presence of abdominal scars had a statistically significantly negative effect on NPV (betas: -11.51, -6.96, and -6.29, p-values: <0.001, 0.003, and 0.007 respectively), while number of sonication had a statistically significantly positive effect on NPV (beta = 5.98, p = 0.011).

CONCLUSION

Regardless of strict inclusion criteria, MRgFUS treatment is less efficient among women with abdominal scars, although still feasible for those who are interested in noninvasive option.

Comparison of (Cost-)Effectiveness of Magnetic Resonance Image-Guided High-Intensity-Focused Ultrasound With Standard (Minimally) Invasive Fibroid Treatments: Protocol for a Multicenter Randomized Controlled Trial (MYCHOICE)

BACKGROUND

Magnetic resonance image-guided high-intensity-focused ultrasound (MR-HIFU) is a rather new, noninvasive option for the treatment of uterine fibroids. It is safe, effective, and has a very short recovery time. However, a lack of prospectively collected data on long-term (cost-)effectiveness of the MR-HIFU treatment compared with standard uterine fibroid care prevents the MR-HIFU treatment from being reimbursed for this indication. Therefore, at this point, when conservative treatment for uterine fibroid symptoms has failed or is not accepted by patients, standard care includes the more invasive treatments hysterectomy, myomectomy, and uterine artery embolization (UAE). Primary outcomes of currently available data on MR-HIFU treatment often consist of technical outcomes, instead of patient-centered outcomes such as quality of life (QoL), and do not include the use of the latest equipment or most up-to-date treatment strategies. Moreover, data on cost-effectiveness are rare and seldom include data on a societal level such as productivity loss or use of painkillers. Because of the lack of reimbursement, broad clinical implementation has not taken place, nor is the proper role of MR-HIFU in uterine fibroid care sufficiently clear.

OBJECTIVE

The objective of our study is to determine the long-term (cost-)effectiveness of MR-HIFU compared with standard (minimally) invasive fibroid treatments.

METHODS

The MYCHOICE study is a national, multicenter, open randomized controlled trial with randomization in a 2:1 ratio to MR-HIFU or standard care including hysterectomy, myomectomy, and UAE. The sample size is 240 patients in total. Women are included when they are 18 years or older, in premenopausal stage, diagnosed with symptomatic uterine fibroids, conservative treatment has failed or is not accepted, and eligible for MR-HIFU. Primary outcomes of the study are QoL 24 months after treatment and costs of treatment including direct health care costs, loss of productivity, and patient costs.

RESULTS

Inclusion for the MYCHOICE study started in November 2020 and enrollment will continue until 2024. Data collection is expected to be completed in 2026.

CONCLUSIONS

By collecting data on the long-term (cost-)effectiveness of the MR-HIFU treatment in comparison to current standard fibroid care, we provide currently unavailable evidence about the proper place of MR-HIFU in the fibroid treatment spectrum. This will also facilitate reimbursement and inclusion of MR-HIFU in (inter)national uterine fibroid care guidelines.

TRIAL REGISTRATION

Netherlands Trial Register NL8863; https://www.trialregister.nl/trial/8863.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/29467.

A feasibility analysis of the ArcBlate MR-guided high-intensity focused ultrasound system for the ablation of uterine fibroids

Purpose

Uterine fibroids are benign gynecologic tumors and commonly occur in women by the age of 50. Women with symptomatic uterine fibroids generally receive surgical intervention, while they do not favor the invasive therapies. To evaluate the feasibility and safety of a novel magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) modality, ArcBlate, in the treatment of uterine fibroids.

Methods

Nine patients with uterine fibroids and one patient with adenomyosis were treated with ArcBlate MRgHIFU. Tumor size and quality of life were evaluated postoperatively at 1 and 3 months by magnetic resonance imaging (MRI) and the 36-Item Short Form Survey (SF-36), respectively.

Results

All patients completed the ArcBlate MRgHIFU procedure and there were no treatment-related adverse effects either during the procedure or during the 3 months of follow-up. Despite limiting the ablation volume to under 50% of the treated fibroid volume as a safety precaution, tumor volumes were markedly reduced in four patients by 15.78–58.87% at 3-month post-treatment. Moreover, SF-36 scale scores had improved at 3 months from baseline by 2–8 points in six patients, indicating relief of symptoms and improved quality of life.

Conclusion

This study evidence demonstrates the safety and feasibility of ArcBlate MRgHIFU and suggests its potential for treating uterine fibroids.

Image-Guided High-Intensity Focused Ultrasound, A Novel Application for Interventional Nuclear Medicine?

Image-guided high-intensity focused ultrasound (HIFU) has been increasingly used in medicine over the past few decades, and several systems for such have become commercially available. HIFU has passed regulatory approval around the world for the ablation of various solid tumors, the treatment of neurologic diseases, and the palliative management of bone metastases. The mechanical and thermal effects of focused ultrasound provide a possibility for histotripsy, supportive radiation therapy, and targeted drug delivery. The integration of imaging modalities into HIFU systems allows for precise temperature monitoring and accurate treatment planning, increasing the safety and efficiency of treatment. Preclinical and clinical results have demonstrated the potential of image-guided HIFU to reduce adverse effects and increase the quality of life postoperatively. Interventional nuclear image-guided HIFU is an attractive noninvasive option for the future.

The efficacy and safety of MR-HIFU and US-HIFU in treating uterine fibroids with the volume <300 cm3: a meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is a promising and non-invasive therapy for symptomatic uterine fibroids. Currently, the main image-guided methods for HIFU include magnetic resonance-guided (MR-HIFU) and ultrasound-guided (US-HIFU). However, there are few comparative studies on the therapeutic efficacy and safety of MR-HIFU and US-HIFU in treating symptomatic uterine fibroids with a volume <300 cm³.

OBJECTIVE

We performed this meta-analysis to evaluate the efficacy and safety of MR-HIFU and US-HIFU in treating symptomatic uterine fibroids with a volume <300 cm³.

METHODS

We searched relevant literature in PubMed, EMBASE, Cochrane Library CNKI from inception until 2021. The mean value, the proportion, and their 95% confidence intervals (CIs) were measured by random-effects models. Publication bias was assessed using funnel plots.

RESULTS

48 studies met our inclusion criteria-28 describing MR-HIFU and 20 describing US-HIFU. The mean non-perfused volume rate (NPVR) was 81.07% in the US-HIFU group and 58.92% in the MR-HIFU group, respectively. The mean volume reduction rates at month-3, month-6, and month-12 were 42.42, 58.72, and 65.55% in the US-HIFU group, while 34.79, 37.39, and 36.44% in the MR-HIFU group. The incidence of post-operative abdominal pain and abnormal vaginal discharge in the US-HIFU group was lower than that of MRI-HIFU. However, post-operative skin burn and sciatic nerve pain were more common in the US-HIFU group compared with MRI-HIFU. The one-year reintervention rate after MR-HIFU was 13.4%, which was higher than 5.2% in the US-HIFU group.

CONCLUSION

US-HIFU may show better efficiency and safety than MR-HIFU in treating symptomatic fibroids with a volume <300 cm³.

Targetability of cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-mediated hyperthermia (HT) for patients receiving radiation therapy

PURPOSE

To evaluate the targetability of late-stage cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-induced hyperthermia (HT) as an adjuvant to radiation therapy (RT).

METHODS

Seventy-nine cervical cancer patients (stage IIIB-IVA) who received RT with lesions visible on positron emission tomography-computed tomography (PET-CT) were retrospectively analyzed for targetability using a commercially-available HT-capable MRgHIFU system. Targetability was assessed for both primary targets and/or any metastatic lymph nodes using both posterior (supine) and anterior (prone) patient setups relative to the transducer. Thirty-four different angles of rotation along subjects' longitudinal axis were analyzed. Targetability was categorized as: (1) Targetable with/without minimal intervention; (2) Not targetable. To determine if any factors could be used for prospective screening of patients, potential associations between demographic/anatomical factors and targetability were analyzed.

RESULTS

72.15% primary tumors and 33.96% metastatic lymph nodes were targetable from at least one angle. 49.37% and 39.24% of primary tumors could be targeted with patient laying in supine and prone positions, respectively. 25°-30° rotation and 0° rotation had the highest rate of the posterior and anterior targetability, respectively. The ventral depth of the tumor and its distance to the coccyx were statistically correlated with the anterior and posterior targetability, respectively.

CONCLUSION

Most late-stage cervical cancer primaries were targetable by MRgHIFU HT requiring either no/minimal intervention. A rotation of 0° or 25°-30° relative to the transducer might benefit anterior and posterior targetability, respectively. Certain demographic/anatomic parameters might be useful in screening patients for treatability.

A Prediction of NPVR ≥ 80% of Ultrasound-Guided High-Intensity Focused Ultrasound Ablation for Uterine Fibroids

Objective: To evaluate factors in predicting the treatment outcome of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for uterine fibroids with a non-perfused volume ratio (NPVR) of at least 80%.

Methods: One thousand patients with uterine fibroids who received USgHIFU were enrolled. Thirty-two independent variables of four dimensions of data set, including general information of patients, clinical symptoms, laboratory tests, and fibroid imaging characteristics, were used to investigate the potential predictors of the NPVR of at least 80% by multivariate logistic regression. NPVR was the gold standard for evaluating the efficiency of HIFU ablation, and a NPVR of at least 80% was considered sufficient ablation, while partial ablation was defined as having an NPVR of <80%.

Results: Out of 1,000 fibroids, 758 obtained sufficient ablation and 242 obtained partial ablation, and the median NPVR was 88.3% (interquartile range: 80.3–94.8%). The probability of NPVR reaching 80% fibroids with a signal intensity of T2WI of hypointense, isointense, and hyperintense was 86.4, 76.5, and 62.6%, respectively; fibroids with an enhancement type of T1WI of slight, irregular, and regular was 81.5, 73.6, and 63.7%, respectively; and fibroids with uterine anteroposterior of 30–130 mm was 57.7–78.3%, respectively. In patients with a platelet count of 50 × 10⁹/L−550 × 10⁹/L, the probability of NPVR reaching 80% is from 53.4 to 80.1%, respectively.

Conclusions: In predicting NPVR ≥ 80%, the signal intensity on T2WI was the most important factor affecting ablative efficiency, followed by enhancement type on T1WI, uterine anteroposterior, and platelet count.

Oxytocin and Misoprostol With Diclofenac in the Preparation for Magnetic Resonance-Guided High-Intensity Ultrasound Treatment of Symptomatic Uterine Fibroids: A Prospective Cohort Study

Uterine fibroids (UFs) are very common benign tumors of the female reproductive tract. According to recent reports, magnetic resonance-guided high-intensity ultrasound (MR-HIFU) appears to be a well-tolerated and efficient treatment option for UFs. However, MR-HIFU still presents several limitations. The treatment is rarely associated with achieving complete non-perfused volume (NPV). Not all patients are qualified for a final procedure, and selected women obtain very good results in such treatment. The primary objective of this experimental study was to assess the effect of transvaginal misoprostol and intravenous oxytocin preparation on UF volume change, sonication time and NPV after MR-HIFU procedure in women of reproductive age with symptomatic UFs. Secondary outcomes included the effect on the peri-procedural effectiveness of misoprostol and oxytocin. This study enrolled 247 women with symptomatic UFs; based on gynecologic examinations and magnetic resonance imaging (MRI) scans, 128 women qualified for MR-HIFU without pharmacologic treatment, 57 women qualified for the misoprostol/diclofenac group and 62 women qualified for the oxytocin group. Pharmacologic pre-treatment improved NPV compared with non-pharmacologic treatment (average NPV: controls 61.9% ± 25.8%; oxytocin 76.8% ± 20.7%; misoprostol/diclofenac 85.2% ± 15.1%; average sonication time: controls 120 min ± 56.4%; oxytocin 111 min ± 45.4%; misoprostol/diclofenac 80 min ± 47.7%). Statistical analysis did not reveal significant intergroup differences in UF volume changes after 6 mo (controls: n = 40, 37.4% ± 27.5%; oxytocin n = 25, 45.8% ± 31%; misoprostol/diclofenac n = 19, 33.4% ± 23.2%). The misoprostol/diclofenac group, which achieved the highest NPV immediately after the MR-HIFU procedure, was characterized by the lowest UF volume change percentages 6 mo later. The administration of vasoconstrictor drugs (oxytocin and misoprostol/diclofenac) to support MR-HIFU in UF treatment is a new issue that may improve the total effectiveness of this method. Randomized controlled trials are necessary to estimate the real effect of vasoconstrictors on MR-HIFU.

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

OBJECTIVE

The assessment of the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) when qualifying patients with uterine fibroids (UFs) for magnetic resonance-guided high-intensity ultrasound (MR-HIFU).

MATERIAL AND METHODS

This retrospective, single center study included 283 women who underwent DCE-MRI and were treated with MR-HIFU. The patients were divided according to non-perfused volume (NPV) as well as by the type of curve for patients with a washout curve in the DCE-MRI study and patients without a washout curve. The studied women were assessed in three groups according to the type of uterotonics administered. Group A (57 patients) received one dose of misoprostol/diclofenac transvaginally and group B (71 patients) received oxytocin intravenously prior to the MR-HIFU procedure. The remaining 155 women (group C) were treated with the traditional non-drug enhanced MR-HIFU procedure.

RESULTS

The average NPV value was higher in no washout group, and depended on the uterotonics used.

CONCLUSIONS

We demonstrated a correlation between dynamic contrast enhancement curve types and the therapeutic efficacy of MR-HIFU. Our results suggest that DCE-MRI has the potential to assess treatment outcomes among patients with UFs, and patients with UFs that present with a washout curve may benefit from the use of uterotonic drugs. More studies are required to draw final conclusions.

Volumetric MRI-guided, high-intensity focused ultrasound ablation of uterine leiomyomas: ASEAN preliminary experience

PURPOSE

We sought to present our preliminary experience on the effectiveness and safety of magnetic resonance imaging (MRI)-guided, high-intensity focused ultrasound (HIFU) therapy using a volumetric ablation technique in the treatment of Association of Asian Nations (ASEAN) patients with symptomatic uterine leiomyomas.

METHODS

This study included 33 women who underwent HIFU treatment. Tissue characteristics of leiomyomas were assessed based on T2- and T1-weighted MRI. The immediate nonperfused volume (NPV) ratio and the treatment effectiveness of MRI-guided HIFU on the basis of the degrees of volume reduction and improvement in transformed symptom severity score (SSS) were assessed.

RESULTS

The median immediate NPV ratio was 89.8%. Additionally, the median acoustic sonication power and HIFU treatment durations were 150 W and 125 min, respectively. At six-month follow-up, the median leiomyoma volume had decreased from 139 mL at baseline to 84 mL and the median transformed SSS had decreased from 56.2 at baseline to 18.8. No major adverse events were observed.

CONCLUSION

The preliminary results demonstrated that volumetric MRI-guided HIFU therapy for the treatment of symptomatic leiomyomas in ASEAN patients appears to be clinically acceptable with regard to treatment effectiveness and safety.

Uterine Myomas: Focused Ultrasound Surgery

Uterine fibroids are the most common neoplasm in women. These lesions may be associated with impaired fertility and adverse obstetric outcomes. Medical treatment, myomectomy, hysterectomy and uterine artery embolization have been employed for the management of uterine fibroids. Focused ultrasound surgery (FUS) is a relatively recent technique that relies on mechanical and thermal energy of ultrasound for the ablation of a target tissue under an imaging guidance, that can be either ultrasound (US-guided FUS, USgFUS) or magnetic resonance (MR-guided FUS, MRgFUS). Pre- and peri-menopausal women are potential candidates for treatment; however, individual criteria need to be evaluated in order to establish the eligibility for the procedure. FUS procedure can be performed in an outpatient setting; it is a safe and effective treatment that has demonstrated to reduce symptoms associated with uterine fibroids. The adverse event rate is 8.7% and only 0.2% of patients experiences major complications. Pregnancy is possible after the treatment, and no damage to the endometrium has been observed following FUS procedure.

Development and clinical evaluation of a 3-step modified manipulation protocol for MRI-guided high-intensity focused ultrasound of uterine fibroids

OBJECTIVES

The clinical applicability of magnetic resonance image-guided high-intensity focused ultrasound (MR-HIFU) treatment of uterine fibroids is often limited due to inaccessible fibroids or bowel interference. The aim of this study was to implement a newly developed 3-step modified manipulation protocol and to evaluate its influence on the number of eligible women and treatment failure rate.

METHODS

From June 2016 to June 2018, 165 women underwent a screening MRI examination, 67 women of whom were consecutively treated with MR-HIFU at our institution. Group 1 (n = 20) was treated with the BRB manipulation protocol which consisted of sequential applications of urinary bladder filling, rectal filling, and urinary bladder emptying. Group 2 (n = 47) was treated using the 3-step modified manipulation protocol which included (1) the BRB maneuver with adjusted rectal filling by adding psyllium fibers to the solution; (2) Trendelenburg position combined with bowel massage; (3) the manual uterine manipulation (MUM) method for uterine repositioning. A comparison was made between the two manipulation protocols to evaluate differences in safety, the eligibility percentage, and treatment failure rate due to unsuccessful manipulation.

RESULTS

After implementing the 3-step modified manipulation protocol, our ineligibility rate due to bowel interference or inaccessible fibroids decreased from 18% (16/88) to 0% (0/77). Our treatment failure rate due to unsuccessful manipulation decreased from 20% (4/20) to 2% (1/47). There were no thermal complications to the bowel or uterus.

CONCLUSIONS

Implementation of the 3-step modified manipulation protocol during MR-HIFU therapy of uterine fibroids improved the eligibility percentage and reduced the treatment failure rate.

TRIAL REGISTRATION

Registry number NL56182.075.16 KEY POINTS: • A newly developed 3-step modified manipulation protocol was successfully implemented without the occurrence of thermal complication to the bowel or uterus. • The 3-step modified manipulation protocol increased our eligibility percentage for MR-HIFU treatment of uterine fibroids. • The 3-step modified manipulation protocol reduced our treatment failure rate for MR-HIFU treatment of uterine fibroids.

Emerging clinical applications of high-intensity focused ultrasound

High-intensity focused ultrasound (HIFU) is a minimally-invasive and non-ionizing promising technology and has been assessed for its role in the treatment of not only primary tumors but also metastatic lesions under the guidance of ultrasound or magnetic resonance imaging. Its performance is notably effective in neurologic, genitourinary, hepato-pancreato-biliary, musculoskeletal, oncologic, and other miscellaneous applications. In this article, we reviewed the emerging technology of HIFU and its clinical applications.

MRI evaluation of endopelvic fascial swelling and analysis of influencing factors in patients with uterine fibroids after high-intensity focused ultrasound ablation

Purpose: To evaluate endopelvic fascial swelling in patients with uterine fibroids after high-intensity focused ultrasound (HIFU) ablation on magnetic resonance imaging (MRI) and investigate the factors that influence endopelvic fascial swelling.Methods: MRI and clinical data from 188 patients with uterine fibroids who were treated with HIFU were analyzed retrospectively. The patients were divided into a fascial swelling group and a non-swelling group, and the degree of swelling was graded. Fascial swelling was set as the dependent variable, and factors such as baseline characteristics and HIFU parameters, were set as the independent variables. The relationship between these variables and fascial swelling was analyzed by univariate and multivariate analyses. Correlations between the factors and the degree of fascial swelling were evaluated by Kruskal-Wallis test.Results: The univariate analysis revealed that the fibroid location, distance from the fibroid to the sacrum, sonication time, treatment time, treatment intensity, therapeutic dose (TD), and energy efficiency (EEF) all affected the endopelvic fascial swelling (p < 0.05). Subsequently, multivariate analysis showed that the distance from the fibroid to the sacrum was significantly correlated with fascial swelling (p < 0.05). Moreover, TD and sonication time were significantly positively correlated with the degree of fascial swelling (p < 0.05). The incidence of sacrococcygeal pain was significantly correlated with fascial swelling (p < 0.05).Conclusion: The distance from the fibroid to the sacrum was a protective factor for fascial swelling. TD and sonication time were significantly positively correlated with the degree of fascial swelling.