Histotripsy: A Method for Mechanical Tissue Ablation with Ultrasound.

Histotripsy is a relatively new therapeutic ultrasound technology to mechanically liquefy tissue into subcellular debris using high-amplitude focused ultrasound pulses. In contrast to conventional high-intensity focused ultrasound thermal therapy, histotripsy has specific clinical advantages: the capacity for real-time monitoring using ultrasound imaging, diminished heat sink effects resulting in lesions with sharp margins, effective removal of the treated tissue, a tissue-selective feature to preserve crucial structures, and immunostimulation. The technology is being evaluated in small and large animal models for treating cancer, thrombosis, hematomas, abscesses, and biofilms; enhancing tumor-specific immune response; and neurological applications. Histotripsy has been recently approved by the US Food and Drug Administration to treat liver tumors, with clinical trials undertaken for benign prostatic hyperplasia and renal tumors. This review outlines the physical principles of various types of histotripsy; presents major parameters of the technology and corresponding hardware and software, imaging methods, and bioeffects; and discusses the most promising preclinical and clinical applications.

Evaluating the safety of high-intensity focused ultrasound treatment for rectal endometriosis: results from a French prospective multicentre study including 60 patients.

STUDY QUESTION: Is increasing the intensity of high-intensity focused ultrasound (HIFU) by 30% in the treatment of rectal endometriosis a safe procedure? SUMMARY ANSWER: This study demonstrates the safety of a 30% increase in the intensity of HIFU in the treatment of rectal endometriosis, with no Clavien-Dindo Grade III complications overall, and namely no rectovaginal fistulae. WHAT IS KNOWN ALREADY: A feasibility study including 20 patients with rectal endometriosis demonstrated, with no severe complications, a significant improvement in digestive disorders, dysmenorrhoea, dyspareunia, and health status, although the volume of the endometriosis nodule did not appear to be reduced. STUDY DESIGN, SIZE, DURATION: A prospective multicentre cohort study was conducted between 2020 and 2022 with 60 patients with symptomatic rectal endometriosis. Following the failure of medical treatment, HIFU treatment was offered as an alternative to surgery. PARTICIPANTS/MATERIALS, SETTING, METHODS: As the main objective of this study was to examine safety, all adverse events observed during the 6 months of follow-up were analysed and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) and Clavien-Dindo classifications. Secondary objectives included evaluating the evolution of symptoms using validated questionnaires: gynaecological and digestive pain symptoms with a visual analogue scale, health status with the Medical Outcomes Study 36-item Short Form (SF-36) questionnaire, average post-operative daily pain level, and analgesic medication required in the 10 days following treatment. MRI was also performed at Day 1 to detect early complications. Finally, we performed a blinded MRI review of the evolution of the nodule at 6 months post-treatment. MAIN RESULTS AND THE ROLE OF CHANCE: The procedure was performed under spinal anaesthesia for 30% of the patients. The median duration of treatment was 32 min. Fifty-five patients left the hospital on Day 1. MRI scans performed on Day 1 did not highlight any early-onset post-operative complication. Using the Clavien-Dindo classification, we listed 56.7% Grade I events, 3.4% Grade II events, and no events Grade III or higher. At 1, 3, and 6 months, all gynaecologic, digestive and general symptoms, as well as health status, had significantly improved. The evolution of the nodule was also significant (P < 0.001) with a 28% decrease in volume. LIMITATIONS, REASONS FOR CAUTION: The main objective was safety and not effectiveness. The study was not randomized and there was no control group. WIDER IMPLICATIONS OF THE FINDINGS: HIFU treatment for rectal endometriosis results in an improvement of symptoms with low morbidity; as such, for selected patients, it could be a valuable alternative to surgical approaches following the failure of medical treatment. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by the company EDAP TMS. Professors Dubernard and Rousset are consultants for EDAP TMS. Dubernard received travel support from EDAP-TMS. Dr F. Chavrier received industrial grants from EDAP-TMS. He has developed a device for generating focused ultrasonic waves with reduced treatment time. This device has been patented by EDAP-TMS. Dr Lafon received industrial grants from EDAP-TMS; he declares that EDAP-TMS provided funding directly to INSERM to support a young researcher chair in therapeutic ultrasound, which is unrelated to the current study. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT04494568.

Focal high-intensity focused ultrasound therapy for localized prostate cancer: An interim analysis of the multinational FASST study.

BACKGROUND: High-intensity focused ultrasound (HIFU) emerged as a novel approach for the treatment of localized prostate cancer (PCa). However, prospective studies on HIFU-related outcomes and predictors of treatment failure (TF) remain scarce. MATERIALS AND METHODS: We conducted a multinational prospective cohort study among patients undergoing HIFU therapy for localized, low- to intermediate-risk PCa. Follow-up data on serial prostate specific antigen (PSA), multi-parametric magnetic resonance imaging (mpMRI), targeted/systematic biopsies, adverse events and functional outcomes were collected. The primary endpoint was TF, defined as histologically confirmed PCa requiring whole-gland salvage treatment. Uni- and multi-variable adjusted hazard ratios (HRs) were calculated using Cox proportional hazard regression models. RESULTS: At baseline, mean (standard deviation) age was 64.14 (7.19) years, with the majority of patients showing T-stage 1 (73.9%) and International Society of Urological Pathology grading system Grade 2 (58.8%). PSA nadir (median, 1.70 ng/mL) was reached after 6 months. Of all patients recruited, 16% had clinically significant PCa, as confirmed by biopsy, of which 13.4% had TF. Notably, T-stage and number of positive cores at initial biopsy were independent predictors of TF during follow-up (HR [95% CI] 1.27 [1.02-1.59] and 5.02 [1.80-14.03], respectively). Adverse events were minimal (17% and 8% early and late adverse events, respectively), with stable or improved functional outcomes in the majority of patients. CONCLUSIONS: This interim analysis of a multinational study on HIFU therapy for the management of low-to-intermediate-risk PCa reveals good functional outcomes, minimal adverse events and low incidence of TF over the short-term. Data on long-term outcomes, specifically as it relates to oncological outcomes, are awaited eagerly.

Novel treatment system using endoscopic ultrasound-guided high-intensity focused ultrasound: A proof-of-concept study.

AIM: High-intensity focused ultrasound (HIFU) is a novel minimally invasive local treatment of solid tumors. Endoscopic ultrasound-guided HIFU (EUS-HIFU) using mechanical effects would have potential benefits, including precise detection of target lesions and enhance drug delivery. The aim of this study is to develop EUS-HIFU device and to prove our concept in porcine model using a locally injected phase change nano droplet (PCND) as the sensitizer. METHOD: A phospholipid PCND contained volatile perfluoro-carbon liquids. The prototype HIFU apparatus comprised a small (20 × 20 mm) transducer with center frequency of 2.1 MHz, attachable to a linear EUS transducer. Under general anesthetic, a single porcine received EUS-guided injection of PCND. The HIFU transducer was placed laparotomically in the stomach, and the liver was ablated through the gastric wall. RESULTS: PCND was injected successfully and a distinct lesion was generated at the HIFU transducer focus only in injected areas that received HIFU exposure at 4.7 kW/cm2 at a duty cycle of 5 % (mean temporal intensity, 0.245 kW/cm2) for 30 s. The generated lesions were mechanically fractionated in macroscopic view. CONCLUSION: The concept of transluminal HIFU ablation using novel EUS-HIFU system was proved in a porcine animal model. This novel treatment system has great potential for future cancer treatment although further investigation in more animals and different organs are warranted.

Focal therapy with high-intensity focused ultrasound for prostate cancer: 3-year outcomes from a prospective trial.

OBJECTIVE: To assess the oncological and functional outcomes of focal high-intensity focused ultrasound (HIFU) in treating localised prostate cancer (PCa), a 3-year prospective study was undertaken using periodic post-ablation saturation biopsies. PATIENTS AND METHODS: Men with two or fewer lesions of grade group (GG) ≤3 PCa were eligible for participation. Additional criteria included a prostate-specific antigen (PSA) level of ≤15 ng/mL, clinical T1c-T2, and a life expectancy of ≥10 years. The primary endpoint was failure-free survival (FFS), defined as absence of clinically significant PCa (csPCa) in- or out-of-field on protocol-mandated saturation biopsy, no whole-gland or systemic salvage treatment, PCa metastasis, or PCa-related death. Results are reported using two distinct definitions of csPCa: (i) the presence of any GG ≥2 and (ii) any GG ≥3 or core involvement of ≥6 mm. Secondary endpoints were functional patient-reported outcome measures addressing urinary, sexual, and bowel function. RESULTS: A total of 91 patients were included: six (7%) with GG1 and 85 (93%) with GG ≥2. In all, 83 (91%) underwent at least one follow-up biopsy. Biopsy attendance at 6, 12, and 36 months was 84%, 67%, and 51%, respectively. The FFS at these time points for any GG ≥2 PCa was 79% (95% confidence interval [CI] 80-88%), 57% (95% CI 48-69%) and 44% (95% CI 34-56%), respectively. Using the second definition, FFS were 88% (95% CI 81-95%), 70% (95% CI 61-81%) and 65% (95% CI 55-77%), respectively. The 3-year cancer-specific survival was 100%, and freedom from metastasis was 99%. Magnetic resonance imaging (MRI) (negative predictive value of up to 89%, 95% CI 84-93%) and relative decrease of PSA values (P = 0.4) performed poorly in detecting residual disease. Urinary and bowel assessment returned to baseline questionnaire scores within 3 months. In all, 17 (21%) patients reported meaningful worsening in erectile function. A significant decrease of PCa related anxiety was observed. CONCLUSIONS: Focal HIFU treatment for localised PCa shows excellent functional outcomes with half of the patients remaining cancer-free after 3 years. Whole-gland treatment was avoided in 81%. Early follow-up biopsies are crucial to change or continue the treatment modality at the right time, while the use of MRI and PSA in detecting PCa recurrence is uncertain.

High-intensity focused ultrasound with visually directed power adjustment for focal treatment of localized prostate cancer: systematic review and meta-analysis.

PURPOSE: To characterize patient outcomes following visually directed high-intensity focused ultrasound (HIFU) for focal treatment of localized prostate cancer. METHODS: We performed a systematic review of cancer-control outcomes and complication rates among men with localized prostate cancer treated with visually directed focal HIFU. Study outcomes were calculated using a random-effects meta-analysis model. RESULTS: A total of 8 observational studies with 1,819 patients (median age 67 years; prostate-specific antigen 7.1 mg/ml; prostate volume 36 ml) followed over a median of 24 months were included. The mean prostate-specific antigen nadir following visually directed focal HIFU was 2.2 ng/ml (95% CI 0.9-3.5 ng/ml), achieved after a median of 6 months post-treatment. A clinically significant positive biopsy was identified in 19.8% (95% CI 12.4-28.3%) of cases. Salvage treatment rates were 16.2% (95% CI 9.7-23.8%) for focal- or whole-gland treatment, and 8.6% (95% CI 6.1-11.5%) for whole-gland treatment. Complication rates were 16.7% (95% CI 9.9-24.6%) for de novo erectile dysfunction, 6.2% (95% CI 0.0-19.0%) for urinary retention, 3.0% (95% CI 2.1-3.9%) for urinary tract infection, 1.9% (95% CI 0.1-5.3%) for urinary incontinence, and 0.1% (95% CI 0.0-1.4%) for bowel injury. CONCLUSION: Limited evidence from eight observational studies demonstrated that visually directed HIFU for focal treatment of localized prostate cancer was associated with a relatively low risk of complications and acceptable cancer control over medium-term follow-up. Comparative, long-term safety and effectiveness results with visually directed focal HIFU are lacking.

Prospective close monitoring of the effect of vascular-targeted photodynamic therapy and high intensity focused ultrasound of localized prostate cancer by multiparametric magnetic resonance imaging.

PURPOSE: The aim of this study is to describe the anatomical and functional changes observed in multiparametric magnetic resonance imaging (mpMRI) during follow-up after focal therapy (FT) for localized prostate cancer (PCa). MATERIALS AND METHODS: In this prospective study, we analyzed pre- and postoperatively acquired mpMRI of 10 patients after FT (7 days; 3, 6, 9, 12 months). 7/10 (70%) patients underwent vascular-targeted photodynamic therapy (VTP). 3/10 (30%) patients underwent high-intensity focused ultrasound (HIFU). MpMR image analysis was performed using a semi-automatic software for segmentation of the prostate gland (PG) and tumor zones. Signal intensities (SI) of T2-weighted (T2w), T1-weighted (T1w),diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) images as well as volumes of the prostate gland (PGV) and tumor volumes (TV) were evaluated at each time point. RESULTS: The results showed a significant increase of PGV 7 days after FT (p = 0.042) and a significant reduction of PGV between 7 days and 6, 9 and 12 months after FT (p < 0.001). The TV increased significantly 7 days after FT (p < 0.001) and decreased significantly between 7 days and 12 months after FT (p < 0.001). There was a significant increase in SI of the ADC in the ablation zone after 6, 9 and 12 months after FT (p < 0.001). 1/9 patients (11%) had recurrent tumor on rebiopsy characterized as a a small focal lesion on mpMRI with strong diffusion restriction (low SI on ADC map and high SI on b-value DWI). CONCLUSION: MpMRI is able to represent morphologic changes of the ablated zone after FT and might be helpful to detect recurrent tumor.

Efficacy of HIFU for the treatment of benign thyroid nodules: a systematic review and meta-analysis.

OBJECTIVE: Thyroid nodules are common and sometimes associated with cosmetic issues. Surgical treatment has several disadvantages, including visible scarring. High-intensity focused ultrasound (HIFU) is a recent noninvasive treatment for thyroid nodules. The present study aims to evaluate the effectiveness and safety of HIFU for the treatment of benign thyroid nodules. METHODS: We searched PubMed, Embase, and Cochrane Library for studies evaluating the outcomes of HIFU for patients with benign thyroid nodules. We conducted a meta-analysis by using a random effects model and evaluated the volume reduction ratio, treatment success rate, and incidence of treatment-related complications. RESULTS: Thirty-two studies were included in the systematic review. Only 14 studies were used in the meta-analysis because the other 18 involved data collected during overlapping periods. The average volume reduction ratios at 3, 6, and 12 months after treatment were 39.02% (95% CI: 27.57 to 50.47%, I2: 97.9%), 48.55% (95% CI: 35.53 to 61.57%, I2: 98.2%), and 55.02% (95% CI: 41.55 to 68.48%, I2: 99%), respectively. Regarding complications, the incidences of vocal cord paresis and Horner's syndrome after HIFU were 2.1% (95% CI: 0.2 to 4.1%, I2: 14.6%) and 0.7% (95% CI: 0 to 1.9%, I2: 0%), respectively. CONCLUSIONS: HIFU is an effective and safe treatment option for patients with benign thyroid nodules. However, the effects of HIFU on nodules of large sizes and with different properties require further investigation. Additional studies, particularly randomized controlled trials involving long-term follow-up, are warranted. CLINICAL RELEVANCE STATEMENT: Surgical treatment for thyroid nodules often results in permanent visible scars and is associated with a risk of bleeding, nerve injury, and hypothyroidism. High-intensity focused ultrasound may be an alternative for patients with benign thyroid nodules. KEY POINTS: • The success rate of HIFU treatment for thyroid nodules is 75.8% at 6 months. Average volume reduction ratios are 48.55% and 55.02% at 6 and 12 months. • The incidence of complications such as vocal fold paresis, Horner's syndrome, recurrent laryngeal nerve palsy, hypothyroidism, and skin redness is low. • HIFU is both effective and safe as a treatment for benign thyroid nodules.

Laser tattoo removal strategies: Part II: A review of the methods, techniques, and complications involved in tattoo removal.

The rising global popularity of cosmetic and corrective tattoos has concurrently led to an increased demand for their removal. While in the past, methods like surgical excision, chemical destruction, and dermabrasion were employed, lasers have emerged as a reliable and effective tool for tattoo removal. Increasing technological options and combination treatment strategies have raised the importance of understanding the various approaches to laser tattoo removal along with their respective clinical impact. This CME aims to describe the multifaceted aspects of laser tattoo removal, including the method selection, application principles, and safety considerations. Furthermore, it addresses the factors considered when selecting the most suitable laser to achieve optimal treatment outcomes.

Evaluation of acoustic-thermal simulations of in vivo magnetic resonance guided focused ultrasound ablative therapy.

PURPOSE: To evaluate numerical simulations of focused ultrasound (FUS) with a rabbit model, comparing simulated heating characteristics with magnetic resonance temperature imaging (MRTI) data collected during in vivo treatment. METHODS: A rabbit model was treated with FUS sonications in the biceps femoris with 3D MRTI collected. Acoustic and thermal properties of the rabbit muscle were determined experimentally. Numerical models of the rabbits were created, and tissue-type-specific properties were assigned. FUS simulations were performed using both the hybrid angular spectrum (HAS) method and k-Wave. Simulated power deposition patterns were converted to temperature maps using a Pennes' bioheat equation-based thermal solver. Agreement of pressure between the simulation techniques and temperature between the simulation and experimental heating was evaluated. Contributions of scattering and absorption attenuation were considered. RESULTS: Simulated peak pressures derived using the HAS method exceeded the simulated peak pressures from k-Wave by 1.6 ± 2.7%. The location and FWHM of the peak pressure calculated from HAS and k-Wave showed good agreement. When muscle acoustic absorption value in the simulations was adjusted to approximately 54% of the measured attenuation, the average root-mean-squared error between simulated and experimental spatial-average temperature profiles was 0.046 ± 0.019 °C/W. Mean distance between simulated and experimental COTMs was 3.25 ± 1.37 mm. Transverse FWHMs of simulated sonications were smaller than in in vivo sonications. Longitudinal FWHMs were similar. CONCLUSIONS: Presented results demonstrate agreement between HAS and k-Wave simulations and that FUS simulations can accurately predict focal position and heating for in vivo applications in soft tissue.

Clinical efficacy and safety of ultrasound-guided high-intensity focused ultrasound for breast fibroadenoma: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this systematic review and meta-analysis was to assess the clinical efficacy and safety of ultrasound (US)-guided high intensity focused ultrasound (HIFU) in the treatment of breast fibroadenoma in different studies. METHODS: Studies evaluating the efficacy and safety of US-guided HIFU in the treatment of histologically-proven FA with follow-up outcomes of more than 3 months were searched through MEDLINE/PubMed databases. Volume reduction rate (VRR) and side effects were extracted and compared for further analysis. RESULTS: Of 29 identified articles, 10 studies involving 385 women and more than 545 FAs met the inclusion criteria. The mean VRR at 6 months and 12 months after HIFU was 52.00% and 72.00%. In terms of intraoperative safety, nine studies reported mild to moderate pain, with an average visual analogue scale (VAS) score ranging from 1.60 to 7.10. The most common postoperative side effect associated with HIFU was subcutaneous ecchymosis and less frequent were pain, erythema, and skin pigmentation, most of which disappeared within weeks. No serious side effects were observed. CONCLUSION: S-guided HIFU is an effective and safe noninvasive treatment for breast FA that does not cause serious side effects. Further studies are needed to explore crucial influencing factors of VRR.

Mild hyperthermia with magnetic resonance- guided high intensity focused ultrasound combined with salvage chemoradiation for recurrent rectal cancer.

INTRODUCTION: Pelvic recurrences from rectal cancer present a challenging clinical scenario. Hyperthermia represents an innovative treatment option in combination with concurrent chemoradiation to enhance therapeutic effect. We provide the initial results of a prospective single center feasibility study (NCT02528175) for patients undergoing rectal cancer retreatment using concurrent chemoradiation and mild hyperthermia with MR-guided high intensity focused ultrasound (MR-HIFU). METHODS: All patients were deemed ineligible for salvage surgery and were evaluated in a multidisciplinary fashion with a surgical oncologist, radiation oncologist and medical oncologist. Radiation was delivered to a dose of 30.6 Gy in 1.8 Gy per fraction with concurrent capecitabine. MR-HIFU was delivered on days 1, 8 and 15 of concurrent chemoradiation. Our primary objective was feasibility and toxicity. RESULTS: Six patients (total 11 screened) were treated with concurrent chemoradiation and mild hyperthermia with MR-HIFU. Tumor size varied between 3.1-16.6 cm. Patients spent an average of 228 min in the MRI suite and sonication with the external transducer lasted an average of 35 min. There were no complications on the day of the MR-HIFU procedure and all acute toxicities (no grade >/=3 toxicities) resolved after completion of treatment. There were no late grade >/=3 toxicities. CONCLUSION: Mild hyperthermia with MR-HIFU, in combination with concurrent chemoradiation for appropriately selected patients, is safe for localized pelvic recurrences from rectal cancer. The potential for MR-HIFU to be applied in the recurrent setting in rectal cancer treatment requires further technical development and prospective evaluation.

Feasibility, safety and efficacy of high intensity focused ultrasound ablation as a preoperative treatment for challenging hysteroscopic myomectomy.

PURPOSE: To investigate the feasibility, safety and efficacy of high intensity focused ultrasound ablation (HIFU) as a preoperative treatment for challenging hysteroscopic myomectomies. MATERIALS AND METHODS: A total of 75 patients diagnosed with types 0-III of uterine fibroids were enrolled. Based on the Size, Topography, Extension of the base, Penetration and lateral Wall position (STEPW) classification scoring system, 25 cases with a score ≥ 5 points were treated with HIFU followed by hysteroscopic myomectomy (HIFU + HM group), whereas 50 cases with a score < 5 points were treated with hysteroscopic myomectomy (HM group). RESULTS: The median preoperative STEPW score was 7 in the HIFU + HM group and 2 in the HM group. The average non-perfused volume (NPV) ratio achieved in fibroids after HIFU was 86.87%. Patients in the HIFU + HM group underwent hysteroscopic myomectomy one to four days after HIFU, and downgrading was observed in 81.81% of fibroids. The operation time for patients in the HIFU + HM group was 73 min and the success rate of myomectomy in a single attempt was 60%. The volume of distention medium used during the operation was greater in the HIFU + HM group than in the HM group (15,500 ml vs. 7500 ml). No significant difference was observed between the two groups in terms of intraoperative blood loss, the incidence of intraoperative and postoperative complications, menstrual volume score, or uterine fibroid quality of life score. CONCLUSION: HIFU can be utilized as a preoperative treatment for large submucosal fibroids prior to hysteroscopic myomectomy. HIFU offers a novel approach in the management of this subset of patients.

Risk factors affecting long-term efficacy of ultrasound-guided high-intensity focused ultrasound treatment for multiple uterine fibroids.

OBJECTIVES: To investigate the long-term efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for multiple uterine fibroids and the factors associated with recurrence. MATERIALS AND METHODS: Five hundred and forty-nine patients with multiple uterine fibroids treated with USgHIFU from June 2017 to June 2019 were retrospectively analyzed. The Pictorial Blood Loss Assessment Chart (PBAC) was used to assess menstrual blood loss. The patients were asked to undergo pre- and post-USgHIFU magnetic resonance imaging (MRI) and complete routine follow-up after USgHIFU. Cox regression analysis was used to investigate the risk factors associated with recurrence. RESULTS: The median number of fibroids per patient was 3 (interquartile range: 3-4), and a total of 1371 fibroids were treated. Among them, 446 patients completed 3 years follow-up. Recurrence, defined as PBAC score above or equal to 100 and/or the residual fibroid volume increased by 10%, was detected in 90 patients within 3 years after USgHIFU, with a cumulative recurrence rate of 20.2% (90/446). The multi-factor Cox analysis showed that age was a protective factor for recurrence. Younger patients have a greater chance of recurrence than older patients. Mixed hyperintensity of fibroids on T2WI and treatment intensity were risk factors for recurrence. Patients with hyperintense uterine fibroids and treated with lower treatment intensity were more likely to experience recurrence than other patients after USgHIFU. No major adverse effects occurred. CONCLUSIONS: USgHIFU can be used to treat multiple uterine fibroids safely and effectively. The age, T2WI signal intensity and treatment intensity are factors related to recurrence.

Complications and adverse events of high-intensity focused ultrasound in its application to gynecological field - a systematic review and meta-analysis.

OBJECTIVE: To analyze and summarize the types, incidence rates and relevant influencing factors of adverse events (AEs) after high-intensity focused ultrasound ablation of gynecological diseases and provide reference and basis for handling such events in clinical practice. METHOD: We searched PubMed, Cochrane Library, Web of Science and Embase databases to retrieve all literature since its establishment until February 2024. We evaluated the quality of included literature and publication bias and conducted a meta-analysis of single group rates for various AEs using Stata 17.0. RESULTS: This systematic review finally included 41 articles. We summarized 34 kinds of AEs in 7 aspects and conducted a single group rate meta-analysis and sub-group analysis of 16 kinds of AEs. Among the common AEs of High-Intensity Focused Ultrasound (HIFU), the incidence of lower abdominal pain/pelvic pain is 36.1% (95% CI: 24.3%∼48.8%), vaginal bleeding is 20.6% (95% CI: 13.9%∼28.0%), vaginal discharge is 14.0% (95% CI: 9.6%∼19.1%), myoma discharge is 24% (95% CI: 14.6%∼34.8%), buttock pain is 10.8% (95% CI: 6.0%∼16.5%) and sacral pain is 10% (95% CI: 8.8%∼11.2%). Serious complications include uterine rupture, necrotic tissue obstruction requiring surgical intervention, third degree skin burns and persistent lower limb pain or movement disorders. CONCLUSION: The common AEs after HIFU surgery are mostly mild and controllable, and the incidence of serious complications is extremely low. By reasonable prevention and active intervention, these events can be further reduced, making it a safe and effective treatment method. It is a good choice for patients who crave noninvasive treatment or have other surgical contraindications.

Study on the safety and efficacy of HIFU in the treatment of VaIN.

PURPOSE: This study aimed to investigate the safety and efficacy of High-Intensity Focused Ultrasound (HIFU) treatment for vaginal intraepithelial neoplasia(VaIN). METHODS: Retrospective analysis was conducted on clinical, pathological, and follow-up data of 43 patients who underwent HIFU treatment for VaIN at Xiangya Third Hospital of Central South University between January 2018 and December 2022. The preliminary efficacy and safety of HIFU in treating VaIN were discussed. RESULTS: The 36 patients were analyzed, and the average age was 50.09 ± 12.06 years, including 24 patients with VaIN I and 12 patients with VaIN II. Five cases had a history of hysterectomy (4 due to cervical lesions, 1 due to hysteromyoma), and 2 cases had conization of cervical intraepithelial lesions (CIN). All 36 cases were complicated by human papillomavirus (HPV) infection, with 3 cases also having grade I-II CIN and undergoing cervical HIFU treatment. All patients successfully completed the HIFU treatment, with an average treatment time of 5.99 ± 1.25 min, treatment power of 3.5 W, and average total treatment dose of 1118.99 ± 316.20 J. Patients tolerated the treatment well, experiencing only slight pain with VAS score of 3. There was a mild postoperative burning sensation, which resolved within approximately 10-20 min. After 6 follow-up visits, 33 patients (91.66%) achieved cure, 1 patient (2.77%) showed persistence, 2 patients (5.55%) exhibited progression, and 27 patients (75%) tested negative for HPV. At 12 months of follow-up, the results were consistent with those of 6 months. No complications occurred during the procedure and the follow-up period. CONCLUSION: HIFU is a safe and effective treatment for VaIN. However, this study had a small sample size, a relatively short follow-up period, and lacked a control group, requiring further investigation.

Ultrasound-guided high-intensity focused ultrasound ablation for uterine arteriovenous fistula: a case series.

PURPOSE: To evaluate the efficacy and safety of high-intensity focused ultrasound (HIFU) ablation in the treatment of uterine arteriovenous fistula (UAVF). MATERIALS AND METHODS: This case series included three patients diagnosed with acquired UAVF. All patients underwent routine laboratory tests, electrocardiography (ECG), chest X-ray, ultrasound, and pelvic contrast-enhanced magnetic resonance imaging (MRI). HIFU treatment was performed under sedation and analgesia using a Model JC Focused Ultrasound Tumor Therapeutic System (made by Chongqing Haifu Medical Technology Co. Ltd., China) with a B mode ultrasound device for treatment guidance. The treatment time, sonication power, sonication time, and complications were recorded. Follow-up evaluations were scheduled at 1-, 3-, 6-, and 12-month to assess symptom improvement and evaluate the post-treatment imaging. RESULTS: All patients completed HIFU treatment in a single session without any major complication. All patients complained of mild lower abdominal and sacrococcygeal pain. Typically, no special treatment is required. Following HIFU treatment, there was a significant relief in clinical symptoms, particularly abnormal uterine bleeding. Ultrasound examinations conducted one month after the treatment revealed a notable reduction in the volume of the lesion, ranging from 57% to 100%. Moreover, the efficacy and safety of HIFU treatment remained consistent during the 12-month follow-up period. CONCLUSION: HIFU ablation appears to be an effective and safe treatment modality for UAVF. It provides a noninvasive approach with favorable clinical outcomes.

Long-term outcome and risk factors of reintervention after high intensity focused ultrasound ablation for uterine fibroids: a systematic review and meta-analysis.

OBJECTIVES: To quantify the reintervention rate and analyze the risk factors for reintervention after high-intensity focused ultrasound (HIFU) ablation of uterine fibroids. METHODS: Eighteen studies were selected from the seven databases. A meta-analysis was applied to synthesize the reintervention rates for fibroids across various follow-up durations. Subgroup-analysis was conducted based on the year of surgery, sample size, guide methods, and non-perfusion volume ratio (NPVR). Signal intensity of T2-weighted imaging (T2WI) was independently evaluated for reintervention risk. RESULTS: The study enrolled 5216 patients with fibroids treated with HIFU. There were 3247, 1239, 1762, and 2535 women reaching reintervention rates of 1% (95% confidence interval (CI): 1-1), 7% (95% CI: 4-11), 19% (95% CI: 11-27), and 29% (95% CI: 14-44) at 12, 24, 36, and 60-month after HIFU. The reintervention rates of patients treated with US-guided HIFU (USgHIFU) were significantly lower than those of patients treated with MR-guided focused ultrasound surgery (MRgFUS). When the NPVR of fibroids was over 50%, the reintervention rates at 12, 36 and 60-month after HIFU were 1% (95% CI: 0.3-2), 5% (95% CI: 3-8), and 15% (95% CI: 9-20). The reintervention risk for hyper-intensity fibroids on T2WI was 3.45 times higher (95% CI: 2.7-4.39) for hypo-/iso-intensity fibroids. CONCLUSION: This meta-analysis showed that the overall reintervention rates after HIFU were acceptable and provided consultative suggestions regarding treatment alternatives for patients with fibroids. Subgroup-analysis revealed that USgHIFU, NPVR ≥ 50%, and hypo-/iso-intensity of fibroids on T2WI were significant factors in reducing reintervention. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42023456094.

Non-contrast enhanced MRI for efficiency evaluation of high-intensity focused ultrasound in adenomyosis ablation.

OBJECTIVE: To investigate the value of T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) in evaluating the therapeutic effect of high-intensity focused ultrasound (HIFU) in adenomyosis ablation. MATERIAL AND METHODS: One hundred eighty-nine patients with adenomyosis were treated with HIFU. The ablation areas on T2WI and DWI sequences were classified into different types: type I, relatively ill-defined rim or unrecognizable; subtype IIa, well-defined rim with hyperintensity; subtype IIb, well-defined rim with hypointensity. The volume of ablation areas on T2WI (VT2WI) and DWI (VDWI) was measured and compared with the non-perfused volume (NPV), and linear regression was conducted to analyze their correlation with NPV. RESULTS: The VT2WI of type I and type II (subtype IIa and subtype IIb) were statistically different from the corresponding NPV (p = 0.004 and 0.024, respectively), while no significant difference was found between the VDWI of type I and type II with NPV (p = 0.478 and 0.561, respectively). In the linear regression analysis, both VT2WI and VDWI were positively correlated with NPV, with R2 reaching 0.96 and 0.97, respectively. CONCLUSIONS: Both T2WI and DWI have the potential for efficient evaluation of HIFU treatment in adenomyosis, and DWI can be a replacement for CE-T1WI to some extent.

Efficacy and influencing factor analysis of high-intensity focused ultrasound therapy for abdominal wall endometriosis: a case series.

OBJECTIVE: The aim of this retrospective study was to investigate the short-term and long-term efficacy of high-intensity focused ultrasound (HIFU) therapy for abdominal wall endometriosis (AWE) and explore its potential influencing factors. MATERIALS AND METHODS: A total of 80 patients with AWE who underwent HIFU therapy were retrospectively analyzed. Follow-ups were also conducted to evaluate the changes in lesion size and pain relief. Multivariate logistic regression analysis was applied to investigate factors influencing HIFU therapy for AWE. RESULTS: Among the 80 patients with AWE who received HIFU therapy, the effective rates were 76.3%, 80.5%, and 90.5% after 3, 12 and 24 months of follow-up, respectively. Multivariate logistic regression analysis revealed that the AWE lesion diameter and sonication intensity had statistically significant effects on the 3-month and 12-month efficacy of HIFU therapy for AWE, while age, BMI, disease duration, average sonication power and grey-scale changes did not have statistically significant effects. Four patients with AWE experienced recurrence after HIFU therapy, for a three-year cumulative recurrence rate of 6.3%. Furthermore, ten patients required reintervention after treatment, for a five-year cumulative reintervention rate of 13.9%. CONCLUSIONS: This study further confirmed the safety and effectiveness of HIFU therapy for AWE. Factors such as AWE lesion diameter and sonication intensity have been identified as key influencers affecting the short-term and long-term efficacy of HIFU therapy for AWE. The first two years following HIFU therapy constitute crucial periods for observation, and judiciously extending follow-up intervals during this timeframe is advised.