Role of Systematic Control Biopsies following Partial Gland Ablation with High-Intensity Focused Ultrasound for Clinically Significant Prostate Cancer.

PURPOSE: Partial gland ablation (PGA) using high-intensity focused ultrasound (HIFU) is currently under investigation for clinically significant prostate cancer (Cs-PCa). Our primary objective was to assess the role of systematic control biopsies following HIFU-PGA in a cohort of Cs-PCa patients. MATERIALS AND METHODS: We studied a single-center retrospective cohort of 77 men treated with HIFU-PGA between October 2015 and December 2019. Patients with unilateral Cs-PCa, defined as Gleason grade group (GGG) ≥2, with visible lesion on multiparametric magnetic resonance imaging (mpMRI) and prostate specific antigen (PSA) ≤15 ng/ml were included. All patients underwent mpMRI with systematic and targeted biopsies before and after HIFU-PGA. The primary outcome was the rate of Cs-PCa at control biopsy within 1 year of treatment. Logistic regression was performed to identify predictive factors of our primary outcome. RESULTS: Median age was 67 years (IQR 61-71), median PSA was 7 ng/ml (IQR 5.5-8.9). Pre-treatment biopsies revealed 48 (62.3%) GGG2 lesions, 24 (31.2%) GGG3 and 5 (6.5%) GGG4 lesions. Cs-PCa was found in 24 (31.2%) patients at systematic control biopsy post-HIFU; Cs-PCa was in the treated lobe for 18 (27%) patients. No variables were identified as significant predictors of Cs-PCa at control biopsy, including PSA kinetics and control mpMRI. Median followup time was 17 months (95% CI 15-21). Median time to any retreatment was 32 months (95% CI 23-42). CONCLUSIONS: Systematic control biopsy within a year after PGA for Cs-PCa can identify the presence of residual Cs-PCa in up to a third of patients. From our early experience, control biopsy should be systematically offered patients regardless of PSA kinetics or control mpMRI results.

Uterine Artery Embolization Compared with High-intensity Focused Ultrasound Ablation for the Treatment of Symptomatic Uterine Myomas: A Systematic Review and Meta-analysis.

OBJECTIVE: This study aimed to compare the clinical effects of uterine artery embolization (UAE) with those of high-intensity focused ultrasound (HIFU) ablation for the treatment of symptomatic uterine myomas. DATA SOURCES: We searched PubMed, EMBASE, Web of Science, Cochrane Library, Google Scholar, and ClinicalTrials.gov for studies from January 2000 to August 2020. Related articles and relevant references of the included studies were also searched. METHODS OF STUDY SELECTION: Two researchers independently performed the data selection. We included comparative studies that compared the clinical outcomes of UAE with those of HIFU ablation in women with myomas. TABULATION, INTEGRATION, AND RESULTS: We assessed the study quality using the Cochrane Handbook for Systematic Reviews of Interventions for evaluating the risk of bias. Two independent researchers performed the article selection according to the screening criteria and rated the quality of evidence for each article. We calculated pooled mean difference with 95% confidence interval (CI) for continuous data and relative risk (RR) with 95% CI for dichotomous data. The systematic review registration number is CRD42020199630 on the International Prospective Register of Systematic Reviews. A total of 7 articles (5 trials), involving 4592 women with symptomatic uterine myomas, were included in the meta-analysis. Compared with the HIFU ablation group, the decrease in "uterine fibroid symptom" scores as well as the increase in quality-of-life scores at the time of follow-up were higher in the UAE group, with overall mean difference 19.54 (95% CI, 15.21-23.87; p <.001) and 15.72 (95% CI, 8.30-23.13; p <.001), respectively. The women in the UAE group had a significantly lower reintervention rate (RR 0.25; 95% CI, 0.15-0.42; p <.001). The women undergoing UAE had a significantly lower pregnancy rate than those undergoing HIFU ablation (RR 0.06; 95% CI, 0.01-0.45; p = .006). The difference in the incidence of adverse events between the 2 groups was not statistically significant (p = .53). CONCLUSION: Compared with HIFU ablation, UAE provided more significant alleviation of symptoms and improvement in quality of life, lower postoperative reintervention rate, and lower pregnancy rate for women with uterine myomas. However, we cannot conclude that HIFU ablation is more favorable for desired pregnancy than UAE because of the confounding factors.

How noninvasive treatment of uterine fibroids affects endometrial receptivity: a prospective cohort study.

OBJECTIVE: To investigate the effect of the ultrasonic energy during MRI-guided high-intensity focused ultrasound ablation (HIFU) of uterine fibroids on molecular and tissue markers of endometrial receptivity in women of reproductive age. MATERIAL AND METHODS: A prospective cohort study of 60 women of reproductive age was conducted. The main group consisted of 32 patients suffering from the symptomatic course of uterine fibroids who received treatment with HIFU ablation of uterine fibroids. The control group consisted of 28 healthy fertile women examined voluntarily. The endometrium obtained with pipelle biopsy on days 20-22 of the cycle was examined by scanning electron microscopy and immunohistochemistry before and three months after the treatment. The results were processed by the method of variation statistics using the SPSS 22.0. RESULTS: The focused ultrasound rays passing through the endometrium did not cause any change in the maturation rate or the state of intercellular contacts. At the same time, a significant increase in the frequency of asynchronous maturation of pinopodia was found to be 14.28% before HIFU versus 50.00% after HIFU; p = .021 and the number of heteromorphic secretory cells 5.88% before HIFU versus 53.33% after HIFU; p = .002 in implantation endometrium. A significant decrease in the stromal expression of CD95+bright in the endometrium to the level comparable with control values was observed after HIFU (from 70.22 ± 9.77 c/s to 48.81 ± 5.47 c/s; p < .001; the control level - 47.80 ± 2.13 c/s). The ratio and expression of steroid receptors, proliferation markers, p53-dependent apoptosis and its blockers, regulators and markers of angiogenesis, LIF and LIF-R signaling molecules in the stroma and endometrial glands did not change significantly after treatment. CONCLUSION: This study did not reveal any significant negative effects of HIFU ablation of uterine fibroids on endometrial receptivity in women of reproductive age.

Role of deep brain stimulation therapy in the magnetic resonance-guided high-frequency focused ultrasound era: current situation and future prospects.

Introduction: Deep brain stimulation (DBS) is a well-established treatment of movement disorders; but recently there has been an increasing trend toward the ablative procedure magnetic resonance-guided focused ultrasound (MRgFU). DBS is an efficient neuromodulatory technique but associated with surgical complications. MRIgFUS is an incision-free method that allows thermal lesioning, with fewer surgical complications but irreversible effects.Areas covered: We look at current and prospective aspects of both techniques. In DBS, appropriate patient selection, improvement in surgical expertise, target accuracy (preoperative and intraoperative imaging), neurophysiological recordings, and novel segmented leads need to be considered. However, increased number of older patients with higher comorbidities and risk of DBS complications (mainly intracranial hemorrhage, but also infections, hardware complications) make them not eligible for surgery. With MRgFUS, hemorrhage risks are virtually nonexistent, infection or hardware malfunction are eliminated, while irreversible side effects can appear.Expert commentary: Comparison of the efficacy and risks associated with these techniques, in combination with a growing aged population in developed countries with higher comorbidities and a preference for less invasive treatments, necessitates a review of the indications for movement disorders and the most appropriate treatment modalities.

Cost-utility analysis of focal high-intensity focussed ultrasound vs active surveillance for low- to intermediate-risk prostate cancer using a Markov multi-state model.

OBJECTIVES: To estimate the relative cost-effectiveness of focal high-intensity focussed ultrasound (F-HIFU) compared to active surveillance (AS) in patients with low- to intermediate-risk prostate cancer, in France. PATIENTS AND METHODS: A Markov multi-state model was elaborated for this purpose. Our analyses were conducted from the French National Health Insurance perspective, with a time horizon of 10 years and a 4% discount rate for cost and effectiveness. A secondary analysis used a 30-year time horizon. Costs are presented in 2016 Euros (€), and effectiveness is expressed as quality-adjusted life years (QALYs). Model parameters' value (probabilities for transitions between health states, and cost and utility of health states) is supported by systematic literature reviews (PubMed) and random effect meta-analyses. The cost of F-HIFU in our model was the temporary tariff attributed by the French Ministry of Health to the overall treatment of prostate cancer by HIFU (€6047). Our model was analysed using Microsoft Excel 2010 (Microsoft Corp., Redmond, WA, USA). Uncertainty about the value of the model parameters was handled through probabilistic analyses. RESULTS: The five health states of our model were as follows: initial state (AS or F-HIFU), radical prostatectomy, radiation therapy, metastasis, and death. Transition probabilities from the initial F-HIFU state relied on four articles eligible for our meta-analyses. All were non-comparative studies. Utilities relied on a single cohort in San Diego, CA, USA. For a fictive cohort of 1000 individuals followed for 10 years, F-HIFU would be €207 520 more costly and would yield 382 less QALYs than AS, which means that AS is cost-effective when compared to F-HIFU. For a threshold value varying from €0 to 100 000/QALY, the probability of AS being cost-effective compared to F-HIFU varied from 56.5% to 60%. This level of uncertainty was in the same range with a 30-year time horizon. CONCLUSION: Given existing published data, our results suggest that AS is cost-effective compared to F-HIFU in patients with low- and intermediate-risk prostate cancer, but with high uncertainty. This uncertainty must be scaled down by continuing to supply the model with new published data and ideally through a randomised clinical trial that includes cost-effectiveness analyses.

Evaluation of high-intensity focused ultrasound ablation for uterine fibroids: an IDEAL prospective exploration study.

OBJECTIVE: To evaluate the clinical outcomes of high-intensity focused ultrasound (HIFU) and surgery in treating uterine fibroids, and prepare for a definitive randomised trial. DESIGN: Prospective multicentre patient choice cohort study (IDEAL Exploratory study) of HIFU, myomectomy or hysterectomy for treating symptomatic uterine fibroids. SETTING: 20 Chinese hospitals. POPULATION OR SAMPLE: 2411 Chinese women with symptomatic fibroids. METHODS: Prospective non-randomised cohort study with learning curve analysis (IDEAL Stage 2b Prospective Exploration Study). MAIN OUTCOME MEASURES: Complications, hospital stay, return to normal activities, and quality of life (measured with UFS-Qol and SF-36 at baseline, 6 and 12 months), and need for further treatment. Quality-of-life outcomes were adjusted using regression modelling. HIFU treatment quality was evaluated using LC-CUSUM to identify operator learning curves. A health economic analysis of costs was performed. RESULTS: 1353 women received HIFU, 472 hysterectomy and 586 myomectomy. HIFU patients were significantly younger (P < 0.001), slimmer (P < 0.001), better educated (P < 0.001), and wealthier (P = 0.002) than surgery patients. Both UFS and QoL improved more rapidly after HIFU than after surgery (P = 0.002 and P = 0.001, respectively at 6 months), but absolute differences were small. Major adverse events occurred in 3 (0.2%) of HIFU and in 133 (12.6%) of surgical cases (P < 0.001). Median time for hospital stay was 4 days (interquartile range, 0-5 days), 10 days (interquartile range, 8-12.5 days) and 8 days (interquartile range, 7-10 days). CONCLUSIONS: HIFU caused substantially less morbidity than surgery, with similar longer-term QoL. Despite group baseline differences and lack of blinding, these findings support the need for a randomised controlled trial (RCT) of HIFU treatment for fibroids. The IDEAL Exploratory design facilitated RCT protocol development. TWEETABLE ABSTRACT: HIFU had much better short-term outcomes than surgery for fibroids in 2411-patient Chinese IDEAL format study.

High intensity focused ultrasound ablation for atrial fibrillation: results from the National Spanish Registry.

BACKGROUND: A National Spanish Registry to compile all patients treated with high intensity focused ultrasound (HIFU) energy for atrial fibrillation (AF) was created to evaluate the safety and efficacy of AF surgical ablation. METHODS: A national Spanish registry was created, and ten hospitals using HIFU to ablate AF joined it. A total of 412 patients undergoing cardiac surgery between 2006 and February 2013 were included. AF was divided between paroxysmal AF (33%) and persistent AF (67%) with a mean AF duration of 29.3±108.2 months. Mean left atrial diameter was 51.2±6.5 mm. Mean underlying heart disease were aortic valve disease (49.3%), ischemic disease (25.2%) and mitral disease (33.2%) Clinical follow-up of patients and a 6 months postoperative echocardiogram were performed in all patients. RESULTS: A pacemaker implantation was needed in 4.9% of patients with a perioperative stroke in 2.5%. Rhythm at discharge from hospital was sinus rhythm in 58%, AF in 35.9% and atrial flutter in 0.8% of patients. Sinus rhythm restoration at 6, 12, 24 and 36 months follow-up was achieved in 66.1%, 63.8%, 63.9% and 45.9% of patients respectively. Multivariate analysis showed paroxysmal AF and sinus rhythm restoration in the operating theatre as factors related to sinus rhythm long term restoration. CONCLUSIONS: The Spanish national registry showed an efficacy of AF ablation with the HIFU Epicor system of 66.1%, 63.8%, 63.9% and 45.9% at 6, 12, 24 and 36 months follow-up. There were no device-related complications.

Ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for the treatment of patients with adenomyosis and prior abdominal surgical scars: A retrospective study.

OBJECTIVE: The aim of this paper was to retrospectively compare the therapeutic efficacy and adverse effects of ultrasound-guided high-intensity focused ultrasound (USgHIFU) treatment for adenomyotic patients with or without prior abdominal surgical scars. METHODS: From January 2011 to March 2014, 534 patients with adenomyosis were referred for HIFU treatment. Among them, 118 patients had prior abdominal surgical scars, 416 patients did not have prior abdominal surgical scars. Contrast-enhanced MRI was used to evaluate the treatment outcomes. All the adverse effects were recorded. RESULTS: All patients completed USgHIFU treatment. A fractional ablation of 74.8 ± 27.8% was achieved in the group of patients without abdominal scars; the fractional ablation was 75.6 ± 22.3% in the group of patients with prior abdominal surgical scars. No significant difference in fractional ablation between the two groups was observed (p > 0.05). The rate of skin burn in the group of patients with prior abdominal surgical scars was significantly higher than that in the group without abdominal scars (2.5% vs. 0.2%, p < 0.05), but it is still acceptable. CONCLUSION: The prior abdominal surgical scars have no significant influence on the effectiveness of HIFU treatment for adenomyosis. The risk of skin burn is higher in patients with abdominal scars than without, but the incidence rate is still acceptable.

The damages of high intensity focused ultrasound to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent and superabsorbent polymer.

The present study investigates the damages of high intensity focused ultrasound (HIFU) to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent (UCA) and superabsorbent polymer (SAP) alone or in combination. A rabbit model with transplanted hydatid cyst was established by implanting hydatid cyst isolated from infected sheep liver, and HIFU was used to ablate the transplanted cysts with the aid of UCA and SAP alone or in combination. The hydatid cyst with thin wall, good elasticity, approximately spherical, and a diameter of approximately 30 mm was selected for the following experiments. According to our previous studies, a mixture of 0.1 g SAP and 0.5 ml anhydrous ethanol, and the solution of 0.1 ml UCA SonoVue, or both materials were injected into different cyst before HIFU ablation, respectively. The cyst inoculated with the SAP and UCA alone or in combination was immediately implanted into the abdominal cavity of rabbit for HIFU ablation at a dosage of 100 W acoustic powers. The ablation mode was spot scanning at the speed of 3 mm/s. Every target point was scanned three times; every ablating time lasted 3 s. The distance of each ablated layer was 5 mm. The total ablation time depended on the volume of cyst. The comparison of ultrasound image for each layer of hydatid cyst was made before and after HIFU ablation. The protoscolices in ablated cysts were stained by trypan blue exclusion assay, and their structures were observed by light microscopy. To estimate ablation effects of HIFU to the walls of hydatid cysts, the ultrastructure changes of cyst walls were examined by electron microscopy. The pathological changes of rabbits' skins through which ultrasound penetrated were observed to investigate the side effects of HIFU ablation. The results demonstrated that HIFU had some lethal effects to hydatid cysts in vivo, namely, echo enhancements of ultrasound images of cysts, increases in mortality rate of protoscolices from 15.19 % (HIFU alone) to 48.66 % (HIFU + SAP), 38.67 % (HIFU + UCA), and 67.75 % (HIFU + SAP + UCA), respectively, serious structural damages of protoscolices, and destructions or even disappearance of laminated layers and germinal layers in the walls of hydatid cysts ablated by HIFU aided with UCA and SAP alone or in combination. This study demonstrated that destructive effects of HIFU to transplanted hydatid cyst could be enhanced by UCA and SAP alone, but the destruction of HIFU aided with a combination of UCA and SAP to hydatid cysts was more effective than those aided with UCA or SAP alone. The enhanced thermal and cavitation effects of HIFU induced by UCA and SAP might be involved in the enhanced destructive effects of HIFU on hydatid cysts. There were no evidences of pathological changes on rabbits' skins overlying the hydatid cysts after HIFU ablation. The results suggested that the rabbit model with transplanted hydatid cyst may serve as an optional animal model for the experiments of HIFU ablation to hydatid cyst in vivo, and the materials of UCA and SAP were proved as enhancing agents of HIFU ablation to hydatid cysts, and HIFU at a dosage of 100 W acoustic powers was a safe and feasible parameter to ablate the hydatid cysts in this special animal model. These results laid a theoretical foundation for improving HIFU therapy for cystic echinococcosis by inoculation of UCA and SAP into hydatid cysts.

Therapeutic effects of focused ultrasound in 4014 patients with symptomatic cervical ectopy.

This study aimed to explore the therapeutic effect of focused ultrasound (FU) therapy in patients with symptomatic cervical ectopy. 4677 patients with symptomatic cervical ectopy were enrolled and treated with FU. Three months after treatment, we analyzed the therapeutic effects and the adverse reactions in 4014 cases with complete records. All influential factors were also analyzed with logistic regression analysis. For the treatment of symptomatic cervical ectopy, the effective rate of FU was 99.8%, and the cure rate was 72.52%. Bleeding that either reached or exceeded normal menstrual volume occurred in 12 cases. Logistic regression analysis showed that the degree of illness, vaginal cleanliness, economic level, occupation, age and artificial abortion frequency were all influential factors. Focused ultrasound is a promising new therapeutic option for the treatment of symptomatic cervical ectopy. Additionally, it can be widely used for a variety of patients.

Safety evaluation of high-intensity focused ultrasound in patients with pancreatic cancer.

INTRODUCTION: This study was performed to analyze the safety of high-intensity focused ultrasound (HIFU) for treating pancreatic cancer. METHODS: 224 cases with advanced pancreatic cancer were enrolled into this study. Real-time sonographic images were taken, and vital signs, liver and kidney function, skin burns, local reactions, and systemic effects were monitored and recorded before, during, and after HIFU. Computed tomography or magnetic resonance imaging (MRI) was also performed before and after HIFU. RESULTS: Serum amylase level increased in 16 cases (7.1%) 1 day after HIFU treatment, and 9 of these cases also had abnormal urinary amylase levels. Gastrointestinal (GI) dysfunction such as abdominal distension and anorexia with slight nausea was observed in 10 cases (4.5%) after HIFU treatment. 1 case with pancreatic head cancer developed obstructive jaundice 2 weeks after HIFU treatment. Vertebral injury, identified by MRI, occurred in 2 cases, although no symptoms were seen. No severe complications such as skin burns, lesion bleeding, GI tract bleeding or GI perforation were observed in any of the cases. CONCLUSION: For specific patients, HIFU treatment is a safe, non-invasive treatment for pancreatic cancer but requires careful preoperative preparation and exact operative performance.

High-intensity focused ultrasound: advances in technology and experimental trials support enhanced utility of focused ultrasound surgery in oncology.

High-intensity focused ultrasound (HIFU) is a rapidly maturing technology with diverse clinical applications. In the field of oncology, the use of HIFU to non-invasively cause tissue necrosis in a defined target, a technique known as focused ultrasound surgery (FUS), has considerable potential for tumour ablation. In this article, we outline the development and underlying principles of HIFU, overview the limitations and commercially available equipment for FUS, then summarise some of the recent technological advances and experimental clinical trials that we predict will have a positive impact on extending the role of FUS in cancer therapy.

Magnetic resonance imaging-guided focused ultrasound treatment of symptomatic uterine fibroids: impact of technology advancement on ablation volumes in 115 patients.

OBJECTIVES: The aim of this study was to assess the impact of the advanced technology of the new ExAblate 2100 system (Insightec Ltd, Haifa, Israel) for magnetic resonance imaging (MRI)-guided focused ultrasound surgery on treatment outcomes in patients with symptomatic uterine fibroids, as measured by the nonperfused volume ratio. MATERIALS AND METHODS: This is a retrospective analysis of 115 women (mean age, 42 years; range, 27-54 years) with symptomatic fibroids who consecutively underwent MRI-guided focused ultrasound treatment in a single center with the new generation ExAblate 2100 system from November 2010 to June 2011. Mean ± SD total volume and number of treated fibroids (per patient) were 89 ± 94 cm and 2.2 ± 1.7, respectively. Patient baseline characteristics were analyzed regarding their impact on the resulting nonperfused volume ratio. RESULTS: Magnetic resonance imaging-guided focused ultrasound treatment was technically successful in 115 of 123 patients (93.5%). In 8 patients, treatment was not possible because of bowel loops in the beam pathway that could not be mitigated (n = 6), patient movement (n = 1), and system malfunction (n = 1). Mean nonperfused volume ratio was 88% ± 15% (range, 38%-100%). Mean applied energy level was 5400 ± 1200 J, and mean number of sonications was 74 ± 27. No major complications occurred. Two cases of first-degree skin burn resolved within 1 week after the intervention. Of the baseline characteristics analyzed, only the planned treatment volume had a statistically significant impact on nonperfused volume ratio. CONCLUSIONS: With technological advancement, the outcome of MRI-guided focused ultrasound treatment in terms of the nonperfused volume ratio can be enhanced with a high safety profile, markedly exceeding results reported in previous clinical trials.

Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging.

PURPOSE: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). MATERIALS AND METHODS: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. RESULTS: The median volume of uterine fibroids was 70.3 cm(3) (interquartile range, 41.1-132.5 cm(3)). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0-100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9-100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2-100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0-100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0-83.9%) in this subgroup. CONCLUSION: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded.

Volumetric MR-guided high-intensity focused ultrasound ablation of uterine fibroids: treatment speed and factors influencing speed.

OBJECTIVES: To assess the treatment speed of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of symptomatic uterine fibroids, with a focus on factors affecting treatment speed. METHODS: We received Institutional Review Board approval, and informed consent was obtained from all participants. Among 109 patients referred, 43 women (39.4 %) (mean age, 43.7 years), with 112 fibroids passed the screening. We treated 53 symptomatic uterine fibroids (47.3 %, 53/112) (volume, 341.2 ± 256.5 ml) using volumetric MR-HIFU ablation. We assessed procedure times, non-perfused volume (NPV) and treatment speed (NPV/treatment time). We statistically analysed the factors affecting treatment speed using multiple logistic regression tests. RESULTS: Technical success was achieved in 42 of 43 cases. MR room time (from entrance to exit) and treatment time (from first to last sonication) were 216.0 ± 40.6 min and 131.5 ± 55.9 min, respectively. Immediate NPV was 178.9 ± 147.3 ml, which was 57.4 ± 25.5 % of the fibroid volume. Treatment speed was 81.8 ± 48.0 ml/h. Multivariate analysis showed that a large fibroid volume (P < 0.001), a low signal intensity ratio of fibroid to skeletal muscle on T2-weighted images (P = 0.009) and timing after completion of the learning curve (P < 0.001) significantly increased treatment speed. CONCLUSION: Volumetric MR-HIFU ablation can effectively treat symptomatic uterine fibroids. The treatment speed appeared to improve when treating large and/or dark fibroids as well as upon completion of the learning curve.

Quantification of target population for ultrasound enhanced thrombolysis in acute ischemic stroke.

BACKGROUND AND PURPOSE: Insonation of the occluded target vessel (sonothrombolysis) has been reported to increase the effect of intravenous thrombolysis in ischemic stroke. Its use has predominantly been described in middle cerebral artery (MCA) occlusions. Sufficient insonation conditions are a mandatory precondition. The impact of these limitations on eligibility rates for sonothrombolysis has not been reported so far. METHODS: Consecutive patients treated with rt-PA and examined by either CT- or MR-angiogram before treatment and by transcranial color-coded duplex sonography (TCCS) during inhospital stay were identified retrospectively at three hospitals from ongoing data registries. RESULTS: One-hundred and seventy-nine patients (age [years], median [IQR] = 75 [65-83]; 42% female; NIH Stroke Scale [NIHSS], median [IQR] = 10 [6-17]) were analyzed. MCA occlusions were detected in 39% of patients (N = 69) with 48 (27%) occlusions in the proximal M1-segment and 21 (12%) in a distal M2-segment. Arterial occlusions others than MCA were seen in an additional 9% (N = 16). TCCS (without contrast agent) revealed sufficient bone windows in 70% of patients with MCA occlusions (N = 48) corresponding to 27% of all patients treated with thrombolysis. CONCLUSION: Conventional sonothrombolysis is restricted to a minority of stroke patients suitable for intravenous thrombolysis. Extending the applicability by utilization of ultrasound contrast agents and targeting non-MCA-occlusions warrants further evaluation.

Feasibility of using Nakagami distribution in evaluating the formation of ultrasound-induced thermal lesions.

The acoustic posterior shadowing effects of bubbles influence the accuracy for defining the location and range of ablated thermal lesions during focused ultrasound surgery when using ultrasonic monitoring imaging. This paper explored the feasibility of using Nakagami distribution to evaluate the ablated region induced by focused ultrasound exposures at different acoustic power levels in transparent tissue-mimicking phantoms. The mean value of the Nakagami parameter m was about 0.5 in the cavitation region and increased to around 1 in the ablated region. Nakagami images were not subject to significant shadowing effects of bubbles. Ultrasound-induced thermal lesions observed in the photos and Nakagami images were overshadowed by bubbles in the B-mode images. The lesion size predicted in the Nakagami images was smaller than that predicted in the photos due to the sub resolvable effect of Nakagami imaging at the interface. This preliminary study on tissue-mimicking phantom suggested that the Nakagami parameter m may have the potential use in evaluating the formation of ultrasound-induced thermal lesion when the shadowing effect of bubbles is strong while the thermal lesion was small. Further studies in vivo and in vitro will be needed to evaluate the potential application.

Inducing occlusion effect in Y-shaped vessels using high-intensity focused ultrasound: finite element analysis and phantom validation.

High-intensity focused ultrasound (HIFU) surgery offers a truly non-invasive treatment method with no skin incision, but precise targeting of tumour tissues for thermotherapy. Clinical experience reveals that the efficacy of tumour destruction not only involves in coagulating necrosis, but also involves in damaging the tumour vessels, which play an important role in tumour progression. These vessels take the elevated temperature away by perfusion, resulting in uncertainty of the occlusion effect during HIFU treatment. In this study, a Y-shaped vessel model comprising common and tumour vessels and an indirect fabrication method are proposed. The physical properties of the fabricated vessel phantom are measured and compared with human tissue. Simulation is performed using finite element modelling according to the tissue parameter, perfusion rate of the tumour vessel and treatment parameters including power intensity and exposure duration. The phantom experiments are carried out with perfusion of egg white to validate the threshold time prediction obtained from the simulation results. Our findings reveal that the threshold time obtained from experiments is consistent with the simulated one.

High-intensity focused ultrasound as an alternative to the surgical approach in primary hyperparathyroidism: a preliminary experience.

BACKGROUND: Surgery is the therapy of choice in primary hyperparathyroidism (PHPT), although other less invasive techniques have been used in the attempt to cure the disease. Recently, high-intensity focused ultrasound (HIFU), a totally non-invasive technique, has become available to cure solid tumors. AIM: The aim of this pilot study has been to assess the safety and efficacy of HIFU in symptomatic patients with PHPT. MATERIAL AND METHODS: Four out of 31 patients with surgical indications within a cohort of 47-screened patients with PHPT were considered eligible for the study. All patients accepted to participate and were submitted to HIFU treatment in a single session. One patient was submitted to surgery after HIFU treatment. Patients were followed-up for 12 months after the procedure. RESULTS: A persistent or a partial remission of the disease, respectively, were obtained in 2 patients (50%), including the one who underwent surgery after HIFU treatment. Safety was assessed performing laryngoscopy in all patients after HIFU procedure. A transient vocal cord paralysis was observed in all patients treated by HIFU only. No permanent side effects were observed in the long term. CONCLUSIONS: HIFU might be a promising technique in treating PHPT, provided that further development of the software decreases the rate of side effects and improves the short- and long-term efficacy.