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.

Transrectal high-intensity focused ultrasound (HIFU) for management of rectosigmoid deep infiltrating endometriosis: results of Phase-I clinical trial.

Objectives: Deep infiltrating endometriosis (DIE) of the rectosigmoid is associated with painful symptoms. When medical treatment is ineffective, surgical resection remains the standard treatment, despite significant risk of adverse events. High-intensity focused ultrasound (HIFU) is a minimally invasive ablative procedure.

Numerical study of a confocal ultrasonic setup for cavitation creation.

Acoustic cavitation has found a wide range of applications in the last few decades. For potential applications involving cavitation, the acoustic characteristics of a confocal ultrasonic setup are studied: two high-intensity focused ultrasound transducers are mounted so that their focal points overlap. A mathematical simulator is developed that takes into account nonlinear propagation, absorption, and diffraction.

Ultrasound-Guided Transesophageal High-Intensity Focused Ultrasound Cardiac Ablation in a Beating Heart: A Pilot Feasibility Study in Pigs.

Catheter ablation for the treatment of arrhythmia is associated with significant complications and often-repeated procedures. Consequently, a less invasive and more efficient technique is required. Because high-intensity focused ultrasound (HIFU) enables the generation of precise thermal ablations in deep-seated tissues without harming the tissues in the propagation path, it has the potential to be used as a new ablation technique.

Design and evaluation of a transesophageal HIFU probe for ultrasound-guided cardiac ablation: simulation of a HIFU mini-maze procedure and preliminary ex vivo trials.

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy.

Contribution of inertial cavitation in the enhancement of in vitro transscleral drug delivery.

In ocular drug delivery, the sclera is a promising pathway for administering drugs to both the anterior and posterior segments of the eye. Due to the low permeability of the sclera, however, efficient drug delivery is challenging. In this study, pulsed ultrasound (US) was investigated as a potential method for enhancing drug delivery to the eye through the sclera.

A multi-element interstitial ultrasound applicator for the thermal therapy of brain tumors.

Interstitial thermal therapy is a minimally invasive treatment modality that has been used clinically for ablating both primary and secondary brain tumors. Here a multi-element interstitial ultrasound applicator is described that allows for increased spatial control during thermal ablation of tumors as compared to existing clinical devices. The device consists of an array of 56 ultrasound elements operating at 6 MHz, oriented on the seven faces of a 3.

Electronic beam steering used with a toroidal HIFU transducer substantially increases the coagulated volume.

Treatment with high-intensity focused ultrasound is well established but requires extended treatment time. A device composed of 256 elements arranged on a toroidal transducer was developed to increase the coagulated volume. When all the elements are working in phase for 40 s, a volume of 6-8 cm(3) can be ablated.

Heart ablation using a planar rectangular high intensity ultrasound transducer and MRI guidance.

The aim of this study was to evaluate a flat rectangular (3×10mm(2)) MRI compatible transducer operating at 5MHz. The main task was to explore the feasibility of creating deep lesions in heart at a depth of at least 15mm. The size of thermal necrosis in heart tissue was estimated as a function of power and time using a simulation model.

Development of a miniaturized HIFU device for glaucoma treatment with conformal coagulation of the ciliary bodies.

This study examined the feasibility of high-intensity focused ultrasound (HIFU) for glaucoma treatment with conformal coagulation of the ciliary bodies (CB). A miniaturized high frequency (21 MHz) device was developed, based on the geometry of the eye and adapted to the anatomy of the rabbit eyeball. Six line-focus lesions were distributed along a circle and produced by six cylindrical transducers.

Interstitial thermal ablation with a fast rotating dual-mode transducer.

Interstitial ultrasound applicators can be a minimally invasive alternative for treating targets that are unresectable or are inaccessible by extracorporeal methods. Dual-mode transducers for ultrasound imaging and therapy were developed to address the constraints of a miniaturized applicator and real-time treatment monitoring. We propose an original treatment strategy that combines ultrasound imaging and therapy using a dual-mode transducer rotating at 8 revolutions per second.

Sector-switching sonication strategy for accelerated HIFU treatment of prostate cancer: in vitro experimental validation.

The study investigates a new sonication strategy with high-intensity focused ultrasound (HIFU), aiming for improvement of the original Ablatherm procedure in the prostate cancer treatment. The currently implemented and clinically used method (defined as reference) uses a single-element transducer, operated with 60% duty cycle. To implement the novel strategy, the active surface was split into two sectors, which can be powered either sequentially (for temporal switching) or simultaneously (equivalent to a single-element transducer).

Gel phantom for use in high-intensity focused ultrasound dosimetry.

An optically transparent phantom was developed for use in high-intensity focused ultrasound (US), or HIFU, dosimetry studies. The phantom is composed of polyacrylamide hydrogel, embedded with bovine serum albumin (BSA) that becomes optically opaque when denatured. Acoustic and optical properties of the phantom were characterized as a function of BSA concentration and temperature.

Experimental evaluation of lesion prediction modelling in the presence of cavitation bubbles: intended for high-intensity focused ultrasound prostate treatment.

The accuracy of high-intensity focused ultrasound (HIFU) lesion prediction modelling was evaluated for a truncated spherical transducer designed for prostate cancer treatment The modelling adapted the bio heat transfer equation (BHTE) to take into account the activity of cavitation bubbles generated during HIFU exposure. This modelling was used to predict the lesions produced by three different transducer geometries: fixed-focus, concentric-ring and 1.5D phased-array.

Damping, amplitude, aging tests of stacked transducers for shock wave generation.

New clinical concepts in lithotripsy demand small shock heads. Reducing the size of piezoelectric shock heads will be possible only if the pressure generated at the surface of each transducer can be increased so that the total pressure at the focus remains the same. To solve this problem, different solutions were proposed.

1.5-D high intensity focused ultrasound array for non-invasive prostate cancer surgery.

The aim of this study is to demonstrate the feasibility of a new spherically curved 1.5-D phased array for the treatment of localized prostatic cancer. The device is designed to conform to the Ablatherm machine (EDAP-Technomed, France), a commercially available machine in which high intensity focused ultrasound (HIFU) treatment for prostate cancer is administered transrectally.

Numerical simulation of the electro-acoustical response of a transducer excited by a time-varying electrical circuit.

Existing methods for the modeling of piezoelectric transducer response are generally frequency domain-based. The major disadvantage of this type of model is that they cannot take into account the electrical elements present in the emitting or receiving circuit whose values vary with respect to time. The need for a method that accounts for time-varying elements arises, for example, when the circuit comprises active electrical elements, such as diodes, or when the transducer is excited by capacitive discharge via a switch.

Modeling of high-intensity focused ultrasound-induced lesions in the presence of cavitation bubbles.

The classical "Bio Heat Transfer Equation (BHTE)" model is adapted to take into account the effects of oscillating microbubbles that occur naturally in the tissue during high-intensity focused ultrasound (HIFU) treatment. First, the Gilmore-Akulichev model is used to quantify the acoustic pressure scattered by microbubbles submitted to HIFU. Because this scattered pressure is not monochromatic, the concept of harmonic attenuation is introduced and a global attenuation coefficient is estimated for bubble-filled tissues.

Theoretical comparison of two interstitial ultrasound applicators designed to induce cylindrical zones of tissue ablation.

Although interstitial techniques are invasive, they are still the first-line therapeutic modalities for certain types of tumour. They are mainly relevant to tumours that are either inoperable or located so deep that access is complicated. Of the various types of radiation that can be delivered by the interstitial route, ultrasound is the most suitable for deep heating.

Motorised resection device for transurethral resection of the prostate: a laboratory evaluation.

Transurethral resection of the prostate is the most common method of relieving urinary outflow obstruction secondary to prostatic enlargement. However, this procedure can be responsible for various complications, including irrigant-fluid absorption and blood loss, both of which are strongly dependent on operation duration time. To reduce the latter, a new resection device has been designed for transurethral prostatectomy.

[Histologic and immunologic study of the testis after ligation of the vas deferens in dogs].

We wanted to study the effect of bilateral ligature and section of the deferentia of 12 dogs from the histological and immunological aspects. We looked for circulating anti-sperm antibodies and anti-basal membrane of the testes antibodies at the same time as histological study to find out what happened to these lesions after epididymo-deferential anastomosis had been carried out 16 weeks later. The histological lesions (disappearance of exfoliation of the germ cells and of necrobiosis of these cells) disapperared after anastomosis.