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W. Apoutou N'Djin

W. Apoutou N'Djin
French Institute of Health and Medical Research, France, Lyon · Laboratory of Therapeutic Applications of Ultrasound (LabTAU), INSERM U1032

M. Eng., M.S., Ph.D.

About

82
Publications
3,761
Reads
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Citations
Introduction
W. Apoutou N'DJIN currently works at the Laboratory of Therapeutic Applications of Ultrasound (LabTAU), French Institute of Health and Medical Research (INSERM U1032, France, Lyon). Apoutou does research in Biomedical Physics and Engineering, espacially in the domain of image-guided ultrasound therapies. http://labtau.univ-lyon1.fr/members/ndjin-william-apoutou
Additional affiliations
September 2017 - present
Claude Bernard University Lyon 1
Position
  • Lecturer
Description
  • Master Degree in Cancerology; Specialty: Focal Destruction of Cancers – CMUT Technology for Biomedical Ultrasound
September 2017 - present
Claude Bernard University Lyon 1
Position
  • Lecturer
Description
  • Master Degree in Medical Imaging Signal System (MISS) - Doppler Ultrasound Imaging - Low Energy Ultrasound in Medicine
September 2016 - August 2017
Claude Bernard University Lyon 1
Position
  • Lecturer
Description
  • Master Degree in Medical Imaging Signal System (MISS) – Low Energy Ultrasound in Medicine
Education
September 2004 - August 2005
Centrale Graduate School of Lyon
Field of study
  • Image & Signal processing
September 2001 - August 2004
Ensicaen, National Graduate School of Engineering & Research Center of Caen
Field of study
  • Instrumentation
September 1999 - June 2001
Lycée La Martinière Monplaisir - Preparatory Class for Entrance to Grandes Ecoles
Field of study
  • Physics - Chemistry - Engineering Sciences

Publications

Publications (82)
Article
Purpose: Focused ultrasound (FUS) is a promising tool to develop new modalities of therapeutic neurostimulation. The ability of FUS to stimulate the nervous system, in a noninvasive and spatiotemporally precise manner, has been demonstrated in animals and human subjects, but the underlying biomechanisms are not fully understood yet. The objective...
Article
Objective: The brain operates via generation, transmission and integration of neuronal signals and most neurological disorders are related to perturbation of these processes. Neurostimulation by Focused Ultrasound (FUS) is a promising technology with potential to rival other clinically-used techniques for the investigation of brain function and tr...
Preprint
Objective: The brain operates via generation, transmission and integration of neuronal signals and most neurological disorders are related to perturbation of these processes. Neurostimulation by Focused Ultrasound (FUS) is a promising technology with potential to rival other clinically-used techniques for the investigation of brain function and tre...
Article
This study demonstrated that high-intensity focused ultrasound (HIFU) produced with an intra-operative toroidal-shaped transducer causes fast, selective liver tumor ablations in an animal model. The HIFU device is composed of 256 emitters working at 3 MHz. A 7.5 MHz ultrasound imaging probe centered on the HIFU transducer guided treatment. VX2 tumo...
Article
Interstitial Ultrasound-guided High Intensity Focused Ultrasound (USgHIFU) therapy has the potential to deliver ablative treatments which conform to the target tumor. In this study, a robot-assisted US-navigation platform has been developed for 3D US guidance and planning of conformal HIFU ablations. The platform was used to evaluate a conformal th...
Article
No PDF available ABSTRACT The objective of this project was to integrate a LEFUS-system to a patch-clamp platform for exploration of LEFUS-modulated and/or -stimulated electrophysiological responses from individual cultured neurons. Mouse primary neurons and human neural progenitor cells were cultured and plated onto 35-mm diameter Petri dishes. A...
Article
No PDF available ABSTRACT The objective of this project was to study the electrical activities elicited by Low-Energy Focused Ultrasound (LEFUS) neurostimulation in ex vivo mouse hippocampal brain slices using a MicroElectrode Array (MEA) system. A mixed LEFUS/MEA platform was developed for spatial-temporal recording of neural responses induced by...
Article
Full-text available
Abstract Focused ultrasound are considered to be a promising tool for the treatment of neurological conditions, overcoming the limitations of current neurostimulation techniques in terms of spatial resolution and invasiveness. Much evidence to support the feasibility of ultrasound activation of neurons at the systemic level has already been provide...
Article
Personalized URL providing 50 days' free access to the article. Anyone clicking on this link before December 22, 2018 will be taken directly to the final version of this article on ScienceDirect, which they are welcome to read or download. No sign up, registration or fees are required. Personalized Share Link: https://authors.elsevier.com/c/1X~-y6...
Conference Paper
The use of ultrasound for therapy has seen a growing interest since the nineties and the development of endorectal transducers for ablating thermally prostatic tissues. Different devices are currently under clinical evaluation for the treatment of many disorders. Numerical modelling plays a significant role in these developments. For each clinical...
Article
Full-text available
A novel ultrasound (US) high-channels platform is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of innovative advanced US techniques. To date, a few systems with more than 1000 transducers permit full and simultaneous control in both transmission and receiving of all single elements of arrays. A p...
Conference Paper
Full-text available
The following study is focused on the CMUT intrinsic efficiency for therapeutic purposes. The simulation work is based on electromechanical equivalent circuit analysis and is verified thanks to impedance measurements and pressure field scanning. The good agreement between the overall experiences provides useful understanding on the CMUT behavior an...
Article
Capacitive micromachined ultrasound transducers (CMUTs) exhibit several potential advantages over conventional piezo technologies for use in therapeutic ultrasound (US) devices, including ease of miniaturization and integration with electronics, broad bandwidth ( several megahertz), and compatibility with magnetic resonance imaging (MRI). In this p...
Conference Paper
Interstitial therapeutic ultrasound devices are a promising technology for performing thermal ablation in a wide variety of organs. In this study, the use of Capacitive Micromachined Ultrasound Transducers (CMUTs) for interstitial heating applications was investigated. CMUTs exhibit potential advantages for use in therapeutic ultrasound application...
Article
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...
Article
Heart rhythm disorders, such as atrial fibrillation or ventricular tachycardia can be treated by catheter-based thermal ablation. However, clinically available systems based on radio-frequency or cryothermal ablation suffer from limited energy penetration and the lack of lesion's extent monitoring. An ultrasound-guided transesophageal device has re...
Article
Full-text available
Organ motion is a key component in the treatment of abdominal tumors by High Intensity Focused Ultrasound (HIFU), since it may influence the safety, efficacy and treatment time. Here we report the development in a porcine model of an Ultrasound (US) image-based dynamic fusion modeling method for predicting the effect of in vivo motion on intraopera...
Patent
Full-text available
An interstitial ultrasound thermal ablation applicator for conformal treatment of an inhomogeneous tumor lesion includes: a body having a longitudinal axis; and a plurality of array transducers mounted on the body, arranged side by side and having azimuth directions parallel to the longitudinal axis of the body, and having outer faces disposed in a...
Article
Purpose: The recent clinical emergence of minimally invasive image-guided therapy has demonstrated promise in the management of brain metastasis, although control over the spatial pattern of heating currently remains limited. Based on experience in other organs, the delivery of high-intensity contact ultrasound energy from minimally invasive appli...
Article
Atrial fibrillation is the most frequent cardiac arrhythmia. Recently, an ultrasound-guided transesophageal high-intensity focused ultrasound (HIFU) device has been designed to perform minimally invasive pulmonary vein isolation. It was made with a 3 MHz 8-ring HIFU transducer including in its center a 5 MHz 64-element imaging transducer. The HIFU...
Article
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. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedur...
Conference Paper
Here we report in-vivo validation of a fusion modeling method which associates real in-vivo motion data acquired from ultrasound speckle tracking imaging and data from a multi-scale modeling tool. This method aims at estimating the impact of in-vivo liver motion on High Intensity Focused Ultrasound (HIFU) treatments by quantifying thermal lesion de...
Article
Purpose: MRI-controlled interstitial ultrasound therapy is being developed as a minimally invasive, image-guided treatment for localized cancers. The method uses an interstitial multielement ultrasound applicator to deliver high-intensity ultrasound energy to tissue in order to achieve thermal coagulation in a target volume. Methods: A new tempe...
Conference Paper
Full-text available
The recent emergence at the clinical level of minimally-invasive focal therapy such as laser-induced thermal therapy (LITT) has demonstrated promise in the management of brain metastasis [1], although control over the spatial pattern of heating is limited. Delivery of HIFU from minimally-invasive applicators enables high spatial control of the hea...
Conference Paper
High-intensity contact ultrasound therapy can generate precise volumes of thermal damage in deep-seated tissue using interstitial or intracavitary devices. Multi-element, dual-frequency transducers offer increased spatial control of the heating pattern by enabling modulation of ultrasound power and frequency along the device. The performance and ac...
Conference Paper
MRI-guided transurethral ultrasound therapy has previously been evaluated in human volunteers by treating a prostate subvolume, prior to radical prostatectomy. Extension of this technique to full clinical use requires validation of the technique for coagulating a volume of tissue equivalent to the entire gland. This in-vitro study evaluates approac...
Article
Purpose: To evaluate the feasibility and safety of magnetic resonance (MR) imaging-controlled transurethral ultrasound therapy for prostate cancer in humans. Materials and methods: This pilot study was approved by the institutional review board and was performed in eight men (mean age, 60 years; range, 49-70 years) with localized prostate cancer...
Article
The feasibility and safety of magnetic resonance imaging (MRI)-controlled transurethral ultrasound therapy were demonstrated recently in a preliminary human study in which a small subvolume of prostate tissue was treated prior to radical prostatectomy. Translation of this technology to full clinical use, however, requires the capability to generate...
Conference Paper
Ultrasound thermal therapy of localized prostate cancer offers a minimally-invasive non-ionizing alternative [1-3] to surgery and radiotherapy. MRI-controlled transurethral ultrasound prostate therapy [4-6] has previously been investigated in a pilot human feasibility study [7], by treating a small sub-volume of prostate tissue. In this study, the...
Article
Transurethral ultrasound therapy uses real-time magnetic resonance (MR) temperature feedback to enable the 3D control of thermal therapy accurately in a region within the prostate. Previous canine studies showed the feasibility of this method in vivo. The aim of this study was to reduce the procedure time, while maintaining targeting accuracy, by i...
Conference Paper
MRI‐guided transurethral ultrasound therapy shows promise for minimally invasive treatment of localized prostate cancer. Previous in‐vivo studies demonstrated the feasibility of performing conservative treatments using real‐time temperature feedback to control accurately the establishment of coagulative lesions within circumscribed prostate regions...
Conference Paper
MRI-guided transurethral ultrasound therapy uses a linear array of transducer elements and active temperature feedback to create volumes of thermal coagulation shaped to predefined prostate geometries in 3-D. Numerical simulations have been used to determine robust feedback control algorithms, optimal transducer designs, effects of various tissue a...
Conference Paper
In the liver, the efficacy of radiofrequency or HIFU ablation is impaired by blood perfusion. This can be overcome by hepatic inflow occlusion using a Pringle manoeuver. Here we report the in vivo evaluation of ablations performed in the liver using a surgical toroidal High Intensity Focused Ultrasound (HIFU) device used during an open procedure wi...
Conference Paper
The feasibility of performing MRI-guided transurethral ultrasound therapy in humans has been shown by our group for the treatment of small subvolumes prior to radical prostatectomy. One challenge is to use this technology to treat a volume of tissue equivalent to the entire prostate gland. This simulation study evaluates the feasibility of treating...
Article
Full-text available
Bleeding is the main cause of postoperative complications of hepatic surgery. To minimize intraoperative bleeding during hepatectomy, resections are generally carried out under hepatic vascular control despite the risk of liver dysfunction in patients with chronic liver disease. This study evaluates the feasibility and safety of high-intensity focu...
Article
Bleeding is the main cause of postoperative complications during hepatic surgery. Blood loss and transfusions increase tumor recurrence in liver metastases from colorectal cancer. A high intensity focused ultrasound (HIFU) device with an integrated ultrasound imaging probe was developed for the treatment of colorectal liver metastasis. The HIFU tor...
Article
Minimally invasive treatments for localised prostate cancer are being developed with the aim of achieving effective disease control with low morbidity. High-temperature thermal therapy aimed at producing irreversible thermal coagulation of the prostate gland is attractive because of the rapid onset of thermal injury, and the immediate visualisation...
Article
MRI-controlled transurethral ultrasound therapy uses a linear array of transducer elements and active temperature feedback to create volumes of thermal coagulation shaped to predefined prostate geometries in 3D. The specific aims of this work were to demonstrate the accuracy and repeatability of producing large volumes of thermal coagulation (>10 c...
Article
Introduction L’hémorragie est la principale cause de complications postopératoires de la chirurgie hépatique. Le recours à la transfusion augmente le risque de récidive tumorale dans le carcinome hépatocellulaire et dans les métastases hépatiques de cancers colorectaux. Le clampage vasculaire pédiculaire hépatique permet de limiter les pertes sangu...
Presentation
MRI?guided transurethral ultrasound therapy is a minimally?invasive treatment for localized prostate cancer that provides local control with a low side?effect profile which would have a major impact in improving disease management. High?intensity ultrasound energy from a device inserted into the prostatic urethra generates an accurate region of the...
Poster
Current radical treatments for prostate cancer can have numerous, permanent side effects including incontinence, sexual dysfunction and bowel dysfunction. The development of an effective, minimally invasive treatment with fewer side effects would enhance treatment options, particularly for younger men with low‐risk disease. MRI‐guided transurethral...
Article
Full-text available
The use of hand-held ultrasound strain imaging for the intra-operative real-time visualization of HIFU (high-intensity focused ultrasound) ablations produced in the liver by a toroidal transducer was investigated. A linear 12 MHz ultrasound imaging probe was used to obtain radiofrequency signals. Using a fast cross-correlation algorithm, strain ima...
Conference Paper
MRI-guided transurethral ultrasound therapy shows promise for minimally invasive treatment of localized prostate cancer. Real-time MR temperature feedback enables the 3D control of thermal therapy to define an accurate region within the prostate. Previous in-vivo canine studies showed the feasibility of this method using transurethral planar transd...
Conference Paper
The development of new cauterization techniques for hepatic resection is critical for improving the safety of the procedure. Previous studies showed the feasibility of using HIFU or radiofrequency precoagulation to limit blood loss during dissection of the organ. Here we report a new therapeutic modality using high intensity focused ultrasound (HIF...
Article
The pig is an ideal animal model for preclinical evaluation of HIFU treatments, especially in the liver. However, there is no liver tumor model available for pigs. In this work, we propose to study an in vivo tumor-mimic model as a tool for evaluating if a sonographycally guided HIFU treatment, delivered by a toroidal-shaped device dedicated for th...
Article
In the liver, the efficacy of radiofrequency or high-intensity focused ultrasound (HIFU) ablation is impaired by blood perfusion. This can be overcome by hepatic inflow occlusion. Here we report the in vivo evaluation of ablations performed in the liver using a surgical toroidal HIFU device used during an open procedure with and without hepatic inf...
Conference Paper
Current development of HIFU strategies for the treatment of localized abdominal tumors are limited by organ motion during respiration. In preliminary studies, a numerical model simulated the effects of in‐vivo movements on HIFU treatments in the liver. It was shown that a HIFU treatment performed during respiration with juxtaposition of millimetric...
Conference Paper
The aim of this study was to demonstrate in a rabbit liver tumor model that high intensity focused ultrasound (HIFU) produced with toroidal‐shaped emitters may have a role in treating colorectal liver metastases. The HIFU device was composed of eight ultrasound emitters created by sectioning a single toroidal piezocomposite transducer. Each of the...
Conference Paper
Organs motion is a key component in the treatment of abdominal lesions by HIFU, since it may influence the efficacy and treatment time. Previous studies on HIFU treatments showed the effect of motor-controlled translations applied to in vitro liver samples. In vivo organs motions are more complex and could lead to various effects on HIFU treatments...
Conference Paper
A new geometry of HIFU transducer is described to enlarge the coagulated volume. The geometry of the transducer was not spherical. The surface of the transducer was built based on a toroid geometry. The transducer was generated by the revolution of a circle about an axis lying in its plane. Eight emitters operating at a frequency of 3 MHz were dice...
Conference Paper
A toroidial-shaped HIFU medical device with integrated ultrasound imaging was developed for the treatment of colorectal liver metastasis. The HIFU toroidïal-shaped transducer contained 256-elements (working frequency: 3 MHz) and allows creating a single conical lesion of 7 cm3 in 40 seconds (Ifocal = 1700 W.cm-2). Volumes of treatment can then be s...
Conference Paper
Presented in this paper is a tumor‐mimic model that allows the evaluation at a preclinical stage of the targeting accuracy of HIFU treatments in the liver. The tumor‐mimics were made by injecting a warm mixture of agarose, cellulose, and glycerol that polymerizes immediately in hepatic tissue and forms a 1 cm discrete lesion that is detectable by u...
Article
Surgical resection is the only treatment of colorectal liver metastases that can ensure long-term survival and cure in some patients. However, only 20% of patients are suitable for surgery. As a result, many nonresectional modalities of treatment have been assessed to provide an alternative to liver resection. Several limitations have been observed...
Article
Full-text available
To demonstrate in a porcine model that high-intensity focused ultrasound (HIFU) with toroid-shaped emitters may have a role in treating unresectable colorectal liver metastases. Surgical resection is the only curative option for colorectal hepatic metastases. Only 20% of patients are suitable for surgery. Many ablative techniques have been assessed...
Article
Presented in this article is a tumor-mimic model that allows the evaluation, before clinical trials, of the targeting accuracy of a high intensity focused ultrasound (HIFU) device for the treatment of the liver. The tumor-mimic models are made by injecting a warm solution that polymerizes in hepatic tissue and forms a 1 cm discrete lesion that is d...
Conference Paper
Full-text available
Here, we report that a new design of High Intensity Focused Ultrasound transducer can significantly enlarge the coagulated volume over short periods of time, and that treatment in the liver can be guided in real-time using an integrated ultrasound imaging probe. Eight ultrasound emitters, divided into 256 elements, were created by sectioning a sing...
Article
There is no established liver tumour model in pigs to study the efficacy of ablative treatment options available for the treatment of liver tumours by physical agents. A tumour-mimic model visible with high contrast on sonograms and on gross pathology has been studied at mid-term on 20 pigs. The aim was to determine if these tumour-mimics are well...
Conference Paper
Here, we report that a new design of High Intensity Focused Ultrasound transducer can significantly enlarge the coagulated volume over short periods of time. Our long-term objective is to develop a device that can be used during a surgery, for eventual clinical use in conjunction with hepatic resection. Eight ultrasound emitters, divided into 256 e...