A5072356464- Ultrasound Imaging and Elastography
- Ultrasound and Hyperthermia Applications
- Advanced MRI Techniques and Applications
- Photoacoustic and Ultrasonic Imaging
- Ultrasonics and Acoustic Wave Propagation
- Neurological disorders and treatments
- Electrical and Bioimpedance Tomography
- Acoustic Wave Phenomena Research
- Cerebral Venous Sinus Thrombosis
- Neuroscience and Neural Engineering
- Trigeminal Neuralgia and Treatments
- Ultrasound and Cavitation Phenomena
- Thyroid and Parathyroid Surgery
- Craniofacial Disorders and Treatments
- Intracerebral and Subarachnoid Hemorrhage Research
- Wireless Body Area Networks
- Meningioma and schwannoma management
- Voice and Speech Disorders
- Neurosurgical Procedures and Complications
- Ultrasound in Clinical Applications
- Microwave Imaging and Scattering Analysis
- Traumatic Brain Injury and Neurovascular Disturbances
- Structural Health Monitoring Techniques
- Piezoelectric Actuators and Control
- Acoustic Wave Resonator Technologies
Focused Ultrasound Foundation
2012-2024
University of Virginia Health System
2022-2024
University of Virginia
2006-2023
MR imaging-guided focused sonography surgery is a new stereotactic technique that uses high-intensity to heat and ablate tissue. The goal of this study was describe imaging findings pre- post-ventralis intermedius nucleus lesioning by as treatment for essential tremor determine whether there an association between these features the clinical response sonography.Fifteen patients with medication-refractory prospectively gave consent; were enrolled in single-site, FDA-approved pilot trial;...
Transcranial magnetic resonance-guided focused ultrasound (TcMRgFUS) brain treatment systems compensate for skull-induced beam aberrations by adjusting the phase and amplitude of individual transducer elements. These corrections are currently calculated based on a preacquired computed tomography (CT) scan patient's head. The purpose work presented here is to demonstrate feasibility using ultrashort echo-time resonance imaging (UTE MRI) instead CT calculate apply aberration clinical TcMRgFUS...
Intracerebral hemorrhage (ICH) is a major cause of death and disability throughout the world. Surgical techniques are limited by their invasive nature associated caused during clot removal. Preliminary data have shown promise for feasibility transcranial MR-guided focused ultrasound (MRgFUS) sonothrombolysis in liquefying clotted blood ICH thereby facilitating minimally evacuation via twist-drill craniostomy aspiration tube.In an vitro model, following optimum parameters were determined:...
Transcranial MR-guided focused ultrasound surgery (MRgFUS) is evolving as a treatment modality in neurosurgery. Until now, the trigeminal nerve was believed to be beyond envelope of existing high-frequency transcranial MRgFUS systems. In this study, authors explore feasibility targeting cadaveric model with temperature assessments using computer simulations and an vitro skull phantom fitted thermocouples.Six nerves from 4 unpreserved cadavers were targeted first experiment. Preprocedural CT...
In preparing a patient for trans-cranial magnetic resonance (MR)-guided focused ultrasound procedure, current practice is to shave the patient's head on treatment day. Here we present an initial attempt evaluate feasibility of in unshaved, ex vivo human model. A skull filled with tissue-mimicking phantom and covered wig made hair was sonicated using 220- 710-kHz transducers acoustic energy transfer. Heating at focal point measured by MR proton shift thermometry. Results showed that had...
The field of therapeutic focused ultrasound, which first emerged in the 1940s, has seen significant growth, particularly over past decade. eventual widespread clinical adoption this non-invasive modality require continued progress, a multitude activities including technical, pre-clinical, and research, regulatory approval reimbursement, manufacturer other commercial public sector investments into field, all within multi-stakeholder environment. We present here snapshot ultrasound describe...
In the ongoing endeavor of fine-tuning, clinical application transcranial MR-guided focused ultrasound (tcMRgFUS), ex-vivo studies wlkiith whole human skulls are great use in improving underlying technology guiding accurate and precise thermal ablation clinically relevant targets skull. Described here designs, methods for fabrication, notes on utility three different phantoms to be used brain research.Three models developed tested accurate, repeatable experimental options provide means...
This paper will focus on the development of second generation Sonic Window prototype, which occupy a package size deck cards and be capable forming C-mode ultrasound images in real-time. An array 3,600 full receive channels—consisting protection circuitry, preamplifier, tuneable bandpass filter, sampler bank, 8-bit ADC—is formed by flip-chip attaching twelve identical 300-channel custom ICs onto double-layer flex circuit substrate. The channel pitch is 200 µm x 275 entire circuitry has form...
During focused ultrasound ablation (FUSA), the presumed stereotactic target is tested with subthreshold sonications before permanent ablation. This testing relies on ultrasound-induced reversible clinical effects (thermal neuromodulation, TN). However, thermal dose and spot size thresholds to induce TN are not yet defined.To define associated TN.We performed a retrospective analysis of intraoperative FUSA data essential tremor patients. Sonications less than 25 cumulative equivalent minutes...
The objectives of this study were to determine long-term patient-reported outcomes with magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for medication-refractory essential tremor (ET) and identify risk factors a poor clinical outcome.We administered telephone or mail-in survey patients who consecutively underwent unilateral MRgFUS ET at our institution over an 8-year period. Patients asked self-report measures hand improvement, degree overall postprocedure activities daily...
Transcranial high-intensity focused ultrasound is used in clinics for treating essential tremor (ET) and proposed many other brain disorders. This promising treatment modality requires high energy resulting eventually undesired cavitation potential side effects. The goals of the present work were: 1) to evaluate increase threshold using pseudorandom gated sonications 2) assess heating capabilities with such sonications. experiments were performed transcranial magnetic resonance...
Preliminary results relating to the design, fabrication, and characterization of a 60 x (3600) element (fully sampled) 5 MHz 2D array are presented here. Our earlier used 32 (1024) elements 3.3 resonant frequency enabled approximately 0.5 mm resolution images. The 'live' yield was estimated at 98.3% by recording impedance 169 regularly spaced in array. Pulse-echo experiments indicated that system operating 4.2 - 9% below anticipated determined Finite Element Analysis (FEA) simulation. A...
Patients treated with deep brain stimulation (DBS) often develop symptom progression. If safe, focused ultrasound (FUS) lesioning could be used for patients unable to undergo further DBS surgery.To test the feasibility and safety of MR-guided FUS surgery in setting a previously implanted system.Three preclinical experiments were designed safety. Hydrogels an electrode, lesions targeted adjacently. Cadavers thalamic contralateral thalamus. Finally, systems swine, was thalamus, MRI assess...
A capacitive micromachined ultrasound transducer (CMUT) capable of selectable-frequency operation through membrane stand-off-controlled collapse-mode is presented using verified finite element analysis models. One method for fabricating stand-off structures presented. Finite (FEA) simulations were with respect to a CMUT fabricated at the University Virginia Microfabrication Laboratory (UVML) correlation coefficient 0.92 and an amplitude error 4.1% when comparing time-domain pressure output...
Presented here are the results of a volumetric, thermal treatment envelope map for transcranial focused ultrasound. The aim was to determine treatable volume intracranial cavity in order identify potential clinical applications and direct future research efforts. It determined that thalamic targets optimal both transcranical MRg-FUS systems used this work, which operate at 220 kHz 650 kHz, respectively. is hoped efforts will focus on expanding these envelopes expand possible neurosurgical technology.
The potential improvement in sonication efficiency achieved by tilting the focused ultrasound (FUS) transducer of transcranial MR-guided FUS system is presented. A total 56 cases patient treatment data were used. relative position clinical to patient's head was reconstructed, and region-specific skull density porosity calculated based on CT volume image. transmission coefficient acoustic waves emitted from each channel calculated. Then, energy penetrating human skull-which represents...
Medical Ultrasound Imaging is widely used clinically because of its relatively low cost, portability, lack ionizing radiation, and real-time nature. However, even with these advantages ultrasound has failed to permeate the broad array clinical applications where use could be value. A prime example this untapped potential routine guide intravenous access. In particular application existing systems required ease-of-use for widespread acceptance. Our team been working a number years develop an...
In the context of our on-going investigation low-cost two-dimensional (2D) arrays, we studied temperature-dependent acoustic properties epoxy blends that could serve as a component in lossy backing for compact 2D transducer array. The impedance and attenuation five - ranging from "soft" (low T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> ) to "hard" (high were analyzed across 35degC temperature range. Fiberglass- tungsten-filled...
Preliminary results relating to the design, fabrication, and characterization of a 3600 (60 x 60) element, fully sampled, 5 MHz two dimensional (2D) array are presented. The viable element yield new was estimated at 98.3%. Single-element pulse-echo experiments indicate that center frequency is 4.7 - 7.8% below resonant determined by Finite Element Analysis (FEA) simulation. Pulse-echo signal fractional bandwidth measured be 60.3% -6 dB level. Ringdown longer than anticipated in experimental...