Publications by authors named "Emad Ebbini"
Image-Guided Measurement of Radiation Force Induced by Focused Ultrasound Beams.
IEEE Trans Ultrason Ferroelectr Freq Control
February 2023
Article Synopsis
- The radiation force balance (RFB) method is effective for measuring the acoustic power of ultrasonic transducers but relies on precise alignment between the ultrasound beam and a reflecting cone, particularly critical for focused therapeutic applications.
- The introduction of dual-mode ultrasound arrays (DMUAs) allows for image-guided measurements that enhance alignment and can track cone displacement, thus improving power measurement accuracy.
- Experimental findings show that even slight misalignments can significantly contribute to measurement errors, and real-time tracking of displacement offers a more sensitive and reliable approach for assessing acoustic radiation force, potentially improving dosimetry in focused ultrasound therapies.
Introduction: Peripheral arterial disease (PAD) is an atherosclerotic disease leading to stenosis and/or occlusion of the arterial circulation of the lower extremities. The currently available revascularisation methods have an acceptable initial success rate, but the long-term patency is limited, while surgical revascularisation is associated with a relatively high perioperative risk. This urges the need for development of less invasive and more effective treatment modalities.
View Article and Find Full Text PDFSpatio-Spectral Ultrasound Characterization of Reflection and Transmission Through Bone With Temperature Dependence.
IEEE Trans Ultrason Ferroelectr Freq Control
May 2022
Article Synopsis
- Transcranial focused ultrasound (tFUS) shows potential for treating neurological disorders, with advances in neuromodulation and ablative applications, including epilepsy.
- Modern technologies, like advanced transducers, enhance the effectiveness of tFUS by maximizing the use of the temporal window in the skull, improving safety and targeting within the brain.
- Research demonstrated that various factors, such as temperature and frequency, significantly impact the reflection and transmission of ultrasound through human skull samples, indicating a complex relationship that must be considered for treatment efficacy.
Article Synopsis
- Carotid bodies are chemoreceptors that help regulate breathing by monitoring blood oxygen, carbon dioxide, and pH levels, and their increased activity is linked to high blood pressure.
- Researchers used a dual-mode ultrasound array system to safely ablate the carotid bodies in spontaneously hypertensive rats, utilizing advanced imaging techniques for precise targeting and monitoring of the treatment.
- The study found that targeting the carotid bodies with focused ultrasound could potentially lower blood pressure, indicating the need for further research in larger animal models and clinical trials in humans.
The Optimization of Transcostal Phased Array Refocusing Using the Semidefinite Relaxation Method.
IEEE Trans Ultrason Ferroelectr Freq Control
February 2020
Tumors in organs partially obscured by the rib cage represent a challenge for high-intensity focused ultrasound (HIFU) therapy. The ribs distort the HIFU beams in a manner that reduces the focusing gain at the target, which could result in treatment-limiting collateral damage. In fact, skin burns are a common complication during the ablation of hepatic tumors.
View Article and Find Full Text PDFBackground: Transcranial focused ultrasound (tFUS) at low intensities has been reported to directly evoke responses and reversibly inhibit function in the central nervous system. While some doubt has been cast on the ability of ultrasound to directly evoke neuronal responses, spatially-restricted transcranial ultrasound has demonstrated consistent, inhibitory effects, but the underlying mechanism of reversible suppression in the central nervous system is not well understood.
Objective/hypothesis: In this study, we sought to characterize the effect of transcranial, low-intensity, focused ultrasound on the thalamus during somatosensory evoked potentials (SSEP) and investigate the mechanism by modulating the parameters of ultrasound.
Nonlinear Imaging of Microbubble Contrast Agent Using the Volterra Filter: In Vivo Results.
IEEE Trans Ultrason Ferroelectr Freq Control
December 2016
Article Synopsis
- A nonlinear filtering method using an adaptive third-order Volterra filter (TVF) effectively images microbubble ultrasound contrast agents (UCAs) in microvessels by separating linear and nonlinear data components.
- The study demonstrates enhanced contrast-to-tissue ratio (CTR) in imaging by utilizing broadband transmission, particularly through QB-mode and CB-mode, outperforming traditional B-mode and pulse inversion techniques.
- In vivo imaging of UCA activity in LNCaP tumors confirmed the effectiveness of TVF, with results showing consistent improvements in echogenicity measurements under varying perfusion conditions.
In Vivo application and localization of transcranial focused ultrasound using dual-mode ultrasound arrays.
IEEE Trans Ultrason Ferroelectr Freq Control
December 2015
Article Synopsis
- Focused ultrasound (FUS) is being researched for various brain applications, including neuromodulation and tumor ablation, with promising results showing its feasibility.
- Recent developments in real-time dual-mode ultrasound array (DMUA) systems provide improved monitoring and imaging for transcranial FUS applications in animal studies.
- Experimental results demonstrate the effectiveness of DMUA in localizing treatment areas, monitoring interactions, and applying subtherapeutic FUS patterns to potentially open the blood-brain barrier.
Article Synopsis
- The study aimed to simulate the effects of high intensity focused ultrasound (HIFU) on atherosclerotic plaques in a non-uniform tissue environment.
- A finite-difference time-domain model was developed using ultrasound images, and two cases of HIFU application on plaque tissue were analyzed.
- The simulation successfully predicted thermal damage patterns in the targeted area and validated the results with histology data, indicating the model's effectiveness in predicting HIFU damage in vivo.
Ultrasound-guided therapeutic focused ultrasound: current status and future directions.
Int J Hyperthermia
March 2015
Article Synopsis
- The paper reviews ultrasound imaging techniques for guiding therapeutic focused ultrasound, focusing on real-time preclinical applications.
- It covers historical methods of monitoring tissue interactions and discusses current imaging techniques' effectiveness for localizing treatment effects.
- The document concludes with insights into the clinical potential of these methods and assesses their feasibility for real-time use.
In vivo ultrasound thermography in presence of temperature heterogeneity and natural motions.
IEEE Trans Biomed Eng
February 2015
Article Synopsis
- Real-time ultrasound thermography is enhanced by a new model for temperature estimation that uses a recursive axial filter, offering improved accuracy over previous methods.
- Experimental results indicate that this new approach effectively suppresses spatial variations in temperature estimates during focused ultrasound treatments, outperforming the traditional infinitesimal echo strain filter (δ-ESF).
- The study also introduces an adaptive spatial filter to correct motion artifacts during data collection, showcasing the potential for sensitive and specific in vivo ultrasound thermography applications.
Objective: To investigate the feasibility of using high-intensity focused ultrasound (HIFU), under dual-mode ultrasound arrays (DMUAs) guidance, to induce localized thermal damage inside ovaries without damage to the ovarian surface.
Design: Laboratory feasibility study.
Setting: University-based laboratory.
Article Synopsis
- The study aimed to assess the safety and feasibility of using high-intensity-focused ultrasound (US) to target atherosclerotic plaques noninvasively in swine.
- All swine tolerated the procedure without serious complications, and various types of lesions were created, showing signs of necrosis and inflammation while keeping the arterial lining intact.
- The findings suggest that targeting atherosclerotic plaques with high-intensity-focused US is safe, but further long-term research is needed to understand its effects on plaque progression.
Real-time implementation of a dual-mode ultrasound array system: in vivo results.
IEEE Trans Biomed Eng
October 2013
A real-time dual-mode ultrasound array (DMUA) system for imaging and therapy is described. The system utilizes a concave (40-mm radius of curvature) 3.5 MHz, 32 element array, and modular multichannel transmitter/receiver.
View Article and Find Full Text PDFRealtime control of multiple-focus phased array heating patterns based on noninvasive ultrasound thermography.
IEEE Trans Biomed Eng
January 2012
Article Synopsis
- The presented system facilitates real-time generation and control of ultrasound heating patterns using a 1-MHz, 64-element phased-array system.
- It integrates advanced driving electronics with a 2-D temperature imaging system to enable precise temperature control at specific coordinates defined on guidance images.
- In vitro experiments confirm the system's effectiveness in dynamically adjusting power and improving temperature stability during high-intensity ultrasound exposures.
Monitoring and guidance of HIFU beams with dual-mode ultrasound arrays.
Annu Int Conf IEEE Eng Med Biol Soc
April 2010
Article Synopsis
- The experimental results highlight the effectiveness of dual-mode array (DMUA) systems in enhancing monitoring and guidance for high intensity focused ultrasound (HIFU) lesion formation.
- DMUAs allow simultaneous imaging and therapy, utilizing the same transducer to provide critical feedback for refocusing, temperature changes, and tissue response during treatment.
- The findings indicate that DMUA feedback is accurate and has a high resolution, making it suitable for identifying important structures like ribs and blood vessels during HIFU procedures.
Real-time two-dimensional temperature imaging using ultrasound.
Annu Int Conf IEEE Eng Med Biol Soc
April 2010
Article Synopsis
- A new system has been developed to provide real-time 2D imaging of temperature changes in tissue using pulse-echo ultrasound.
- The setup uses a SonixRP ultrasound scanner to control the ultrasound beams and access real-time radio frequency (RF) data.
- The processed temperature data is displayed instantly, enabling immediate feedback for controlling heating sources, with successful tests showing high accuracy in tissue mimicking phantoms and porcine heart tissue.
A 2D post-beamforming filter for contrast restoration in medical ultrasound: in vivo results.
Annu Int Conf IEEE Eng Med Biol Soc
April 2010
Article Synopsis
- Recently developed a 2D post-beamforming filter that enhances contrast in ultrasound using high frequency ultrasound arrays with coarse sampling.
- The filter works by transforming the problem into k-space and applying a regularized 2D pseudoinverse, allowing for efficient processing compared to traditional matrix operations.
- Initial tests show that this filter successfully improves tissue/blood contrast by 4 dB in real imaging of the carotid artery, which could enhance future applications in tissue and blood displacement tracking.
Monitoring and guidance of minimally-invasive thermal therapy using diagnostic ultrasound.
Annu Int Conf IEEE Eng Med Biol Soc
April 2010
Article Synopsis
- Specialized ultrasound imaging modes can monitor and guide noninvasive and minimally-invasive thermal therapies.
- One method utilizes two-dimensional imaging to track temperature changes during treatments like HIFU and RF ablation, validated through various tests.
- The development of advanced imaging techniques enables real-time monitoring, enhancing the precision and effectiveness of thermal therapies with high spatial and temporal resolutions.
Article Synopsis
- Researchers have developed noninvasive ultrasound methods for real-time temperature change estimation, which have been validated in various settings but face adoption challenges in clinical applications like RF ablation and HIFU.
- The new system uses a commercial ultrasound scanner with a special research interface, employing a high-frame-rate method (M2D) to capture tissue response during pulsed HIFU treatments.
- Initial results indicate that the real-time temperature imaging algorithm is accurate and effective in visualizing tissue changes during HIFU, showcasing its potential for enhancing minimally invasive thermal therapies.
A post-beamforming 2-D pseudoinverse filter for coarsely sampled ultrasound arrays.
IEEE Trans Ultrason Ferroelectr Freq Control
September 2009
Article Synopsis
- Coarse discretization of imaging apertures limits the effectiveness of high-frequency array probes, as adhering to Nyquist sampling is challenging with current technology, particularly in the 25-35 MHz range.
- A new design approach for 2-D regularized pseudoinverse filters is proposed to enhance imaging contrast in systems with coarse sampling, utilizing a discretized 2-D imaging model based on Cartesian grid scattering.
- The method utilizes a computationally efficient transformation to derive the filtering equation and presents simulation data that demonstrates the effects of regularization on the point-spread functions (PSFs), illustrating the balance between imaging contrast and spatial resolution.