A5066478724- Ultrasound and Hyperthermia Applications
- Ultrasound Imaging and Elastography
- Photoacoustic and Ultrasonic Imaging
- Advanced MRI Techniques and Applications
- Ultrasonics and Acoustic Wave Propagation
- Soft Robotics and Applications
- MRI in cancer diagnosis
- Astrophysics and Star Formation Studies
- Advanced Radiotherapy Techniques
- Ultrasound in Clinical Applications
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Surgical Simulation and Training
- Advanced Neuroimaging Techniques and Applications
University of Utah
2016-2023
Advanced Imaging Research (United States)
2017
GE Global Research (United States)
2012-2014
General Electric (United States)
2014
Princeton University
2009
Abstract Purpose: To demonstrate a three‐echo fat‐referenced MR thermometry technique that estimates and corrects for time‐varying phase disturbances in heterogeneous tissues. Materials Methods: Fat protons do not exhibit temperature‐dependent frequency shift. Fat‐referenced methods exploit this insensitivity use the signal from fat to measure correct magnetic field disturbances. In study, we present method uses interpolation of free regions. Phantom ex vivo tissue cool‐down experiments were...
This paper presents and evaluates a breast-specific magnetic resonance guided focused ultrasound (MRgFUS) system. A first-in-human evaluation demonstrates the novel hardware, sophisticated tumor targeting algorithm volumetric imaging (MRI) protocol.
Purpose To develop and characterize a tissue-mimicking phantom that enables the direct comparison of magnetic resonance (MR) ultrasound (US) imaging techniques useful for monitoring high-intensity focused (HIFU) treatments. With no additions, gelatin phantoms produce little if any scattering required US imaging. This study characterizes MR image characteristics as function psyllium husk concentration, which was added to increase scattering.Methods Gelatin were constructed with varying...
Purpose A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) proton resonance frequency (PRF)‐shift thermometry has been developed tested. This could be an important tool evaluating the success of MR‐guided focused ultrasound procedures which MR‐thermometry measures temperature thermal dose MR‐ARFI detects changes in tissue mechanical properties. Methods was performed using a gradient recalled echo segmented echo‐planar pulse sequence with...
Magnetic resonance thermometry (MRT) is an attractive means to non-invasively monitor in vivo temperature during head and neck hyperthermia treatments because it can provide multi-dimensional information with high spatial resolution over large regions of interest. However, validation MRT measurements a clinical set-up crucial ensure the maps are accurate. Here we demonstrate unique approach for probe sensor localisation test phantoms.We characterise proton frequency shift coefficient...
Magnetic resonance thermometry (MRT) offers non-invasive temperature imaging and can greatly contribute to the effectiveness of head neck hyperthermia. We therefore wish redesign HYPERcollar hyperthermia applicator for simultaneous radio frequency (RF) heating magnetic thermometry. In this work we tested feasibility goal through an exploratory experiment, in which used a minimally modified prototype heat model phantom MR scanner measure its distribution. identified several distorting factors...
Combining the unmatched soft-tissue imaging capabilities of magnetic resonance (MRI) with high precision robotics has potential to improve accuracy, precision, and safety a wide range image-guided medical procedures. However, goal highly functional MRI-compatible robotic systems not yet been realized because conventional electromagnetic servomotors used by robots can become dangerous projectiles near strong field an MRI scanner. Here we report novel servomotor design that is constructed from...
Clinical studies have established a strong benefit from adjuvant mild hyperthermia (HT) to radio- and chemotherapy for many tumor sites, including the head neck (H&N). The recently developed HYPERcollar allows application of local radiofrequency HT tumors in entire H&N. Treatment quality is optimized using electromagnetic thermal simulators and, whenever placement risk tolerable, assessed invasively placed thermometers. To replace current invasive procedure, we are investigating whether...
The number of low-mass brown dwarfs and even free floating planetary-mass objects in young nearby star-forming (SF) regions associations is continuously increasing, offering the possibility to study end initial mass function greater detail. In this paper, we present six new candidates for (very) Taurus SF region one which was recently discovered parallel by Luhman et al. underlying data use part a database from deep near-infrared survey at Calar Alto observatory. more than 4 mag deeper Two...
Abstract Purpose To implement and evaluate an efficient multiple‐point MR acoustic radiation force imaging pulse sequence that can volumetrically measure tissue displacement stiffness using focused ultrasound (FUS) force. Methods Bipolar motion‐encoding gradients were added to a gradient‐recalled echo segmented EPI with both 2D 3D acquisition modes. Multiple FUS‐ON images (FUS power > 0 W) interleaved single FUS‐OFF image = on the TR level, enabling simultaneous measurements of volumetric...
Purpose To present a novel MR shear wave elastography (MR‐SWE) method that efficiently measures the speed of propagating packets generated using acoustic radiation force (ARF) impulses. Methods ARF impulses from focused ultrasound (FUS) transducer were applied sequentially to preselected set positions and motion encoded MRI was used acquire volumetric images wavefront emanating each point. The position at multiple propagation times in phase image train encoding gradient lobes. Generating...
Purpose To demonstrate that concomitant magnetic fields can cause significant spatially dependent biases in relaxometry measurements with implications for clinical applications such as BOLD and dynamic susceptibility contrast-enhanced MRI. Theory Methods After developing a theoretical framework intravoxel dephasing signal loss from fields, this the effect of on are validated phantom experiments numerical simulation. In lower leg renal mapping, we quantify measurement bias imaging protocols...
Abstract A magnetic resonance (MR) shear wave elastography technique that uses transient acoustic radiation force impulses from a focused ultrasound (FUS) transducer and sinusoidal-shaped MR displacement encoding strategy is presented. Using this strategy, an analytic expression for calculating the speed in heterogeneous medium was derived. Green’s function-based simulations were used to evaluate feasibility of maps using expression. Accuracy simulation confirmed experimentally homogeneous...
Purpose To develop an efficient MRI pulse sequence to simultaneously measure multiple parameters that have been shown correlate with tissue nonviability following thermal therapies. Methods A 3D segmented EPI was used proton resonance frequency shift (PRFS) MR thermometry (MRT), T 1 relaxation time, and shear wave velocity induced by focused ultrasound (FUS) push pulses. Experiments were performed in mimicking gelatin phantoms ex vivo bovine liver. Using a carefully designed FUS triggering...
Abstract Purpose To validate single reference variable flip angle (SR‐VFA) dynamic T 1 mapping with and without 2 * correction against inversion recovery (IR) measurements. Methods A custom cylindrical phantom three concentric compartments was filled variably doped agar to produce a smooth spatial gradient of the relaxation rate as function across each compartment. IR , VFA B + measurements were made on before rotation, multi‐echo stack‐of‐radial images acquired during rotation via an...