Russell S Witte

University of Arizona | UA · Department of Radiology

Objective/Background: Although functional magnetic resonance imaging (fMRI) and scalp electroencephalography (EEG) are powerful tools to study the human brain and behavior for many clinical and research applications, they are limited in both resolution and accuracy. Transcranial Acoustoelectric Brain Imaging (tABI) is a new modality that combines f...

Significance Changes in lipid, water, and collagen (LWC) content in tissue are associated with numerous medical abnormalities (cancer, atherosclerosis, and Alzheimer’s disease). Standard imaging modalities are limited in resolution, specificity, and/or penetration for quantifying these changes. Short-wave infrared (SWIR) photoacoustic imaging (PAI)...

Acoustoelectric imaging (AEI) is a technique that combines ultrasound with radiofrequency recording to detect and map local current source densities. This study demonstrates a new method called Acoustoelectric Time Reversal (AETR), which uses AEI of a small current source to correct for phase aberrations through a skull or other ultrasound-aberrati...

Acoustoelectric Imaging (AEI) is a disruptive technology that exploits an ultrasound (US) beam to transiently interact with physiologic or artificial currents, producing a radiofrequency signature detected by one or more surface electrodes. By rapidly sweeping the US beam and simultaneously detecting the acoustoelectric modulations, 4D current dens...

Acoustoelectric (AE) imaging can potentially image biological currents at high spatial (~mm) and temporal (~ms) resolution. However, it does not directly map the current field distribution due to signal modulation by the acoustic field and electric lead fields. Here we present a new method for current source density (CSD) imaging. The fundamental A...

Injuries caused by surgical incisions or traumatic lacerations compromise the structural and functional integrity of skin. Immediate approximation and robust repair of skin are critical to minimize occurrences of dehiscence and infection that can lead to impaired healing and further complication. Light‐activated skin sealing has emerged as an alter...

Acoustoelectric cardiac imaging (ACI) is a hybrid modality that exploits the interaction of an ultrasonic pressure wave and the resistivity of tissue to map current densities in the heart. This study demonstrates for the first time in vivo ACI in a swine model. ACI measured beat-to-beat variability ( ${{n}} = {{20}}$ n = 20 ) of the peak of the car...

Noninvasive thermal therapies for treatment of breast cancer depend on accurate monitoring of tissue temperature to optimize treatment and ensure safety. This work describes a real-time system for 3D thermoacoustic imaging and thermometry (TAI-TAT) for tracking temperature in tissue samples during heating. The study combines a 2.7 GHz microwave pul...

Thermoacoustic (TA) imaging is a modality where pulsed microwaves are used to generate ultrasound waves in tissue, which are highly correlated with temperature. This study uses a self-calibration approach to improve the estimation of temperature using 3D real-time TA thermometry in porcine tissue during localized heating. The self-calibration metho...

Objective: New innovations in deep brain stimulation (DBS) enable directional current steering - allowing more precise electrical stimulation of the targeted brain structures for Parkinson's disease, essential tremor and other neurological disorders. While intra-operative navigation through MRI or CT approaches millimeter accuracy for placing the...

Improvised explosive devices (IEDs) have always been a major threat to personnel safety with continuous evolutions and new variants. Traditional methods for detecting IEDs, such as X-ray, have some drawbacks, so safe and efficient new detection techniques are highly desired. Microwave-induced thermoacoustic imaging (MITAI), being widely investigate...

Acoustoelectric (AE) effect is a basic physical interaction that focused ultrasound that alters the resistivity at the focal spot. Exploiting the AE effect, noninvasive AE imaging (nAEI) of resistivity distribution is investigated based on lead field theory. According to lead field theory, measured AE signal is of good spatial position property, wh...

This review describes emerging techniques within the last 5 years that employ ultrasound for detecting and staging malignancy, tracking metastasis, and guiding treatment. Ultrasound elastography quantifies soft tissue elastic properties that change as a tumor grows and proliferates. Hybrid imaging modalities that combine ultrasound with light or mi...

We describe a new application of acoustoelectric imaging for non-invasive mapping of the location, magnitude and polarity of current generated by a clinical deep brain stimulation (DBS) device. Ultrasound at 1 MHz was focused near the DBS device as short current pulses were injected across different DBS leads. A recording electrode detected the hig...

Introduction: In the United States, one in three deaths is attributed to cardiovascular disease (CVD). With CVD, sudden cardiac death is a common cause of mortality, specifically by way of ventricular tachycardia (VT) and ventricular fibrillation. We propose the application of our custom software to evaluate the electrophysiologic (EP) properties o...

The acoustoelectric (AE) effect is a basic physical phenomenon, which underlies the changes made in the conductivity of a medium by the application of focused ultrasound. Recently, based on the AE effect, several biomedical imaging techniques have been widely studied, such as ultrasound-modulated electrical impedance tomography and ultrasound curre...

Estrogen receptor positive (ER+) breast cancer patients undergoing treatment with aromatase inhibitors (AI) tend to discontinue the supplement when to painful side effects appear. It is believed that women with AI-induced musculoskeletal syndrome (AIMSS) have specific physiological conditions that differentiate them from women with normal aging-rel...

Ultrasound modulated electrical impedance tomography (UMEIT) is a novel hybrid imaging technique, which utilizes coupling between electric and acoustic modalities. Based on the forward solver along different current directions, an instrumental electrode configuration is proposed for 3D UMEIT. The proposed electrode configuration can produce a simil...

In the past 2 decades, sonoelastography has been progressively used as a tool to help evaluate soft-tissue elasticity and add to information obtained with conventional gray-scale and Doppler ultrasonographic techniques. Recently introduced on clinical scanners, shear-wave elastography (SWE) is considered to be more objective, quantitative, and repr...

This work describes the viscoelastic behavior of a tendon. In this paper we develop a mathematical model of the Posterior Tibial Tendon (PTT) for assisting in the prognosis of tendinopathy. The mathematical model is derived from a generalized Maxwell model for viscoelastic materials. To validate the model, a strain is asserted and the associated st...

We present a novel two-dimensional (2D) MAET scanner, with a rotating object of interest and two fixed pairs of electrodes. Such an acquisition scheme, with our novel reconstruction techniques, recovers the boundaries of the regions of constant conductivity uniformly well, regardless of their orientation. We also present a general image reconstruct...

Although the drug-eluting stent (DES) has dramatically reduced the rate of coronary restenosis, it still occurs in up to 20% of patients with a DES. Monitoring drug delivery could be one way to decrease restenosis rates. We demonstrate real-time photoacoustic imaging and spectroscopy (PAIS) using a wavelength-tunable visible laser and clinical ultr...

We have found that folate-targeted, ultrasound-activated phase-change contrast agents (PCCAs) composed of volatile perfluorocarbons are able to bind and internalize within breast cancer cells prior to vaporization into intracellular microbubbles. We here report studies assessing internalization, stability to thermal activation, and ultrasound activ...

Breast cancer is a diverse and complex disease that remains one of the leading causes of death among women. Novel, outside-of-the-box imaging and treatment methods are needed to supplement currently available technologies. In this study, we present evidence for the intracellular delivery and ultrasound-stimulated activation of folate receptor (FR)-...

Objective: The objective of this study was to define the clinical relevance of in-vivo electrophysiologic (EP) studies in a rat model of chronic ischemic heart failure (CHF). Methods: Electrical activation sequences, voltage amplitudes, and monophasic action potentials (MAPs) were recorded from adult male Sprague-Dawley rats six weeks after left...

Ultrasound elasticity imaging (UEI) is a noninvasive method for characterizing mechanical properties of soft tissue. This technique potentially provides important feedback for making treatment decision for advanced tendinopathies, such as posterior tibial tendon dysfunction (PTTD). Highly variable lateral strain along the length of the tendon has b...

Introduction: We have developed a computer user interface able to provide prescribed programmed electrical stimulation (PES) to induce sustained-ventricular tachycardia (VT) in rats with chronic heart failure (CHF). We propose this program to examine the cardiac electrophysiology (EP) properties and arrhythmogenic potential in varying disease model...

Accurate 3-D mapping of multiple bioelectric sources in nerve fibers with high spatial resolution is challenging for the diagnosis and treatment of a variety of neural abnormalities. Ultrasound current source density imaging exploits the acoustoelectric (AE) effect, an interaction between electrical current and acoustic pressure waves propagating t...

We characterized the thermoacoustic and photoacoustic properties of large-area, few-layer gra-phene by pulsed microwave and optical excitations. Due to its high electric conductivity and low heat capacity per unit area, graphene lends itself to excellent microwave and optical energy absorption and acoustic signal emanation due to the thermoacoustic...

We characterized the thermoacoustic and photoacoustic properties of large-area, few-layer graphene by pulsed microwave and optical excitations. Due to its high electric conductivity and low heat capacity per unit area, graphene lends itself to excellent microwave and optical energy absorption and acoustic signal emanation due to the thermoacoustice...

INTRODUCTION: Posterior tibial tendon dysfunction (PTTD) is a common (affecting 3.3% of women over the age of 40) and debilitating tendinopathy that can lead to a profound decrease in walking ability. It has classically been treated with surgery using tendon transfer to restore inversion power and osteotomies to reconstruct the arch and restore ali...

Purpose Electronic brachytherapy (eBT) has gained acceptance over the past 5 years for the treatment of non-melanomatous skin cancer (NMSC). Although the prescription depth and radial margins can be chosen using clinical judgment based on visual and biopsy-derived information, we sought a more objective modality of measurement for eBT planning by u...

Microwave-induced thermoacoustic imaging (TAI) has been actively researched in the past decade and shown to be a promising non-ionizing technology for various applications, such as breast cancer imaging, brain imaging, renal calculi detection, and foreign body detection. TAI develops an image exhibiting internal structures of a lossy sample by expl...

As a hybrid mechanism integrating the advantages of microwave imaging and ultrasound imaging, such as non-ionizing radiation, high dielectric contrast and excellent spatial resolution, microwave-induced thermoacoustic imaging (TAI) holds promise for breast cancer detection (R. A. Kruger et al, Radiology, 216, 279–283, 2000).

Carbon nanotubes have attracted interest as contrast agents for biomedical imaging because they strongly absorb electromagnetic radiation in the optical and microwave regions. This study applies thermoacoustic (TA) imaging and spectroscopy to measure the frequency-dependent absorption profile of single-walled carbon nanotubes (SWNT) in the ranges o...

Diagnostic ultrasound techniques used in the evaluation of the musculoskeletal system are rapidly evolving. Conventional B-mode and Doppler ultrasound imaging methods are workhorses in the diagnosis and treatment decision making for traumatic and pathologic conditions of joints, tendons, muscles, ligaments, and peripheral nerves. Recently developed...

Thermoacoustic imaging (TAI) has been shown to be promising for breast cancer detection. Contrast-enhanced TAI (CETAI) applying exogenous contrast agents can enhance the contrast in the dielectric properties between the tumor and its surrounding tissues. Combining compressive sensing (CS) and CETAI can make the measurements much more time-efficient...

Thermoacoustic imaging (TAI) is a non-ionizing, high-contrast and high-resolution modality for biomedical applications. The resolution of the reconstructed image by traditional imaging algorithm, such as back-projection (BP), is dependent on the input microwave pulse width. In this work, it is experimentally demonstrated that the quality of images...

Owing to its intrinsic advantages of favorable contrast and spatial resolution, microwave-induced thermoacoustic imaging (TAI) has drawn great attention in biomedical imaging applications, such as breast cancer detection. Many experimental studies have demonstrated the promising potential of TAI. Several TAI modeling studies have also been publishe...

Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with...

Devices are disclosed for obtaining data of a sample, particularly data capable of being processed to produce an image of a region of the sample. An exemplary device includes a light-beam source, an acoustic-wave source, an optical element, and an acoustic detector. The optical element is transmissive to a light beam produced by the light-beam sour...

Microwave-induced thermoacoustic imaging (TAI) has been actively researched in the past decade and shown to be a promising non-ionizing technology for breast cancer detection [1, 2]. TAI develops an image indicative of the internal structures of a biological sample by exploiting emanated acoustic waves from absorbed microwave energy in the sample d...

Ultrasound current source density imaging (UCSDI) is a noninvasive method for mapping electrical current based on the acoustoelectric (AE) effect. This technique can potentially overcome the limitations (i.e. poor resolution, inaccurate anatomical registration) of the conventional electrical mapping procedures typically used during treatment of sus...

Microwave-induced thermoacoustic imaging (TAI), which exploits the high resolution of ultrasound imaging and high contrast of microwave imaging, is an emerging modality in medicine. Traditional TAI employs a relatively narrow-band ultrasound transducer to detect TA signals, which requires acoustic coupling and physical contact between the transduce...

Ultrasound current source density imaging (UCSDI), based on the acoustoelectric (AE) effect, is a noninvasive method for mapping electrical current in 4D (space + time). This technique potentially overcomes limitations with conventional electrical mapping procedures typically used during treatment of sustained arrhythmias. However, the weak AE sign...

Thermoacoustic imaging (TAI) is an emerging promising hybrid modality for biomedical imaging. High spatial resolution of TAI is conventionally accomplished by utilizing a short exciting microwave pulse, but squeezing the microwave pulse simultaneously degrades the signal-to-noise ratio (SNR) of the thermoacoustic image. There is usually a tradeoff...

Ultrasound current source density imaging (UCSDI), which has application to the heart and brain, exploits the acoustoelectric (AE) effect and Ohm���s law to detect and map an electrical current distribution. In this study, we describe 4-D UCSDI simulations of a dipole field for comparison and validation with bench-top experiments. The simulations c...

During the past 2 decades, high-resolution ultrasonography (US) has been increasingly utilized in the diagnosis of musculoskeletal trauma and diseases with results comparable with MR imaging. US has an advantage over other cross-sectional modalities in many circumstances due to its superior spatial resolution and ability to allow dynamic assessment...

Background Varying strategies are currently being evaluated to develop tissue-engineered constructs for the treatment of ischemic heart disease. This study examines an angiogenic and biodegradable cardiac construct seeded with neonatal cardiomyocytes for the treatment of chronic heart failure (CHF). Methods We evaluated a neonatal cardiomyocyte (N...