Acoustic droplet vaporization is the ultrasound-induced conversion of perfluorocarbon droplets into microbubbles. We are researching the use of this phenomenon in the induction of targeted occlusions in the vasculature of tumors. The goals are to enhance the efficacy of drug delivery and to "starve tumors to death" by cutting off their blood supply. We currently utilize the rat cremaster for intra-vital microscopy experiments and an ectopic hepatocellular carcinoma model in mice to test our proposed treatment.
Acoustic droplet vaporization-induced occlusion seen in the rat cremaster muscle.
Microbubble contrast agent seen in an ectopic tumor using B-mode ultrasound imaging.
Peripheral edema is a common problem in patients with chronic kidney disease or end stage renal disease. Current clinical practice is to grade the edema using a semi-quantitative scale of 1+ (mild) to 4+ (severe). The examination briefly consists of compressing a region of the edematous extremity with the thumb and observing the behavior of the indentation. The reliability of this test depends on clinician experience. We are investigating ultrasound-based methods for quantifying the mechanical properties of edematous tissue. Specifically, we are interested in model-based approaches to measure the effective Poisson's ratio of tissue.
Our model-based poroelastography reconstructions can produce quantitative maps of the tissue Poisson's ratio that are less sensitive to strain-estimation errors than standard methods.
In this project, we perform simulations on nitric-oxide (NO) releasing catheters that combat bacterial infection and thrombosis. Emphasis is placed on simulating the NO concentration profile near the surface of the catheter and the NO flux out of the catheter. The simulations will help inform the design of the catheter to have a safe level of NO release without sacrificing the clinical benefits.
Simulation of the NO concentration profile in a dual-lumen catheter.
Lung Comets (B-lines) are imaging artifacts seen in clinical lung ultrasound. Excess lung comets indicate the presence of pulmonary edema. We focus on developing automatic quantification methods for lung ultrasound comets that improve the consistency of counting by applying image processing and machine learning methods. An accurate and consistent quantification of the lung comets may be useful in quantifying lung edema and aiding diagnosis.
Computer identified ultrasound comets in a B-mode cine loop (right, red lines).