Projects

The Ultrasound Research Center is pleased to announce the recipients of the 2017 Pilot Grants Supporting Novel Directions in Ultrasound Research.

Characterization of Carotid Plaque Vulnerability With Shear Wave Elastography and Contrast-Enhanced Ultrasound

Investigative team

Matthew W. Urban, Ph.D.; Patricia A. Pellikka, M.D.; Thanila A. Macedo, M.D.

Central hypothesis

The investigative team is studying patients with significant carotid plaques and patients undergoing endarterectomy. The goal of the project is to establish how parameters derived from different ultrasound modalities correlate with histology, vulnerability of atherosclerotic plaques and adverse cardiovascular events.

The investigative team uses ultrasound-based shear wave elastography (SWE) methods to measure plaque stiffness and carotid contrast-enhanced ultrasound (CEUS) to evaluate intraplaque neovascularization. Combining SWE and CEUS imaging methods along with regular B-mode ultrasound characteristics may improve recognition of plaque vulnerability.

Potential outcomes and advances

Stroke is a debilitating and fatal condition that is often caused by embolic blockage of blood vessels in the brain. Traditionally, the degree of narrowing (stenosis) in the carotid artery has been used to stratify patient risk and guide therapy. However, carotid stenosis accounts for only 10 to 20 percent of strokes and transient ischemic attacks.

The emerging imaging techniques used in this study, which allow for characterization of plaque vulnerability, hold promise for improved identification of patients who are at risk of stroke.

Evaluation of Crohn's Disease Using Ultrasound Microvessel Imaging

Investigative team

Shigao Chen, Ph.D.; David H. Bruining, M.D.; John M. Knudsen, M.D.

Central hypothesis

In a pilot study, the investigative team used a new ultrasound technology, VesselQuest, to measure microvessel density and correlate it with inflammation in Crohn's disease, without using microbubble contrast agents.

In this project, the team is using Food and Drug Administration-approved microbubbles for super-resolution (less than 50 µm) ultrasound imaging of the small bowel for more accurate and sensitive evaluation of Crohn's disease.

Superresolution ultrasound images of patients with Crohn's disease are obtained at baseline, at four weeks and at six months after initiation of new medical therapy. Results will be compared to contrast-enhanced MRI obtained at six months (the reference standard) to investigate the efficacy of ultrasound for early prediction of treatment response.

Potential outcomes and advances

Crohn's disease is a chronic inflammatory bowel condition that affects over 1 million people in the U.S., costing billions of dollars every year. Due to the relapsing nature of the disease, frequent imaging follow-ups are often necessary. Ultrasound is safe, cost-effective and widely accessible, and thus provides an attractive alternative to CT and MRI for Crohn's disease imaging.

Successful completion of this project will lead to a noninvasive, safe, economical and widely available technology for grading and frequently following up on inflammation associated with Crohn's disease.

Sex Disparities in Arthrogenic Muscle Inhibition Following ACL Injury

Investigative team

Timothy Hewett, Ph.D.; Michael J. Stuart, M.D.; Shigao Chen, Ph.D.; Kristin D. Zhao, Ph.D.

Central hypothesis

The investigative team is utilizing simple, noninvasive tools to provide an accurate objective measure of atrophy of the musculature surrounding the knee (arthrogenic muscle inhibition, or AMI) after injury or re-injury of the anterior cruciate ligament (ACL).

A major knowledge gap in the understanding of AMI is the characterization of the knee musculature neuromotor activation in vivo and its resultant muscle stiffness, especially following injury. This project addresses the critical need to develop an objective, reproducible and reliable measure of neuromotor activation — which is directly correlated with AMI — and neuromuscular-elicited muscle stiffness for both injury prevention and rehabilitation.

Potential outcomes and advances

ACL injuries and re-injuries occur significantly more often in female athletes than in their male counterparts. This injury rate disparity may be due to differences in joint stabilization strategies between sexes. After ACL injury and throughout rehabilitation, AMI is a ubiquitous impairment that limits athlete progression to return to sport.

Results from this study will allow researchers to develop improved prevention and rehabilitation strategies via novel use of shear wave elastography ultrasound to measure passive and active muscle stiffness. This advance will immediately improve patient care through early diagnosis and prevention criteria, sex-specific prescription of effective neuromuscular intervention, individualized therapy, and improved assessment of post-surgery therapeutic outcomes.

Use of Intraoperative Shear Wave Ultrasound Vibrometry for Characterization of Esophageal Malignant Tumors

Investigative team

Dennis Wigle, M.D., Ph.D.; Matthew W. Urban, Ph.D.

Central hypothesis

Malignant tissues in a variety of organ systems are stiffer than their nonmalignant counterparts. In this study, the investigative team is exploring the use of mechanical properties of the tissue as biomarkers for cancerous tissue.

The team employs ultrasound-based shear wave elastopraphy, implemented on a clinical scanner, to measure the mechanical properties of the esophagus intraoperatively in patients undergoing esophageal resection. The team performs post-surgical histological analysis of the excised tissues and compares results with the ultrasound-based measurements to understand the relationships between mechanical properties and histologically confirmed tumor extent.

Potential outcomes and advances

Currently, determining the optimal surgical resection margin for esophageal cancer is difficult and is based on distance from gross tumor alone, likely leading to increased resection length and, consequently, more-complicated reconstruction. This project will establish the utility of shear wave-based measurements of mechanical properties for the differentiation of esophageal cancer from normal esophagus in a relevant surgical population.

Utilizing Bone Ultrasound to Assess Forearm Fracture Healing in Children

Investigative team

Todd A. Milbrandt, M.D.; A. Noelle Larson, M.D.; Mostafa Fatemi, Ph.D.; Azra Alizad, M.D.

Central hypothesis

The goal of the project is to use a novel resonance ultrasound technique — which is noninvasive, in real time and low cost — to perform a quantitative assessment of fracture healing in children and to critically evaluate the traditional period of immobilization.

Possible outcomes and advances: Fractures are a common occurrence in childhood, with up to one-third of all people in the U.S. sustaining a broken bone. Fracture treatment in children usually entails simple methods of reduction and stabilization via cast immobilization. Fracture healing is traditionally assessed by pain at the fracture site (physical examination) and bony callus formation (radiographic evidence of healing) — both qualitative measures.

The six-week period of immobilization that is usually chosen is based on tradition, not any objective measurement of stability. The investigative team's novel resonance ultrasound technique may allow researchers to quantify the biomechanical properties of a healing fracture, thus improving the accuracy of healing measurement and immobilization time.