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New medical imaging technique

August 14, 2017

???Relative stiffness imaging could be an important diagnostic tool for such things as finding a tumor in soft tissue or detecting tissue damage from a heart attack,??? said Joyce McLaughlin, director of the Center for Inverse Problems and the Ford Foundation Professor of Mathematical Sciences at Rensselaer. ???Our goal is to create images depicting tissue stiffness by computing the variations of shear wave speed in biological tissue.???

McLaughlin said her research is inspired by the centuries-old medical examination in which a doctor presses on the surface of the body to detect abnormal, or stiff, tissue underneath.

After analyzing data gathered from an ultrasound-based system developed by Mathias Fink of Laboratoire Ondes et Acoustique, ESPCI, Universite Paris VII that measures the amplitude of shear waves as they pass through biological tissue, McLaughlin, along with Rensselaer research scientists Dan Renzi and Jeong-Rock Yoon, recognized that the changes of the shape and position of the wave fronts as they pass through tissue would allow them to create an image that could be used as a diagnostic tool.

Shear wave speed can more than double in abnormal, or stiff, tissue, and the high contrast helps make a high-quality image, according to McLaughlin. The researchers first developed an algorithm to identify the location of the very front of the wave as it passes through the tissue. Using only this data, the team computes the shear wave speed at each section of tissue and produces an image of stiffness variations.

???We call what we have developed the Arrival Time Algorithm, and the initial images we have created using this computation are very promising,??? said McLaughlin.

McLaughlin was recently honored by both the Association for Women in Mathematics and the Society for Industrial and Applied Mathematics when they selected her to present at the AWM-SIAM Sonia Kovalevsky Lecture at the SIAM Annual Meeting. The lecture is intended to highlight significant contributions of women to applied computational mathematics, according to the AWM-SIAM selection committee.

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Sevanian's group recently found that estrogen and some estrogenic compounds prevent the production of radicals by endothelial cells experiencing turbulent flow conditions, and enhance the tolerance of vascular cells to oxidative stress. They are presently working to identify the molecules within oxidized LDL that contribute to atherosclerosis??”and determine which steps of the atherosclerotic process they affect.

Sevanian states "identification of the specific molecular sites where estrogen acts to prevent atherogenesis provides us with targets for medical intervention using more precise drugs."

"Soy components, which have estrogenic properties, bind to the LDL and prevent it from becoming oxidized," he said. "Preliminary work indicates that soy can slow the progression of atherosclerosis without estrogen??™s potentially harmful side effects. Some of the cellular mechanisms affected by soy components are similar to estrogen??™s and provide important focal points for further interventional studies."

Sevanian is currently collaborating on the new Women's Isoflavone Soy Health (WISH) clinical trial with Howard Hodis, M.D., professor of preventive medicine at the USC Keck School of Medicine and the Department of Molecular Pharmacology and Toxicology at the USC School of Pharmacy. WISH is the first randomized, double-blind, long-term study on soy protein isoflavones and their effects on vascular disease among postmenopausal women.

"WISH will have a tremendous impact on the clinical use of soy as a prevention method," Sevanian said, "and could pave the way to better targeted pharmaceutical agents that prevent atherosclerosis."

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