Insana Lab: Ultrasonic Imaging - The University of Illinois at Urbana-Champaign
Insana Lab: Videos
Ultrasonic Shear Wave Imaging
Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign.
The video illustrates the principles behind ultrasonic shear wave imaging. It is the result of a simulation on a super computer of sound waves being generated in a tissue-like medium. While some labs use similar techniques for diagnostic imaging, our lab is developing these methods for mechano-biology investigations of cancer in 3-D cell cultures.
Video Part 1: A linear array transducer (top) transmits a high-intensity beam of sound (blue lines). The transmitted sound pulse applies a radiation force at the focal length that briefly displaces the medium downward. This medium is a collagen gel that contains a sphere of cancer cells (red).
The first response of the medium to the force is for fast pressure waves to emerge vertically traveling upwards and downwards. We ignore the fast pressure waves. Of greater interest are the slow shear waves that emerge later and travel laterally toward (and away from) the red sphere of cancer cells. Low-intensity Doppler pulses (blue lines) are transmitted throughout the volume by the same linear array to detect the shear waves. Notice that when shear waves enter the red sphere, they become distorted, racing ahead, because their speed of propagation is faster in the sphere than outside of the sphere. Measuring the shear wave speed, we can create images of stiffness (shear modulus) and viscosity (viscous coefficient). These images help us assess changes in the extracellular matrix indicative of malignant cell progression and tumor formation. Although the fast pressure waves are reflected from the top and bottom of the cube, our signal processing methods can eliminate their effects.
Video Part 2: The experiment is repeated to show the propagation of shear waves from the top view. In this view, the pressure waves disappear at first out of the plane, but later return as reflected waves. The change in shear wave patterns caused by the sphere of cancer cells is much clearer in the top view.
Special thanks to the Image Technology Group (ITG) at the Beckman Institute for video editing. This material is based upon work supported by the NIH/NCI under Award No. R01 CA082497.
Leading an Imaging Revolution
Insana, interim head of the Bioengineering Department at Illinois, is interested in biomedical imaging and biological modeling and instrumentation. His research focuses on "the development of novel ultrasonic instrumentation and methods for imaging soft tissue microstructure, elasticity and blood flow" toward understanding the "basic mechanisms of lesion formation, disease progression, and responses to therapy."
One project of Insana's lab is development of applications for imaging the elasticity of breast tissue, a diagnostic technique that will allow noninvasive visualization of soft tissue stiffness. A current project in Insana's Ultrasonic Imaging Laboratory measures the elasticity of cancer tissue using sonographic imaging, a technique that converts high-frequency sound waves into a picture on a video monitor. Their goal is to dynamically optimize diagnostic capabilities for different examination types and patient physiologies and therefore significantly improve diagnosis of breast cancer, a disease that affects one in eight American women.
In this video, Insana talks about the role his research plays in advancing bioimaging technology, especially sonographic imaging, as well as the importance of elasticity imaging for diagnosing breast cancer, how this technology can track tumors, and the advantages it offers to patients.