Ultrasound’s effectiveness and safety as a diagnostic tool have been givens for decades. Its use in measuring the elasticity of tissue – a relatively new technology called elastography – could make ultrasound a game changer in a number of fields.
“In examinations, the doctor always does two things. He takes a stethoscope to your chest and back and listens, and he does a lot of poking, trying to feel for hard things because, basically, in soft tissue, hardness is abnormal,’’ said Frederick Kremkau, PhD, director of the Program for Medical Ultrasound at Wake Forest School of Medicine. “But with ultrasound, we’re not just feeling it. We’re seeing it, and we can do it at a depth which palpation can’t. Poking on the surface can’t get deep.’’
Elastography employs a high-intensity pulse of sound waves to push on the tissue and compress the target area. That compression is tracked, and an image is created by the scattering of the sound waves “hitting” the tissue.
Aarti Sarwal, MD, an assistant professor of neurology, sees potential for elastography as a noninvasive method to diagnose problems in tendons and ligaments.
One simple example she gives is tennis elbow. Currently, physicians assess the severity of an injury from examination and basic imaging and offer medication or rehabilitation. Using elastography to measure the severity of tissue damage – and comparing it against an algorithm that would be developed to set standards for the tissue damage – could lead to targeted and more effective rehabilitation.
In the next few years, Sarwal said, elastography also may be used to measure the severity of liver, breast and thyroid cancer, and could better guide physicians in obtaining biopsies of tumors.
Sarwal, who has been trained in elastography, said she expects the technique to be in widespread clinical use within five years. Right now, she sees two shortcomings slowing the expansion of use of elastography: more people need to be trained to perform the technique, and standardized algorithms must be developed for different organs so the tissue-property measurements obtained through elastography can be properly assessed.
Kremkau has high hopes for elastography.
“Viewing the anatomy is useful diagnostically; we’ve been doing X-rays for 100 years,’’ he said.
“Elastography gives us the ability to non-invasively measure the elasticity of tissue, which is something we couldn’t do before.”