por Loren Bonner
, DOTmed News Online Editor | January 16, 2014
An ultrasound technique in the early stages of development could prove one day to offer enhanced image quality-- maybe even reaching the likeness of MRI.
Researchers, including groups at the University of Southern California in Los Angeles and Oxford University, among others, are working to develop electromagnetic acoustic imaging (EMAI), an imaging technique that makes use of radiofrequency and ultrasound.
Dr. Jane Emerson, a professor of clinical pathology who leads the EMAI research team at USC, calls it an "enhancement of ultrasound."
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Through the use of RF electromagnetic waves to induce ultrasound emission, conductivity-weighted ultrasound images are generated that can help differentiate between benign and malignant lesions as well as blood-filled spaces for cardiovascular applications.
EMAI claims to offer images approaching MRI quality because it uses radiofrequency — just like MRI.
"MRI uses RF coils and we use RF coils so that part is similar," Emerson told DOTmed News. "It will penetrate tissue the same way MRI does."
Different tissue types vibrate at a certain frequency when they are stimulated, and cancerous tissue is known to be 50 times more conductive than benign tissue.
"If you could do conventional ultrasound and also record which lesions or areas in the ultrasound image are highly conductive, then that could be a useful diagnostic parameter," said Emerson.
In physical form, the EMAI technology Emerson's research group is developing works as a dual-mode EMAI/ultrasound apparatus. A technologist can operate the ultrasound conventionally using pulse echo (sending ultrasound in and getting it back out) and then flip the switch and instead of sending out ultrasound, it can send in radiofrequency.
"That generates ultrasound wherever you have high conductivity gradient. Then you have conventional ultrasound and you can look at what the hot spots are," said Emerson.
EMAI could also be used for the diagnostic applications that ultrasound is traditionally used for: breast, prostate, thyroid, cardiovascular and kidney. In fact, Emerson said that much of her team's motivation in developing the technique stemmed from wanting to improve the diagnostic capabilities for breast imaging. Specifically, when more information is needed in detecting a benign from a malignant tumor after something suspicious turns up on a mammogram.
Jon L. Brubaker, a senior analyst at MD Buyline, an evidence-based, clinical and technology research firm for health care systems, said the technology is perfectly suited for advances in ultrasound in recent years, especially for breast cancer, where new techniques like shear-wave elastography — also ultrasound based — are gaining traction.