RSNA: Elasticity Imaging Aims at Unnecessary Breast Biopsies

CHICAGO, Nov. 28 -- A way to use ultrasound to measure the elasticity of tissue surrounding suspicious breast lesions demonstrated 100% diagnostic sensitivity and 99% specificity in a small study.

In the study of 80 women with 123 suspect breast lesions, elasticity imaging identified 18 lesions as malignant and biopsy confirmed that 17 were malignant, radiologist Richard G. Barr, M.D., Ph.D., Northeastern Ohio College of Medicine.

The 80 women were referred for ultrasound-guided biopsy of lesions detected on mammography or by clinical examination, Dr. Barr said at the Radiological Society of North America meeting here.

Standard ultrasound and elasticity ultrasound were used to measure the length and width of each lesion. The elasticity ultrasound, employing software just approved by the FDA, measures "the movement of the tissue and this difference in movement affects the size of the ultrasound image of the lesion."

Malignant lesions appeared larger on elasticity ultrasound scans than they did on the standard ultrasound, he said.

"I tell people to think of this like a marble in a bowl of Jello -- you can compress the Jello, but the marble won't compress or change size," he said at a press conference.

Like the marble, the "lesion doesn't change size, but the tissue surrounding it does -- it moves and compresses."

He said it is possible that the tissue surrounding a malignant lesion does not represent clean margins but rather tissue that is already invaded by micrometastases, which could affect its elasticity.

In any case, Dr. Barr said that if the findings are confirmed in a larger multicenter study "this technology could significantly reduce a number of unnecessary breast biopsies."

Joseph Tashjian, M.D., president of St. Paul Radiology, in St. Paul, Minn., said the findings seemed promising, but he cautioned that Dr. Barr was reporting results from a small, single-center, non-randomized study, with the inherent uncertainties of such studies.

"Very often when we first hear about advances in imaging technology the results are much better than what we see in every day practice," he said.

He pointed out, for instance, that "no imaging modality currently in use has a sensitivity of 100% and specificity of 99%."

Moreover, he noted that Dr. Barr did not report lesion size. "If the lesion is big enough, anything can identify it," Dr. Tashjian said.

Those caveats aside, Dr. Tashjian said the findings "really are promising and I hope this does pan out because the benefit would be very significant."

And, Dr. Tashjian said that it has the added appeal of simplicity. "I double there would be a very steep learning curve with this because ultrasound is something that we already do."

Dr. Barr said the elasticity images are displayed on split screen along side the standard ultrasound image so the results "are real-time and the whole process only adds about two-minutes to standard ultrasound."

He said it would, however, probably create the need for a new billing code that would add about or less to the fee for ultrasound imaging of suspicious breast lesions.

Dr. Barr also cautioned that there are no data to suggest that elasticity ultrasound would be useful as a screening tool.

The elasticity software was developed by Siemens Medical, which funded the study. Dr. Barr said the software was approved by the FDA last week and is expected to be available by early next year.

Dr. Barr said the technology is also being tested to assess kidney and liver tumors and "it has already demonstrated efficacy for assessing thyroid lesions."