BioEd Online

A new ultrasound technique could help to tell a benign lump in the breast from a malignant tumour, reducing the number of painful and expensive biopsies carried out.

The procedure, called elasticity imaging, measures how much tissues are compressed in response to pressure. Because tumours tend to be harder and less elastic than benign lumps, the test can tell a dangerous growth from a harmless one.

Preliminary tests, which were reported today at the annual meeting of the Radiological Society of North America in Chicago, found that of 123 tumours scanned, elasticity imaging correctly identified all 17 cancerous lesions, and 105 out of 106 benign ones.

"This technique could significantly reduce the number of biopsies and increase the confidence of women that a detected lesion is truly benign," says Richard Barr, professor of radiology at Northeastern Ohio Universities College of Medicine in Youngstown, who presented the results.

Hard or soft

For the patient, the scan is not much different from a routine ultrasound which is already used in some cases to try and spot lumps. But for doctors, a piece of software can translate the data to determine how much the tissue is distorting.

Ultrasound works in the same way as sonar does for ships at sea: sound waves are passed through the body, and as the sound hits a body part it bounces back as an echo. These echoes are interpreted by a computer and transformed into moving pictures.

Once a suspect area is identified, a sonographer watches to see how the scan changes as a patient's heartbeat and breathing moves their body against the pressure of the ultrasound device. A tumorous lump should distort very little in response to movement, Barr says, whereas a benign one is much more malleable.

The trick works very well. Mammograms can show an abnormal change in breast tissue 90% of the time, but only a biopsy can determine whether or not it is malignant. If further trials support this one, Barr says, ultrasound could eliminate about half of the biopsies that are currently done on breast lesions.

Barr adds that this type of diagnostic medicine could be used on other parts of the body such as the liver, but it will be harder to do the deeper inside the tumour lies. And the software would have to be re-written.

For now, "we are not cancelling any biopsies based on this report," says Barr. Results still need to be confirmed with a large multi-centre trial, which will take another year to complete.

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