OAK BROOK, Ill.-- A new study shows that combining a technology calledoptical tomography with standard ultrasound imaging can helpdistinguish early-stage breast cancer from non-cancerous lesions--andpotentially reduce the number of breast biopsies performed. The studyappears in the October issue of the journal Radiology.
Ultrasound, which uses reflected sound waves to produce images ofthe internal structures of the body, is often used to further evaluatesuspicious breast lesions found by mammography. But its results are notalways reliable enough to avoid a biopsy, in which some of the breasttissue is surgically removed and examined.
"Only 10 to 15 percent of women who undergo a breast biopsy actuallyhave a malignant tumor, leading many women to experience unnecessaryanxiety, discomfort and expense," said the study's lead author, QuingZhu, Ph.D., associate professor of electrical and computer engineeringat the University of Connecticut in Storrs.
By combining ultrasound with optical tomography, which employs diffusedlight in the near infrared (NIR) spectrum, the researchers were able tocalculate the concentration of oxygen-carrying blood cells--orhemoglobin--and microvessels present in each lesion. A high density ofmicrovessels in a tumor is known to be highly correlated withmalignancy.
"We found that early-stage invasive cancers have a two-fold highertotal hemoglobin concentration compared with benign lesions," Dr. Zhusaid. "These findings demonstrate that this technique has greatpotential for non-invasively distinguishing malignant and benign massesto reduce benign biopsies."
In the study, 65 patients with a total of 81 breast lesions wereexamined with ultrasound and optical tomography. Breast lesions werethen biopsied. The biopsy results confirmed eight invasive cancers and73 benign lesions. The average total hemoglobin concentration withinthe malignant group was more than twice that of benign group.
To perform the dual imaging exam, engineers in Dr. Zhu's lab added NIRsensors to an ultrasound transducer, creating a hand-held probe capableof acquiring both ultrasound images and light waves. The collectedimages and optical data were then processed using a computer algorithm.
"The combination of the two technologies is key," said Dr. Zhu."Ultrasound locates the lesion, while optical tomography helpscalculate the blood volume in the lesion."
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