Noninvasive imaging technique could reduce breast biopsies

Scientists at Washington University in St. Louis are investigating if ultrasound-guided diffuse light tomography, a noninvasive imaging technique, could help radiologists differentiate cancers from benign tumors. This could lead to fewer unnecessary biopsies, the team believes, and reduce healthcare costs.

The researchers, led by Quing Zhu, PhD, a professor of biomedical engineering at the university, are utilizing ultrasound-guided diffuse light tomography specifically look at blood vessels in suspicious tumors. 

The technique involves an ultrasound transducer and near-infrared optical imaging sensors located on the ultrasound probe. Once the suspicious tumor in the breast is identified, optical imaging sensors take images of the total hemoglobin concentration in the tumor. While a higher level of hemoglobin increases the overall suspicion for cancer, a lower level of hemoglobin decreases that suspicion. 

Zhu and colleague Steven Poplack, MD, professor of radiology at the School of Medicine’s Mallinckrodt Institute of Radiology and a breast-imaging radiologist at the Siteman Cancer Center, are now planning a clinical trial with 300 patients. The patients will have already had mammograms that indicate suspicious lesions and will be referred for biopsies. When the tumors are identified via imaging, they will be rated on a scale of two (benign) to five (highly suggestive of cancer). Biopsies are performed when the rating is a four or higher.

“Before the biopsy, these patients will have the ultrasound-guided diffuse light tomography scan,” Popack said in a news release from the university. “We’ll ask the radiologist to decide how suspicious the tumor is based on conventional imaging, then we’ll give them the information from the diffuse light tomography and ask if their assessment changed.”

Another group of patients will undergo conventional imaging before a contrast-enhanced mammogram (CEM) using an iodine-based injection. Radiologists will determine if their initial assessment changed after reading the results of the CEM. 

Zhu and Poplack will then compare the results of the ultrasound-guided diffuse light tomography to the CEM method to determine if either method could be used to decrease the need for biopsies and the frequency of agreement between both methods.

In a prior retrospective study of 288 patients, the researchers sought to assess the efficacy of the ultrasound-guided diffuse light tomography on suspicious breast tumors. They found that, with the optical imaging technique, the number of referrals for biopsies would have decreased by 45 percent.

“It has a lot of potential and promise as a diagnostic application, and that’s why we want to evaluate this technology in a clinical trial,” he said.