Nancy A. Melville
Mar 02, 2012
March 2, 2012 (Vienna, Austria) — Multimodal tomography (MUT), a novel 3-dimensional (3D) imaging technology, is effective in detecting and classifying breast lesions as small as 2 mm in size, according to research presented here European Congress of Radiology (ECR) 2012.
The unique imaging method, first introduced at ECR 2011, uses transmission ultrasound to perform a 3D scan of a pendulant breast in a water bath, and reconstructs multiple images for each coronal slice.
The technology offers several key advantages over mammography in terms of reduced radiation exposure and discomfort, said coauthor Vasilis Marmarelis, PhD, who is professor of biomedical engineering at the University of Southern California, Los Angeles.
“The MUT technology is much simpler for the technician, far more comfortable for the patient, and without the ionizing radiation of x-ray mammography,” explained Dr. Marmarelis, who invented the technology.
The ongoing clinical trials involve about twice as many patients as reported in 2011, compare MUT imaging in 103 women with Breast Imaging Reporting and Data System (BI-RADS) category 4 lesions, and involve histopathology from minimally invasive core biopsy of the suspicious lesions.
The lesions ranged in size from 2.0 to 28.0 mm, with an average size of 7.1 mm.
The results indicated that MUT was able to detect and accurately classify 33 of 34 malignant lesions in the biopsy samples, for a sensitivity of 97.1%.
Fifteen of the 33 (45%) detected malignant lesions had maximum dimensions of 5 mm or less, and were primarily ductal carcinoma in situ (DCIS). The smallest detected malignant lesions (all DCIS) were 2 mm in size.
There was 1 false-positive result (98.5% specificity) with MUT.
“The findings of our ongoing trials…corroborate a key capability of our MUT technology to detect reliably malignant lesions down to 2 mm…, even in a dense breast,” Dr. Marmarelis told Medscape Medical News.
The technology, which takes about 12 minutes per breast, uniquely combines ultrasound and tomography readings to better detect lesions, he explained.
“The key capability of the MUT technology that sets it apart from existing modalities is its demonstrated ability to differentiate lesions from normal breast tissue, as well as malignant from benign lesions, using proper combinations of multiple acoustic attributes at the tissue-voxel level.”
“These attributes are measured by MUT with ultrasound transmission tomography — an approach fundamentally different from the current echo-mode clinical ultrasound — and they represent novel and rigorous calibrated measures of the bulk acoustic properties of cellular microstructure.”
“Since the cellular microstructure of malignant and benign lesions, as well as normal breast tissue, is distinctly different, these measured attributes, properly combined, can differentiate the lesions through computational classification clustering.”
The use of a water-bath technique for ultrasound is not new, but might appear foreign and somewhat awkward to some patients, said Stamatia Destounis, MD, a managing partner at Elizabeth Wende Breast Care in Rochester, New York.
“We used to do the water-bath technique the 1980s when we first were trying to figure out how to image patients with ultrasound, so this is interesting,” said Dr. Destounis, who is a fellow with the American College of Radiology.
Dr. Marmarelis noted that one practical limitation of the MUT technology is the inability to scan breast tissue near the chest wall (pectoral muscle) and in the axillary region of the breast extension near the armpit because of the way the breast is positioned for scanning in the water bath.
He added that he is confident the problem can be overcome in the future with design changes, but Dr. Destounis said the issue is common with ultrasound.
“That’s a limitation with all ultrasound in a water bath in which the breast is pendulous,” she explained “Particularly with large-breasted women, you may not be able to penetrate as well as you would like. The far medial or inferior, or I would think all the edges of the breasts, would be limitations.”
Dr. Destounis also questioned how the breast would be biopsied with the technique once a lesion is detected. “In the current study, the lesions were biopsied with another method; I’m curious about how the biopsy would work in this kind of situation.”
Dr. Marmarelis responded that the biopsy process currently follows the “established standard clinical procedure.”
“In other words, our MUT results are not allowed to alter the established biopsy procedure yet, according to the approved study protocol. However, I expect that as soon as MUT becomes accepted as a reliable screening, detection, and localization technology, it will also become extremely useful in assisting biopsies because of its 3D fixed-coordinate system.”
Dr. Marmarelis reports being the inventor and developer of MUT, and a cofounder and shareholder of the start-up company MastoScopia S.A., which is performing the initial clinical validation trials in the European Union. Dr. Destounis has disclosed no relevant financial relationships.
European Congress of Radiology (ECR) 2012: Abstract B-0218. Presented March 1, 2012.0