Grant may set stage for optical imaging with all mammos
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| Reconstructed image sections for the right breast in 45-year-old woman. The breast contains a 2.5-cm invasive ductal carcinoma. Image Source: Radiology. |
Fang, a radiology instructor at Massachusetts General Hospital (MGH), Harvard Medical School in Boston, and colleagues have been investigating the potential of optical imaging to provide functional breast imaging information and improve diagnosis for the past six years.
“One particularly big challenge with mammography is the high false positive rate, with as many as 70 to 80 percent of women referred for biopsies presenting with benign results. To better differentiate benign lesions, especially solid benign lesions, from malignancies, is one of the major ideas of this project,” Fang told Health Imaging News.
Whereas mammography traditionally provides radiologists with a 2D structural image from which to detect abnormalities, optical imaging offers functional information by allowing physicians to compare varying hemoglobin concentrations within healthy, benign and malignant breast tissues.
In the cover article of Radiology in January, Fang and co-researchers demonstrated significant differences in hemoglobin concentration between healthy breast tissue, benign lesions, cysts and malignancies. Optical imaging allows researchers to differentiate the varying oxygenation of tissues from the quantitative reconstruction of oxy- and deoxy-hemoglobin concentrations. The levels of oxygen saturation recovered from the optical measurements serve as indicators of breast tissue metabolism, which varies according to the benignity or malignancy of the tissue.
“It’s important to emphasize that because optical imaging uses infrared rays, it’s a noninvasive, safe procedure that does not expose patients to ionizing radiation,” Fang offered.
Fang’s principal objective with the two-year grant is to complete a prototype and embark on the FDA approval process for an optical system that could inexpensively be added onto mammography systems across the country. The grant was awarded as a collaborative project between Fang’s team at MGH and Philips Healthcare of Andover, Mass., which Fang believes will assist with the industrial design of the device and its potential introduction to 9,000 compatible mammography systems.
Although other research teams have investigated the possibility of using multi-modality imaging to enhance radiologists’ visualization of breast lesions, notably using MRI, Fang said his project offers the potential advantages of lower costs and quickly co-registered functional and structural images.
“The major challenge we face now is the development of a registration process for mapping the separate x-ray and optical compressions. This is where we will collaborate with Philips to figure out algorithmic approaches that can match the 2D x-ray image with the 3D optical image,” Fang noted.
If successful, Fang’s research could dramatically affect women’s health. “While we’ll definitely need more experiments in the clinical environment, our target is to implement optical imaging for every mammography exam—the whole screening population—because it really only costs a few minutes and causes no harm.
“We believe the system could significantly advance mammography screening by improving sensitivity and specificity and detecting malignancies earlier on,” Fang said.
The day after receiving the Massachusetts Life Sciences Center grant, the Gates Foundation awarded Fang a $100,000 Grand Challenges in Global Health grant for his research into the use of cell phone cameras to acquire images of brain injury in infants. “I realized that cell phone cameras already have the capability to acquire near-infrared images. For neonatal babies in developing countries that have limited access to resources, if the neonates undergo brain injuries that are not identified and attended to, the babies can die or experience devastating problems as they grow up,” Fang explained.
Still in an early research phase, Fang’s idea is to use optical imaging with infrared light, as in the optical breast imaging devices. Cell phone cameras are typically capable of capturing near-infrared radiation, but producers normally filter out this window of light wavelengths because it can diminish the quality of normal pictures.
In regions without access to adequate care, cell phones could potentially acquire deep tissue images of neonates’ brain vasculature and metabolism maps and then process and transmit the images to be interpreted by a professional.
“We are currently conducting similar studies using more advanced and expensive instruments,” Fang said. “My idea is to explore the possibility of replacing the expensive detectors with cell phone cameras.”