Digital magnifying glass allows mammograms to be digitized and selectively analyzed

November 12, 2003

Point-and-shoot CCD technology enhances images instantlyIt would be hard to find an area of radiology less able to afford digital technology than mammography. Low reimbursement rates have strained the budgets of mammographers, yet

Point-and-shoot CCD technology enhances images instantly

It would be hard to find an area of radiology less able to afford digital technology than mammography. Low reimbursement rates have strained the budgets of mammographers, yet they must pay five times the cost of a film-based system to buy a full-field digital unit.

A Gainesville, FL, company called MaxxVision may have a way around the problem: a digital camera that snaps pictures of selected parts of a film mammogram, processes the data on the fly, then allows the operator to manipulate the results on an LCD monitor. Priced at $34,500, this solution, called iView, needs only film and a light box to work.

"We studied the way radiologists work, how they make decisions, and we've come up with a technique to help," said Fred Derwitsch, president and COO of MaxxVision.

The system is being packaged as an "electronic magnifying glass," a replacement for the optical eyeglass that mammographers have come to depend on. What makes iView so appealing is that it fits neatly into the way mammographers currently work.

Operators point the CCD-based camera at a light-board-mounted mammogram, much as they would position an optical magnifying glass. But instead of leaning in and straining to see details in the actual image, they snap a digital image of the region of interest. This is sent to a PC, which instantly displays the processed image on a tabletop monitor. There the image can be manipulated as necessary to magnify or enhance the contrast.

The key to this system is on-the-fly processing, Derwitsch said, which generates a digital image immediately from the film image hanging on the light board.

"These are powerful video processing algorithms," he said.

The system uses the same kind of data-processing algorithms-image inversion, edge enhancement, and magnification-found on full-field digital mammography systems. Consequently, mammographers might be able to make sense of hard-to-see areas, eliminating the need to recall patients with suspicious findings for a second exam on a diagnostic unit that produces magnified views.

A preliminary clinical study conducted at the H. Lee Moffitt Cancer Center and Research Institute in Tampa, FL, involving 114 cases and carried out over an eight-week period with five radiologists, demonstrated an 11% increase in the rate of cancer detection, a 14% decrease in missed cancers, and a 4% decrease in the number of callbacks. Publication of the data in a radiological peer-reviewed journal is pending.

"It helps in the decision-making process, especially in characterizing areas of calcification on screening mammograms," said Dr. Patricia Romilly, administrative leader for breast imaging at the Moffitt Cancer Center. "The ability to magnify calcifications in a digitized format really adds a lot to the diagnosis."

About a half-dozen beta sites, including the Moffitt Cancer Center, helped MaxxVision evaluate iView. The company has since begun production of its first model, which is being sold mostly by in-house staff to customers in the U.S. and Canada. Europe and South America represent future markets. Negotiations are under way with three distributors to take over the bulk of the sales effort in the U.S.

Radiology is the prime focus, but offshoots of the product may be sold for other medical applications, including endoscopy, as well nonmedical applications such as nondestructive testing.

The iView is designed to provide the benefits of digital mammography on a wide scale. The majority of mammography operations still use only film-based mammography systems. Even the few that have invested in full-field digital technology use film-based systems or read film mammograms from outside physicians who request second readings. The iView brings these systems into the digital realm, allowing mammographers to identify indicators of disease that are often difficult to discern in suspicious areas.

"The data are on the film," Derwitsch said. "The problem is getting them out."

The information may be difficult to detect because of the density of the film that contains it. Ultrabright light boards are needed to bring out these data, but the intense luminosity may be so bright that it obscures the subtler details.

"That is where our system comes in," he said. "It provides the radiologist with enhancements in real-time-but only of the areas of interest."

These areas are relatively small, about one and a half to two inches square. When they are digitized, they can be enhanced to highlight the details. Because these regions are relatively small and contain limited numbers of pixels, iView can process them on the fly.

The current version of iView will evolve into more advanced forms. Several developmental paths are already being followed, according to Derwitsch.

"We have a plan going forward that will lead to additional products with significantly more capability," he said. "Computer-aided diagnosis is a natural and obvious fit."