Digital Mammography Takes Off

Like an airplane gathering speed, adoption of digital mammography has gained momentum as centers recognize the benefits of this technology. Research findings such as the DMIST (Digital Mammographic Imaging Screening Trial) study that revealed the advantageous aspects of digital screening exams for women with dense breasts, improved vendor solutions that address connectivity and workflow concerns and innovative new products that tackle specific issues for busy departments and centers have propelled facilities towards the digital realm for mammography.

Margarita Zuley, MD, assistant professor of imaging science at the University of Rochester in New York reports that “the number of sites, according to the FDA, with digital usage [for mammography] is up to 16 percent now, up from 10 percent a couple of months ago.” For those centers where other forms of digital imaging were already employed, adding digital mammo capabilities was a natural progression. Centers that budgeted for digital last year are swapping film screen for full field digital mammography (FFDM) now.

Connectivity and smooth integration of the images captured on digital mammography units have brought challenges. Considering the need for exceptional image quality coupled with effective and efficient workflow, concerns have been raised for individual stand-alone imaging centers as well as large medical centers. Within any given imaging center, several vendors’ equipment may be used to manage images from acquisition and display through reporting, archiving and distribution. Additionally, as digital mammography achieves greater adoption rates, the patient who enters an imaging center with one vendor’s equipment may bring CD copies of prior exams produced on a second or even third vendor’s equipment.

In response to these major concerns, the IHE (Integrating the Healthcare Enterprise) Mammography subcommittee has worked to improve connectivity throughout the mammography imaging chain. The IHE Mammography Image Profile (IHE Mammo), published in April 2006, was devised to address mammography requirements and is now available for vendors to use as they refine and develop products.

Zuley co-chaired the IHE mammography profile with a Connectathon in January where 26 pieces of equipment were connected, including six mammography workstations. The ultimate goal is to enable images from any vendor’s acquisition equipment to be displayed for review and manipulation on any given workstation. IHE also demonstrated these capabilities at the Society of Breast Imaging (SBI) 8th Postgraduate Course in mid-April in Hollywood, Fla.


Efficient workflow holds the key

Bruce Schroeder, MD, director of breast imaging at Eastern Radiologists, based in Greenville, N.C., uses the GE Healthcare Senographe DS and Senographe Essential. Their three fellowship-trained mammographers work at the breast center as well as providing mammography reading services for 13 centers within a 100 mile radius. The outlying centers still using film-screen mammography courier films to the central location, while all mammograms in their hub location are performed on digital units.

Raw image data from the Senographe are sent over a gigabit local area network (LAN) to a computer where the images are analyzed and marked by the R2 CAD (computer aided detection) algorithm. The combined image is then sent to the mammography workstation to be read, and the images are stored with CAD markings.

Schroeder emphasizes the need for a robust network infrastructure. The size of image files depends on image resolution produced by the acquisition detector. The Senographe systems generate a 100 micron/pixel image, which means images produced on the 19 X 23cm detector are about 9 megabytes (MB), while those captured on the 24 X 31cm detector are about 15 MB. “So a four or five view case is about 50 MB.” Pushing their load of 40 or 50 individual patient study results each day across a network requires a backbone that can support the load. This center stores approximately 1 terabyte (TB) of data per year.

As an aside, Schroeder notes that other vendors’ acquisition systems do utilize 50-micron or 70-micron/pixel resolution which means their image data sets may be significantly larger.

Considering that radiologists at Eastern Radiologists also read screen-film studies from their other imaging clinics, they looked at addressing the need to read both types of studies. To accomplish this, they use a prototype view box by Control Research that features digital monitors recessed into an analog viewer. “You could have two separate devices, but we have a row of analog machines above our digital monitors so you can go through cases with automatic shuttering.”

They use the GE Seno Advantage FFDM Review Workstation integrated with the Mammography Reporting System (MRS) mammography information system. “We use a bar code in MRS to pull up the case on the mammo machine which sends a message to the workstation. This adds to our speed and accuracy because no one has to type in patient information,” says Schroeder.

Patricia Shapiro, MD, radiologist at the Imaging Center of Southcoast Medical Group in Savannah, Ga., suggests that when a center has been digital in other modalities, the transition to digital mammography is relatively painless. “Many management newsletters talk about [digital mammography] slowing radiologists down while it speeds technologists up, but here everyone was accustomed to digital flow. The only people I know who have had difficulties are those for whom mammo [was] the first [digital] modality on board.” Their six radiologists were familiar with computers and reading from workstations when they brought digital mammography online in 2005 with Siemens Medical Solutions’ Novation Mammomat systems.

To facilitate workflow, Southcoast Medical chose Merge Healthcare’s Merge Mammo, a multi-modality, vendor-neutral softcopy workstation for reading and review of digital mammography images. On the workstation, breast images from any modality can be displayed which facilitates rapid comparison of images on a single screen. Shapiro says that if she wants to look at a digital mammography image and then an MR image, she opens two sets of software to accomplish that feat.

Because Merge Mammo is vendor-neutral, users are able to simultaneously read images produced by any vendor’s device. This means radiologists are not required to learn multiple mammography workstation software applications.

The other reality Shapiro notes is that once a center has used digital mammography for a year or two, many aspects of image comparison are simplified. “We’re now into our second year using digital, so with one year of digital [images] stored, I can compare last year’s digital with this year’s digital.” While they currently still hang films, eventually that will no longer be necessary. They decided not to digitize old films because they felt the image quality was not worth the time and money. They do digitize films that will be checked out, to insure that they maintain a copy onsite.


The CR mammography choice

Facilities seeking the advantages of digital mammography now have the alternative of computed radiography. In July 2006, Fujifilm Medical Systems USA received FDA approval to sell the Fuji Computed Radiography for Mammography (FCRm) system. The FCRm offers both 18 X 24 cm and 24 X 30 cm fields-of view with 50-micron pixel sampling for resolution, in either a multi-plate or single-plate version. This digital mammography solution does not require replacing an existing mammography acquisition unit; rather film cassettes are replaced with FCR cassettes. The ClearView-CSm multi-plate reader can accommodate the volume of up to three screening mammography rooms.

CR was the choice for Solis Women’s Health in Austin, Texas, which is expanding into a nationwide enterprise, according to Chief Development Officer Gerald R. Kolb. In making the decision to deploy CR mammography, they took into account that any decisions they made about digital mammography would most likely be carried forward for several years as they acquire future practices.

Solis Women’s Health is a successor to Women’s Diagnostic of Texas, but is now expanding beyond the Texas borders into a nationwide enterprise. “With our national scope, we will acquire practices that have other equipment, so we need an infrastructure that ‘plays well’ with all of them,” Kolb explains. “Because we think that with digital mammography, we will be sending images across state lines to be read for screening, we wanted an interpretive platform that would ‘play’ with everything.”

Breast radiologists were consulted on the CR decision and asked to review images captured on different systems to decide which ones they preferred. The majority of the physicians expressed a clear preference for the Fuji digital images because they look as good as analog images.

While a typical analog room includes a mammography acquisition unit with control console, they added a Fuji single plate reader with a footprint of approximately 2 foot by 18 inches, and 3.5 feet high, right next to the control console. The CR plate is placed in the acquisition unit for image capture, and is then moved to the reader for processing while a new cassette is placed in the acquisition unit for the next image capture.

Kolb suggests that cost comparisons between systems are difficult to make because there are so many variables, especially since many facilities purchase their systems as components. For example, a digital mammography acquisition unit would run approximately $250,000, but with CR implementation, existing acquisition units retain their functionality. Other components such as PACS, mandated printer and the workstation could run an additional $320,000.

Solis initiated a policy not to purchase any of this equipment without a service contract because individual components within any given system can prove quite expensive to replace. Rather than considering the cost of specific systems, Kolb suggests looking at life-cycle costing, which means you take an arbitrary period, the theoretical life of the equipment, and consider both equipment purchase price and the service contract costs that will accrue over that period.

In terms of patient scheduling, in their analog practice they would typically perform one screening study every 15 minutes, and could push to every 10 minutes. The first day they switched to CR, they could accomplish a study in 8 minutes. However, Kolb cautions that image acquisition time is not the only variable, and that the entire human implementation chain is equally important to consider. In addition, you need to consider the patient flow from where dressing rooms are located, to “overbooking” to reflect “no-show” rates, to patient interaction time.

In March 2007, Eastman Kodak Health Group announced it received Health Canada approval for their Kodak DirectView CR Mammography Feature that enables digital mammography images. They are in the final stages of FDA review.


The multi-modality approach

While digital mammography is proving to be an asset to screening women for breast cancer, when lesions are detected, further evaluation and testing is often required. To meet those needs, breast centers have begun a trend towards employing a variety of imaging modalities in one place.

Battlefield Imaging in Ringgold, Ga., opened as a comprehensive imaging center in October 2004 involving a collaborative effort between Hutcheson Medical Center and a group of radiologists.

Barbara Marshall, RT, who serves as director of Battlefield Imaging explains that they offer the first and only all-digital imaging center in their region. Designed as a completely digital center from inception, they feature Siemens Mammomat Novation FFDM systems on which they perform 800 mammograms per month. In addition, they offer stereotactic biopsy, ultrasound, PET/CT, a dedicated breast MR system (Siemens Espree Open 1.5 Tesla) where invasive breast procedures can be performed, digital radiography and digital fluoroscopy. This unique center integrates the medical subspecialties including medical oncology, radiation oncology and surgical intervention with all services provided under one roof.

“We offer a healing environment be-cause we believe that the best form of treatment is to integrate the entire process and bring everything to the patient,” says Marshall. This approach streamlines patient care with an average mammogram taking 15 minutes from start to finish. Besides their scheduled patients, they also accommodate “walk-ins” because there are many factories nearby. Often women must take a day off from work for routine physician visits, so if a mammogram is required, this center can provide that in the same day.

The University of Rochester also has just opened a new outpatient digital all-modality center with ultrasound, Hologic Selenia digital mammography systems, and MR using a Kodak PACS with their mammography workstation. They use the Suros ATEC vacuum-assisted biopsy system with either ultrasound or MR guidance.

“The major reason for breast MRI is that finding something indeterminate may mean we want to biopsy it, and the patient now doesn’t need to go to the operating room for that,” Zuley explains.

Zuley believes that the next technologies that hold promise for the future include tomosynthesis, cone beam CT for the breast and whole breast ultrasound.

Liane Philpotts, MD, associate professor of radiology, chief of breast imaging in the department of radiology at Yale University School of Medicine and co-director of the Yale Breast Center at the Yale-New Haven Hospital is using the Hologic Selenia FFDM unit for screening approximately four patients per hour. They also use this unit for needle localization and for breast compression biopsy.

“I like reading on the monitors because we can enlarge and see calcifications. There’s no question, we see calcifications we couldn’t see on film,” she notes.

This center also serves as one of five beta sites for the new Hologic Tomosynthesis system. “With regular mammography, you have only one projection, but with tomosynthesis you can scroll through the breast in slices, and you get clues such as architectural distortion, and calcification,” Philpotts explains. She anticipates development of CAD programs for tomosynthesis that will prove quite valuable.

Pamela H. Boland, director of Boland Women’s Imaging in Savannah, Ga., has the advantage of a small, boutique-type office setting for her start-up mammography practice. They use a GE Senographe with a Sectra mammography workstation loaded with NU Design Technologies software reporting system that meets ACR (American College of Radiology) and MQSA (Mammography Quality Standards Act) requirements so far as tracking reports is concerned.

NU Design Medical software offers a modular selection of functions to meet the needs of individual end-users. Boland selected the MOM (Mammography Operational Management) Standard that manages workflow and the MQSA reporting process with automated software solutions to track patient exams, procedures and any pathology discovered.

The system tracks results, and if a patient has an abnormal mammogram, it follows that through to summation. It serves as an electronic patient chart, plus they use it as a scheduler and it populates patient information to the imaging modality, which eliminates human error in entering data. MOM generates a report to the referring physician, and for the patient. They have a fax server, so reports are automatically faxed to physicians, and printed out to be mailed to patients.

“One other thing about NU Design, because it is web-based, I have the security of knowing that my information is stored in two different places off site,” Boland says.


Surging ahead

Adoption of FFDM is well underway nationwide as clinicians recognize the advantages of managing digital mammographic studies. The future suggests greater numbers of installed units with new technologies waiting in the wings for the battle against breast cancer.