Digital Mammography Takes Off

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Patricia Shapiro, MD, radiologist at the Imaging Center of Southcoast Medical Group in Savannah, Ga., reviews digital mammograms on the Merge Healthcare Merge Mammo multi-modality, vendor neutral softcopy workstation.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