Breast Imaging Update
In the United States, breast cancer is the most commonly diagnosed noncutaneous cancer among women, with approximately 213,000 new cases expected to be diagnosed this year alone. 1 Of these new cases, the American Cancer Society estimates that only 63% will be diagnosed at the localized stage when the survival rate is 97%. 2 They further note that nearly 41,000 women will die of breast cancer this year, making it second only to lung cancer in the number of cancer deaths among women. 1
It is clear that early detection is the key to improving survival rates and mammography remains the gold standard for the detection of breast cancer. Until recently, all mammography was film-based, but with the advent of digital mammography, clinicians now have a choice of mammography systems.
This year, there has been a great deal of discussion about the relative efficacy of the two types of mammography systems and, in particular, on the findings of the American College of Radiology Imaging Network (ACRIN) Digital Mammographic Imaging Screening Trial (DMIST). 3 This 2-year study, involving more than 42,000 women, compared the sensitivity and specificity of analog and digital mammography. Overall, the authors reported no significant differences in the accuracy of the two methods for detecting cancer. They did, however, report that digital mammography has some advantages over film-based mammography for certain subsets of women, particularly younger women, those with heterogeneously dense or extremely dense breasts, and women who are pre- or perimenopausal.
Some experts believe that these findings will spur more widespread use of digital mammography, and many healthcare facilities have begun to make the migration to digital technology for their breast cancer screening and diagnosis. For these facilities, the transition requires careful planning and coordination between many shareholders, stretching well beyond the borders of the radiology department to include PACS administrators, information technology staff, facilities managers, clerical supervisors, and others. Switching to or adding digital mammography can have a significant impact on workflow, and healthcare facilities must plan carefully before implementing such changes.
Despite an increase in the use of digital mammography, in clinical practice today, most mammograms are still performed on analog systems-it is currently estimated that <10% of all facilities have digital systems-and new technology is also improving the quality of film-screen mammography.
One such development in analog mammography is a non-rotating compression paddle that curves slightly, providing a downward slope from the chest wall to the nipple, resulting in a more effective spreading of the fibroglandular tissue. Another improvement is the introduction of double-emulsion film and an improved intensifying screen with smaller, more densely packed phosphor particles that is designed to increase contrast and image sharpness in film-screen systems.
Mammographic findings can be inconclusive at times, however, and additional imaging methods are often used in the diagnostic workup. One such adjunct method is breast-specific gamma imaging (BSGI), a functional imaging technique designed to assess changes in tissue function rather than in anatomic structure. BSGI, which is now part of the standard clinical practice at some breast centers, allows clinicians to detect functional changes in breast tissue, often before the structural changes are visible on anatomic imaging.
As BSGI, breast magnetic resonance imaging, ultrasound, and other techniques become more common in clinical breast imaging, the workstations used to view these images must change as well. New multimodality, vendor-neutral workstations allow clinicians to view images from all acquisition modalities at a single workstation, thereby increasing productivity and enhancing workflow.
Such innovations in technology are helping clinicians detect and diagnose breast cancer at its earliest stage, thereby saving the lives of countless women every year.