Emerging Breast Imaging
Modalities
By Bonnie Rush, RT(R)(M)(QM)
EXECUTIVE SUMMARY
• Current limitations in mammography
have impelled the development of alternative imaging modalities for general
and/or high-risk screenings, problem-solving, diagnosis, staging, pre-surgical
planning, and determination of treatment efficacy.
• From initial studies, emerging breast
modalities may overcome the inherent weaknesses of current imaging
procedures.
• Among the modalities discussed here
are digital breast tomosynthesis (DBT),
molecular breast imaging, automated
breast ultrasound, breast elasticity
ultrasound imaging, and cone beam
breast CT (CBBCT).
This article is excerpted and adapted from the National Consortium of Breast Centers, Inc. (NCBC) newsletter, Breast
Center Bulletin (No. 118, March 2010 and No. 119, April 2010).
Used with permission. For more information on NCBC, visit
www.breastcare.org.
Mammography is
considered the gold standard of breast imaging
as documented in many studies including the organized service screening in
seven Swedish counties, covering approximately 33% of the population. This study
resulted in a 40–45% reduction in breast carcinoma mortality among women actually
screened. 1
Despite this dramatic reduction in
breast cancer mortality, the breast imaging
community has long recognized there is
room for improvement in mammography. Two-dimensional planar imaging
cannot eliminate superimposition of
breast tissue, thus recall rates are increased.
As breast density increases, sensitivity
decreases, leading to false negatives. And,
the extent of the disease is often underestimated. Ultrasound is a valued partner to
mammography to further define masses—
not microcalcifications—but has not been
proven to reduce deaths from breast
cancer. MRI of the breast is expensive
to implement, has a long learning curve,
and is difficult to interpret with a higher
sensitivity than mammography but lower
specificity. Even in combination these
three anatomic tools do not specifically
define the make-up (physiology) of any
breast findings.
These limitations have impelled the
development of alternative imaging modali-
ties for general and/or high-risk screenings,
problem-solving, diagnosis, staging, pre-
surgical planning, and determination of
treatment efficacy. This article will briefly
describe some of these contending
modalities.
Digital Breast Tomosynthesis
Digital breast tomosynthesis (DBT) is a
potential screening tool that circumvents
the overlapping tissue problem of mammography by generating a 3D image
from a series of thin high resolution
images of the breast. See Figure 1. Utilizing a modified full field digital mammography (FFDM) unit with a synchronized
moving tube and detector, 11–25 images
(depending on system configuration) are
obtained immediately after the conventional FFDM image is completed. Compression must be tolerated for the length
of both imaging procedures. The images
can be displayed in a dynamic cine mode
or individually at any level.
FFDM plus DBT has been shown to
reduce recall rates by up to 30%. When
interpreting DBT alone, the recall rate still
decreased by about 10%. However, there
was no indication if sensitivity is an additional benefit with FFDM plus DBT or
DBT alone. 2 One vendor has submitted a
premarket approval application to the US
Food and Drug Administration (FDA), and
two others have work-in-progress units.
