Mammographic Measurements Before and After Augmentation Mammaplasty

Melvin J. Silverstein, M.D., Neal Handel, M.D., Parvis Gamagami, M.D., Ellen Waisman, B.S., and Eugene D. Gierson, M.D.

Summary:Thirty-five augmented women underwent mamography using both the
standard implant-compression technique and, when possible, the implant-displacement
technique; all had pre augmentation film-screen mammography available for
evaluation.  The area of mammographically visualized breast tissue before and after
augmentation mammaplasty was measured using a transparent grid.  Patients with sub
glandular implants had a mean decrease of 49 percent of measurable tissue area with
compression mammography a 39 percent decrease with displacement mammography. 
Patients with submuscular implants had a 28 percent decrease in measurable tissue
area with compression mammography and a 9 percent decrease with displacement
mammography.  Anterior breast tissue was seen better with displacement mammography;
posterior breast tissue, with compression mammography.  Most patients had some
degree of parenchymal scarring and lower image quality after augmentation.  State-of
the-art mammography was not possible in most patients augmented with silicone-gel
filled implants.

Full text:

Currently, in the United States, more than 150,000 women undergo augmentation
mammaplasty annually, and the number is increasing.  Recent estimates suggest that
more than 2 million women have already been augmented.  Little is known about the
effect of augmentation mammaplasty on breast cancer diagnosis, treatment, and
prognosis.  Since as many as 10 percent of all American women, including those with
silicone-gel implants, can expect to develop breast cancer during their lifetime,
there is a clear need to investigate this subject.

In 1988, we reported 20 women who developed breast cancer an average of 6.9 years
after augmentation mammaplasty.  We questioned our ability to perform state-of-the
art mammography in the presence of silicone-gel filled implants.  Since that report,
Hayes and associates have substantiated that augmentation mammaplasty obscures 22 to
83 percent of glandular tissue when mammography is performed with standard
compression techniques.  Gumucio and associates reported that silicone-gel-filled
implants can totally obscure mammographic detection of micro calcifications and soft
tissue masses.  Since the most favorable breast carcinomas, those with 90 to 95
percent 5-year survivals, are occult (non palpable) lesions found in asymptomatic
women undergoing screening mammography, and decrease in the sensitivity of
mammography may lead to a delay in diagnosis and, in some cases, to decreased
survival.  In an attempt to improve the quality and quantity of breast tissue seen
following augmentation mammaplasty, Eklund et al. introduced displacement
mammography.

This study as undertaken to compare the area of mammographically visualized
breast tissue before and after augmentation mammaplasty using both the standard
implant-compression and implant-displacement techniques.

Subjects and Method: Thirty-five patients had pre augmentation film screen
mammograms and post augmentation compression mammograms available for review and are
the subject of the measurement data in this study.  Thirty-one of these patients
also had implant-displacement mammograms; in four women, displacement mammography
was not possible because of severe capsular contracture.

Implant-compression mammography was performed using standard mediolateral oblique
and exaggerated craniocaudal views, with the implant included in the compression
field.  Implant-displacement mammography was obtained by pinching the anterior
breast tissue and pulling it forward while displacing the implant posteriorly,
flattening it against the chest wall.  The pinched area was then compressed between
the film holder and the compression paddle of the mammography machine.  The same
mediolateral oblique and exaggerated craniocaudal views were obtained.

The surface area visualized mammographically was measured using a transparent
grid calibrated to one-tenth of 1 cm.  In all mediolateral views, the pectoralis
major muscle was used as the posterior boundary.

Results: Pre augmentation and post augmentation mammographic measurement
data were available in 35 patients; 14 had sub glandular (anterior to the pectoralis
major muscle) augmentations (Fig. 1), and 21 had sub muscular (posterior to the
pectoralis major muscle) augmentations (Fig 2).  All augmentations were performed
with single-or double-lumen silicone-gel filled implants.  One of the patients had
saline-filled or textured implants.

The measurable area in the pre augmentation films ranged in size from 13 to 173
cm (mean 78 cm).  Post augmentation implant compression films ranged in measurable
area from 7 to 111 cm (mean 50 cm),  a 36 percent mean decrease in measurable area
when compared with pre augmentation films.  Post augmentation implant-displacement
films ranged from 11 to 120 cm (mean 63 cm), a mean decrease of 19 percent when
compared with pre augmentation films. 
 

Table I subdivides the patients into two groups by implant position.  In sub
glandular  augmentation mammaplasty patients, compression mammography revealed a
decrease in mean measurable area of 49 percent; displacement mammography revealed a
39 percent decrease.  In sub muscular augmentation, the mean decrease using
compression mammography was 28 percent; with displacement mammography, the average
decrease was 9 percent.

Table II further subdivides patients not only by implant position, but also by
mammographic view: mediolateral and craniocaudal.  The mediolateral views were
reduced in sub glandular augmented patients using the compression technique by 49
percent.  Using displacement mammography, they were reduced by 35 percent.  When sub
muscular augmentation had been done, the mediolateral views using compression
mammography were reduced by 30 percent; using displacement mammography, there was a
5 percent decrease in measurable area.

The craniocaudal views were similar, although less area was measured in this
view.  In patients with sub glandular implants, compression mammography yielded a
reduction of 49 percent; displacement mammography resulted in a reduction of 36
percent.  In women with sub-muscular implants, compression mammography yielded a
reduction of 24 percent, while displacement mammography resulted of 14 percent.

Anterior breast tissue was seen best using displacement mammography; posterior
breast tissue was seen  best using compression mammography.  No damage was caused to
any implant by breast compression during mammography.

Discussion: The major breast cancer breakthrough in the 1980's was
improvement in mammography combined with the development of hooked-wire-direct
breast biopsy.  This has led to a dramatic increase in the number of occult non
palpable cancers detected, many of which are noninvasive and have a better
prognosis.  At modern facilities, the percentage of occult breast carcinomas is now
20 to 30 percent and increasing.  Most centers report rates of axillary node
metastases below 20 percent for occult breast cancers compared with more than 40
percent for palpable carcinomas.  Mammography is the tool responsible for these
results.  Any factors that decrease mammographic utilization or reliability may
adversely affect the diagnosis of early breast cancer.

Gumucio and associates used an American College of Radiology phantom to simulate
micro calcifications and soft-tissue masses.  Radiographs were taken with the
implant resting on the phantom using the following combinations; an empty silicone
shell and silicone shells filled with silicone-gel, it completely obscured all
phantom artifacts.

Hayes and associates reported that augmentation mammaplasty obscures 22 to 83 of
visualizable breast volume.  In their study, six previously augmented patients
underwent standard compression mammography, each patient generating four films. 
These 24 films were analyzed by a radiation physicist, and the volume of obscured
tissue was calculated.  Since no pre augmentation films were available for
comparison, the actual volume of obscured tissue may be different.  In an attempt to
see more breast tissue in the augmented patient and see it better, Eklund et al.
developed and popularized displacement mammography.  This type of mammography
yielded improved films in terms of image area and quality.  Some physicians believed
that a mammographic breakthrough had occurred and that the displacement technique
would solve all the problems associated with implant mammography.  Unfortunately,
since the implant cannot be completely flattened against the chest wall, posterior
breast tissue is generally seen better with standard implant-compression views. 
Anterior breast tissue is almost always seen better with displacement mammography. 
The exception occurs when severe capsular contracture does not allow any significant
posterior displacement of the implant.  Since both techniques have advantages and
disadvantages, and they vary with position of the implant and degree of capsular
contracture, it is often necessary to use both methods for complete imaging of an
augmented breast.  This means that routine screening may require four films of each
breast, rather than two, doubling x-ray exposure.

Capsular contracture is a major problem for the displacement technique.  The more
intense this reaction, and it is significant in 30 to 50 percent of patients
augmented with smooth-walled silicone-gel filled implants, the more difficult
displacement mammography is to perform.  Severe capsular contracture makes
displacement mammography almost impossible and often extremely painful.  In 4 of 35
patients with pre augmentation films in this series, a complete set of displacement
mammograms could not be performed because of the rigidity of the capsules.  If these
films had been done, they would have shown little measurable breast tissue and would
have further reduced the measured area in the displacement subgroup.  Capsular
contracture also makes compression mammography, breast self-examination, and
physician examination more difficult.

Compression during standard mammography in the non augmented patient is used to
spread out the tissue, making it uniform in thickness.  Compression of the
prosthesis defeats this purpose.  During compression mammography in the augmented
patient, even in a soft breast, the implant is  relatively incompressible, often
leading to poor image detail.  Whatever compression is possible pushes some of the
implant anteriorly, commonly leading to a mammogram with band-like under penetrated
breast tissue.

Prior to 1988, there was little discussion in the medical literature regarding
augmentations mammaplasty and any effect the procedure might have on mammography. 
Since most augmentation patients were relatively young, few received routing pre
augmentation mammography, explaining why only 35 of 212 (17 percent) augmented
patients evaluated at our facility during the last 18 months had pre augmentation
mammograms available for measurement.

In our study, all post augmentation mammograms yielded mean decreases in
measurable area.  However, a decrease in measurable area does not necessarily mean
an equivalent decrease in the amount of tissue visualized.  The extend of this
artifact is impossible to quantitate.

The best possible compression is routinely obtained before augmentation, without
an implant present.  Following augmentation, compression will certainly be no
better, and in most cases, it will be worse.  With less compression, the area of
measurable tissue will be smaller, but the volume of breast tissue imaged may not
have decreased to the same extent.  In other words, more tissue may be imaged in a
smaller space; this causes more superimposition of structures, resulting in lower
image quality.  

Many post augmentation mammograms (particularly in patients with sub glandular
augmentations) revealed some intraparenchymal scarring and decreased intramammary
contrast, making mammographic interpretation more difficult.  State-of-the-art
mammography is extremely difficult to achieve in sub glandular augmentation
mammaplasty patients regardless of the type of mammography employed.  The best films
in augmented women, in terms of image quality and quantity, are obtained when the
implant is sub muscular, there is no significant capsular contracture, and
displacement mammography is used.

Currently, we apprise all women considering augmentation mammaplasty of the
mammographic measurement data and their potential implications.  Consideration
should be given to recommending against augmentation in patients with an increased
likelihood of developing breast cancer; for example, patients with a strong family
history of breast cancer, patients with a history of previous contralateral breast
cancer, and patients with a previous breast biopsy revealing severe atypical
epithelial hyperplasia.

Transcribed with permission from Plastic and Reconstructive Surgery Journal, Volume 86:#6, Pages 1126-1130, December 1990.

This article is often quoted as showing that mammography might be more accurate if implants are under the muscle rather than over the muscle. Actually, the article does not show that at all. The article only shows that there is a greater decrease in cross-sectional area of radiographically visualized breast tissue with overs than with unders. Some radiologists do say that over-the-muscle mammograms take them longer to read than under-the-muscle mammograms, however, the same accuracy is being achieved. There has never been any evidence to suggest that breast cancers are being missed with breast implants, either over or under the muscle. There has also never been any evidence to suggest that breast cancers are being detected less often, or later, with over-the-muscle implants than with under-the-muscle implants.

Keywords: Breast implants through the navel; Transumbilical breast implants; Belly-button breast implants; Through-the-navel breast enlargement; Through-the-navel breast augmentation; Trans-umbilical breast augmentation; Trans-umbilical breast enlargement; Belly-button breast enlargement; Belly-button breast augmentation; Breast enlargement through the navel; Breast augmentation through the navel; Navel breast enlargement; Navel breast augmentation; 'Scarless' breast enlargement; 'Scarless' breast augmentation.