AJR 2002; 178:465-472
© American Roentgen Ray Society
MR Imaging of Extracapsular Silicone from Breast Implants
Diagnostic Pitfalls
Wendie A. Berg1,2,
Thuy Khanh Nguyen1,
Michael S. Middleton3,
Mary Scott Soo4,
Gene Pennello5 and
S. Lori Brown6
1
Department of Radiology, University of Maryland, University Imaging Center,
419 W. Redwood St., Ste. 110, Baltimore, MD 21201.
2
Greenebaum Cancer Center, University of Maryland, University Imaging Center,
Baltimore, MD 21201.
3
Department of Radiology, University of California San Diego, MRI Institute,
410 W. Dickinson St., San Diego, CA 92103.
4
Department of Radiology, Duke University Medical Center, Box 3808 Hospital
South, Durham, NC 27710.
5
Division of Biostatistics, HFZ-542, Center for Devices and Radiological
Health, Food and Drug Administration, 1350 Piccard Dr., Rockville, MD
20850.
6
Office of Surveillance and Biometrics, Center for Devices and Radiological
Health, Food and Drug Administration, Rockville, MD 20850.
Received June 26, 2001;
accepted after revision August 14, 2001.
The opinions or assertions presented herein are the private views of the
authors and are not to be construed as conveying either an official
endorsement or criticism by the United States Department of Health and Human
Services, the Public Health Service, or the Food and Drug Administration.
Presented at the annual meeting of the Radiological Society of North
America, Chicago, November 2000.
Address correspondence to W. A. Berg.
Abstract
OBJECTIVE. We sought to identify pitfalls in recognition of
extracapsular silicone on MR imaging.
MATERIALS AND METHODS. Three experienced observers reviewed MR
images from 359 women with current (n = 320), prior (n =
15), or both current and prior (n = 24) silicone gel implants. Axial
and sagittal fast spin-echo T2-weighted images with water suppression, axial
inversion-recovery T2-weighted images with water suppression, and axial
T2-weighted images with silicone suppression were obtained in a dedicated
phased array breast coil on a 1.5-T magnet. Images were reviewed again when
only one observer saw extracapsular silicone, and reasons for disagreement
were recorded.
RESULTS. Rupture was identified in 265 women (77%) with current
silicone implants and 378 (55%) of 687 implants. Observers agreed in
describing extracapsular silicone in 85 (12%) of 687 breasts with current
silicone gel implants, of which 81 (95%) showed definite evidence of rupture
on MR imaging. One observer reported extracapsular silicone in another 79
breasts. Confusion over contour deformity due to weakening versus breach of
the capsule accounted for 33 (42%) of 79 disagreements. Another 20 (25%) of
the 79 disagreements were attributed to poor conspicuity of extracapsular
silicone on fast spin-echo T2-weighted images combined with intermittent
observer failure to review inversion-recovery images. Subtlety of findings
(n = 17, 22%) and technical issues (n = 9, 11%) with failed
water suppression of pleural effusion or cysts and ghosting artifacts
accounted for remaining disagreements.
CONCLUSION. Extracapsular rupture is usually manifest as local
spread of silicone in the breast and is not well-depicted on fast spin-echo
T2-weighted images. Water-suppressed inversion-recovery T2-weighted images are
often needed to identify extracapsular silicone. Distinction of the bulge in
the fibrous capsule from herniation through the capsule remains
problematic.
Introduction
It was recently reported that on MR imaging, the prevalence of silicone gel
implant rupture in a population-based study of 344 women in Birmingham,
Alabama, was 55% and that 22% of ruptured implants showed extracapsular spread
of silicone [1]. In that and
other series, increasing risk of rupture correlated with increasing age of the
implant and with placement of the implant behind the pectoralis major muscle
[1,2,3].
Most series on implant failure are based on explanation
[2,
3]; however, dedicated breast
MR imaging is highly accurate in identifying rupture, with sensitivities of
72-94% and specificities of 85-100% across several series
[3,4,5,6,7].
The performance of MR imaging is superior to that of mammography, sonography,
and CT in depicting rupture [3,
5,
8]. When the shell collapses
into the gel, creating the linguine sign
[9], rupture is readily and
accurately identified. More subtle findings of rupture are also depicted on MR
imaging. These include small amounts of silicone gel that collect at the
surface of the implant shell creating the "subcapsular line" sign
[6] or that collect in radial
folds creating the "noose"
[10] or "keyhole"
[7] signs. As many as 50% of
these subtle ruptures, sometimes also called gel leakage, may appear as normal
findings on MR imaging [5].
Most important, as many as 52% of ruptured implants will show only these more
subtle findings [11]. This
phenomenon has been termed "uncollapsed rupture"
[7] because essentially all
such implants have some failure in the implant shell.
When the shell of silicone gel implants fails, the surrounding fibrous scar
or capsule that forms usually contains the gel
[12] and creates a so-called
intracapsular rupture. In 12-26% of patients
[1,
5,
7,
9], the gel will spread into
the adjacent breast or beyond in what is termed "extracapsular
rupture." Several groups of researchers have described using MR imaging
to reveal extracapsular silicone gel and silicone granulomas
[4,
7,
13]. Sonography may be
particularly useful in revealing extracapsular silicone
[14,15,16].
However, because MR imaging has become the standard for evaluating implant
integrity, it is desirable that extracapsular silicone gel and granulomas in
the breast, when present, should also be identified on MR images.
As part of a population-based study
[1], three radiologists
independently reviewed MR imaging studies. Whereas agreement on the presence
of rupture was high, agreement on the presence or absence of extracapsular
soft-tissue silicone was only moderate. We review our experience, explore
sources of disagreement, and offer suggestions for standardizing technique and
interpretation.
Materials and Methods
As part of the Food and Drug Administration Breast Implant Study
[1], 359 randomly selected
women, who were a subset of a National Cancer Institute study
[17], accepted the invitation
to undergo MR imaging as described by Brown et al.
[1]. Symptoms of self-reported
physician-diagnosed connective tissue diseases and fibromyalgia were recorded
and reported separately [18].
An institutional review board—approved protocol was used. Scanning was
performed on a 1.5-T scanner, using a dedicated phased array breast coil
(revision 8.2, Signa Horizon; General Electric Medical Systems, Milwaukee,
WI). Axial and sagittal fast spin-echo T2-weighted images with water
suppression (TR/TE, 
3000/224; slice thickness, 3 mm; matrix, 256 x
256; repetitions, 2; field of view, 16 cm) and axial inversion-recovery
T2-weighted sequences with water suppression ( 3000/156; inversion time,
180 msec; echo-train length 16; slice thickness, 4 mm; matrix, 256 x
192; repetition, 1; field of view, 20 cm) were obtained through each breast
separately. We then obtained axial fast spin-echo T2-weighted images with
silicone suppression, using the same parameters and slice selection.
Images were independently reviewed by three radiologists experienced in
breast implant imaging. The initial radiologist's interpretation served as the
clinical interpretation, and the other two as research interpretations. Each
radiologist was provided the date of implantation, history of prior silicone
gel implants, and type of implant. The radiologists confirmed the type of
implant present (silicone, saline, or double lumen) and the location of the
implant (subglandular or subpectoral) and recorded rupture status (no
evidence, indeterminate, or rupture) and presence or absence of extracapsular
soft-tissue silicone (no evidence, possible, suspicious, probable, or
definite). One radiologist also recorded the extent of extracapsular silicone
present. Breasts in which at least two of the three radiologists agreed that
the presence of extracapsular silicon was at least possible were considered
agreement. MR images of the 79 breasts in which only one of the three
radiologists identified extracapsular silicone were reviewed again by all
observers, and sources of error in interpretation were identified. Patients
were not given specific recommendations for treatment when rupture or
extracapsular silicone was identified because there is no consensus on this
issue. Histopathologic proof of rupture status was thus beyond the scope of
this study.
Results
Of the 359 women, 344 had 687 silicone gel implants in place, 14 women had
28 saline implants and a history of removal of silicone gel implants, and one
woman no longer had implants
[1]. Of the 344 women currently
with silicone implants, 24 had also undergone removal of a prior silicone gel
implant. The mean age of patients with silicone implants was 51.4 ± 8.4
years (range, 33-76 years), and average age of breast implants, when known,
was 16.5 ± 3.4 years (range, 6.4-28 years).
Of the 687 silicone gel implants, 378 (55%) were described as ruptured by
at least two radiologists as previously reported
[1]. Even after correcting for
implant age, implants in the subpectoral location were more likely ruptured
than those in the subglandular location: 270 (66%) of 408 subpectoral implants
were ruptured compared with 108 (39%) of 279 subglandular implants (p
< 0.001 by Student's t test). The median age of implant at rupture
was 10.8 years (95% confidence interval, 8.4-13.9 years) for all implants. Of
the 344 women with current silicone gel implants, 265 women (77%) had at least
one implant rated as ruptured or indeterminate for rupture. Nearly perfect
agreement of the radiologists occurred regarding rupture status
[19]: when compared in
pairwise fashion, weighted kappa value was always 0.88 or greater.
The radiologists agreed less often regarding the presence of extracapsular
silicone, with pairwise weighted kappa values ranging from 0.5 to 0.65,
indicating moderate to substantial agreement. At least two radiologists
described extracapsular silicone in 85 (12.4%) of 687 breasts. Eighty-one
(95%) of these 85 breasts with extracapsular silicone were implants showing
definite evidence of rupture on MR imaging and by consensus of at least two
observers. Thus 81 (21%) of 378 ruptured implants showed evidence of
extracapsular silicone. Of 50 implants considered indeterminate for rupture,
three (6%) were noted to have extracapsular silicone and, therefore, were
almost certainly ruptured, and one (0.3%) of 309 apparently intact implants
showed evidence of extracapsular silicone.
Seventy (82%) of the 85 breasts consistently described as having
extracapsular silicone showed silicone spreading into the breast adjacent to
the implant (Fig.
1A,1B).
Less often, in 15 (18%) of the 85 breasts, discrete isolated masses of
silicone gel were evident in the breast (Fig.
2A,2B,2C).
Of 344 women, 73 (21.2%) had evidence on MR imaging of extracapsular silicone
in one or both breasts. We found no difference in the average age or location
of implants with extracapsular silicone and of those without. Women with
breast implant rupture (by consensus interpretation) were no more likely to
report that they had been diagnosed with selected connective tissue and
autoimmune disease (scleroderma, systemic lupus erythematosis,
Sjögren's syndrome), Raynaud's disease,
fibromyalgia, chronic fatigue syndrome, or other connective tissue diseases
[18]. However, women with
extracapsular silicone (by consensus interpretation) were three times more
likely to report that they had been diagnosed with fibromyalgia than were
women without extracapsular silicone
[18].
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Fig. 1A. —45-year-old woman with extracapsular rupture of 15-year-old
subpectoral single-lumen silicone gel implant. Axial fast spin-echo
T2-weighted MR image with water suppression shows several small foci of
silicone gel (curved arrows) anterior to implant. Note collapsed
shell (open arrows) indicating rupture.
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Fig. 1B. —45-year-old woman with extracapsular rupture of 15-year-old
subpectoral single-lumen silicone gel implant. Axial inversion-recovery
T2-weighted MR image with water suppression shows silicone gel
(arrows) in breast. Note extensive silicone granulomata adjacent to
implant anteriorly and laterally. Extent of soft-tissue silicone is best seen
here.
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Fig. 2A. —46-year-old woman with ruptured 18-year-old subpectoral
single-lumen silicone gel implant and isolated mass of extracapsular silicone
gel. Axial inversion-recovery T2-weighted MR image with water suppression
shows silicone gel (arrow) posterolateral to implant.
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Fig. 2B. —46-year-old woman with ruptured 18-year-old subpectoral
single-lumen silicone gel implant and isolated mass of extracapsular silicone
gel. Axial fast spin-echo T2-weighted MR image with silicone suppression shows
discrete mass of silicone gel (arrow) in breast adjacent to
implant.
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Fig. 2C. —46-year-old woman with ruptured 18-year-old subpectoral
single-lumen silicone gel implant and isolated mass of extracapsular silicone
gel. Sagittal fast spin-echo T2-weighted MR image shows posterolateral
silicone gel (arrow) in breast, isointense to silicone in
implant.
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Only one of three observers suspected soft-tissue silicone in another 79
breasts, of which 70 had a current silicone implant and of which nine now had
saline implants with a history of removal of silicone gel implants.
Extracapsular silicone was reported by only the first radiologist in 32
breasts, by only the second radiologist in another 29 breasts, and by only the
third radiologist in another 18 breasts. Those cases in which only one
radiologist reported soft-tissue silicone were reviewed again, and sources of
error were the following:
Contour Deformities: Extracapsular Extrusion of Gel Versus Weakness
of Capsule
The most common source of difficulty in interpretation was attributable to
contour deformities of the implant in which distinction of a weakened, but
otherwise intact, fibrous capsule from extracapsular spread of gel was
problematic (Figs.
3A,3B
and 4). These accounted for 33
(42%) of 79 disagreements. At times, a capsule could be identified by a
continuous, but deformed, or a discontinuous hypointense line (Fig.
5A,5B).
When the implant itself was intact, such contour deformities were attributed
to weakness of the capsule with focal herniation of the implant. When the
implant was ruptured, reviewers continue to debate whether all such contour
deformities constitute breach of the capsule.
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Fig. 3A. —58-year-old woman with ruptured subglandular 19-year-old
single-lumen silicone gel implant and contour deformity equivocal for breach
of capsule. Sagittal fast spin-echo T2-weighted MR image with water
suppression shows inferior contour deformity (arrow).
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Fig. 3B. —58-year-old woman with ruptured subglandular 19-year-old
single-lumen silicone gel implant and contour deformity equivocal for breach
of capsule. Axial fast spin-echo T2-weighted MR image with water suppression
shows medial contour deformity (arrow).
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Fig. 4. —48-year-old woman with ruptured subglandular 19-year-old
single-lumen silicone gel implant. Superomedial contour deformity
(arrow) on this sagittal fast spin-echo T2-weighted MR image with
water suppression is surrounded by hypointense scar. This implant was
prospectively called negative for extracapsular rupture by two-thirds
consensus. Retrospectively, reviewers could not agree whether image represents
extracapsular spread of gel, focally weakened fibrous capsule, or just contour
deformity.
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Fig. 5A. —65-year-old woman with rupture of subglandular single-lumen
silicone gel implant placed 17 years previously. Serial sagittal fast
spin-echo T2-weighted MR image with water suppression shows break of
hypointense fibrous capsule superiorly with extracapsular extrusion of gel
(arrows). Reviewers agreed retrospectively that this is true break in
capsule and not just weakening or simple contour defect of fibrous
capsule.
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Fig. 5B. —65-year-old woman with rupture of subglandular single-lumen
silicone gel implant placed 17 years previously. Serial sagittal fast
spin-echo T2-weighted MR image with water suppression shows break of
hypointense fibrous capsule superiorly with extracapsular extrusion of gel
(arrows). Reviewers agreed retrospectively that this is true break in
capsule and not just weakening or simple contour defect of fibrous
capsule.
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Failure to Review Inversion-Recovery Images, Reviewer Error
In four (5%) of 79 breasts, disagreement over the presence of extracapsular
silicone was attributed to a radiologist's failure to review
inversion-recovery images when the current implants were ruptured. Extension
of silicone into the adjacent breast is often subtle or occult on standard
fast spin-echo T2-weighted images but readily apparent on inversion-recovery
images (Figs.
1A,1B
and
6A,6B).
Inversion-recovery T2-weighted images with water suppression have the highest
contrast between silicone and breast tissue
[4] but show less detail inside
the implant than conventional fast spin-echo T2-weighted images.
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Fig. 6A. —75-year-old woman with ruptured 26-year-old subpectoral
single-lumen silicone gel implant. Presence of extracapsular silicone
posteriorly and laterally is seen only on inversion-recovery sequence and was
missed by two observers. Axial fast spin-echo T2-weighted MR image with water
suppression shows silicone gel (arrowheads) outside implant shell,
indicating rupture. Hypointense Dacron (DuPont, Wilmington, DE) fixation
patches (open arrows) are evident along posterior implant wall,
consistent with 530 FP series Cronin implant (Dow Corning Wright, Arlington,
TN). Patches are meant to stabilize implant position by facilitating ingrowth
of tissue. Silicone granuloma (arrow) posterolateral to implant is
not well seen.
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Fig. 6B. —75-year-old woman with ruptured 26-year-old subpectoral
single-lumen silicone gel implant. Presence of extracapsular silicone
posteriorly and laterally is seen only on inversion-recovery sequence and was
missed by two observers. Axial inversion-recovery T2-weighted MR image with
water suppression shows silicone granuloma (arrow) in breast tissue
posterolaterally with associated decrease in signal relative to gel in
capsule.
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Whereas the first radiologist was responsible for the clinical
interpretation of these images and meticulously reviewed each set of images,
interpretations of the second and third radiologists were intended primarily
to evaluate the integrity of the implant and, therefore, focused on the
standard fast spin-echo T2-weighted images. Research interpretations did not
require review of the inversion-recovery sequences in which the rupture status
was less conspicuous. As observers became aware of having overlooked
extracapsular silicone on the fast spin-echo T2-weighted images, they were
more likely to include review of the inversion-recovery images in which
extracapsular silicone was more conspicuous.
In our study, 77 breasts in 39 women had a history of prior ruptured
silicone gel implant removal and were thus at risk for residual extracapsular
silicone. Indeed, 16 (20%) of 79 disagreements regarding extracapsular
silicone were seen in this group. Overall 16 (21%) of 77 of these breasts
showed MR imaging evidence of soft-tissue silicone although the current
implants were considered intact. Inversion-recovery images were not reviewed
by the second and third observers when saline or intact double-lumen implants
were identifiable on a cursory review of the T2-weighted images; this omission
resulted in the failure of these two observers to detect residual silicone
from a previously ruptured implant in these 16 breasts (Fig.
7A,7B).
Thus, overall, 20 (25%) of 79 disagreements in describing extracapsular
silicone status were attributable to failure to review the inversion-recovery
images.
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Fig. 7A. —46-year-old woman with current intact subpectoral
double-lumen implant placed 7 years previously, who had history of prior
silicone gel implants and residual extracapsular silicone. Axial fast
spin-echo T2-weighted MR image with water suppression shows intact
double-lumen implant with outer lumen saline hypointense and inner lumen
silicone hyperintense. Two reviewers missed residual siliconoma
(arrow) from prior (presumed) rupture because siliconoma is
isointense to fat on this sequence.
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Fig. 7B. —46-year-old woman with current intact subpectoral
double-lumen implant placed 7 years previously, who had history of prior
silicone gel implants and residual extracapsular silicone. Axial
inversion-recovery T2-weighted MR image with water suppression clearly shows
hyperintense siliconoma (arrows) posteromedially. Sequences in which
silicone is hyperintense to fat are needed when extracapsular silicone is
suspected.
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Subtle Findings
In 17 (22%) of 79 breasts with reviewers' disagreement regarding the
presence of extracapsular silicone, only tiny foci of silicone that were
overlooked by the other reviewers were identified by one reviewer in the
breast or adjacent to the implant.
Technical Issues
For nine (11%) of 79 disagreements over potential extracapsular silicone,
volume averaging, motion artifact, and inhomogeneous water suppression
contributed to disagreements. Respiratory motion and resultant ghost artifacts
resulted in findings falsely suggesting for soft-tissue silicone. Small
pleural effusions layering at the anterior chest wall rarely failed to
suppress on water-suppressed images and contributed to errors in
interpretation. Similarly, breast cysts and axillary lymph nodes rarely
remained hyperintense because of failure of water-suppression and thus
resembled foci of extracapsular silicone. Possibly, the presence of silicone
in the lymph nodes could produce hyperintense signal characteristics on
water-suppressed sequences and actually represent true-positive findings.
Discussion
The fibrous capsule that forms around implants usually keeps silicone gel
from spreading into the surrounding breast even when the implant shell fails.
Aside from presumed increased risk of extracapsular spread of silicone, the
clinical significance of intracapsular rupture is not clear
[20]. When silicone gel
spreads beyond the capsule, however, it usually incites scar and granuloma
formation [12,
21] that can result in painful
masses. No definite association has been shown between classic autoimmune
syndromes and silicone implants, although women in our series with
extracapsular rupture were more likely to report fibromyalgia
[18]. Complete removal of
extracapsular silicone can be difficult. Silicone can spread to the brachial
plexus, down the arms, and to the abdominal wall and groin
[22,
23], although most often it is
found in the breast itself and axillary lymph nodes. Silicone in the liver in
women with breast implants has been reported on the basis of H-1 MR
spectroscopy results [24,
25].
As discussed, the consensus of experienced observers' interpretations of MR
images was the gold standard in our series. Although imaging methods in the
detection of implant rupture have improved, there is no consensus on the
appropriate treatment of women with ruptured implants. Because there is no
consensus on treatment of ruptured implants, histopathologic verification of
rupture status was not obtained because removal was not required as part of
the study. Thus, our results may understimate the true frequency of rupture
and extracapsular silicone in this patient population.
Just as subtle intracapsular rupture can be missed on MR imaging, so can
subtle extracapsular spread. Extracapsular silicone can be identified on
mammography as dense masses when the affected area can be adequately imaged.
Extracapsular silicone granulomata have a characteristic
"snowstorm" appearance on sonography
[16], which may be more
accurate than MR imaging for this particular purpose
[21], but the operator must
scan the appropriate site and recognize the appearance. Rarely, cystic areas
can be seen on sonography
[15]. The patients in our
study did not undergo mammography or sonography.
Several patterns of extracapsular rupture were identified. The most common
by far was local silicone granuloma, with or without associated discrete
masses of silicone gel, in contiguity with the original implant. Rarely,
isolated discrete foci of silicone gel were evident in the breast and might be
termed a "silicone cyst." Often the extracapsular silicone was not
well shown on conventional fast spin-echo T2-weighted imaging, likely because
of the intense fibrotic reaction usually incited by silicone gel
[12,
21] (Fig.
8A,8B)
resulting in silicone granulomas or "siliconomas." With this
fibrotic reaction, the signal intensity of extracapsular silicone becomes
nearly isointense or slightly hypointense to fat on water-suppressed fast
spin-echo T2-weighted images. On water-suppressed inversion-recovery images
even tiny foci of soft-tissue silicone are conspicuous. Observer agreement for
silicone granulomata was nearly perfect with re-review of the
inversion-recovery images. Alternatively, it is usually possible to
distinguish fat from silicone on standard T2-weighted images in the breast if
a sufficiently long TE is used (usually greater than 200 msec with an
echotrain length of 8). We did not have the opportunity to further lengthen
the TE in this study because of software limitations. Recognition of
soft-tissue silicone may be of clinical importance if removal is sought by the
patient because these masses can be remote from the implant itself. Use of
intraoperative sonography may also be of value in this setting
[26].
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Fig. 8A. —Siliconoma removed from 47-year-old woman with ruptured
12-year-old silicone implants. Dense scar formed around extracapsular
silicone. (Reprinted with permission from
[21]) Photograph of gross
specimen of resected siliconoma shows dense fibrous halves of mass connected
by strand of silicone gel (arrow).
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Fig. 8B. —Siliconoma removed from 47-year-old woman with ruptured
12-year-old silicone implants. Dense scar formed around extracapsular
silicone. (Reprinted with permission from
[21]) Photomicrograph of
histopathologic specimen shows dense fibrosis. Silicone gel is lost in
processing leaving empty spaces (arrowheads) in specimen. (H and E,
x40)
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Distinction of weakness of the capsule and extracapsular extrusion of
silicone remains problematic. The fibrous capsule appears hypointense on all
MR imaging sequences. Everson et al.
[8] diagnosed extracapsular
rupture if the hypointense capsule was disrupted in any way. Often, however,
the fibrous capsule is not well seen, or it can be focally thinned without
being disrupted. One reliable indicator that the capsule has been breached and
not just weakened is the decrease in signal intensity of extruded silicone
(Fig.
6A,6B).
Relying on this decrease in signal intensity to identify a breach of the
capsule, however, is not sufficient because discrete masses of silicone gel in
the soft tissues can retain their original signal characteristics (Fig.
2A,2B,2C).
Isolated contour deformities, without decrease in signal intensity of the gel,
continue to be a source of reviewer disagreement. The clinical significance of
this latter distinction is not clear. In such cases, complete surgical removal
is not likely to be problematic because the silicone is in contiguity with the
original implant.
Extracapsular rupture may be more common than previously reported. In our
series, as many as 133 (35%) of the 378 ruptured implants showed evidence of
extracapsular spread of silicone. It is rare to visualize extracapsular
silicone in the absence of rupture. Indeed, only one (0.3%) of the 309
apparently intact implants showed evidence of extracapsular silicone. Women
having had prior removal of a ruptured silicone implant were also likely to
have residual extracapsular silicone, seen in 16 (21%) of the 77 breasts in
women with this history.
In conclusion, silicone breast implant rupture is common and occurs more
frequently as implants age. When the rupture is contained by the fibrous scar
or capsule, it is of unclear clinical significance. Extracapsular rupture or
spread of the gel into the surrounding breast or beyond is difficult to remove
and may increase the risk of fibromyalgia and other connective-tissue diseases
[18]. Recognition of
extracapsular silicone can be challenging on MR imaging. It is usually
manifest as local spread of silicone in contiguity with the implant, which
often is not well depicted on fast spin-echo T2-weighted images.
Water-suppressed inversion-recovery T2-weighted images are often needed to
identify such spread of gel and should be performed whenever there is high
suspicion for extracapsular silicone (i.e., current rupture or a history of
removal of a previously ruptured silicone breast implant). Distinction of a
weakened fibrous capsule from extrusion of silicone gel through the capsule
remains problematic.
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Robinson OG Jr, Bradley EL, Wilson DS. Analysis of explanted
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Abstract
Introduction
