an increasing number of patients have breast implants for cosmetic augmentation of the breast , reconstruction after mastectomy or correction of congenital malformations .
implant rupture can have various causes , but most ruptures have no obvious traumatic origin and sometimes occur in asymptomatic patients .
the incidence of rupture increases with implant age ; the average incidence is approximately 2 implant ruptures per 100 implant - years , with an estimated probability of being intact after 5 and 10 years of implantation of 98% and 8385% , respectively [ 36 ] .
clinical diagnosis is difficult , being based solely on nonspecific findings such as palpable nodules , asymmetry or tenderness .
free silicone from ruptured implants has in rare cases spread to distant body regions , giving rise to symptoms .
if implant rupture is accompanied by loss of the shape of the breast , the diagnosis of breast implant rupture at physical examination is feasible .
however , clinical evaluation may fail to detect breast implant rupture that occurs over time without loss of breast volume and misshapenness .
breast pain on the clinical examination of implants is a strong predictor of rupture , but the absence of pain does not exclude rupture . according to tark et al .
, the most common symptom in breast implant rupture is contour deformity ( 44% ) , followed by displacements ( 20% ) , mass formations ( 17% ) , pain ( 13% ) and inflammation ( 3% ) .
however , physical examination fails to diagnose implant rupture in more than 50% of cases .
magnetic resonance imaging ( mri ) , mammography , ultrasonography ( us ) and exceptionally computed tomography ( ct ) have all been used to diagnose silicone breast implant rupture .
each technique has specific strengths and weaknesses that may make a particular technique the study of choice for an individual patient .
familiarity with both the typical and atypical findings for implants is essential to enable abnormalities to be detected .
many factors can influence which imaging technique should be used to evaluate the integrity of silicone breast implants in a particular patient .
these factors include the cost of the examination , the availability of an imaging technique , the expertise of the radiologist performing and interpreting the study , and potential contraindications or limitations of a patient that would prevent the use of a specific imaging technique .
furthermore , knowing which implant the patient has can help determine the type of imaging findings to expect in case of rupture .
each type of silicone gel - filled implant has slightly different imaging findings for implant failure related to the manufacturing process and viscosity of the silicone gel .
breast reconstruction may involve the insertion of various types of implant or the modelling of autologous myocutaneous flaps . according to the literature
, breast implants can be categorised into five implant generations reflecting product development over time .
the recent generations of silicone gel implants have a cohesive viscous silicone gel . as a result of this feature
, these implants will rarely have a totally collapsed implant shell , differing from the older generations .
the third and fourth implant generations offered models of breast implants with textured or uniformly smooth surfaces ( fig .  1 ) , and it seems that capsular contracture rarely occurs in women with recent generations of breast implants . all implants in this article are silicone breast implants including single - lumen implants ( the majority ) and less commonly double - lumen implants ( fig .  5 ) .
single - lumen implants have a single lumen of silicone gel delimited by a multilayer shell , while double - lumen implants have a fixed amount of saline and silicone within them , or a fixed outer lumen usually filled with silicone and an inner lumen that can be expanded , as necessary , with saline ( inverse double - lumen ) .fig .
( d ) different implant types . a and b breast tissue expander with metallic component visualised by computed tomography scan .
silicone gel implants with textured surface ( c ) and with smooth surface ( d ) finally , another surgical breast reconstruction technique uses autologous myocutaneous flaps
. flaps are most commonly either transverse rectus abdominis musculocutaneous ( tram ) flaps or latissimus dorsi flaps , and are used to reform the breast either alone or in conjunction with an implant .
another alternative more rarely encountered in clinical practice is direct silicone gel injection in the breast .
breast implants may be placed in a subglandular ( anterior to the pectoralis major muscle ) or subpectoral ( posterior to the pectoralis major muscle ) location ( fig . 
( left ) submammary implant located in front of the pectoralis major muscle and ( right ) submuscular implant located behind the pectoralis major muscle , visualised by mammography localisation of breast implants .
( left ) submammary implant located in front of the pectoralis major muscle and ( right ) submuscular implant located behind the pectoralis major muscle , visualised by mammography before implant insertion , especially in oncoplastic breast reconstruction , a tissue expander ( fig . 
1 ) is usually placed in the mastectomy site to stretch the remaining skin in preparation for the placement of a permanent implant later .
the expander is like an inflatable breast implant that is inserted into a pocket under the skin and muscle of the chest .
the expander is usually placed in its collapsed form at the time of mastectomy and then , after surgery , fluid is introduced into the tissue expander to slowly inflate it .
it is important to realise that , as their function is to expand , they might not be fully inflated and thus may appear to have multiple folds or wrinkles on the surface .
depending on the type of expander , the fluid is either introduced directly into the expander ( magnetic marker ) or is injected into a distant port .
this process continues for several weeks until the tissue expander is filled to an optimal volume , when a permanent breast implant can be inserted .
notably , some kind of breast tissue expanders should be considered a contraindication to mri because of the magnetic marker of the filling valve : expander manufacturers list possible consequences such as overheating , possible expander displacement , and possible reduction of magnetisation of the marker .
after placement , a thin fibrous capsule ( scar tissue ) normally forms around the prosthesis .
this occurs around all silicone implants to some degree ; however , pronounced fibrous capsule formation causes discomfort and alters the shape of the breast .
changes owing to marked fibrous capsule contraction often can not be appreciated on imaging , and clinical examination is the best way to diagnose this condition . magnetic resonance imaging ( mri )
its sensitivity for rupture is between 80% and 90% , and its specificity is between 90% and 97% [ 3 , 516 ] ( fig . 
right implant with extracapsular rupture exhibiting the typical  linguine sign  at the posterior margin of the implant .
intact left silicone implant magnetic resonance imaging scan of a woman with bilateral breast silicone implants .
right implant with extracapsular rupture exhibiting the typical  linguine sign  at the posterior margin of the implant .
intact left silicone implant mri may be used to exclude a ruptured prosthesis , and it may aid explantation surgery as it documents the presence and extent of silicone leakage better than other imaging techniques . despite this , conventional breast imaging techniques are the methods of choice when breast implant failure is suspected because well - defined and discernible sonographic features have been established for ruptured implants , as we shall show throughout this article .
moreover , mri is more expensive , and many women have contraindications ( cardiac pacemakers , aneurysm clips , metallic foreign bodies and claustrophobia ) to mri . in this article
, we describe the preeminent role of mri in detecting implant failures , illustrating the spectrum of appearances of normal silicone gel implants and of implant ruptures .
furthermore , we summarise the advantages and limitations of other imaging techniques and describe the key findings in detection of silicone implant failure .
magnetic resonance imaging of silicone breast implants , with its high sensitivity and specificity for detection of rupture , is an excellent technique to assess implant integrity .
mri has proven accurate in locating free silicone and evaluating implant rupture [ 3 , 516 ] .
a dedicated mri breast coil should be used to obtain high - resolution images , allowing detection of subtle signs of implant leakage or rupture .
mri s usefulness derives from its ability to suppress or emphasise the signal from water , fat , or especially silicone .
its high spatial and soft - tissue resolutions make it ideal for the characterisation of breast implants .
figure  4 shows the mri sequences used at our institution for breast implant study . the use of contrast agents in mri studies for assessment of breast implant integrity is not recommended .
however , when the priority is the detection of recurrence or residual tumors , contrast - enhanced mri of the breast is useful for characterising parenchymal lesions [ 11 , 13 ] .
high - field - strength magnets of at least 1.5 t are preferred when imaging patients with silicone breast implants because of the ability to use magnetic resonance sequences that can more readily suppress or emphasise the signal from water , fat or silicone .
turbo - spin - echo t2-weighted images , short - time inversion recovery silicone excited ( silicone hyperintense , water suppressed ) , and silicone - saturated ( water hyperintense , silicone suppressed ) are the most common and most important sequences in silicone breast implant assessment .
a single - lumen silicone implant has an outer shell containing homogeneous high - signal - intensity viscous silicone on t2-weighted images .
a double - lumen silicone implant typically has an inner lumen of high - signal - intensity silicone surrounded by a smaller outer lumen that contains saline and has different signal intensities , depending on the pulse sequence ( fig . 
4our mri examination protocol includes a 1.5-t superconducting mr system ( philips mr systems gyroscan nt ) with a sense - body coil , with the following sequences .
5mri of a 61-year - old woman with bilateral implants : a single - lumen implant ( right breast ) and a double - lumen implant ( left breast ) .
( a ) axial silicone - suppression and ( b ) axial t2-weighted turbo spin echo sequences .
the right implant has homogeneous signal intensity , representing a single lumen with silicone gel ( * ) .
the left implant has an inner lumen ( open arrow ) of low - signal - intensity or high - signal - intensity silicone surrounded by a smaller outer lumen ( solid arrow ) that contains saline our mri examination protocol includes a 1.5-t superconducting mr system ( philips mr systems gyroscan nt ) with a sense - body coil , with the following sequences .
we always include a post - contrast study to detect possible malignant lesions mri of a 61-year - old woman with bilateral implants : a single - lumen implant ( right breast ) and a double - lumen implant ( left breast ) .
( a ) axial silicone - suppression and ( b ) axial t2-weighted turbo spin echo sequences .
the right implant has homogeneous signal intensity , representing a single lumen with silicone gel ( * ) .
the left implant has an inner lumen ( open arrow ) of low - signal - intensity or high - signal - intensity silicone surrounded by a smaller outer lumen ( solid arrow ) that contains saline breast implant ruptures can be divided into two major categories : intracapsular implant rupture and extracapsular implant rupture , which is less common [ 1 , 310 , 12 , 1518 ] .
up to half of all ruptures in women with augmented breasts occur within 12 years .
intracapsular implant rupture is defined as rupture of the implant shell with silicone leakage that does not macroscopically extend beyond the fibrous capsule .
the most reliable mri criterion for intracapsular rupture is the presence of multiple curvilinear low - signal - intensity lines within the high - signal - intensity silicone gel , the so - called  linguine sign  .
these curvilinear lines represent the collapsed implant shell floating within the silicone gel [ 5 , 7 , 9 , 10 , 12 , 13 , 16 ] ( fig .  6 )
. the linguine sign will not be present in an uncollapsed rupture . in an uncollapsed rupture
, mri shows free silicone outside the implant shell but still contained by the fibrous capsule .
focal silicone invagination between the inner shell and fibrous capsule are common , resulting in the  teardrop sign  and the  key - hole sign  [ 5 , 7 , 9 ] .
an uncollapsed silicone implant rupture is defined as a tear of the silicone implant shell and is considered an intracapsular rupture ( fig .  7 ) .
only these more subtle findings will be present in up to 52% of ruptured implants .fig .
( a ) axial t2-weighted turbo spin - echo and ( b ) axial silicone - excited sequence .
the study shows a hypointense subcapsular line at the anterior margin of the implant ( solid arrow ) ; the  teardrop sign  and  key - hole sign  are also present ( open arrows ) .
focal change in signal at the anterior margin of the implant ( white open arrow ) can also be observed magnetic resonance imaging scan of a woman with bilateral ruptured implants .
typical  linguine sign  within implants representing collapsed implant shell mri of a woman with intracapsular rupture of a single - lumen silicone implant .
( a ) axial t2-weighted turbo spin - echo and ( b ) axial silicone - excited sequence .
the study shows a hypointense subcapsular line at the anterior margin of the implant ( solid arrow ) ; the  teardrop sign  and  key - hole sign  are also present ( open arrows ) .
focal change in signal at the anterior margin of the implant ( white open arrow ) can also be observed extracapsular silicone implant rupture is defined as rupture of both the implant shell and the fibrous capsule , with macroscopic silicone leakage that extends beyond the fibrous capsule into surrounding tissues .
focal areas of high signal intensity in sequences that enhance only the silicone represent free silicone [ 5 , 9 , 12 , 16 ] ( fig . 
8mri of a woman with an extracapsular rupture of a single - lumen silicone implant .
a and b sagittal silicone - excited sequences demonstrate the presence of free silicone gel around the implant ( white arrows ) .
( c ) axial silicone - excited sequence shows free silicone gel located in the internal mammary chain ( black arrow ) mri of a woman with an extracapsular rupture of a single - lumen silicone implant .
a and b sagittal silicone - excited sequences demonstrate the presence of free silicone gel around the implant ( white arrows ) .
( c ) axial silicone - excited sequence shows free silicone gel located in the internal mammary chain ( black arrow ) unlike rupture , gel bleed is microscopic silicone leakage through an intact implant shell .
this phenomenon is closely related to the chemical affinity between the outer shell of the silicone elastomer and the gel contained therein .
indeed , the gel , if in contact with the outer shell , can break the noncovalent molecular bonds between the polymer chains , causing swelling and weakening of the shell itself .
once it separates from its shell , silicone can migrate , even reaching the upper limbs , the liver , the inguinal lymph nodes , the synovium , the skin , and the pleura fluid .
for this reason , the presence of silicone gel in regional lymph nodes can be due to gel bleed and not be always indicative of a present implant rupture . with the introduction of new cohesive gel implants ,
most normal transudation of microscopic amounts of silicone gel can not be detected by mri .
only when a gel bleed is extensive can silicone gel be detected outside the implant shell and form the inverted teardrop sign .
an uncollapsed implant rupture can have a similar or identical magnetic resonance appearance to a large gel bleed .
mri often shows radial folds or normal infoldings of the shell extending to the periphery of the implant .
these folds may appear prominent and complex , but should not be confused with implant rupture or leak .
this is one of the major pitfalls and causes of false positives on mri , mimicking the total collapse of the implant shell [ 9 , 10 , 13 , 16 ] .
radial folds and periprosthetic fluid are considered normal variants of breast implants ( fig . 
this reactive fluid probably results from an inflammatory response and is not indicative of implant rupture.fig .
9axial t2-weighted turbo spin - echo image ( a ) and axial ct scan ( c ) of single - lumen implants show small amount of reactive fluid ( arrows ) .
( b ) axial t1-weighted turbo spin - echo image demonstrates normal radial folds of the membrane ( arrowhead ) . simple or complex folds are not in themselves indicative of rupture axial t2-weighted turbo spin - echo image ( a ) and axial ct scan ( c ) of single - lumen implants show small amount of reactive fluid ( arrows ) .
( b ) axial t1-weighted turbo spin - echo image demonstrates normal radial folds of the membrane ( arrowhead ) .
simple or complex folds are not in themselves indicative of rupture radial folds are frequently observed in patients with capsular contracture .
it is caused by excessive scar tissue around the implant that tightens and squeezes the implant . occasionally , the capsule tears , allowing part of the implant to herniate into adjacent parenchyma .
the capsule sometimes calcifies , and rigid calcium deposits may be palpated immediately adjacent to the implant ( fig . 
10chest plain film of a woman with capsule calcification ( arrowheads ) adjacent to the implant .
many augmented patients develop capsular contracture chest plain film of a woman with capsule calcification ( arrowheads ) adjacent to the implant .
many augmented patients develop capsular contracture rarely , intracapsular rupture will show multiple hyperintense foci on t2-weighted images or multiple hypointense foci on water - suppression images within the implant lumen ; these findings are referred to as the  salad oil sign  or  droplet sign  . without other mri evidence of implant rupture , like the identification of the collapsed implant shell or free silicone within the breast parenchyma ( with no previous history of implant rupture ) , water droplets or small amounts of air within a silicone implant are not reliable signs of implant rupture [ 9 , 10 , 16 ] .
however , this sign should prompt the search for subtle signs of intracapsular rupture   ( figs . 
the entire spectrum of mri findings for silicone breast implants is illustrated in figs . 
11a sagittal silicone - excited mri sequence and ( b ) axial t2-weighted turbo spin - echo image of a 64-year - old woman with changes in the signal intensity of the silicone gel ( black arrows ) .
the margins of the implant are slightly irregular and a small amount of fluid surrounds the prosthesis ( white arrow ) .
12mri of a 54-year - old woman with a ruptured breast implant confirmed at surgery . a axial silicone suppression .
a moderate amount of water and probably serum is mixed in the silicone gel around the implant ( black asterisks ) .
note also the punctuate changes in signal intensity  droplets within the implant ( arrows ) and punctuate and hyperintense images due to calcifications in the implant periphery ( arrowheads)fig .
a intact implant has an uninterrupted shell and fibrous capsule adjacent to the breast parenchyma .
b periprosthetic fluid . presence of a small - to - moderate amount of reactive fluid surrounding the implant .
lines extending from the surface of the implant and inwards in a rather perpendicular manner .
the border of the implant is bulging more than usual ( called the  rat - tail sign  when very pronounced ) .
the last two images represent silicone gel leakage through a small focal implant shell tearfig .
the beginning and the end of the line can be followed to the surface of the implant .
disruption of the shell and fibrous capsule will allow silicone to extravasate into surrounding breast tissue .
c  linguine sign  . folded wavy multidirectional lines within the silicone gel , representing the collapsed implant shell .
two parallel lines in close proximity forming a double - contoured subcapsular line within the silicone gel a sagittal silicone - excited mri sequence and ( b ) axial t2-weighted turbo spin - echo image of a 64-year - old woman with changes in the signal intensity of the silicone gel ( black arrows ) .
the margins of the implant are slightly irregular and a small amount of fluid surrounds the prosthesis ( white arrow ) .
mri of a 54-year - old woman with a ruptured breast implant confirmed at surgery . a axial silicone suppression .
a moderate amount of water and probably serum is mixed in the silicone gel around the implant ( black asterisks ) . note also the punctuate changes in signal intensity 
droplets within the implant ( arrows ) and punctuate and hyperintense images due to calcifications in the implant periphery ( arrowheads ) variants of normal breast implants .
a intact implant has an uninterrupted shell and fibrous capsule adjacent to the breast parenchyma .
b periprosthetic fluid . presence of a small - to - moderate amount of reactive fluid surrounding the implant .
c simple or complex radial folds . lines extending from the surface of the implant and inwards in a rather perpendicular manner . d calcification and thickening of the fibrous capsule findings of possible breast implant rupture . a deformity in contour .
the border of the implant is bulging more than usual ( called the  rat - tail sign  when very pronounced ) .
the last two images represent silicone gel leakage through a small focal implant shell tear definitive findings of breast implant rupture . a subcapsular lines .
the beginning and the end of the line can be followed to the surface of the implant .
disruption of the shell and fibrous capsule will allow silicone to extravasate into surrounding breast tissue .
c  linguine sign  . folded wavy multidirectional lines within the silicone gel , representing the collapsed implant shell .
two parallel lines in close proximity forming a double - contoured subcapsular line within the silicone gel although mri is the most accurate technique for evaluating implant integrity , it is important to know the mammographic , us and ct findings for implant rupture .
mammography is of little value in the assessment of implant integrity , although it may be useful for the assessment of the surrounding breast tissue .
silicone implants should be evaluated on a yearly basis to detect any change in configuration or identify any new free silicone within the breast parenchyma .
mammographic features that are not specific to implant rupture include a measurable periprosthetic dense band , periprosthetic calcification , asymmetry of implant size or shape , and focal herniation of the implant .
16 ) is significantly associated with extracapsular rupture ( p    0.05 ) and inhomogeneous , reduced radiopacity seems to indicate rupture , without discriminating the type of rupture ( p    0.05 ) .
specific mammographic evidence of implant rupture is extravasation of silicone outside the implant shell .fig .
diffuse areas of increased density are visualised adjacent to the implant ( arrows ) oblique mammograms in a 29-year - old transsexual with subglandular implants and silicone injections .
diffuse areas of increased density are visualised adjacent to the implant ( arrows ) because mammography can easily detect free silicone within the breast parenchyma , extracapsular silicone implant ruptures can be identified .
unfortunately , silicone is dense and is not easily penetrated by the x - ray energies used for mammography ; therefore , intracapsular rupture can not be identified by mammography .
the sensitivity of mammography for the rupture of silicone implants is variable but always low , ranging between 2530% [ 10 , 12 ] and 68% .
the best mammograms are obtained when the breast is maximally compressed so the x - ray beam penetrates the thinnest possible layer of tissue . in 1988 , eklund et al . [
13 , 15 ] introduced the displacement technique to facilitate mammography in augmented women ( fig . 
a thorough clinical history should be obtained before mammography to ensure that the patient has not had a previous implant rupture or has not had direct silicone injections.fig .
patients with submammary implants have fewer visualised area compared to patients with submuscular implants . the displacement technique introduced by eklund
is visualised with displacement ( below ) than with standard compression mammography ( above ) implant position is an important factor when studying the breasts .
the displacement technique introduced by eklund facilitates mammography in women with implants . slightly more tissue
assessments of the usefulness of ultrasonography ( us ) for detecting implant ruptures vary widely .
typically , us breast implant examination involves evaluation of morphology , contour and contents , periimplant tissues and axillae .
thus , the transversal - to - longitudinal ratio of the implants is calculated , the regularity of implant margins ( radial folds ) and the homogeneity of the implant lumen are checked , and signs of free silicone or granulomas in the breast or in the axillary lymph nodes are sought ( fig . 
a completely negative us examination strongly supports implant integrity , limiting the application of mammography or mri to cases suspicious at us [ 1 , 10].fig .
breast gland ( black asterisk ) , pectoralis major muscle ( black arrow ) , and implant shell ( white arrow ) visualised as a thin and continuous echogenic line at the parenchymal tissue - implant interface , and silicone implant ( white asterisk ) .
( c ) a small fluid collection around the implant ( arrowhead ) and ( d ) a simple infolding of the shell silicone implant ( arrowhead ) a and b ultrasonography of a woman with an intact implant .
breast gland ( black asterisk ) , pectoralis major muscle ( black arrow ) , and implant shell ( white arrow ) visualised as a thin and continuous echogenic line at the parenchymal tissue - implant interface , and silicone implant ( white asterisk ) .
( c ) a small fluid collection around the implant ( arrowhead ) and ( d ) a simple infolding of the shell silicone implant ( arrowhead ) reverberation artefacts are commonly encountered in the anterior aspect of the implant and should not be confused with abnormalities .
one limitation of us is that marked attenuation of the ultrasound beam by silicone hinders the evaluation of the back wall of an implant and the tissue posterior to it .
similarly , residual silicone granulomas from extracapsular rupture or from previous direct silicone injections compromise the evaluation of a new implant ( figs .  19 and 20).fig .
19(above ) a coronal maximum intensity projection from a silicone - excited sequence in a transsexual ( fig .
16 ) demonstrating multiple nodules with high signal throughout both breasts representing free silicone ( arrows ) .
( below ) it is extremely difficult to evaluate the silicone implants by ultrasonography because of attenuation of the ultrasound beam by the free injected silicone and granuloma formation in the subcutaneous tissuefig .
20a coronal silicone - excited sequence and ( b ) coronal contrast - enhanced fat - suppressed t1-weighted image of the previous patient show multiple nodules of free silicone (  siliconomas  ) in the gluteal muscles ( above ) a coronal maximum intensity projection from a silicone - excited sequence in a transsexual ( fig .
16 ) demonstrating multiple nodules with high signal throughout both breasts representing free silicone ( arrows ) .
( below ) it is extremely difficult to evaluate the silicone implants by ultrasonography because of attenuation of the ultrasound beam by the free injected silicone and granuloma formation in the subcutaneous tissue a coronal silicone - excited sequence and ( b ) coronal contrast - enhanced fat - suppressed t1-weighted image of the previous patient show multiple nodules of free silicone (  siliconomas  ) in the gluteal muscles radial folds present as echogenic lines that extend from the periphery to the interior of the implant .
small amounts of free silicone mixed within the surrounding breast tissues give rise to the characteristic echogenic  snowstorm 
( statistically significant for extracapsular rupture , p    0.05 and the most sensitive and specific sign at us ) .
this sign is the most reliable sign of extracapsular rupture   and consists of a group of focal nodules with a generalised increase in echogenicity of the breast tissue and loss of normal parenchymal interfaces resulting from dispersion of the ultrasound beam .
the nodules represent silicone granulomas , composed of free silicone and surrounding fibrous tissue reaction , lying outside the confines of the fibrous capsule .
21extracapsular silicone implant rupture in a 52-year - old woman with a history of breast cancer who presented with a palpable lesion in the supraclavicular right region .
mammogram shows an irregular lump from the implant ( arrowhead ) and ultrasonography demonstrates the presence of a nodular lesion with typical inhomogeneity ( the  snowstorm sign  ) at the posterior margin , suspicious for a lymph node containing siliconefig .
22cytology of the node shows multinucleated foreign - body giant cells ( arrowhead ) with abundant birefringent particles inside and outside the cytoplasm , compatible with gel silicone ( arrows ) .
axial t2-weighted turbo spin - echo mri study corroborated an extracapsular rupture of the implant extracapsular silicone implant rupture in a 52-year - old woman with a history of breast cancer who presented with a palpable lesion in the supraclavicular right region .
mammogram shows an irregular lump from the implant ( arrowhead ) and ultrasonography demonstrates the presence of a nodular lesion with typical inhomogeneity ( the  snowstorm sign  ) at the posterior margin , suspicious for a lymph node containing silicone cytology of the node shows multinucleated foreign - body giant cells ( arrowhead ) with abundant birefringent particles inside and outside the cytoplasm , compatible with gel silicone ( arrows ) .
axial t2-weighted turbo spin - echo mri study corroborated an extracapsular rupture of the implant us can also detect intracapsular rupture by identifying a series of horizontal echogenic straight or curvilinear lines , somewhat parallel , traversing the interior of the implant , commonly known as the  stepladder sign  ( statistically significant for intracapsular rupture , p    0.05 ) .
this sign is analogous to the linguine sign seen on mri , and it is the most reliable sign of intracapsular rupture . it is important not to confuse the stepladder sign with normal prominent radial folds .
at ct , an intact silicone implant is characterised by an oval shape and homogeneous grey density within a surrounding high - density ring .
the ct findings of intracapsular silicone implant rupture are similar to the mri findings , and the linguine sign can also be seen at ct .
because silicone and soft tissues have similar radiodensities , extracapsular silicone can be difficult to identify on ct .
however , in most cases of extracapsular silicone implant ruptures , ct can detect the collapsed implant shell , so the ruptured implant is not usually missed.fig .
a axial ct scan shows a severe deformity of the right implant surface representing a collapsed ruptured prosthesis ( arrow ) .
b sagittal multiplanar reconstruction and ( c ) axial ct scan of the left implant show high - density curvilinear lines within the implant (  linguine sign  , arrows)fig .
( a ) axial ct scan shows small high - density lines within the silicone gel in the right implant , suggestive of collapsed rupture ( arrow ) .
( b ) axial silicone - excited mri sequence confirmed intracapsular rupture , showing hypointense wavy lines at the posterior margin of the right implant (  linguine sign  ) and subcapsular line at the anterior margin ( arrows ) .
normal infoldings in the left implant ( arrowhead ) bilateral ruptured implants in a woman with primary lung cancer ( asterisk ) .
a axial ct scan shows a severe deformity of the right implant surface representing a collapsed ruptured prosthesis ( arrow ) .
b sagittal multiplanar reconstruction and ( c ) axial ct scan of the left implant show high - density curvilinear lines within the implant (  linguine sign  , arrows ) unilateral implant rupture .
( a ) axial ct scan shows small high - density lines within the silicone gel in the right implant , suggestive of collapsed rupture ( arrow ) .
( b ) axial silicone - excited mri sequence confirmed intracapsular rupture , showing hypointense wavy lines at the posterior margin of the right implant (  linguine sign  ) and subcapsular line at the anterior margin ( arrows ) .
normal infoldings in the left implant ( arrowhead ) nevertheless , ct uses ionising radiation ; for this reason and its low sensitivity and specificity , ct should not be the study of choice , especially in young women .
most ct images of ruptured breast implants are incidental findings in asymptomatic patients or in already known failed implants .
all breast diseases can also occur in women with implants ; among these , the most important for its prognosis and treatment is breast cancer .
the risk of breast cancer is not increased in augmented women [ 11 , 16 ] , and there is no significant difference in breast cancer survival rates between women with and those without implants [ 11 , 12 ] . however , because augmented women will sometimes develop breast cancer , there should be persistent precautions concerning cancer detection .
implants might interfere with the earliest possible detection of a cancer by altering physical examination of the breast or impairing various imaging techniques   ( figs . 
the sensitivity of mammography and us for cancer detection may be reduced in augmented woman .
however , the presence of the implant does not seem to decrease the sensitivity of breast mri [ 11 , 14 ] . when evaluating these patients , physical and mammographic findings should be correlated .
25breast ultrasonography of a 39-year - old ( a ) and a 30-year - old ( b ) augmented women . in both studies there
c ultrasonography of a 46-year - old augmented woman with a history of breast cancer .
us shows a lesion suspicious of recurrent tumor ( arrow ) that was confirmed by histology .
26an oblique mammogram of a 57-year - old woman with a submammary implant ( a ) .
a cluster of suspicious microcalcifications can be identified in the breast gland ( arrows ) .
a magnified mammogram ( b ) confirms the presence of malignant microcalcifications ( arrows ) breast ultrasonography of a 39-year - old ( a ) and a 30-year - old ( b ) augmented women . in both studies there
c ultrasonography of a 46-year - old augmented woman with a history of breast cancer .
us shows a lesion suspicious of recurrent tumor ( arrow ) that was confirmed by histology .
breast implant ( asterisk ) an oblique mammogram of a 57-year - old woman with a submammary implant ( a ) .
a cluster of suspicious microcalcifications can be identified in the breast gland ( arrows ) .
a magnified mammogram ( b ) confirms the presence of malignant microcalcifications ( arrows ) mri is clearly recommended in augmented woman with suspicion of a tumor .
all suspicious lesions should be analysed by fine - needle aspiration or core needle biopsy with maximum caution to avoid damaging the implant ( fig . 
( right ) real - time ultrasound is used to guide the needle tip ( arrow ) ( left ) metallic clip placed in the microcalcifications site after biopsy .
( right ) real - time ultrasound is used to guide the needle tip ( arrow )
the risk of implant rupture increases with implant age . radiologists need to be able to recognise the normal appearance of commonly used implants on various imaging techniques .
the role of mri in the evaluation of breast implants resides in implant integrity evaluation and breast cancer detection ( especially in women with oncoplastic reconstructive surgery ) .
intracapsular rupture , which is frequent but often clinically silent , can not be easily detected by mammography because of the radiopacity of the implant .
the sensitivity of ultrasonography is greater if discontinuous echogenic lines within silicone gel (  stepladder sign  ) are detected .
periprosthetic hyperdensity on mammography and the  snowstorm sign  on ultrasonography are significantly associated with extracapsular rupture .
mri is also the most accurate technique for differentiating intracapsular from extracapsular rupture and for assessing the extent of silicone leakage into the breast parenchyma and granuloma formation .
mri can reliably reveal collapsed intracapsular rupture by detecting shell fragments floating inside the silicone gel implant (  linguine sign  ) .
an uncollapsed silicone implant rupture is seen as a sometimes subtle silicone invagination between the inner shell and fibrous capsule , known as the  teardrop sign  or the  key - hole sign  .
other imaging signs , such as the  salad oil sign  or  droplet sign  , are nonspecific and not reliable without other mri evidence of implant rupture .
it is essential to be aware of the spectrum of normal appearances to avoid false - positive findings ( prominent radial folds ) .
moreover , the information provided by plastic surgeons is critical and often essential in the evaluation of breast implant integrity .
the surgical technique of implantation , intraoperative complications that may have occurred , and the clinical monitoring of patients are very useful tools that the radiologist need to know about . in general , in symptomatic patients , after conventional imaging , non - contrast mri is recommended to confirm or exclude rupture .
mri is not recommended for screening for implant rupture in asymptomatic patients . in patients with oncoplastic surgery
 the number of women with breast implants is increasing . 
 radiologists must be familiar with the normal and abnormal findings of common implants . 
 implant rupture is a well - known complication after surgery and is the main cause of implant removal . 
 although mammography and ultrasonography are the standard first steps in the diagnostic workup , magnetic resonance imaging ( mri ) is the most useful imaging modality for the characterisation of breast implants because of its high spatial resolution and contrast between implants and soft tissues and absence of ionising radiation . 
 mri has the highest sensitivity and specificity for implant rupture , thanks to its sequences that can suppress or emphasise the signal from silicone . 
 regardless of the technique used , the overall aim of imaging breast implants is to provide essential information about tissue and prosthesis integrity , detect implant abnormalities and detect breast diseases unrelated to implants , such as breast cancer . 
Introduction
Magnetic resonance imaging
Mammography
Ultrasonography
Computed tomography
Additional lesions found in breast implant study
Conclusion