IMAGING OF BREAST IMPLANTS

IMAGING OF BREAST IMPLANTS
M.Sklair-Levy, M.D Radiology Department Sheba Medical Center Israel

Imaging the Breasts in Patients with Breast Implants
The goal of imaging: To evaluate breast tissues To evaluate the implants for complications sonography in evaluation of patients who do not have implants—to evaluate palpable and mammographic abnormalities.

Background Breast augmentation has been performed for more than a century Different substances have been used: Fat from lipomas Czerny Paraffin Polyvinyl alcohol plastic sponges Free silicone injections

Background Associated with unacceptably high complication rates
Inflammation Granuloma formation Necrosis Hardening and deformity of the breast Migration of the implanted materials,embolization and death.

Background The Cronin implant - the modern silicone gel-filled implant Outer silicone elastomer membrane - shell Filled with silicone gel Early silicone gel-filled peripheral seam backing of implants had thick shell (or envelope) Dacron mesh meant to promote tissue ingrowth and fixation along the posterior surface. fully coated with polyurethane, a peripheral seam, and an internal Y-shaped baffle 1970s implants were available without fixation OVER THE YEARS IMPROVMENTS WERE MADE TO REDUCE THE COMPLICATIONS THAT OCCURRED LIKE GELBLEED AND CPSULAR CONTRACTURE AND WE WILL TALK ABOUT TI LATER Single-lumen silicone gel implants are the prototype implants. First used in 1962, in use for more than 40 years, these single-lumen implants are composed of an outer silicone elastomer membrane (“shell”) and are filled with silicone gel. Use of such single-lumen smooth membrane silicone implants was associated with a relatively high rate of complications—rupture and especially contracture due to severe encapsulation. The silicone elastomer shell is permeable to the oily components of the heterogeneous silicone gel that it envelops. Thus, over time, microscopic amounts of silicone can pass through the intact elastomer membrane to the outside. This phenomenon is known as “gel bleed Silicone that passes outside the shell incites a foreign-body reaction that is thought to be responsible for the formation of a fibrous capsule that forms around the implant as a normal foreign-body reaction in all patients The capsule is fibrous and is the body’s response to the implant; thus, it must be distinguished from the shell, which is an elastomer membrane and part of the implant. single-lumen smooth membrane silicone implants Complications – rupture , encapsulation To improve the cosmetic results of implantation and to reduce complications, many different variations of breast augmentation have been developed and employed Implants designed to reduce silicone fluid bleed middle 1980s - Texturing of implant shells to reduce capsular contracture. Consist of a silicone envelope filled with silicone gel The envelope is a silicone rubber made of either polydimethylsiloxane or polydiphenylsiloxane. Textured shells - outer surfaces have been roughened The gel consists of cross-linked silicone polymers

Background In 1992 the FDA limited the use of silicone implants
Concern about the safety of silicone implants Only saline-filled implants have been available for cosmetic augmentation

Background Current scientific data does not demonstrate an association between breast implants and various diseases The greatest concern was that implants may stimulate Autoimmune reactions Rheumatoid syndromes local complications of implant rupture are frequent silicone is not completely inert but may have antigenic properties. Silica may also occur in association with silicone and potentially result in silicosis.

Introduction FDA recommended removal of ruptured implants
Led to the demand for accurate diagnosis Clinical diagnosis ; breast size or consistency misses 50% of ruptures Implant Accurate diagnostic imaging Medical and public concern regarding implant safety and the recommendation by the Food and Drug Administration that ruptured implants be removed led to increasing demands for accurate diagnostic imaging. Led to increasing demands for accurate diagnostic imaging. For an accurate diagnosis important to know the different type of the implant Implant rupture suspected by breast size change or consistency is difficult to diagnose by physical examination, which misses 50 percent of ruptures. For an accurate diagnosis important to know the different type of the implant

Introduction Since estimated 1.5 to 2 million women have had placement of breast implants 80% - placed for breast augmentation 20% - for breast reconstruction following mastectomy

Types of Implants There are numerous types of implants
More than 200 different types The most common types: Single-lumen saline Single-lumen silicone Double-lumen implants Consist of a silicone envelope filled with silicone gel or saline

Single-Lumen Saline Implants
Outer silicone envelope filled with saline Various valves in the envelope for filling or positioning may be palpable and mistaken for a mass may also be evident by mammography The type most frequently implanted today in the USA Various valves may be present to allow adjustment of the size of the implant that contains saline. Saline implants have the advantage over silicone gel implants of being implantable through smaller incisions because they can be placed while collapsed and inflated later

Disadvantages Less optimal cosmetic result than does silicone gel More prone to rupture with minor trauma the saline is almost always rapidly resorbed

Double-lumen Implants

Double-Lumen (Bilumen) Implants
Inner silicone gel compartment Outer saline compartment Silicone elastomer membrane surrounds each compartment fill valve degree of filling varies contain inner and outer compartments The outer elastomer shell may be either smooth or textured. Double-lumen implant – saline surrounding an internal silicone-filled implant Reverse double-lumen implant contains silicone surrounding saline In most cases, only a small volume of saline

Reverse double-lumen Implants
Double-lumen expander implants (Becker implants) Inner saline compartment Outer silicone gel compartment Silicone elastomer membrane surrounds each compartment Most often used for breast reconstruction after mastectomy Size adjustability The inner compartment has a fill port that may be removable. Like single-lumen saline and double-lumen implants, Becker expanders can be placed while deflated and subsequently expanded, usually by several small injections over time in order to stretch tissues gradually and to expand the space into which a permanent single-lumen saline implant will later be placed. Silicone gel in the outer and saline in the inner lumen Size adjustability is provided by adding saline to the inner lumen, while preserving the feel of a silicone gel-filled implant The inner lumen can be filled through a leaflet valve or valves The most common implants of this type in use in the United States at this time are the Becker implants Double-Lumen Expander Implants (Becker Implants is provided by adding saline to the inner lumen, while preserving the feel of a silicone gel-filled implant Advantages smaller than single-lumen silicone implants when implanted can be expanded using the outer saline compartment fill valves later less likely to incite an abnormally thick, contracted capsule the inner silicone gel component gives a better cosmetic result than saline alone collapse of the outer saline compartment will not adversely effect the appearance of the breast in most patients because the center silicone gel component is mainly responsible for the implant size rupture of the inner compartment and gel bleed will be contained within the outer saline compartment.

IMAGING

Mammography Conventional MLO , CC views Implant displacement views
Spot-compression and magnification views are possible

Conventional Mammography
Standard views - MLO and CC the implants in the field of view compression sufficient to hold the breast Rupture of implants during mammography is rare but has been reported Excess compression only pushes the implant toward the skin and compresses the tissues in the wrong direction. as far into the field of view as possible to permit evaluation of the tissues deep and around the implant Mammography usually is not associated with implant rupture

Mammography

Mammography Implant displacement views - MLO, CC
Improve the ability to image the breast tissues Displacing the implant back against the chest wall Breast tissues pulled forward as with a normal mammogram Direct compression applied separating overlapping structures

Positioning of the implants
The implantation site subglandular retropectoral To improve the cosmetic results of implantation and to reduce the percentage and severity of complications, many different variations of breast augmentation have been developed and employed The implantation site also varies. Implants can be placed in either subglandular or retropectoral locations. Finally, implants can be placed from inframammary, periareolar, and axillary routes, and they can also be placed endoscopically through paraumbilical incisions. It is estimated that there are more than 200 different types and variations of mammary implants

Subglandular Position
Mainly in the past The implant is placed behind the breast tissue In front of the pectoralis major muscle

Subpectoral Placement Behind the pectoralis major muscle
reduce the development of capsule formation and contracture commonly occurs around subglandular implants. due to motion of the muscle over the surface of the implant The subtropectoral implant is preferable for mammography because it facilitates implant displacement and permits better compression of the breast .

Mammography – Type of Implant
The type of implant can usually be determined Possible to distinguish between saline and silicone gel single-lumen implants The type of implant and the site of implantation can usually be determined

Mammography - Type of Implant
single-lumen silicone gel implant double-lumen implant single-lumen saline implant

Mammography of Intact Implants
Bulges, irregularities, in the outer contour of silicone implants are nonspecific Likely due to pressure deformity from the surrounding tissues Incomplete fibrous encapsulation Herniation - protrusion of the implant through opening in the fibrous capsule

Capsular Calcifications
Focal or diffuse calcifications may be seen along the surface of the implant Tend to increase with the age of the implant probably due to microscopic gel bleed through the capsule Do not indicate rupture of the implant No clinical significance

Complications of Breast Implants
As expected with other surgical procedure in which a prosthetic device is implanted Acute Late

Acute Complications Bleeding and infection Asymmetry
Loss of nipple sensation Pain and tenderness

Acute Complications Asymmetry - implants can be asymmetric in size, shape, or position. Advantage of saline and double-lumen implants is that the size can be adjusted Loss of Nipple Sensation Occurs most frequently with the periareolar approach

Late - Complications Capsular contracture
Rupture (intracapsular or extracapsular) Migration Herniation Hematoma/seroma Infection

Capsular Contracture Most common complication Occurs in 10%
Capsule formation begins within weeks of implantation All implants become encapsulated by fibrous tissue A response to foreign body Contraction can occur weeks to years after implantation

Capsular Contracture The exact cause of capsular contracture is uncertain Gel bleed - silicone gel leakage through microperforations in an intact implant envelope Stimulate production of collagen around the implant Leading to fibrous capsule formation and capsular contracture

Implant Rupture The second most common complication
Loss of integrity of the implant envelope/shell Most implants show some evidence of implant leakage after 15 years Spectrum of ruptures ranging from microscopic rents to complete collapse of the implant The silicone elastomer shell that envelops all implants weakens with age The most important to rule out – diagnosis is rarely clinical , usually imaging

Incidence The absolute incidence and prevalence of implant rupture is not known The reported incidence varies 5% -10% - initial studies - in asymptomatic patients based on clinical and mammography 34% - MRI studies The incidence of spontaneous implant rupture is uncertain because many cases are subclinical The reported incidence varies greatly, depending on the patient population and the method of documenting rupture. initial studies suggested only about a 5% to 10% rate of rupture in asymptomatic patients based on clinical and mammographic findings, recent MRI studies have found that as many as 34% of implants may show evidence of rupture Rupture of implants during mammography is rare but has been reported Our more recent experience with ultrasound of implants is that intracapsular rupture is the rule, rather than the exception, in implants that are 15 years old or older.STAVROS depending on the patient population method of documenting rupture

Symptoms Symptoms - depending on the type of implant
Ruptured saline implants deflate rapidly Rupture of single-lumen silicone gel implants or of double-lumen implants - more difficult to evaluate The clinical findings in rupture of single-lumen silicone gel implants or of double-lumen implants, on the other hand, are much more difficult to evaluate may be dramatic or totally unsuspected. Rupture can be caused by obvious trauma but can also occur spontaneously Often, the time of rupture is indeterminate.

Single-Lumen Saline Implant
Complete collapse of the implant and its capsule almost immediately after rupture Marked asymmetry of the breasts Diagnostic imaging - unnecessary Clinical findings enough Imaging to rule out breast pathology The role of mammography in patients with collapsed saline implants is primarily to exclude cancer before explantation or replacement of the implants Additionally, the collapsed implant shell is readily apparent on mammograms as well as clinically The role of ultrasound in such patients, as in patients without implants, is to evaluate palpable lumps and mammographic abnormalities to determine the need for concurrent biopsy at the time of explantation or reimplantation. Typically results in a complete collapse of both the implant and its capsule almost immediately after rupture The distinction between intracapsular and extracapsular rupture is irrelevant The extravasated saline is rapidly absorbed

Single Lumen Saline Implant Rupture
Mammography, although readily able to demonstrate rupture of single-lumen saline implants (A), is generally not useful for diagnosing intracapsular rupture of single-lumen silicone gel implants (B). The ruptured and completely collapsed shell of the single-lumen silicone gel implant shown in part B is silhouetted by the equally dense extravasated silicone gel that remains contained within the fibrous periimplant capsule sensitive for rupture of saline implants insensitive for detection of intracapsular rupture in patients with single-lumen silicone gel implants Intracapsular ruptures are missed by mammography because the radiographically dense extravasated silicone gel is contained within the fibrous capsule, which has the same shape as the intact implant

Saline Implant Rupture
A completely collapsed saline implant shell may be seen as an incidental finding during targeted sonography for evaluation of a palpable or mammographic abnormality. FIGURE 59. Split-screen mirror-image scans of the right and left implants show an intact single-lumen saline implant on the patient’s left side but a completely collapsed implant shell containing no saline on the right side. The layered folds of collapsed implant shell create an appearance similar to linguini; thus, this finding has been termed the “linguini sign” in the magnetic resonance imaging literature. It appears as a collection of parallel, horizontally oriented echogenic lines, very similar to the “linguini sign” described in the MRI literature. Although collapse of the ruptured saline implant and resorption of the extravasated saline are both usually complete, in certain cases, collapse may be incomplete, and some saline that is not under pressure may remain within folds of the implant shell. Intact saline implant Collapsed saline implant

Silicone Gel Implant Rupture
Intracapsular rupture – most common Rupture of the shell , silicone gel that leaks out of the implant remains confined within the periimplant fibrous capsule Extracapsular rupture - implant envelope rupture with silicone gel extruded outside of the fibrous capsule Implants were interpreted as intact, intact with gel bleed, intracapsular rupture, or extracapsular rupture Intracapsular ; Extracapsular Intracapsular rupture - the most common, defined as rupture of the elastomer shell with silicone leakage that does not extend outside of the fibrous capsule. Extracapsular rupture - If both the fibrous capsule and implant envelope are disrupted, free silicone gel extending into the breast tissue. The degree of leakage of silicone gel from the shell into the intracapsular space varies Early / mild - the amount of extravasation and the degree of shell collapse can be minimal Complete shell collapse - all silicone gel escapes from the shell into the intracapsular space

Implants Shell / Fibrous Capsule
The capsule is fibrous and is the body’s response to the implant; thus, it must be distinguished from the shell, which is an elastomer membrane and part of the implant

Symptoms The clinical findings - difficult to evaluate
can be clinically inapparent The implant can remain almost fully expanded even in complete collapse the outer contour of the periimplant capsule can remain normal the breast size will appear normal Because of the very high viscosity of silicone gel, leaks through defects in the elastomer shell are usually very slow, the leak may be limited by inflammatory response, and the shell does not usually rapidly decompress With only a thin layer of sticky, extravasated silicone deposited along its outer surface even in intracapsular ruptures in which all of the silicone gel extravasates from the shell and the shell collapses completely Rupture of the elastomer shell surrounding the inner silicone gel compartment mixing of saline and silicone gel within the intact outer compartment Will not affect the overall size of the implant Rupture of the elastomer shell surrounding the outer saline compartment may not be clinically obvious The outer saline compartment is small compared to the size of the inner silicone gel compartment

Mammography of Silicone Gel Implant Rupture
Extracapsular rupture Irregular collections of free silicone outside the implant – unusual Silicone in axillary lymph nodes Contour abnormalities – more common - may be misleading cannot be differentiated from herniation may be suggested by bulges in the implant contour

Implant Bulge

Extracapsular rupture
clear indication that an implant has ruptured. Mammographic signs of extracapsular rupture Irregular collections of silicone seen outside the implant Silicone in axillary lymph nodes

Mammography - Intracapsular Rupture Low Sensitivity
Note that the mammogram is incapable of showing intracapsular rupture because the mammographic density of the collapsed silicone elastomer shell and the surrounding extravasated silicone gel are identical. If a capsule has formed around the implant, the envelope may have completely disintegrated but the implant appears intact on the mammogram because the gel is contained by the fibrous capsule. as silicone is highly attenuating and blocks most of the low-energy x-rays used in mammography. an abnormal mammogram more reliably predicts implant rupture than does a normal mammogram predict an intact implant.

Imaging After Explantation
Residual silicone Residual fibrous capsule and calcifications Explantation through a capsulotomy Capsulectomy in addition to explantation As a consequence of the attention paid to concerns over implants, more and more women are having their implants removed imaging findings after explantation vary, depending on whether the patient underwent explantation through a capsulotomy or had capsulectomy in addition to explantation Patients who have undergone explantation occasionally require sonographic evaluation. The imaging findings after explantation vary, depending on whether the patient underwent explantation through a capsulotomy or had capsulectomy in addition to explantation. When implants are removed through a capsulotomy, but the capsule is not removed, the capsule can undergo dense calcification, or serous fluid can accumulate within the fibrous capsule, resulting in an acute or chronic intracapsular seroma This is more likely to occur if the removed implant was a textured polyurethane implant because polyurethane stimulates a chronic inflammatory periimplant effusion and because flecks of polyurethane are likely to remain within the capsule and intracapsular space after explantation, perpetuating the inflammatory effusion even after the implant is removed Finally, seroma formation after explantation is also more common when the removed implant was subglandular in location rather than retropectoral Large intracapsular postexplantation seromas can simulate the presence of an intact implant on mammograms (Fig. 109).

Imaging After Explantation
Residual fibrous capsule Residual silicone

ULTRASOUND

Technique The same supine or oblique position
Linear transducer MHz Large implants or severe contracture - 5-MHz linear or even curved linear transducers Light compression during scanning

Echogenicity of Implant Contents
Intact silicone & saline implants are anechoic

Reverberation Artifact
Reverberation echoes in the near field not uncommon Must be distinguished from the echogenicity Light compression- minimize reverberation echoes

Reverberation Artifacts

Radial Folds Normal variants
May be palpable – when occur on the anterior surface Dynamic - not fixed in position and size

Radial Fold

Implant Fill Valves Saline implants, expanders, and certain double-lumen implants have fill valves can be palpable

Fill Valve - Single-Lumen Saline Implant

Periimplant Effusions

Implantation Site Subglandular implant Retropectoral implant

US of Implant Rupture Saline implants
Single lumen silicone gel implant Complex implants – Double lumen implants Reverse double lumen implants

Extracapsular Rupture
Snow storm appearance - The classic sonographic description of extravasated silicone Homogeneous hyperechoic noise/nodule Posterior shadowing Extracapsular extravasated silicone gel is rapidly walled off by inflammatory response that leads to formation of a silicone granuloma. Such granulomas may cause tender or non-tender palpable lumps, or they may be asymptomatic and unsuspected clinically The classic sonographic description of silicone granuloma is that of the “snowstorm” appearance—a nodule that is markedly and homogeneously hyperechoic; has a well-circumscribed, rounded anterior border; and causes “dirty” incoherent shadowing posteriorly that obscures its posterior border (Fig. 60A) However, not all extravasated extracapsular silicone results in the classic snowstorm appearance. In fact, there is a spectrum of sonographic appearances of silicone granulomas. Some extravasated silicone gel collections have a complex cystic appearance (Fig. 60B). Others can appear to be isoechoic solid nodules. Very old silicone granulomas can progress to the fibrotic phase of foreign-body reaction and can become spiculated mammographically and cause acoustic shadowing on sonography that is suspicious for malignancy. The hallmark of extracapsular rupture is the presence of macroscopic amounts of silicone gel outside of both the implant shell and the periimplant capsule The presence of extracapsular silicone gel implies that there is either simultaneous or preexisting intracapsular rupture. However, intracapsular rupture is not always sonographically demonstrable in patients who have extracapsular rupture granuloma

Snowstorm Appearance In cases in which the extravasated silicone has a classic snowstorm appearance, a definitive diagnosis of silicone granuloma is possible with ultrasound alone

Extracapsular Silicone
There is a spectrum of sonographic appearances of silicone granulomas size chronicity Final diagnosis - biopsy complex cystic appearance Multiple phases can coexist in the same patient isoechoic solid nodules acoustic shadowing And spiculated mammographically - suspicious for malignancy Very old silicone granulomas can progress to the fibrotic phase of foreign-body reaction In cases in which the extravasated silicone has a classic snowstorm appearance, a definitive diagnosis of silicone granuloma is possible with ultrasound alone. in cases that have appearances other than the snowstorm appearance, findings can be nonspecific, and histologic diagnosis may be necessary The variation in the appearances of silicone granulomas appears to be related to several factors–the size of extravasate silicone gel droplets, the amount of fibrous and foreign-body reaction, and the age of the collection Silicone granulomas tend to progress from one appearance to another over time The size of extravasate silicone gel droplets the amount of fibrous and foreign-body reaction the age of the collection However, not all extravasated extracapsular silicone results in the classic snowstorm appearance

Complex Cystic Nodules Acute Extravasation
Large acute extravasations generally have a complex cystic appearance. The 2nd phase is the isoechoic solid nodule The 3rd phase is the classic snowstorm appearance The last phase is the fibrotic phase – shadowing snowstorm appearance is the most common complex cystic - the next most common isoechoic solid nodule and fibrotic phases the least frequently seen. Multiple phases can coexist in the same patient depending on the size and chronicity of the leakage.

Isoechoic Nodule Silicone Granulomas of Intermediate Age

Acoustic Shadowing Old Silicone Granulomas

Silicone in Lymph Nodes
May be associated with extracapsular rupture Appear hyperechoic beginning in the hilum progressing to the cortex snowstorm shadowing Microscopic amounts of silicone can be found within intramammary and axillary lymph nodes even in patients with intact silicone implants, presumably because of microscopic gel bleed Such small amounts of silicone are not identifiable by imaging studies. The earliest finding is increased echogenicity within the lymph node mediastinum that is difficult to distinguish from the normal echogenicity of the lymph node mediastinum unless dirty shadowing is also present (Fig. 68 in the presence of implant rupture, macroscopic amounts of silicone can be carried through lymphatic channels to axillary lymph nodes

Silicone in Lymph Nodes
FIGURE 69. Split-screen images comparing right and left axillary lymph nodes facilitate sonographic assessment of the hyperechogenicity of the silicone gel–bearing left axillary lymph node (right image, arrows

Intracapsular Rupture
Stepladder Sign - multiple folds of the collapsed implant shell floating within a extravasated silicone gel Occurs in large rupture with complete or nearly complete collapse The collapsing envelope appears as linear specular reflections from the torn envelope as it slowly sinks into the gel, which itself remains contained within the fibrous capsule. “linguine sign” (described on MRI ) appears as linear specular reflections from the torn envelope as it slowly sinks into the gel, which itself remains contained within the fibrous capsule. multiple folds of the collapsed implant shell that is floating within a extravasated silicone gel create horizontal echoes that are arranged parallel to each other the sonographic counterpart to the MRI linguini sign

Stepladder Sign

Ultrasound & Intracapsular rupture
There is a spectrum of intracapsular rupture that varies: size of rupture the degree of collapse

Increased Echogenicity
In intracapsular rupture, gel extravasates from the shell into the space between the capsule and shell resulting in an abnormal widening of the space between the capsule and the shell Thus, the key finding in intracapsular rupture is the presence of an abnormal space between the capsule and the shell the stepladder sign sign is only the final and most complete stage The degree of separation between the fibrous periimplant capsule and the shell is directly proportional to the degree of extravasation of silicone from the implant the degree of collapse of the shell FIGURE 74. One of the classic signs of intracapsular rupture is hyperechoic extravasated intracapsular silicone gel (left split-screen image, patient’s right side). Assessing echogenicity of gel is best done on split-screen mirror-image scans of the right and left sides. There is a wide spectrum of intracapsular rupture that varies with the size of rupture and the degree of collapse Intact implant Intracapsular rupture

Separation between the Capsule and Shell
FIGURE 80. The normal triple echogenic line representing the intact capsule–shell complex is present on the patient’s intact right implant (arrows indicate shell; arrowheads indicate superficial surface of capsule). Only a single echogenic line representing the fibrous periimplant capsule (arrowheads) is present on the patient’s left side, where the implant is ruptured. The extravasated gel on the patient’s left side is hyperechoic, and the completely collapsed shell has fallen posteriorly away from the capsule and is not visualized in these images. To summarize, in evaluating a patient with silicone gel–containing implants for intracapsular rupture, three questions must be asked: 1. Is there a separation between the capsular and shell echo complexes? 2. Is the configuration of the separation sheetlike or foldlike? 3. Is the fluid in the space between the capsule and the shell abnormally echogenic? The specific but insensitive classic findings of abnormally echogenic extravasated silicone gel and the stepladder sign which are present only in the small minority of patients with intracapsular rupture in whom collapse of the implant shell is complete or nearly complete The more sensitive but less specific sign of a two-dimensional, sheetlike, abnormal separation of the shell from the capsule The more sensitive but less specific- radial fold that contains abnormally echogenic extravasated silicone gel, the most sensitive, least specific sign of radial fold containing anechoic fluid the less sensitive, more specific sign of radial fold containing echogenic fluid the least sensitive, highly specific sign of radial fold containing the snowstorm appearance Intact implant 3 echogenic lines Intracapsular rupture 1 echogenic line

US of Double-Lumen Implants Rupture
More difficult to evaluate rupture Extracapsular rupture of outer saline shell may simulate single-lumen silicone gel implants Intracapsular rupture - mixing of saline and silicone gel components a mottling of echogenicity, simulating intracapsular rupture of single-lumen silicone gel implants probably not clinically significant single-lumen implants IF WE DON’T KNOW THE TYPE OF THE IMPLANT THAN…. Periimplant effusion can simulate the outer saline compartment of double-lumen implants

Technique MRI exams - 1.5T In prone position
Phased-array breast surface coil Scan parameters High-resolution T2-weighted water/silicone suppressed T1W fat suppressed No I.V. contrast Total scan time - 45min. The combination of the 3-point Dixon and inversion recovery fast spin-echo sequences in our series enabled us to correctly identify silicone in the axilla and to detect silicone around the fibrous capsule, differentiating silicone from reactive fluid. FOV- 20-cm, 256 × 192 matrix ; 4-mm-thick slices with a 2-mm skip

MR Appearance of Normal Implants
The location - subpectoral or subglandular Occasionally, a small amount of reactive fluid surrounds the implant, despite the fact that it is intact

Radial folds - infoldings of redundant envelope
Low signal intensity linear bands extending from the periphery of the implant into the gel or saline as undulations of the implant contour are creases in the implant envelope due to tissue pressure or contraction of the fibrous capsule. Reactive fluid around the implant and water droplets were recorded as nonspecific findings

Radial Folds Simple radial folds- short and straight

Complex Radial Folds - Long Curved

MRI of Ruptured Implant
Intracapsular rupture Extracapsular rupture In case of definite rupture, it was classified as intracapsular (silicone contained within the fibrous capsule) or extracapsular (silicone present outside the fibrous capsule) Intracapsular rupture - the most common, defined as rupture of the elastomer shell with silicone leakage that does not extend outside of the fibrous capsule. Extracapsular rupture - If both the fibrous capsule and implant envelope are disrupted, free silicone gel extending into the breast tissue.

Linguine sign- Ruptured envelope floating within the silicone gel Sensitivity - 76% to 94% Specificity - 97% to 100% Accuracy - 92% PPV - 99% ; NPV - 79% linguine sign - to be a definite sign of intracapsular rupture in more than one-third of the MRI-diagnosed ruptures in this study a teardrop -The least sensitive sign of partial collapse was the teardrop [10]. We did not allow a rupture diagnosis solely on the basis of a teardrop or a noose/keyhole sign, but found alone these signs could generate the diagnosis possible rupture if seen in more than one picture and preferably also in two planes. MR - linguine sign - low signal intensity curvilinear lines within the implant. Best seen on FSE T2W - silicon is very bright and the collapsed elastomer shell is dark.

Linguine Sign

MRI yielding an accuracy of 92%, a of sensitivity 89%, and a specificity of 97%. Correspondingly, the predictive value of a positive MRI examination was 99% and the predictive value of a negative MRI examination was 79%. THE RUPTURE MAY BE PARTIAL OR COMPLETE Linguine sign- complete collapse Intracapsular rupture

Subcapsular Line local shell displacement
subcapsular lines - local shell displacement as the subcapsular line and keyhole sign was also found in a few intact and gel-bleeding implants, but if more than one of these signs were found the sensitivity increased, as it did if subcapsular lines were 3 cm or longer

Keyhole Sign - silicone within a short radial fold
a teardrop -The least sensitive sign of partial collapse was the teardrop [10]. We did not allow a rupture diagnosis solely on the basis of a teardrop or a noose/keyhole sign, but found alone these signs could generate the diagnosis possible rupture if seen in more than one picture and preferably also in two planes. Subcapsular line

Mottled Appearance punctuate changes in signal intensity were found in addition.punctuate changes in signal intensity called for a possible rupture diagnosis, which in one case was maintained at surgery The punctuate changes in signal intensity or "droplets" have in other studies also been interpreted as indicative of rupture, although not certain, and several authors have stressed that such findings can be seen if substances such as antibiotics or steroid have been injected into the implant [12 and 23].

The fibrous capsule and the shell are both ruptured Diagnosis - silicone outside of the fibrous capsule breast parenchyma Axillary lymph nodes However, the intracapsular phase of the process can be difficult to detect on imaging studies The extravasated silicone gel might escape from the implant directly through a coexisting rent in the fibrous capsule into surrounding breast tissues without ever accumulating within the capsule in large enough amounts to be detectable. Theoretically, intracapsular ruptures precede all extracapsular ruptures Extravasated silicone gel no longer remains confined within the intracapsular space but extends into surrounding breast tissues extravasated silicone may be absorbed into lymphatic vessels linear extension of silicone along the chest wall

silicone outside of the implant either separate or contiguous with the implant The linguine sign is commonly present

Silicon in axillary lymph nodes Intra &extra rupture

Extracapsular rupture; intracapsular rupture not seen

MRI - Double Lumen Implants
Can be difficult to evaluate,especially when implant type is unknown Cannot be differentiated from a single lumen implant with a periimplant effusion

MRI - Double Lumen Implants
Extracapsular rupture - leak of the water from the outer compartment Can completely mimic an intact single lumen silicon implant Intracapsular rupture - rupture of the inner membrane – Mixing of water and gel linguine sign , subcapsular line, teardrops

Reverse Double Lumen- Becker expender
saline saline

Implants and Breast Cancer
There is no evidence that implants cause breast cancer Breast implants interfere with performance and interpretation of screening mammography Delayed detection of breast cancer US , MRI can be useful Contrast enhanced sequence added There is no evidence that implants cause breast cancer . However, Handel et al. have shown that breast tumors in patients with implants are larger, have a higher stage, and have a poorer prognosis than those detected in women without implants. This situation is thought to be due to interference of the implant with the performance of mammography rather than a carcinogenic effect Subglandular implants obscure between 22% and 83% (mean, 44%) of the breast on routine mammographic views, depending on breast size and consistency. Even with pushback implant exclusion views, Silverstein found that 36% of the breast was obscured by subglandular implants. Retropectoral implants obscure less breast tissue than do subglandular implants—an average of 25% of the breast tissue on routine views and an average of 15% of breast tissue pushback views

Mammography - extracapsular rupture Ultrasound – extracapsular rupture
Summary Mammography - extracapsular rupture Insensitive for intracapsular rupture Ultrasound – extracapsular rupture Intracapsular rupture MRI Advantages - Sensitivity 94% ; Specificity 97% Disadvantage - most expensive, less available tiplanar imaging entire extent of implant no radiation sensitivity 94% and specificity 97% most expensive MR imaging can demonstrate implant construction more clearly than most other modalities, particularly with respect to internal structure and of complex implants. MRI shows the anterior and posterior aspects of the shell and capsule nearly equally well and therefore has a theoretical advantage in showing isolated mild posterior intracapsular rupture ography , ultrasound , and MR - used to evaluate implant integrity An accurate and complete understanding of the various types of implants and their component features is necessary for diagnostic accuracy. The less frequently seen and rare implant types may result in misdiagnosis even by experienced breast imagers The absolute incidence and prevalence of implant rupture in the population of all women with implants is not known The use of silicone breast implants has been a controversial and hotly debated topic, with most of the controversy centering on the suggested association between silicone and connective tissue disorders (1). Local adverse effects of noncontained silicone are well documented and include granuloma formation, fibrosis, and migration. Although the need to identify and remove a ruptured silicone implant remains somewhat controversial, the timely removal of a ruptured implant is desirable because delays may increase the degree of silicone leakage and migration, thus making complete removal difficult or impossible.

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Focal or diffuse calcifications may be seen along the surface of the implant Tend to increase with the age of the implant probably due to microscopic gel bleed through the capsule Do not indicate rupture of the implant No clinical significance Focal or diffuse calcifications of the inner surface of the capsule commonly occur even in the absence of rupture, usually in reaction to microscopic gel bleed Capsular calcifications tend to increase with the age of the implant. Capsular calcifications are considered to be of no clinical significance unless they simulate malignant calcifications on mammograms. Capsular calcifications that are mammographically visible in patients with intact implants are usually thin and closely applied to the surface of the implant and have a characteristically benign mammographic appearance Dense calcification can create enough acoustic shadowing to prevent sonographic assessment of the implant for rupture Calcifications can be troublesome in patients who have undergone explantation without capsulectomy. The calcifications in the unresected capsule can simulate malignancy, especially in cases in which there is associated intracapsular hematoma, seroma, or fat necrosis. usually lie along the inner surface of the capsule

Acute Complications Bleeding and Infection
The risk for bleeding and infection is similar to the risks of any surgery Infection occurring in the acute phase may persist until the implant is removed

Acute Complications Asymmetry - implants can be asymmetric in size, shape, or position. Advantage of saline and double-lumen implants is that the size can be adjusted Loss of Nipple Sensation Occurs most frequently with the periareolar approach

Capsular Contracture Most common complication Occurs in 10%
Capsule formation begins within weeks of implantation All implants become encapsulated by fibrous tissue A response to foreign body Contraction can occur weeks to years after implantation

Capsular Contracture The exact cause of capsular contracture is uncertain Gel bleed - silicone gel leakage through microperforations in an intact implant envelope Stimulate production of collagen around the implant Leading to fibrous capsule formation and capsular contracture Silicone envelopes with rough textured surfaces [Polyurethane] Texturing the envelope – reduce gel bleed

The Baker Score A standardized scoring system
Clinically evaluates the breast’s appearance, texture, and tenderness 4 grades of severity, ranging from normal to deformed American Society of Plastic Surgeons: Silicone breast implant surgery. Holmes JD: Capsular contracture after breast reconstruction with tissue expansion. Br J Plast Surg 1989 O’Toole M, Caskey CI: Imaging spectrum of breast implant complications: mammography, ultrasound, and magnetic resonance imaging. Semin Ultrasound CT MR 2000

Treatment Implant – various textures, shapes, and locations
Changing the site of implantation from sub-glandular to retropectoral Saline implants Double - lumen implants Closed or open capsulotomy Capsule removal Implant revision and replacement Implant shells and implantation techniques have been altered to minimize the risks for capsular contracture (a) addition of fluorsilicone to the elastomer shell (b) texturing of the outer surface of the elastomer shell, (c) addition of polyurethane to the textured outer surface of the elastomer shell (d) use of saline implants, (e) use of double-lumen implants, (f) changing the site of implantation from sub-glandular to retropectoral. The pectoralis muscles may massage the implant during normal physical activity in a manner similar to deep external massage, thereby preventing capsular thickening

US & Capsular Contraction
The diagnosis is made clinically The sonographic findings include Abnormal spherical shape The capsule is thickened > 1.5 mm The number of radial folds increases redundancy of the shell Split-screen mirror-image scans of the right and left sides in patients who have unilateral contracture nicely contrast the shape differences between capsular contracture and normal implants In patients with capsular contracture, the capsule is abnormally thickened (and usually isoechoic) to more than 1.5 mm Instead of the thin, echogenic line seen in normal thin capsules, the thickened capsule presents as a double echogenic line with an isoechoic space between the lines. The capsular thickness is best demonstrated in regions where the capsule and shell are not in contact with each other—around the periimplant effusion at the edges of the implant (Fig. 50) or at the bases of radial folds (Fig. 51). Because the spherical shape of contracted capsules has a smaller volume than the normal lentiform shape, the shell becomes redundant, and the number of radial folds increases (Fig. 52) The thickness of contracted capsules frequently varies from one part of the capsule to another (Fig. 52). Areas where there is less thickening of the capsule are prone to rupture and herniation, which will be discussed later in this chapter. Although the abnormally thick, contracted capsule is usually isoechoic, in a few cases, it can appear hyperechoic (Fig. 53). is best demonstrated in regions where the capsule and shell are not in contact with each other—around the periimplant effusion at the edges of the implant or at the bases of radial folds increased redundancy of the shell spherical shape of contracted capsules has a smaller volume than the normal lentiform shape, the shell becomes redundant, and the number of radial folds increases

Capsular Contraction Normal implant Contracted spherical implant
FIGURE 49. Split-screen mirror-image scans of the center of implants show a more rounded and spherical shape and much larger anteroposterior dimension for the contracted right implant than for the normal left implant. Note that the abnormally contracted implant has a posterior wall that is convex posteriorly because it is under pressure. Note that the soft normal left implant is convex anteriorly because it is soft enough to be indented by the chest wall deep to the implant. The larger field of view of the 5-MHz curved linear transducer improves the ability to assess implant shape in patients with capsular contracture.

Capsular Contraction 3.5mm 1mm

Disadvantages Less optimal cosmetic result than does silicone gel More prone to rupture with minor trauma the saline is almost always rapidly resorbed Prominent folds and wrinkles are also more common with saline implants than with silicone gel implants because saline implants are sometimes only partially filled and because saline is so much less viscous than silicone gel. The more numerous and deeper wrinkles and folds associated with saline-filled implants may be subject to fatigue fractures that account for at least some of their increased risk for sudden rupture when saline implants do rupture, the saline is almost always rapidly resorbed and does not give rise to inflammation or granuloma formation

Acute Complications Bleeding and infection Asymmetry
Loss of nipple sensation Pain and tenderness

Diagnosis of Implant Rupture
Mammography Ultrasound MRI

Mammography & Implant Rupture
The sensitivity depends upon: Type of implant – saline , silicone gel implant Type of rupture – intracapsular , extracapsular

Single Lumen Saline Implant Rupture
Rupture of single lumen saline implants is usually both clinically and mammographically obvious because virtually all ruptures are rapid and complete (with the exception of slow valve leaks)

Technique The same supine or oblique position
Linear transducer MHz Large implants or severe contracture - 5-MHz linear or even curved linear transducers Light compression during scanning Evaluation of the periphery of the implant is especially important because the shell is thinner along the edges, rupture is more common there, and extravasated extracapsular silicone gel leading to silicone granuloma formation has a propensity to either occur in the periphery or migrate to the periphery of the implant. Assessing the periphery of the implant is also important in sonographic determination of the type of implant and in distinguishing the periimplant fibrous capsule from the implant shell. It is at the edges of the implant and at the bases of radial folds where the separation between the capsule and shell is greatest and easiest to demonstrate sonographically We rely heavily on split-screen imaging of mirror-image locations in the right and left breasts, using the contralateral side as a control when evaluating implants This approach is especially important in evaluating the alterations in internal echogenicity that can occur in patients with intracapsular rupture of single-lumen silicone gel implants, in which a subtle increase in echogenicity may be the primary clue to the presence of an intracapsular rupture The entire implant should be examined , pathology often occurs at the edges

Radial Folds Normal variants
May be palpable – when occur on the anterior surface Dynamic - not fixed in position and size Folds that are thin, that course into the implant contents nearly perpendicular to the outer membrane surface, and that do not contain significant space or fluid within them are Because radial folds are dynamic, such a fold may be present and cause a palpable abnormality when the patient is in the upright position, but not when she is in the supine position in which patients are normally scanned. In such a case, scanning the patient in the supine position will fail to reveal the definitive cause of the palpable abnormality. For this reason, patients with implants who complain of palpable lumps that are present only in a certain position (upright) should be scanned in that position (upright) to maximize the chances of finding a definitive cause (Fig. 20). They occur because the relative size and position of the shell and capsule may vary in different patient positions and with different patient activities

Radial Fold The right image demonstrates a short-axis view through a radial fold. The shell (arrowhead) has invaginated away from the capsule (arrow), creating a potential space for either periimplant effusion or extravasated intracapsular silicone gel to accumulate. The left image shows a wrinkle in a different part of the same implant. The fibrous periimplant capsule (arrow) remains parallel to the silicone elastomer implant shell (arrowhead) throughout the course of the undulation. The degree of wrinkling, folding, and lobulation in the implant membrane varies: generally greater in saline than silicone gel implants Wrinkles should be distinguished from folds. In wrinkles - the outer contour of the implant is lobulated, but the fibrous periimplant capsule and the elastomer shell remain parallel and tightly apposed throughout the course of the lobulation In radial folds - on the other hand, the outer contour of the implant may be maintained, but the elastomer shell invaginates and separates from the capsule, creating a potential space between the shell and capsule

Implant Fill Valves Saline implants, expanders, and certain double-lumen implants have fill valves can be palpable There are various types and locations for fill ports Two main classes of fill valves can be identified sonographically: diaphragm fill valves, which are by far the most frequently seen; and leaflet fill valves, which are less common The valves are typically placed bilaterally symmetrically in the subareolar region, where they are sonographically visible, but not palpable However, in some cases, a valve may not initially be placed subareolarly, and in other cases, it may migrate or rotate out from the subareolar reason as a result of asymmetric capsular contracture or capsular herniation. A valve that is not subareolar in location often has less breast tissue overlying it than does a subareolar valve and therefore may become palpable. That the valve causes the palpable abnormality for which the patient presents can be shown definitively by sonography, allaying patient and referring physician fears (Fig. 26 In other cases, a valve may become palpable because it has become everted owing to increased intraimplant pressure caused by capsular contracture. The eversion of the valve causes it to become palpable (Fig. 27). That the valve causes the palpable abnormality for which the patient presents can be shown definitively by sonography, allaying patient and referring physician fears

Fill Valve - Single-Lumen Saline Implant
FIGURE 25. These are leaflet-type fill valves within a single-lumen saline implant. The leaflet fill valve on the left (arrows) is collapsed. The leaflet fill valve on the right (arrows) is distended with saline

MRI Protocol Sagital / Axial T2 W- FSE water-suppressed
Axial T1-weighted GRE localizer Sagital / Axial T2 W- FSE water-suppressed Axial/Sag T1W silicon suppressed low signal intensity on fat-suppressed T1-weighted MR images or high signal intensity on water-suppressed T2-weighted MR images. . Water suppression- improves the differentiation of silicone from fluid on the T2 images. silicone gel appears as the brightest signal and cysts or peri-implant fluid collections are suppressed and have low signal. fat remains of medium signal intensity Double-lumen implants have a saline compartment, and water suppression is useful in distinguishing this as well.

Mammography Breast cancer detection - sensitivity is reduced
Radiopaque - obscuring large volumes of breast tissue Evaluation of implant integrity Opposite to the compression needed to spread the tissues apart for optimal tissue evaluation. Implants present a problem The implant compresses the tissues toward the skin opposite to spreading

Mammography - Implant Location
Seen on MLO views sometimes possible on CC views

Complications of Breast Implants
As expected with other surgical procedure in which a prosthetic device is implanted Acute Late bleeding and infection tolerance to foreign body - some individuals tolerate implants and others do not.

Late - Complications Capsular contracture
Rupture (intracapsular or extracapsular) Migration Herniation Hematoma/seroma Infection Capsular calcifications Explantation or revision complications Possible long-term complications include: Autoimmune disorder (human adjuvant disease) Carcinogenesis

Mammography of Intact Implants
Bulges, irregularities, in the outer contour of silicone implants are nonspecific Likely due to pressure deformity from the surrounding tissues Incomplete fibrous encapsulation Herniation - protrusion of the implant through opening in the fibrous capsule If the bulge is angular rather than curved, it is more likely to represent extracapsular rupture than herniation They may correspond to herniation of the implant, silicone granuloma, or a combination of both the fibrous capsule may become discontinuous A mammogram cannot differentiate herniation from a rupture Intracapsular rupture- the gel may stay together and maintain a smooth surface by the surrounding fibrous capsule , so that the implant appears normal may represent folds in the surface of an intact implant.

Implant Type Difference in the speed of sound –
Slower through silicone gel m/s Soft tissues - 1,540 m/s through In silicone implants - there will be a step-off in the chest wall at the edge of the implant the chest wall will appear deeper behind the implant In saline implants - there is no step-off in the chest wall Surprisingly, many patients do not know the type of implants they have. In such patients, determining the type of implant from US determination of the mammography is usually possible. However, mammograms are not available in some cases sonography can usually help determine the type of implants This determination is not made from differences in the echogenicity of the filling material but rather by the presence or absence of a sonographic artifact created by the slower speed of sound through the silicone gel (997 m/s through silicone gel versus 1,540 m/s through soft tissues . By scanning the edge of the implant so that the implant extends halfway across the field of view, the apparent depth of the chest wall deep to the implant can be compared with the depth of the chest wall peripheral to the edge of the implant Because of the slowing of sound in silicone, the chest wall deep to a silicone gel implant appears to be deeper than it really is.

US of Silicone & Saline Implants
Silicon implant Saline implant Chest wall-step off Chest wall In vivo scans of subglandular single-lumen silicone gel (left) and single-lumen saline (right) in two different patients show a step-off in the chest wall at the edge of the silicone gel–containing implant (right, arrow), but no step-off at the edge of the saline-containing implant (left, arrow). If a silicone gel–containing implant is soft and compressible, scanning the edge of the implant with excessive scan pressure may flatten the edge of the implant, decrease the thickness of silicone gel traversed, and minimize or even completely obscure the step-off (Fig. 15). Therefore, it is important to use light scan pressure when evaluating the edge of an implant for determining whether the implant contains silicone gel or saline. No step off

Periimplant Effusions
FIGURE 42. Periimplant effusions can accumulate between the implant shell and the surrounding periimplant fibrous capsule. Effusions are more common with textured silicone gel–filled implants than they are with nontextured saline-filled implants but can occur with any type of implant. Periimplant effusion tends to accumulate along the periphery of the implant and within radial folds. Polyurethane-coated implants invariably incite effusion formation

Implantation Site Subglandular implant Retropectoral implant
In patients with subglandular or prepectoral implants, breast tissue and fibrous capsule lie superficial to the implant, whereas the pectoralis major muscle lies posterior to the implant (Fig. 46A). In patients with retropectoral implants, the pectoralis major muscle lies superficially, separating the glandular tissue from the implant and its capsule (Fig. 46B) Subglandular implant Retropectoral implant

US of Complications

Capsule – Shell Complex
Outer surface of capsule Middle line –merged echo of inner surface capsule and outer surface of shell; the space between - the thickness of the capsule Posterior line-inner surface of the shell capsule shell FIGURE 36. This in vivo image shows the capsule–shell echo complex in a patient who has a nontextured single-lumen implant and capsular contracture. The capsule–shell complex is represented by three echogenic lines. The anterior echogenic line is the outer surface of the capsule (arrow), the middle echogenic line is the merged echo of the inner surface of the capsule and outer surface of the shell (arrowhead), and the posterior echogenic line represents the inner surface of the shell (hollow arrow). The space between the anterior and middle echogenic lines (C) represents the thickness of the capsule and is typically isoechoic. The space between the middle and posterior echogenic lines represents the thickness of the shell (S) and is anechoic. silicon

Subcapsular Line - local shell displacement Teardrop or keyhole sign - silicone within a short radial fold Lees sensitive Sensitivity increases if seen in more than one picture and in two planes Mottled appearance of the silicone within the implant Indirect signs- increase the likihood of intracapsular rupture subcapsular line teardrop noose sign small intracapsular rupture cannot be differentiated from gel bleedsubcapsular lines - local shell displacement as the subcapsular line and keyhole sign was also found in a few intact and gel-bleeding implants, but if more than one of these signs were found the sensitivity increased, as it did if subcapsular lines were 3 cm or longer a teardrop -The least sensitive sign of partial collapse was the teardrop [10]. We did not allow a rupture diagnosis solely on the basis of a teardrop or a noose/keyhole sign, but found alone these signs could generate the diagnosis possible rupture if seen in more than one picture and preferably also in two planes. inverted c-sign/noose sign punctuate changes in signal intensity were found in addition.punctuate changes in signal intensity called for a possible rupture diagnosis, which in one case was maintained at surgery The punctuate changes in signal intensity or "droplets" have in other studies also been interpreted as indicative of rupture, although not certain, and several authors have stressed that such findings can be seen if substances such as antibiotics or steroid have been injected into the implant [12 and 23].

Double Lumen Implant

Reverse Double Lumen - Becker Expender

Reverse Double Lumen

US of Implant Rupture Silicone gel single lumen implants
Complex implants Intracapsular rupture Extracapsular rupture

Reverberation Artifact
Reverberation echoes in the near field not uncommon Must be distinguished from the echogenicity Light compression- minimize reverberation echoes

Reverberation Artifacts
High-frequency coded harmonics (right) can greatly reduce the amount of near-field clutter (*) and reverberation artifacts (arrow) present on fundamental images (left) and can make sonographic evaluation of the implant capsule and shell easier and more accurate.

Imaging of Breast Implants
Implants composed of : Inner compartment – silicone , saline Outer membrane – Shell (silicone elastomer membrane) – part of the implant Fibrous Capsule – not part of the implant is the body’s response to the implant

IMAGING OF BREAST IMPLANTS

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