The Role of Breast Ultrasound in Monitoring Breast Implants

Compared to mammograms and MRI, breast ultrasound offers several advantages for implant monitoring [4]:

• Lower cost and no radiation exposure
• Widely available even at small imaging centers
• Non-contrast enhanced procedure
• Simultaneous detailed imaging of breast tissue and implants
• Allows dynamic evaluation during compression/release
• Not affected by implant material or type

When Should Breast Ultrasound be Performed for Implant Surveillance?

Medical organizations provide guidelines on when women with breast implants should undergo imaging evaluations:

• Post-operative checks - Ultrasound should be performed shortly after surgery and at follow up visits to establish a baseline and check for early complications like hematoma or fluid accumulation [5].
• 1-3 years after surgery - Routine surveillance ultrasound is recommended 1-3 years post-op and then every 2-3 years for life to screen for silent rupture [6].
• Symptomatic patients - Patients presenting with breast pain, lumps, swelling, distortion or other concerns should receive a prompt ultrasound exam.
• Screening timeline - Annual ultrasound exams may be warranted in some high risk patients, such as those with a history of capsular contracture or implant rupture [7].
• Uncertain mammogram findings - Ultrasound should be performed after mammograms reveal suspicious areas or uncertain readings in women with augmented breasts.
• MRI screening - Ultrasound may precede MRI to avoid unnecessary MRI exams if no abnormalities are found.

Women should discuss an appropriate ultrasound monitoring schedule with their surgeon based on individual risk factors and implant details. More frequent or additional imaging may be needed beyond standard recommendations in some cases.

How is Breast Ultrasound Performed for Implant Evaluation?

Breast ultrasound exams for implant assessment involve detailed imaging of the breasts and implanted areas. The key components of a breast implant ultrasound include:

• High-frequency transducer - A linear array transducer with frequencies between 10-15 MHz or higher provides optimal resolution of breast implant structures. Lower frequencies (5-8 MHz) have deeper penetration for visualizing tissue behind implants [8].
• Bilateral evaluation - Both breasts are fully evaluated, including medial, lateral, inferior and posterior areas with comparison views of each side.
• Systematic scanning approach - Each area is scanned in transverse/axial and sagittal/longitudinal planes starting near the chest wall out to the nipple and entire breast. Radial scans may also be performed from the nipple outwards.
• Implant measurements - Implant dimensions, fill volumes for saline implants, shell thickness and implant pocket dimensions are measured.
• Compression technique - Moderate compression is applied during scanning to evaluate implant fold integrity, valve function, shell flexibility and identify crease fluid.
• Implant shell - The implant envelope is thoroughly examined for tears, holes, leaks, collapse, folds, valve site integrity and segmental contour irregularities.
• Peripheral assessment - The tissue surrounding the implants is evaluated for fluid collections, masses, lymph nodes or capsular complications.
• Adjunctive B-mode and color Doppler - Color flow imaging highlights ripples or color aliasing indicating rupture sites. Power/spectral Doppler quantifies suspicious internal fluid movements.
• Image documentation - Static images are recorded of all implant areas, along with video clips to allow comparison on serial exams.

Having a complete set of baseline images is important for following up potential issues over long-term implant surveillance.

Indications of Breast Implant Rupture on Ultrasound

Detecting implant rupture is a major goal of surveillance ultrasound exams. There are various sonographic signs that may indicate an implant rupture:

Saline Implant Rupture

• Irregularity or collapse of implant outline, shape or folds
• Decreased implant volume - A saline implant should normally stay fully inflated
• Hyper-echoic lines extending from ruptured valve sites
• Direct visualization of a tear or hole in the implant shell
• Peri-implant fluid collection with internal echo debris
• New hyperechoic mass representing saline solution leakage
• Increased sound wave transmission and posterior enhancement

Silicone Implant Rupture

• Stepladder configuration - Collapsed upper half above a prevailingly filled lower half
• Gummy bear sign - Focal areas of adherent silicone putty against the implant shell
• Turbulent fluid motion on video compression
• Microcysts or microbubbles visualizing silicone droplets
• "Channel sign" - Fluid traversing silicone chambers through a ruptured barrier
• Snowstorm appearance - Echoic specks dispersed within the gel
• Milk of calcium sign - Layering hyperechoic calcifications
• "Strawberry pattern" - Hyperechoic dots settling in gravity-dependent locations

Other suspicious findings include:

• New peri-implant fluid collections or masses
• Enlarged or heterogeneous lymph nodes
• Increased vascularity around implants
• Skin thickening or Cooper's ligament changes

Diagnosing Capsular Contracture with Breast Ultrasound

Another important purpose of breast ultrasound surveillance is detecting capsular contracture. This complication occurs when collagen fibers deposited around the implant during natural healing harden and contract. Signs of capsular contracture on ultrasound include [9]:

• Increased capsule thickness - Normally <2mm, >4mm indicates contracture
• Hyperechoic capsule appearance
• Straightened or angled posterior capsule contour
• Implant deformation - Teardrop shape, compression folds, diameter differences
• Higher echogenicity of implant contents
• Dilated or compressed peripheral veins
• Reduced compressibility and mobility during ultrasound

Capsular contracture is classified into 4 Baker grades based on physical exam findings. Ultrasound can determine the Baker grade which guides treatment:

• Grade I - Soft natural appearance, capsule <2mm
• Grade II - Minimal firmness, capsule 2-4mm
• Grade III - Noticeable distortion, >50% compressibility, capsule >4mm
• Grade IV - Severecontracture with painful rock-hard breasts, capsule >5mm

3D ultrasound provides even greater detail for evaluating breast capsule structure, thickness regularity and contracture severity.

Other Breast Implant Complications Detectable on Ultrasound

In addition to rupture and capsular contracture, ultrasound can also detect other potential breast implant complications:

• Seroma - peri-prosthetic fluid collection, anechoic on ultrasound
• Hematoma - blood accumulation near the implant, complex echogenic fluid
• Abscess - infected fluid collection with debris and increased vascularity
• Bottoming out - inferior displacement or sagging of the implant within the pocket
• Malposition - rotation or lateral displacement of the implant
• Extracapsular implant - shell herniation through the fibrous capsule
• Lymphadenopathy - enlarged or abnormal lymph nodes near implant
• Delayed wound healing - skin thickening, inflammation and fluid at incision site

Many of these issues require surgical correction after being identified on ultrasound. Careful screening allows complications to be diagnosed in early stages before symptoms become severe.

Breast Cancer Detection in Augmented Breasts

Women with implants can still develop breast cancer that needs to be evaluated on imaging. However, mammography has limitations in augmented breasts, especially in dense glandular tissue. Ultrasound is often a more effective tool for detecting breast masses or abnormalities after augmentation.

Signs of concern on ultrasound include [10]:

• Solid hypoechoic masses with irregular or microlobulated margins
• Combined cystic-solid lesions with thick walls and internal septations
• Masses with increased peripheral or internal vascularity
• Enlarged lymph nodes with eccentric cortical thickening
• Architectural distortion of breast tissue or skin thickening

Targeted ultrasound allows clear visualization and characterization of masses obscured on mammogram. Biopsy under ultrasound guidance can obtain samples from suspicious areas to make a definitive breast cancer diagnosis when indicated.

Guiding Interventional Procedures Related to Breast Implants

Ultrasound is an excellent tool for guiding interventional procedures involving breast implants given its real-time visualization and lack of radiation. Some examples include:

• Breast cyst aspiration - draining peri-implant fluid using ultrasound guidance
• Abscess drainage - inserting a catheter into a walled-off infected fluid collection under ultrasound
• Seroma aspiration - sampling peri-implant fluid for analysis
• Fine needle biopsy - sampling suspicious masses or lymph nodes seen on ultrasound
• Pre-operative measurements - using ultrasound to plan surgical approach based on precise implant measurements
• Injections - instilling drugs into the implant capsule using sonographic targeting
• Hematoma drainage - relieving pressure and pain from blood collecting around an implant