Implants and Other Types of Augmentation
Breast MRI for implant assessment evaluates implant integrity, complications, and the surrounding breast tissue.
Key Principles
- Implant assessment MRI does not require contrast — no BI-RADS assessment is given for non-contrast implant-only exams
- Silicone-specific sequences suppress both water and fat so only silicone appears bright
- T2-weighted images assess peri-implant fluid
- Bilateral imaging should be performed
Implant Descriptors
1. Location
| Descriptor | Definition |
|---|---|
| Implant — Prepectoral | Anterior to pectoralis major |
| Implant — Retropectoral | Deep to pectoralis major |
2. Material and Integrity
| Material | Key Features |
|---|---|
| Implant Material — Saline | Water signal on all sequences; filling valve characteristic; rupture is clinically evident |
| Implant Material — Silicone | Bright on silicone-specific sequences; rupture may be “silent” |
| Other | Autologous flaps (TRAM, DIEP, latissimus), direct injection (silicone, paraffin) |
3. Lumen Type
- Single — most common
- Double — inner/outer lumens (silicone/saline or silicone/silicone); can mimic intracapsular rupture
4. Intracapsular Silicone Findings
| Finding | Significance |
|---|---|
| Implant — Radial Folds | Normal variant — infolding of intact shell |
| Implant — Subcapsular Line Sign | Intracapsular rupture |
| Implant — Keyhole Sign | Intracapsular rupture |
| Implant — Linguine Sign | Intracapsular rupture (collapsed shell) |
| Implant — Water Droplets | Can occur in intact OR ruptured implants |
5. Extracapsular Silicone
| Location | Significance |
|---|---|
| Breast | Current or prior extracapsular rupture |
| Lymph nodes | Rupture or “silicone bleed” from intact implants |
6. Other Implant Findings
- Focal contour bulge — intact implant distortion from capsular contraction
- Peri-implant fluid — trace is normal; >trace suspicious for infection, seroma, or BIA-ALCL
Board Pearl
BIA-ALCL (breast implant-associated anaplastic large cell lymphoma) presents with delayed peri-implant effusion (>1 year after placement). A persistent delayed effusion should prompt fine-needle aspiration to evaluate for BIA-ALCL. Ultrasound is the primary modality to further assess suspicious peri-implant fluid.
FDA Recommendations
- Asymptomatic silicone implant patients: imaging (US or MRI) 5–6 years after placement, then every 2–3 years for “silent rupture”