A breast implant rupture is a recognised complication of a breast implant. It can be intra or extra capsular.
After implantation of a silicone or saline breast implant, a fibrous capsule (scar) forms around the implant shell.
Among implant ruptures, 77 – 89% are intra-capsular and 11 – 23% are extra-capsular 4.
An intracapsular rupture occurs when the shell of the implant ruptures but the fibrous capsule formed by the breast remains intact. Silicone does not freely extravasate. This makes it difficult to detect on clinical exam or mammography. Intracapsular rupture is best seen on MRI.
An extracapsular rupture can lead to a change in the implant contour and may be detected on clinical examination or mammography. An extracapsular rupture implies intracapsular rupture as well 3.
In an intracapsular rupture the contents of the implant are contained by the fibrous scar, while the shell appears as a group of wavy lines. This has been termed the “linguine sign” and has been most commonly described with MR imaging 1. The “keyhole sign, noose sign or teardrop sign” is the appearance of silicone on both sides of a radial fold and also suggests an implant rupture 2.
Detection of implant ruptures (particularly silicone implant ruptures) are difficult on mammography and detection of intra-capsular silicone ruptures are almost impossible on mammography.
Ultrasound may demonstrate a snowstorm appearance of an extra-capsular rupture, or thestepladder sign of an intra-capsular rupture (a normal implant should usually be anechoic). At the time of writing (2010), the overall sensitivity and specificity rates on ultrasound are thought to range between ~ 59 – 85 % and ~ 55 – 79 % respectively 7.
Considered most sensitive for detection of implant rupture. Often does not required contrast if the indication is solely for this purpose
Non-contrast MRI may also be able to distinguish between silicone and / or saline implants by using silicone or water only sequences. With the use of multi-planar imaging, MR may also be able to distinguish between radial folds or true ruptures. A ‘linguine sign’ may be seen which is specific for an intra-capsular rupture is due to the free floating shell within the implant. A gross extra-capsular rupture is evident as free silicone, separate from the implant, which has extended beyond the implant capsule into the breast or axilla. Free silicone has an increased signal in T2-stir weighted sequence without any enhancement in T1 weighted fat-suppressed sequence.
The “salad oil sign” has also been described in a double lumen implant rupture, where there is mixing of the saline and silicone, although this on its own is non-specific.
INFO from radiopaedia.org