Intracapsular rupture defined as a disruption of the implant envelope, with the implant contents contained by the surrounding fibrous capsule.

The MR appearance of intracapsular rupture include serpentine low signal intensity linear bands within the silicone implant as indicative of a disrupted envelope collapsing and falling into the gel. In cross section it was thought to look like a piece of pasta weaving back and forth on a plate and was termed the linguine sign. Others call it the fallen envelope sign.

In an intracapsular rupture the implant gel is held in place by the fibrous capsule, which may or may not be identified on the MR images.

The linguine sign is the best evidence of a ruptured implant, several series show a high correlation of the linguine sign with rupture, reporting 76-94% sensitivities and 97-100% specificities.

Spontaneous ruptures can occur in 10-20 percent, and traumatic ruptures are usually clinically evident.