The Linguine sign - a reliable sign in intra-capsular breast implant rupture

Clinical History

The patient is a 36-year-old pregnant woman in her 2nd trimester. She has had bilateral breast implants inserted 6 years before. She presented with recent onset of discomfort in her left breast. The referring physician requested imaging to look for implant integrity.

Imaging Findings

MR imaging of breast was performed in a GE Signa 1.5T scanner using sagittal T2 water suppression sequence, T2 STIR sequence at orthogonal planes and a sagittal T2 water only sequence with silicone suppression were performed.

The right breast implant was intact.
The left breast implant showed an inner wall with undulating wavy margin and multiple linear low signal lines floating in the gel, which is elastomer collapsed into the gel. This was consistent with the 'linguine sign' described in literature [2, 3]. Additionally, the 'subcapsular line sign' and the less reliable, 'noose sign' were also shown. These findings in combination were useful in making a diagnosis of intra-capsular rupture of breast implant.

Additionally there were multiple peripherally placed round / elliptical foci showing water signal intensities best identified in T2 water only silicone suppressed sequence. This is the 'salad oil sign.'

Discussion

Background and Clinical perspective:
Breast augmentation surgeries which were most popular in the western world earlier has caught on in the Middle East as well. MR imaging is a reliable imaging tool [5] used in imaging implants and to look for implant integrity. Intra-capsular rupture is one of the more common problems and the onus falls on the radiologist to direct the clinician as it is more often difficult to make a clinical decision.

Imaging Perspective
Breast augmentation imaging
In MR imaging, T2 weighted images in orthogonal planes and T2 STIR sequences are important. Most MR scanners have T2 silicone suppression water only sequence which are useful. The other useful sequence is a Silicone only sequence which shows the silicone implant bright against a background of dark breast tissue.
Breast implant normally show a smooth contour with normal appearances of the outer fibrous margin and inner radial patterns.
The 'linguine' sign [Figure 3] described here is a reliable sign in making the diagnosis of an intra-capsular rupture of breast implants and helps in distinguishing from a minimal extra-capsular leak [4]. Linguine is a variety of pasta. As the ruptured elastomer floating in gel has a similar appearance to pasta floating in sauce the sign is described thus.

The 'sub-capsular line' sign [Figure 4] which is the next reliable sign is a dark line seen just below the outer implant capsule which represents a thin layer of silicone interposed between shell and fibrous capsule. The 'noose sign' or 'keyhole' sign [Figure 4] represent focal invagination of implant shell caused by small collection of silicone outside shell.

The peripherally placed water droplets [Figure 6] which is the 'salad oil' sign is a misleading sign as it can be seen in patients who have had steroid injections to treat implant contracture. If seen on MR imaging in solitude it must be treated with caution and other signs of implant rupture needs to be identified.


Outcome
The difficulty in making a satisfactory clinical distinction between and intra-capsular rupture and a minor extra-capsular leak makes imaging investigation, particularly MR imaging a mainstay in the diagnosis of this complication of breast augmentation surgery by prosthesis.

Differential Diagnosis List

Final Diagnosis

Intra-capsular rupture of breast implant

URL:	https://www.eurorad.org/case/9951
DOI:	10.1594/EURORAD/CASE.9951
ISSN:	1563-4086