Is it Possible to Differentiate Types of Breast Implants by Imaging in the Era of Implant-associated Lymphoma?

[OBJECTIVES] Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) has been recognised in recent years, and there is extensive ongoing research. Although the exact mechanism and cause are still unclear, we now know that the disease is more associated with textured implants. To the best of our knowledge, no previous studies investigating the radiological differential of various implants have been conducted. In this essay, we aimed to demonstrate dicriminating in vitro and in vivo imaging features of variuos types of breast implant devices using mammography, ultrasound, and Magnetic Resonance Imaging (MRI).

[METHODS] Five different implant devices from various manufacturers with various surface textures, including smooth, micro-textured, regular macro-textured, lightweight macro-textured, and polyurethane- coated were used. In vitro mammography was performed with a digital mammogram (Amulet Innovality, Fuji, Japan), and in vitro and in vivo sonography were performed with Esaote MyLab9 using a 7.5 MHz linear probe. In vitro MRI was performed with a 1.5T magnet (Symphony TIM upgrade and Aera, Siemens Healthcare, Erlangen, Germany) with a 7-channel breast coil (Sense coil, Innova, Germany). MRI studies included fat sat T2 weighted sequences (T2WS), non-fat sat T2WS, and silicone only sequences.

[RESULTS] Each imaging technique had different contributions to dealing with this challenge. Mammography and MRI were limited to identifying the capsule's double bands. We could only differentiate the lightweight macro-textured implant on the mammogram as the borosilicate microspheres were represented by tiny, round lucencies within the gel. Ultrasound imaging with the proper technique was very helpful in identifying the surface. The inner capsule (implant shell) was identified as parallel double echogenic bands on the in vitro sonogram. Bands of the smooth implant were better delineated compared to the textured implants. The double echogenic bands of the polyurethane-coated implant were not even identified individually. The reverberation artifact caused by the smooth implant was the main discriminating in vivo sonographic feature of smooth implants. The hyperintense polyurethane-coated capsule was identified on fat-saturated T2WS and non-fat-saturated T2WS via in vitro MRI. The tiny hypointense microspheres of the lightweight implant were also identified on the silicone-only sequence of the in vitro MRI.

[CONCLUSION] In this study, we have shown that breast implant material and type may differ with the help of in vitro and in vivo imaging characteristics on different radiological modalities. These different imaging features could be used for recognising and labelling the implant type, especially macrotextured implants that are reported to be more associated with breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) compared to other types. We believe evaluating these imaging characteristics during daily practice will help radiologists become aware of the implant type and possible complications or diseases associated with that type.