Reply To: Curvilinear echoes in older implants

[Stephen Bird]

Yes, I have seen this in older implants and I think it represents the actual echogenicity of the silicone gel. Over time I suspect the gel changes in consistency and these interfaces are created by the gel itself as it becomes less homogonous. Machines with thin slice thickness and excellent contrast resolution are now capable of seeing some echoes from within the silicone gel. In a new implant the silicone gel is very homogenous and hence without any acoustic impedance miss matches you get no echoes. As the implant ages it becomes less homogenous and first you see a background of low level echoes being generated from the gel. As it ages further you see short linear lines within the implant generated by minor heterogeneity of the gel.