In vivo 1 H chemical shift imaging of silicone implants

In order to study the aging process (i.e., silicone migration, fat infiltration) of silicone (polydimethylsiloxane, PDMS) based biomaterials in living subjects by NMR imaging a hybrid 1 H selective excitation and saturation chemical shift imaging technique (IR/CHESS‐CSSE) has been developed. This sequence allows selective mapping of the distribution of silicone protons in vivo , while suppressing the contributions of fat and water. Our results indicate that a combined inversion recovery and CHESS pulse, followed by a spoiler gradient, must be applied to suppress all contributions of fat protons to the NMR signal. The sensitivity of our experiments allows the detection of a chemically unchanged silicone concentration of 5% in a voxel of 0.9 mm 3 at a signal/noise ratio of 2.