29Si imaging of silicone breast implants and intraocular silicone oil

Silicon-29 (²⁹Si) imaging was investigated as a potential imaging modality for monitoring silicone prostheses in humans. The ²⁹Si relaxation times of several silicone gels were measured and found to average T₁ = 21.2 ± 1.5 s and T₂ = 207 ± 40 ms, with no significant difference between virgin and explanted gels. A single-shot half-Fourier rapid acquisition with relaxation enhancement (RARE) and a refocused gradientecho sequence were used for acquiring ²⁹Si images with 5 × 5 mm² resolution and no slice selection. Three volunteers with silicone-gel-filled breast implants and one subject with an intraocular silicone oil injection were thus examined in a total acquisition time of 10–15 min per image. On all ²⁹Si images, the shape of the silicone object was well depicted. Although at present, conventional proton images are superior in resolution and signal-to-noise ratio, ²⁹Si imaging has the advantage of optimal specificity, since only the silicone itself is visible.