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Abstract

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.