²⁹Si imaging of silicone breast implants and intraocular silicone oil

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 gradient-echo sequence were used for acquiring 29Si images with 5 x 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.

Applications of heteronuclear NMR spectroscopy in biological and medicinal inorganic chemistry

“…29 Si is a spin I = 1/2 nucleus (4.7% natural abundance) and the only spectroscopically observable isotope of silicon. 29 Si MRI has potential for imaging silicone prostheses in humans [98]. 29 Si relaxation times of silicone gels average T 1 = 21.2 ± 1.5 s and T 2 = 207 ± 40 ms, with no significant difference between virgin and explanted gels.…”

Asymmetric Synthesis of Densely Functionalized Medium‐Ring Carbocycles and Lactones through Modular Assembly and Ring‐Closing Metathesis of Sulfoximine‐Substituted Trienes and Dienynes

“…Hall and Webb8 recorded a 2D 29 Si image of liquid tetramethyldisiloxane and showed a signal enhancement through a 1 H→ 29 Si J‐coupling polarization transfer and multiple‐echo acquisition. Haselhorst et al9 demonstrated a possible application of 29 Si MRI for monitoring silicone prostheses in humans by demonstrating in vitro 29 Si images of silicone breast implants and silicone oil. Koptyup et al10 presented a 2D phase encoded image using specialized imaging equipment (i.e.…”