Silicone migration

[Guest guest]

Date: Wed, 12 Nov 1997 02:01:33 -0500 (EST)

Subject: Fwd: Silicone migration

From Ruby, Background Info:

Nuclear Magnetic Resonance Imaging (NMRI) is similar

to Magnetic Resonance Imaging (MRI).

MRI Definition: When certain atomic nulcei with an odd

number of protons and nertrons or both are subjected

to a strong magnetic field, they absorb and re-emit

electromagnetic energy. Analysis of the net

magnetization vector's deflection by application of a

radiofrequency pulse provides image information. This

technique is valuable in providing images of the

heart, large blood vessels, brain and other soft

tissues.

In addition: NMRI is able to provide detailed

information about a substances chemical composition

and molecular architecture, both reflected in the

chemical shift spectrum, as well as about the

molecular and polymer chain dynamics related to NMRI

parameters, such as the spin-lattice (T1) and

spin-spin (T2) NMRI is a standard characterization

technique in polymer science for the study of kinetics

of polymerization, cross- linling, hydrolysis,

degradation etc. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Migration and Accumulation of Silicone in the Liver of

Women with Silicone Gel-Filled Breast Implants Bettina

Pfleiderer, Leoncio Garrido Magnetic Resonance in

Medicine 1995 Jan .Vol. 33, Pg. 8-17 Abstract: 1H NMR

localized spectroscopy (STEAM), combined with

echocardiography (ECG), respiratory gating, and water

and fat suppression, was used to quantify silicone

concentrations in the liver of women with silicone

gel-filled breast implants. Localized spectroscopy was

performed on 15 patients with silicone gel-filled

breast prostheses and on eight volunteers with no

implants.

The 1H spectra in the liver of patients showed

silicone resonances from 0.3 to -0.8 ppm, attributable

to protons in the methyl groups of silicone. The

presence of silicone in the liver could first be

detected 3-4 years after breast prostheses

implantation.

No correlation between silicone concentrations and

implantation times was observed. However, our results

indicated that silicone concentrations may reflect

implant integrity: detectable silicone concentrations

in the liver appeared to be higher when the implants

were ruptured than when the implants appeared intact.

Moreover, new resonances in the range of -2.6 to -4

ppm were observed in most patients after long-term

implantation. As these species increase with

implantation time, the new resonances may reflect

chemically changed silicone (paramagnetically shifted

silicon complexes bound to iron) accumulated over

time. The sensitivity of 1H NMR localized spectroscopy

is sufficient to detect silicon concentrations as low

as 0.20 mM.

Results from one patient whose implants had been

removed 14 months prior to the NMR examination showed

no detectable silicone in the liver, indicating that

it may have been excreted via bile or degraded to

silica and high coordinated silicon complexes.

Quantitative 1H localized spectroscopy of the liver in

women with silicone gel-filled breast implants may

provide valuable information concerning silicone

accumulation and degradation in vivo, as well as about

the kinetics of its elimination from the body after

implant removal.

Author: Pfleiderer B., Garrido L

Abbreviated Journal Title: Magn Reson Med Date Of

Publication: 1995 Jan .Vol. 33, Pg. 8-17

Bettina Pfleiderer, PhD. Leoncio Garrido, PhD.

Massachesetts General Hospital Department of Radiology

NMR Center 149 13th Street town, MA 02129

Hope this will be of some help.

Good Luck, God Bless and Best Wishes,

Ruby