2107 "Bright when tight": a wireless resonant staple for interventional MRI
© Kim et al; licensee BioMed Central Ltd. 2008
Published: 22 October 2008
Catheter-delivered fixation devices may be useful for MRI-guided endovascular surgery to fasten devices and tissues.
Successful deployment and attachment must be clearly evident. Passively-visualized staples may not provide the high contrast against the surrounding tissue and blood necessary to indicate geometry and fixation state. We have designed an active wireless device that employs a resonant circuit tuned to resonate only when the staple is successfully deployed. In the deployed state, the receiver coil inductively couples to surface and body coils for visualization.
SNR values obtained from the short axis view of the staple.
Device to Background CNR
Micro Coil Orientation
0.197 ± 0.002
2.146 ± 0.083
0.234 ± 0.007
2.146 ± 0.083
0.198 ± 0.003
0.664 ± 0.019
We have developed a prototype staple with two resonant states: low SNR when loaded for delivery and high SNR with great contrast to the background when deployed. In the delivery state, packing the nitinol fixation hooks within the vicinity of the micro coil detunes the circuit to sufficiently suppress inductive coupling. This staple has been designed to accommodate up to 0.036" guidewire for a dedicated delivery system. A safer catheter-based application of this device should be feasible after further miniaturization.
This article is published under license to BioMed Central Ltd.