Neuroscience 2005 Abstract
| Presentation Number: | 456.20 |
|---|---|
| Abstract Title: | Phase and susceptibility-weighted imaging for the <i>in vivo</i> detection of implanted silicon microelectrodes. |
| Authors: |
Martinez, F. M.*1
; Chenevert, T. L.2
; Swanson, S. D.2
; Noll, D. C.1
; Anderson, D. J.1,3,4
1Biomedical Engineering, Univ. of Michigan, Ann Arbor, MI 2Radiology, Univ. of Michigan, Ann Arbor, MI 3Elect. Eng. and Comp. Sci., Univ. of Michigan, Ann Arbor, MI 4Kresge Hearing Research Inst., Univ. of Michigan, Ann Arbor, MI |
| Primary Theme and Topics |
Techniques in Neuroscience - Staining, Tracing, and Imaging Techniques |
| Session: |
456. Imaging by MRI and PET II Poster |
| Presentation Time: | Monday, November 14, 2005 11:00 AM-12:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # VV86 |
| Keywords: | IMPLANT, MRI, ANIMAL MODEL, MULTIELECTRODE |
Wire microelectrodes made of platinum-iridium, tungsten, or other alloys, are commonly used for the study of the Central Nervous System in animal models. Normally, they do not represent a risk in Magnetic Resonance Imaging (MRI), but they may produce significant image artifacts.
Besides some advantages, such as batch fabrication, channel density, high reproducibility, and precise dimensions, silicon based microelectrodes have a low magnetic susceptibility signature and their thickness is smaller than the smallest dimension of a MRI voxel, even under standard micro-MRI techniques. Therefore, the detection of this type of microelectrode using MRI is challenging, especially for in vivo studies and at low magnetic fields.
We address this problem and present a method for the in vivo detection of silicon microelectrodes using MRI at 2 Tesla. We apply concepts of micro-MRI, phase imaging, and susceptibility weighted imaging to detect sub-voxel size features that accurately define the shape of the electrodes. First, we analyzed MR images of phantoms with implanted silicon microelectrodes. Then, we used a fixed Guinea pig brain with several electrodes implanted on the cortex. Finally, the procedure was evaluated in vivo with electrodes implanted in the inferior colliculus of Guinea pigs.
Using the presented procedures, we were able to detect silicon microelectrodes with single shank dimensions as small as 3000x33x15 μm³ at reasonable acquisition times and unnoticeable MR image distortions.
The small magnetic signature of silicon microelectrodes allows the acquisition of high-resolution anatomical MR images, and opens the possibilities for in vitro and in vivo studies of electrode localization, migration, tissue reaction, and simultaneous functional-MRI and electrophysiology.
Besides some advantages, such as batch fabrication, channel density, high reproducibility, and precise dimensions, silicon based microelectrodes have a low magnetic susceptibility signature and their thickness is smaller than the smallest dimension of a MRI voxel, even under standard micro-MRI techniques. Therefore, the detection of this type of microelectrode using MRI is challenging, especially for in vivo studies and at low magnetic fields.
We address this problem and present a method for the in vivo detection of silicon microelectrodes using MRI at 2 Tesla. We apply concepts of micro-MRI, phase imaging, and susceptibility weighted imaging to detect sub-voxel size features that accurately define the shape of the electrodes. First, we analyzed MR images of phantoms with implanted silicon microelectrodes. Then, we used a fixed Guinea pig brain with several electrodes implanted on the cortex. Finally, the procedure was evaluated in vivo with electrodes implanted in the inferior colliculus of Guinea pigs.
Using the presented procedures, we were able to detect silicon microelectrodes with single shank dimensions as small as 3000x33x15 μm³ at reasonable acquisition times and unnoticeable MR image distortions.
The small magnetic signature of silicon microelectrodes allows the acquisition of high-resolution anatomical MR images, and opens the possibilities for in vitro and in vivo studies of electrode localization, migration, tissue reaction, and simultaneous functional-MRI and electrophysiology.
Supported by This work was funded by NIH/NIBIB Resource Center Grant P41 EB2030 to the Center for Neural Communication Technology at the University of Michigan.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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