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  Suitability of miniature inductively coupled RF coils as MR-visible markers for clinical purposes

Garnov, N., Thörmer, G., Gründer, W., Trampel, R., Moche, M., Kahn, T., et al. (2011). Suitability of miniature inductively coupled RF coils as MR-visible markers for clinical purposes. Medical Physics, 38(11), 6327-6335. doi:10.1118/1.3655027.

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Item Permalink: http://hdl.handle.net/11858/00-001M-0000-0012-06E6-D Version Permalink: http://hdl.handle.net/11858/00-001M-0000-002B-C63F-3
Genre: Journal Article


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Garnov, Nikita1, Author
Thörmer, Gregor1, Author
Gründer, Wilfried2, Author
Trampel, Robert3, Author              
Moche, Michael1, Author
Kahn, Thomas1, Author
Busse, Harald1, Author
1Department of Diagnostic and Interventional Radiology, University Hospital Leipzig, Germany, ou_persistent22              
2Department of Medical Physics and Biophysics, University of Leipzig, Germany, ou_persistent22              
3Department Neurophysics, MPI for Human Cognitive and Brain Sciences, Max Planck Society, ou_634550              


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 Abstract: Purpose: MR-visible markers have already been used for various purposes such as image registration, motion detection, and device tracking. Inductively coupled RF (ICRF) coils, in particular, provide a high contrast and do not require connecting wires to the scanner, which makes their application highly flexible and safe. This work aims to thoroughly characterize the MR signals of such ICRF markers under various conditions with a special emphasis on fully automatic detection. Methods: The small markers consisted of a solenoid coil that was wound around a glass tube containing the MR signal source and tuned to the resonance frequency of a 1.5 T MRI. Marker imaging was performed with a spoiled gradient echo sequence (FLASH) and a balanced steady-state free precession (SSFP) sequence (TrueFISP) in three standard projections. The signal intensities of the markers were recorded for both pulse sequences, three source materials (tap water, distilled water, and contrast agent solution), different flip angles and coil alignments with respect to theB 0 direction as well as for different marker positions in the entire imaging volume (field of view, FOV). Heating of the ICRF coils was measured during 10-min RF expositions to three conventional pulse sequences. Clinical utility of the markers was assessed from their performance in computer-aided detection and in defining double oblique scan planes. Results: For almost the entire FOV (±215 mm) and an estimated 82% of all possible RF coil alignments with respect toB 0, the ICRF markers generated clearly visible MR signals and could be reliably localized over a large range of flip angles, in particular with the TrueFISP sequence (0.3°–4.0°). Generally, TrueFISP provided a higher marker contrast than FLASH. RF exposition caused a moderate heating (≤5 °C) of the ICRF coils only. Conclusions : Small ICRF coils,imaged at low flip angles with a balanced SSFP sequence showed an excellent performance under a variety of experimental conditions and therefore make for a reliable, compact, flexible, and relatively safe marker for clinical use.


Language(s): eng - English
 Dates: 2011-10-312011-11
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: DOI: 10.1118/1.3655027
 Degree: -



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Title: Medical Physics
  Other : Med. Phys.
Source Genre: Journal
Publ. Info: New York, etc. : Published for the American Association of Physicists in Medicine by the American Institute of Physics
Pages: - Volume / Issue: 38 (11) Sequence Number: - Start / End Page: 6327 - 6335 Identifier: ISSN: 0094-2405
CoNE: https://pure.mpg.de/cone/journals/resource/991042742884000