gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

Effect of 3 Tesla MRI on the function of shunt valves : evaluation of Paedi GAV, Dual Switch and proGAV

Einfluss eines 3 Tesla Magnetfeldes auf die Ventilfunktion: Untersuchung an Paedi GAV, Dual Switch und proGAV

Meeting Abstract

  • corresponding author D. Lindner - Klinik für Neurochirurgie, Universität Leipzig
  • C. Preul - Max-Planck-Institut für Kognitions- und Neurowissenschaften Leipzig
  • C. Trantakis - Klinik für Neurochirurgie, Universität Leipzig
  • H. Moeller - Max-Planck-Institut für Kognitions- und Neurowissenschaften Leipzig
  • J. Meixensberger - Klinik für Neurochirurgie, Universität Leipzig

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc10.05.-16.04

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2005/05dgnc0172.shtml

Veröffentlicht: 4. Mai 2005

© 2005 Lindner et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

There is no universal protocol for the assessment of MR- compatibility of shunt valves in terms of function and the apparatus to characterize the hydrodynamic performance after exposure to high magnetic fields differs among manufacturers. That’s why we initiated together with Miethke-Aesculap our study to evaluate independently their typical gravitational valves, the Dual switch, the Paedi GAV and as a new programmable one the proGAV in a 3 Tesla magnetism field.

Methods

MR scan evaluation were analysed in a typical producing protocol comparable the standard ASTM F647. A roll-pump delivers a constant flow of water or air through the valve in an adjustable range of 5 –50 ml / hour. A computerized system measured the opening pressure permanently with a tolerance of ±0,5 cm H20 (standard deviation).After completion of the pre- scan tests, the valves underwent MRI- scan. All magnetic resonance imaging (MRI) experiments were performed on a 3-T Magnetom Trio (Siemens, Erlangen, Germany). The MRI protocol is analogous to clinical practice and consists of a scout, T 2-weighted (T2w) two-dimensional (2D) spin-echo (SE) imaging, T 1-weighted (T1w) three-dimensional (3D) gradient-recalled echo (GRE) imaging, and diffusion-weighted (dw) 2D echo planar imaging (EPI). For T2w-imaging, RARE ('rapid acquisition with relaxation enhancement') sequences were acquired. A sagittal 3D slab (thickness 176 mm) was acquired for T1w-imaging with MP-RAGE ('magnetization-prepared rapid gradient echo'). The valves remained in the magnet for 45 min with a total scanning time of 34:57 min.

Results

The results from pre- scan and post- scan measurements were calculated as a mean value from 3 single measurements. The average deviation of the valves without the negative control (no. SN 010048) was 0,6 H20 ±0,2 for the air flow test and 0,7 H20 ±0,2 for the water flow test. Note, that the results for the negative control differ significantly indicating a shift of the pressure adjustment.

Conclusions

The aim of the study was to evaluate the function of different valves after exposure to a 3 T MR field. In sum, our 3T magnetic field had no influence on stability and safety of the tested Miethke valves. The proGAV as a programmable valve can only be exposed to 3 Tesla if the brake mechanism is safely adjusted.