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. 2006 Mar;27(3):661-5.

Programmable CSF shunt valve: in vitro assessment of MR imaging safety at 3T

F G Shellock  1 , R Habibi, J Knebel
Affiliations

Programmable CSF shunt valve: in vitro assessment of MR imaging safety at 3T

F G Shellock et al. AJNR Am J Neuroradiol. 2006 Mar.

Abstract

A programmable CSF shunt valve was assessed for magnetic field interactions, heating (transmit-receive body radio-frequency coil; whole-body averaged specific absorption rate, 2.1 W/kg), functional alterations, and artifacts at 3T. The programmable valve showed minor magnetic field interactions and heating was not excessive (+0.8 degrees C). The function of the programmable valve was not altered by multiple exposures to the 3T scanner or from exposure to various MR imaging conditions. Therefore, this implant is safe for a patient undergoing MR imaging at 3T or less when the radiologist follows specific safety guidelines. Artifacts for the programmable valve were relatively large in relation to the size and shape of the valve; this finding may impact the diagnostic use of MR imaging if the area of interest is in proximity to this implant.

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Figures

Fig 1.
Fig 1.
The programmable valve that underwent evaluation for MR imaging safety at 3T.
Fig 2.
Fig 2.
The experimental setup used to assess MR imaging–related heating for the programmable valve, showing the implant in position on the plastic frame placed on the bottom of the head/torso phantom. Note the cables going to the fluoroptic thermometry probes.
Fig 3.
Fig 3.
The 18 samples of the programmable valve shown attached to the cylinder-shaped phantom in preparation for the static magnetic field exposures (sagittal orientation).
Fig 4.
Fig 4.
The 18 samples of the programmable valve shown attached to the cylinder-shaped phantom in preparation for the static magnetic field exposures (simulated patient orientation).
Fig 5.
Fig 5.
Examples of MR images showing artifacts for the programmable valve (gradient-echo pulse sequence; TR/TE, 100/15; flip angle, 30°; section thickness, 5 mm; field of view, 24 cm) at 3T. A, Section location oriented to the long axis of the programmable valve. B, Section location oriented to the short axis of the programmable valve.
See this image and copyright information in PMC

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