Programmable CSF shunt valve: in vitro assessment of MR imaging safety at 3T.
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.
Keck School of Medicine, University of Southern California and Institute for Magnetic Resonance Safety, Education, and Research, Los Angeles, Calif 90045, USA.
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Shellock
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Habibi
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Knebel
D002557:Cerebrospinal Fluid Shunts / Q000295:instrumentation*; D004574:Electromagnetic Fields; D004867:Equipment Design; D006358:Hot Temperature; D008279:Magnetic Resonance Imaging; D012449:Safety