title: Evaluation of MRI issues for a new neurological implant, the Sensor Reservoir.
abstract: OBJECTIVE
  A new neurological implant, the Sensor-Reservoir, was developed to provide a relative measurement of ICP, which permits a noninvasive technique to detect and localize occlusions in ventricular drainage systems and, thus, to identify mechanical damage to shunt valves. The "reservoir" of this device can be used to administer medication or a contrast agent, to extract cerebral spinal fluid (CSF), and with the possibility of directly measuring ICP. The Sensor-Reservoir was evaluated to identify possible MRI-related issues at 1.5-T/64-MHz and 3-T/128-MHz.
  
  
  METHODS
  Standard testing techniques were utilized to evaluate magnetic field interactions (i.e., translational attraction and torque), MRI-related heating, and artifacts at 3-T for the Sensor-Reservoir. In addition, 12 samples of the Sensor-Reservoir underwent testing to determine if the function of these devices was affected by exposures to various MRI conditions at 1.5-T/64-MHz and 3-T/128-MHz.
  
  
  RESULTS
  Magnetic field interactions for the Sensor-Reservoir were not substantial. The heating results indicated a highest temperature rise of 1.8 °C, which poses no patient risks. Artifacts were relatively small in relation to the size and shape of the Sensor-Reservoir, but may interfere diagnostically if the area of interest is near the device. All devices were unaffected by exposures to MRI conditions at 1.5-T/64-MHz and 3-T/128-MHz.
  
  
  CONCLUSIONS
  When specific guidelines are followed, the Sensor-Reservoir is "MR conditional" for patients undergoing MRI examinations at 3-T or less.
authors.affiliation: Keck School of Medicine, University of Southern California and Institute for Magnetic Resonance Safety, Education, and Research, Los Angeles, CA 90045, USA. frank.shellock@mrisafety.com
authors.forename: Frank G
authors.initials: FG
authors.lastname: Shellock
authors.forename: Jörg
authors.initials: J
authors.lastname: Knebel
authors.forename: Angelina D
authors.initials: AD
authors.lastname: Prat
mesh_terms: D016477:Artifacts; D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation; D004869:Equipment Safety / Q000295:instrumentation; D006801:Humans; D007427:Intracranial Pressure; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008991:Monitoring, Physiologic / Q000295:instrumentation; D019736:Prostheses and Implants; D011474:Prosthesis Design; D015203:Reproducibility of Results; D013696:Temperature
keywords: Cerebral spinal fluid; Intracranial Pressure; MRI; safety