After joining a new site on facebookI had some new friends ask if anyone had ever heard of a shunt that programmed with a magnet? My first response was... HUH?? Then I read some of the comments! This is a group for spina bifida and hydrocephalus Women.
Several had never heard of programmable shunts. One made a comment it sounded like Star Trek. I Now see that I need to get my act together and get back to my job at blogging.
This is information on codmen hikim which has been having a lot of complications with their shunts lately and I don't recomend for any one. It was the one I had to live with for 14 moths that was faulty. But This explains how they work pretty well.
I don't have a problem with Codmen I just want them to fix this constant problem with this shunt.
There are several other programmables also you can find on my blog one is the Medtrinic.
Magnetically programmable shunt valve: MRI at 3-Tesla Frank G. Shellocka,b,4, Stephen F. Wilsonc, Chrospinal fluid. istophe P. Maugec aKeck School of Medicine, University of Southern California, Los Angeles, CA, USA bInstitute for Magnetic Resonance Safety, Education, and Research, Los Angeles, CA 90045, USA cResearch and Development, Codman, a Johnson & Johnson Company, Raynham, MA 02767, USA Received 25 September 2006; revised 6 December 2006; accepted 7 December 2006 Abstract
A magnetically programmable cerebrospinal fluid (CSF) shunt valve (Codman Hakim Programmable Valve, Codman, a Johnson & Johnson Company, Raynham, MA) was assessed for magnetic field interactions, heating, artifacts and functional changes at 3-Tesla. The programmable valve showed minor magnetic field interactions and heating (+0.48C). Artifacts were relatively large in relation to the size and shape of this implant and, as such, may create a problem if the area of interest is in proximity to this implant. While multiple exposures and various magnetic resonance imaging (MRI) conditions at 3-Tesla changed the settings of some valves (i.e., reprogramming was needed), the function of the programmable valve was not permanently affected. Therefore, this magnetically programmable CSF shunt valve is acceptable for a patient undergoing MRI at 3-Tesla or less when specific safety guidelines are followed, including resetting the valve, as needed.
D 2007 Elsevier Inc. All rights reserved. Keywords: Magnetic resonance imaging; Safety; MRI; Implants; Specific absorption rate; Artifacts; Hydrocephalus; CSF; Programmable valve 1. Introduction A hydrocephalus shunt valve is an implantable device that provides constant intraventricular pressure and drainage of the cerebrospinal fluid (CSF) for the management of hydrocephalus and other conditions of impaired CSF flow and absorption. Programmable shunt valves allow surgeons to noninvasively optimize the opening pressure of a shunt system before and after implantation, permitting the implementation of specialized treatment regimes. Programmable valves are typically adjusted using an externally applied programmer tool to magnetically couple to the adjustable components of these devices. Accordingly, exposure to powerful magnetic fields can cause inadvertent changes in valve settings or permanently damage CSF shunt valves. With regard to magnetic resonance imaging (MRI), various other issues exist for programmable valves, including the possibility of movement of the implant, extreme heating and the impact of substantial artifacts.
The increasing clinical use of 3-T scanners necessitates the evaluation of implanted devices at this higher field strength.
Therefore, the objective of this investigation was to assess magnetic field interactions, heating, artifacts and functional changes for a commonly used  programmable valve (Codman Hakim Programmable Valve, Codman, a Johnson & Johnson Company, Raynham, MA) in relation to the use of a 3-T MR system. 2. Materials and methods 2.1. Programmable valve The programmable valve (Codman Hakim Programmable Valve, Codman, a Johnson & Johnson Company) is an implantable device that provides constant intraventricular pressure and drainage of CSF for the management of hydrocephalus and other conditions in which CSF flow and absorption are impaired. Intraventricular pressure is controlled by a bball and coneQ valve that is under the control of a calibrated flat spring and can be noninvasively adjusted with the use of an external programmer with a magnetic mechanism. Hard magnets fixed within the base of a moveable cam react to the presence of the magnetic field by rotating the cam to achieve equilibrium. The adjustable valve accommodates 18 valve settings from 30 to 200 mm H2O in 10-mm H2O increments. Metallic 0730-725X/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.mri.2006.12.004 4 Corresponding author. Institute for Magnetic Resonance Safety, Education, and Research, Los Angeles, CA 90045, USA. Tel.: +1 310 670 7095; fax: +1 310 417 8639. E-mail address: firstname.lastname@example.org (F.G. Shellock). Magnetic Resonance Imaging 25 (2007) 1116– 1121 materials for the programmable CSF valve include 316L stainless steel, Vacoperm (Ni–Fe), Vacomax (Sm–Co) and unalloyed titanium. 2.2. MR system A 3-T (Excite, Software G3.0-052B, General Electric Medical Systems, Milwaukee, WI) active-shielded, horizontal field scanner was utilized for all tests conducted on the programmable valve. 2.3. Magnetic field interactions Magnetic field interactions were determined for the programmable valve in association with the 3-T MR system. 2.3.1. Translational attraction Translational attraction was assessed for the programmable valve using the deflection angle technique [12,17–19]. The programmable valve was attached to a test fixture to measure the deflection angle. The test fixture has a protractor mounted to the top of the structure and included a bubble level to ensure proper orientation in the scanner. Measurements were obtained at the position in the 3-T MR system that produced the greatest magnetically induced deflection angle. This point was determined using gauss line plots, magnetic field measurements and visual inspection to identify the location of the highest spatial gradient. The highest spatial gradient for the 3-T MR system occurs at a position that is 74 cm from the isocenter of the scanner [12,19]. The magnetic spatial gradient at this position is 720 G/cm. The deflection angle from the vertical direction to the nearest 18 was measured three times, and an average value was calculated. . Torque Magnetic-field-induced torque was assessed qualitatively for the programmable valve using previously described methodology. This procedure utilized a flat plastic material with a millimeter grid. The programmable valve was placed on this test platform in an orientation that was 458 relative to the direction of the static magnetic field of the 3-T MR system. The test apparatus with the programmable valve was then positioned in the center of the scanner, where the effect of torque is the greatest (based on the known characteristics for the 3-T MR system), and observed for alignment or rotation . The programmable valve was then moved 458 relative to its previous position and again observed for alignment or rotation. This procedure was repeated to encompass a 3608 rotation of positions for the programmable valve in the scanner. A qualitative scale was applied to the results to characterize torque: 0, no torque; +1, mild or low torque, the implant slightly changed orientation but did not align to the magnetic field; +2, moderate torque, the implant aligned gradually to the magnetic field; +3, strong torque, the implant showed rapid and forceful alignment to the magnetic field; +4, very strong torque, the implant showed very rapid and very forceful alignment to the magnetic field. Of note is that one of the investigators (F.G.S.) has more than 20 years of experience applying this qualitative scale to the characterization of torque. 2.4. MRI-related heating An in vitro experiment was performed at 3-Tesla/ 128-MHz to determine MRI-related heating for the programmable valve according to a previously described protocol [12,17,19–21]. The programmable valve was placed to approximate its intended in vivo use position in a plastic head/torso phantom (head portion: width, 16.5 cm; length, 29.2 cm; height, 16.5 cm; torso portion: width, 43.2 cm; length, 61.0 cm; height, 16.5 cm). The phantom was filled with a gelling agent in an aqueous solution (i.e., 0.8 g/L NaCl plus 5.85 g/L polyacrylic acid in distilled water) [12,17,19–21]. Temperatures were recorded using a fluoroptic thermometry system (Model 3100, Luxtron, Santa Clara, CA) with fluoroptic thermometry probes (Model SFF, 0.5 mm in diameter) positioned on the programmable valve to record temperatures associated with the greatest heating during MRI, as follows : Probe 1, sensor portion of the probe placed in direct contact with one end of the programmable valve; Probe 2, sensor portion of the probe placed in direct contact with the other end of the programmable valve; Probe 3, sensor portion of the probe placed in direct contact with the middle portion of the programmable valve. The positions of the fluoroptic thermometry probes were verified immediately before and after the heating experiment. The accuracy of the fluoroptic thermometry equipment used to record temperatures in this study is F0.18C. MRI was performed at 3-Tesla/128-MHz on the gelled, saline-filled phantom with the programmable valve using a transmit radio frequency (RF) body coil to produce a relatively high level of RF energy, as follows: fast spin-echo pulse sequence; axial plane; multislice; repetition time, 425 ms; echo time, 14 ms; echo train length, 4; flip angle, 908; bandwidth, 16 kHz; field of view, 40 cm; imaging matrix, 256 256; section thickness, 10 mm; number of