Design change can reduce MRI-induced heating in implanted devices

24 November 2005

Rochester, NY, USA. Relatively minor manufacturing design modifications made to implanted medical device leads can substantially decrease MRI-induced heating risks, according to a study published in Magnetic Resonance Imaging.

Biophan Technologies, Inc. announced the publication of the scientific paper co-authored by Robert W. Gray and W. Timothy Bibens, members of Biophan’s research staff, and a third author, Dr. Frank G. Shellock of the University of Southern California in Los Angeles. The paper describes a novel, cutting-edge scientific solution to an important patient safety issue.

The tested alternative to current designs could have significant implications for improving patient safety related to MRI-induced heating of leads in medical implants. Biophan has developed a portfolio of proprietary solutions consistent with the authors’ findings, to eliminate heating risks.

“In general, magnetic resonance imaging (MRI) is considered to be an extremely safe diagnostic modality,” the article notes. “However, under certain conditions, patients with electrically conducting implants may be seriously injured during MRI due to the generation of excessive heat. This is particularly problematic for implants that have leads (e.g., spinal fusion stimulators, cardiac pacemakers, and neurostimulation systems), since MRI-induced heating tends to occur in extended wires that form resonant antennae.”

MRI's electromagnetic environment can create safety problems in a wide range of medical devices. In some of the most dramatic cases, MRI's electromagnetic fields can cause the devices to heat or create induced voltages, or to malfunction, potentially causing serious harm to patients. In light of those accidents, the article notes, “It is obvious that there is a critical need for a means of reducing MRI-induced heating for implanted leads used with medical devices.” The authors propose as an acceptable and practical answer, the development of leads “that inherently minimize heating.”

Based on their research, the authors conclude that “Minor modifications to a wire form greatly reduce MRI-related heating. Because these modifications change the wire form’s basic electrical characteristics, it is expected that similar results (i.e., reduction in MRI-induced heating) will apply to longer leads and to other physiological positions of lead wires. As such, these findings have important implications for implanted leads used in medical devices.”

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