ferromagnetic detector implants

Can Ferromagnetic Detection Systems find implants too?

Dr. Mark Keene, Metrasens’ Chief Technology Officer, recently presented an educational MRI safety session reviewing the published evidence for the effectiveness of Ferromagnetic Detection Systems (FMDS) for detecting ferromagnetic implants and other indwelling items such as shrapnel.

A total of five studies were reviewed, all published in US peer-reviewed journals over the period 2013-2018*. All studies used Metrasens’ Ferroguard Screener as their FMDS system of choice. In all cases, the Ferroguard Screener used was an unmodified, standard product.

Recent studies indicate Metrasens FMDS provide effective implant screening

A study completed in 2018 at Mayo Clinic indicated high levels of sensitivity (99.6%) and specificity (100%) for the detection of 34 different models of cardiac pacemaker implanted in 75 patients. There was no significant difference reported in the capability to detect MR Conditional compared with MR Unsafe models.

Published studies into the effectiveness of screening for unexpected implanted materials other than cardiac pacemakers were also reviewed. A laboratory-based study by Shellock and Karacozoff (2013) reported a detection sensitivity of 92% and specificity of 100% for a selection of 67 different ferromagnetic implants.

Not all FMDS are the same

There is significant peer-reviewed published evidence that Metrasens’ Ferroguard Screener system is effective for detecting unexpected ferromagnetic implants and other indwelling items.

However, the ability of FMDS to detect small and implanted ferromagnetic risk items is dependent upon the detection sensitivity of the particular device used. FMDS systems are not the same, and only Metrasens Ferroguard Screener has been demonstrated effective for this application. Find out more about Ferroguard FMDS for MRI Safety here.



Watson, R. E., Walsh, S. M., Felmlee, J. P., Friedman, P. A., & Keene, M. N. (Accepted/In press). Augmenting MRI Safety Screening Processes: Reliable Identification of Cardiac Implantable Electronic Devices by a Ferromagnetic Detector System. Journal of Magnetic Resonance Imaging. https://doi.org/10.1002/jmri.26277

Linnemeyer, H., Shellock, F.G., Ahn, C.Y. In vitro assessment of MRI issues at 3-Tesla for a breast tissue expander with a remote port. Magnetic Resonance Imaging (2014) 32: 297-302

Shellock, F.G., Karacozoff, A.M. Detection of ferromagnetic implants using a ferromagnetic detection system: implications for patient screening prior to MRI. American Journal of Roentgenology (2013) 201: 720-725

James, C.A., Karacozoff, A.M., Shellock, F.G. Undisclosed and undetected foreign bodies during MRI screening resulting in a potentially serious outcome. Magnetic Resonance Imaging (2013) 31: 630-633

Karacozoff, A.M., Pekmezci, M., Shellock, F.G. Armor-Piercing bullet 3-T MRI findings and identification by a ferromagnetic detection system. Military Medicine (2013) 178: 380-384

Review of published evidence only

Ferroguard Screener, and all other FMDS, are not approved products for implant detection and detections may be used for indication only. Metrasens accepts no responsibility for any adverse consequences arising from positive or negative indications of implants.

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