Research Training Group 2154 - Materials for Brain

RTG Online Colloquium talk by Dr. Martin Meier: MRI and Metals in Brain: a Matter of concentration

Small Animal Imaging, Institute for Laboratory Animal Science and Central Animal Laboratory (ZTL), Medizinische Hochschule Hannover (MHH)

Nov 19, 2020 from 05:00 PM to 06:00 PM


Link to the video-meeting
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Before you receive an MRI, a technician will ask you to remove any metal items you are wearing. Metals can distort the MRI image and make it difficult to read. Indeed, living organisms have many requirements for metals. Metals play an important role in biochemical and physiological functions and various enzymes and vitamins contain metals. Some are for small amounts of an ion bound in specialized site, while others are for ‘bulk’ quantities at millimolar or higher concentrations. Magnetic resonance imaging (MRI) is the most potent and sensitive technique for detecting metal deposition. Most substances in the body are diamagnetic, thus barely influencing magnetic fields. Most metals are paramagnetic (Mg!), showing magnetization only in the presence of a surrounding magnetic field. Paramagnetism influences the T1 and T2 relaxation times in MRI due to the influence of unpaired electrons. Some metals, nonionic nickel, iron, and gadolinium are ferromagnetic and show strong magnetization causing signal changes or artifacts in MRI. However, ferromagnetic metals do not ex-ist in the body, except in implants. Most metal deposition causes high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. These signal intensity changes are rather specific for metal deposition in vivo. This talk focuses on the use and harm of metal deposition in the brain for brain MRI.

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