Experimental MRI visible resonant prosthetic heart valves

Erwin Immel, F. J. Gilbert, Andreas Melzer

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    Abstract

    Artificial heart valves comprising metal can cause significant MR image artifacts due to the material (susceptibility artifact) and/or electromagnetic characteristics (RF artifact). The purpose of our study was to examine current commercially available heart valve prostheses, integrate resonant circuits and to produce a protoype self-expanding heart valve for MRI-guided placement. Different types of commercially available heart valves were tested in MRI. Freshly excised porcine heart valves were sutured with 6-0 prolene into a 21 mm. Nitinol stent. Resonant circuits were integrated into the heart valves and tuned to the Larmor frequency of the MRI (42.58 MHz for 1.0 T and about 64 MHz for 1.5 T and 128 MHz for 3T). The artifacts caused by the non-ferromagnetic heart valves and the Nitinol stent could be overcome. MRI signal could be enhanced using low flip angles <40 and visualization improved in 1T, 15T and 3T MRL MRI-guided implantation was facilitated. A resonant circuit tuned to the Larmor frequency of the MR tomography can overcome the RF artifacts and thus improve the visualization of prosthetic heart valves.

    Original languageEnglish
    Pages (from-to)149-155
    Number of pages7
    JournalMinimally Invasive Therapy and Allied Technologies
    Volume18
    Issue number3
    DOIs
    Publication statusPublished - 2009

    Keywords

    • Magnetic resonance imaging
    • Resonant circuits
    • Heart valves
    • Conductive coupling
    • MR visualization
    • MRI compatibility
    • MRI safety
    • Interventional MRI
    • Transcatheter implantation

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