Experimental MRI visible resonant prosthetic heart valves

Erwin Immel, F J Gilbert, Andreas Melzer

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

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, 1.5T and 3T MRI. 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 & 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

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