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Ex vivo evaluation of ferromagnetism, heating, and artifacts produced by heart valve prostheses exposed to a 1.5‐T MR system
Author(s) -
Shellock Frank G.,
Morisoli Stacy M.
Publication year - 1994
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880040521
Subject(s) - ex vivo , specific absorption rate , magnetic resonance imaging , implant , heart valve , biomedical engineering , materials science , nuclear medicine , nuclear magnetic resonance , in vivo , medicine , radiology , surgery , physics , computer science , telecommunications , microbiology and biotechnology , antenna (radio) , biology
Ex vivo testing techniques were used to determine the ferromagnetic qualities of, presence of heating in, and artifacts produced by 13 different heart valve prostheses exposed to a 1.5‐T (64‐MHz) magnetic resonance (MR) system. None of the heart valve prostheses showed a measurable deflection in the 1.5‐T static magnetic field. Only minimal artifacts were produced during MR imaging with a fast spoiled GRASS (gradient‐recalled acquisition in the steady state) pulse sequence. The largest temperature changes measured during a “worst case” MR imaging sequence (estimated average specific absorption rate, 2.5 W/kg; estimated spatial peak specific absorption rate, 7.6 W/kg) were +0.2°C with the implant imaged “in air” and +0.3°C with the implant imaged in normal saline. Therefore, MR procedures performed with a 1.5‐T (64‐MHz) MR system may be performed safely in patients with any of the 13 different heart valve prostheses evaluated in this study.