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In vitro assessment of the lenz effect on heart valve prostheses at 1.5 T.
MedLine Citation:
PMID:  24436215     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
PURPOSE: Increasing numbers of patients with cardiac valve prostheses are being referred for magnetic resonance imaging (MRI) despite concerns about the potential for functional valve impedance due to Lenz forces. This study aims to determine, in vitro, the occurrence of Lenz forces on 9 heart valve prostheses at 1.5 T and assess the risk of impedance of valve function.
MATERIALS AND METHODS: A specially designed hydro-pneumatic system was used to record pressure changes across the valve indicative of any MR induced alteration in leaflet performance. Nine cardiac valve prostheses were exposed to the B0 field at 1.5 T. Each valve was advanced through the B0 field and continuous signals from high frequency pressure transducers were recorded and pressure drops across the valve were assessed using time correction superimposition. The delta p across the valve was assessed as a marker of any MRI induced alteration in leaflet performance.
RESULTS: All prostheses produced sinusoidal waveforms. Profiles were asymmetrical and there was no consistency in complex shape and valve type/sub-group. Irregularities in pressure profiles of 4 prostheses were detected indicating resistance of the occluder to the B0 field.
CONCLUSION: This study provides empirical evidence of the Lenz Effect on cardiac valve prostheses exposed to the MR B0 field causing functional valve impedance and increasing the risk of valvular regurgitation and reduced cardiac output. Thus, it is essential to consider the potential for the Lenz Effect when scanning cardiac valve implant patients in order to safeguard their wellbeing.J. Magn. Reson. Imaging 2014. © 2014 Wiley Periodicals, Inc.
Authors:
Maria-Benedicta Edwards; John McLean; Stephanos Solomonidis; Barrie Condon; Terence Gourlay
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-1-17
Journal Detail:
Title:  Journal of magnetic resonance imaging : JMRI     Volume:  -     ISSN:  1522-2586     ISO Abbreviation:  J Magn Reson Imaging     Publication Date:  2014 Jan 
Date Detail:
Created Date:  2014-1-17     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9105850     Medline TA:  J Magn Reson Imaging     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2013 Wiley Periodicals, Inc.
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