In vitro assessment of the lenz effect on heart valve prosthesis at 1.5T

Maria-Benedicta Edwards, John McLean, Stephanos Solomonidis, Barry Condon, Terence Gourlay

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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. 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. 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. 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.
LanguageEnglish
Pages74-82
Number of pages9
JournalJournal of Magnetic Resonance Imaging
Volume41
Issue number1
Early online date16 Dec 2014
DOIs
Publication statusPublished - 5 Jan 2015

Fingerprint

Heart valve prostheses
Heart Valve Prosthesis
Prosthetics
Electric Impedance
Pressure
Prostheses and Implants
Magnetic resonance
Magnetic Resonance Imaging
Pressure Transducers
Heart Valves
Imaging techniques
Cardiac Output
Pressure transducers
Pneumatics
Pressure drop
In Vitro Techniques
Scanning

Keywords

  • lenz effect
  • heart valve prosthesis
  • MRI
  • functional valve impedence

Cite this

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title = "In vitro assessment of the lenz effect on heart valve prosthesis at 1.5T",
abstract = "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. 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. 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. 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.",
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In vitro assessment of the lenz effect on heart valve prosthesis at 1.5T. / Edwards, Maria-Benedicta; McLean, John ; Solomonidis, Stephanos; Condon, Barry; Gourlay, Terence.

In: Journal of Magnetic Resonance Imaging, Vol. 41, No. 1, 05.01.2015, p. 74-82.

Research output: Contribution to journalArticle

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