OBJECT: The gradient fields generated during magnetic resonance imaging (MRI) procedures have the potential to induce electrical current on implanted endocardial leads. Whether this current can result in undesired cardiac stimulation is unknown. MATERIALS AND METHODS: This paper provides a detailed description of how to construct an optically coupled sensor for the measurement of gradient-field-induced currents into endocardial leads. The system is based on a microcontroller that works as analog-to-digital converter and sends the current signal acquired from the lead to an optical high-speed, light-emitting diode transmitter. A plastic fiber guides the light outside the MRI chamber to a photodiode receiver and then to an acquisition board connected to a PC laptop. RESULTS: The performance of the system has been characterized in terms of power consumption (8 mA on average), sampling frequency (20.5 kHz), measurement range (-12.8 to 10.3 mA) and resolution (22.6 µA). Results inside a 3 T MRI scanner are also presented. CONCLUSIONS: The detailed description of the current sensor could permit more standardized study of MRI gradient current induction in pacemaker systems. Results show the potential of gradient currents to affect the pacemaker capability of triggering a heartbeat, by modifying the overall energy delivered by the stimulator.
OBJECT: The gradient fields generated during magnetic resonance imaging (MRI) procedures have the potential to induce electrical current on implanted endocardial leads. Whether this current can result in undesired cardiac stimulation is unknown. MATERIALS AND METHODS: This paper provides a detailed description of how to construct an optically coupled sensor for the measurement of gradient-field-induced currents into endocardial leads. The system is based on a microcontroller that works as analog-to-digital converter and sends the current signal acquired from the lead to an optical high-speed, light-emitting diode transmitter. A plastic fiber guides the light outside the MRI chamber to a photodiode receiver and then to an acquisition board connected to a PC laptop. RESULTS: The performance of the system has been characterized in terms of power consumption (8 mA on average), sampling frequency (20.5 kHz), measurement range (-12.8 to 10.3 mA) and resolution (22.6 µA). Results inside a 3 T MRI scanner are also presented. CONCLUSIONS: The detailed description of the current sensor could permit more standardized study of MRI gradient current induction in pacemaker systems. Results show the potential of gradient currents to affect the pacemaker capability of triggering a heartbeat, by modifying the overall energy delivered by the stimulator.
Authors: Peter Nordbeck; Florian Fidler; Ingo Weiss; Marcus Warmuth; Michael T Friedrich; Philipp Ehses; Wolfgang Geistert; Oliver Ritter; Peter M Jakob; Mark E Ladd; Harald H Quick; Wolfgang R Bauer Journal: Magn Reson Med Date: 2008-08 Impact factor: 4.668
Authors: Emanuel Kanal; A James Barkovich; Charlotte Bell; James P Borgstede; William G Bradley; Jerry W Froelich; J Rod Gimbel; John W Gosbee; Ellisa Kuhni-Kaminski; Paul A Larson; James W Lester; John Nyenhuis; Daniel Joe Schaefer; Elizabeth A Sebek; Jeffrey Weinreb; Bruce L Wilkoff; Terry O Woods; Leonard Lucey; Dina Hernandez Journal: J Magn Reson Imaging Date: 2013-01-23 Impact factor: 4.813
Authors: Edward T Martin; James A Coman; Frank G Shellock; Christopher C Pulling; Robert Fair; Kim Jenkins Journal: J Am Coll Cardiol Date: 2004-04-07 Impact factor: 24.094
Authors: Eugenio Mattei; Michele Triventi; Giovanni Calcagnini; Federica Censi; Wolfgang Kainz; Gonzalo Mendoza; Howard I Bassen; Pietro Bartolini Journal: Biomed Eng Online Date: 2008-03-03 Impact factor: 2.819