In vitro study to simulate the intracardiac magnetohydrodynamic effect

Buchenberg, Waltraud B.; Mader, Wolfgang; Hoppe, G.; Lorenz, Ramona; Menza, Marius; Büchert, Martin; Timmer, Jens; Jung, Bernd

doi:10.1002/mrm.25456

Cited by 5 publications

(7 citation statements)

References 32 publications

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“…32,33 Of greater practical concern is that positive and negative ions in blood are pushed in opposite directions by the Lorentz force, causing a charge separation and an electric field that corrupts electrocardiograms and complicates the task of performing cardiac-gated MRI. [35][36][37] It is well known that movement in a magnetic field can induce a voltage (due to Faraday's law of induction, discussed in more detail later) in electrically conductive materials, including biological tissues, especially when the motion is through regions of space where the magnetic field changes steeply. For example, near the entry to the bore of a 3T MRI where j$B o j tends to be greatest, it can be shown that current densities over 0.1 A/m 2 may be produced in conductive tissues due to the voltage induced by normal movement.…”

Section: Direct Interactions Between the Static Magnetic Field And LImentioning

confidence: 99%

“…Blood flowing in a direction orthogonal to a magnetic field experiences a reverse pressure impeding the flow, but this is expected to result in an insignificant increase in blood pressure even in a high‐field MRI . Of greater practical concern is that positive and negative ions in blood are pushed in opposite directions by the Lorentz force, causing a charge separation and an electric field that corrupts electrocardiograms and complicates the task of performing cardiac‐gated MRI …”

Section: The Static Magnetic Fieldmentioning

confidence: 99%

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The physics of MRI safety

Panych

Madore

2017

Magnetic Resonance Imaging

133

150

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The main risks associated with magnetic resonance imaging (MRI) have been extensively reported and studied; for example, everyday objects may turn into projectiles, energy deposition can cause burns, varying fields can induce nerve stimulation, and loud noises can lead to auditory loss. The present review article is geared toward providing intuition about the physical mechanisms that give rise to these risks. On the one hand, excellent literature already exists on the practical aspect of risk management, with clinical workflow and recommendations. On the other hand, excellent technical articles also exist that explain these risks from basic principles of electromagnetism. We felt that an underserved niche might be found between the two, ie, somewhere between basic science and practical advice, to help develop intuition about electromagnetism that might prove of practical value when working around MR scanners. Following a wide‐ranging introduction, risks originating from the main magnetic field, the excitation RF electromagnetic field, and switching of the imaging gradients will be presented in turn. Level of Evidence: 5 Technical Efficacy: 1 J. Magn. Reson. Imaging 2018;47:28–43.

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Section: Direct Interactions Between the Static Magnetic Field And LImentioning

confidence: 99%

Section: The Static Magnetic Fieldmentioning

confidence: 99%

The physics of MRI safety

Panych

Madore

2017

Magnetic Resonance Imaging

133

150

View full text Add to dashboard Cite

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“…[ 74,79 ] Similarly, a phantom in vitro model was developed to record bipolar VMHD signals ( Figure 4 a) and shown to be comparable to a simplifi ed analytical model in an MRI environment (Figure 4 b), predicting a linear dependence on fi eld strength. [ 80 ] The phantom model was constructed using rigid plastic tubing, a fl uid reservoir, and a ventricular assist device, allowing the device to circulate a volume of conducting fl uid while maintaining MRI-compatibility.…”

Section: Other Microscale Mhd Devices and Applicationsmentioning

confidence: 99%

The Magnetohydrodynamic Effect and Its Associated Material Designs for Biomedical Applications: A State‐of‐the‐Art Review

Gregory

Cheng

Tang

et al. 2016

Adv Funct Materials

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The presented article discusses recent advances in biomedical applications of classical Magnetohydrodynamics (MHD), with a focus on operating principles and associated material considerations. These applications address novel approaches to common biomedical problems from micro-particle sorting for lab-on-a-chip devices to advanced physiological monitoring techniques. 100 papers in the field of MHDs were reviewed with a focus on studies with direct biomedical applications. The body of literature was categorized into three primary areas of research including Material Considerations for MHD Applications, MHD Actuation Devices, and MHD Sensing Techniques. The state of the art in the field was examined and research topics were connected to provide a wide view of the field of biomedical MHDs. As this field develops, the need for advanced simulation and material design will continue to increase in importance in order to further expand its reach to maturity. As the field of biomedical MHDs continues to grow, advances towards micro-scale transitions will continue to be made, maintaining its clinically driven nature and moving towards real-world applications.

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“…Using a flow phantom placed inside an MRI, as well as a pump which provided pulsatile flow, V MHD was reproduced in vitro. In addition, the correlation between V MHD observed on conventional ECG traces and cardiac blood flow was demonstrated [19]. Current modeling approaches have been able to successfully simulate the induced V MHD as a linear combination of the true ECG signal and a V MHD term (Eq 1) with an additional scaling factor which was dependent on the measurement electrode selected [20].…”

Section: Introductionmentioning

confidence: 99%

Exploring magnetohydrodynamic voltage distributions in the human body: Preliminary results

et al. 2019

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Background The aim of this study was to noninvasively measure regional contributions of vasculature in the human body using magnetohydrodynamic voltages (V MHD ) obtained from electrocardiogram (ECG) recordings performed inside MRI’s static magnetic field (B 0 ). Integrating the regional V MHD over the S wave -T wave segment of the cardiac cycle (V segment ) provides a non-invasive method for measuring regional blood volumes, which can be rapidly obtained during MRI without incurring additional cost. Methods V MHD was extracted from 12-lead ECG traces acquired during gradual introduction into a 3T MRI. Regional contributions were computed utilizing weights based on B 0 ’s strength at specified distances from isocenter. V segment mapping was performed in six subjects and validated against MR angiograms (MRA). Results Fluctuations in V segment , which presented as positive trace deflections, were found to be associated with aortic-arch flow in the thoracic cavity, the main branches of the abdominal aorta, and the bifurcation of the common iliac artery. The largest fluctuation corresponded to the location where the aortic arch was approximately orthogonal to B 0 . The smallest fluctuations corresponded to areas of vasculature that were parallel to B 0 . Significant correlations (specifically, Spearman’s ranked correlation coefficients of 0.96 and 0.97 for abdominal and thoracic cavities, respectively) were found between the MRA and V segment maps (p < 0.001). Conclusions A novel non-invasive method to extract regional blood volumes from ECGs was developed and shown to be a rapid means to quantify peripheral and abdominal blood volumes.

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In vitro study to simulate the intracardiac magnetohydrodynamic effect

Abstract: The in vitro model allows investigation of MHD effects on intracardiac electrograms. A phase contrast MR scan was successfully applied to characterize and estimate the MHD distortion on intracardiac signals allowing correction of these effects.

Cited by 5 publications

References 32 publications

The physics of MRI safety

The physics of MRI safety

The Magnetohydrodynamic Effect and Its Associated Material Designs for Biomedical Applications: A State‐of‐the‐Art Review

Exploring magnetohydrodynamic voltage distributions in the human body: Preliminary results

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