Calculating RF-Induced Voltages for Implanted Medical Devices in MRI Using Computational Human Models
Summary
Patients with active implantable medical devices (AIMDs) can now undergo magnetic resonance imaging (MRI) safely. This study investigates how computational human models (CHMs) affect radiofrequency-induced voltage calculations for cardiac implantable electronic devices (CIEDs).
Area of Science:
- Biomedical Engineering
- Medical Imaging Physics
- Electromagnetics
Background:
- Magnetic Resonance Imaging (MRI) is a crucial diagnostic tool, but its electromagnetic fields pose risks to patients with Active Implantable Medical Devices (AIMDs).
- Assessing the radiofrequency (RF)-induced energy at AIMD ports is vital for risk evaluation, often involving electromagnetic simulations with Computational Human Models (CHMs).
Purpose of the Study:
- To investigate the influence of different CHMs on the calculation of RF-induced voltages at the antenna port of Cardiovascular Implantable Electronic Devices (CIEDs).
- To enhance the accuracy of risk assessments for CIEDs during MRI procedures.
Main Methods:
- Electromagnetic simulations were conducted using various CHMs to model the MRI environment.
- RF-induced voltages at the antenna port of CIEDs were calculated and analyzed based on the selected CHMs.
Main Results:
- The choice of CHM significantly impacts the calculated RF-induced voltages at the CIED antenna port.
- Variations in CHM geometry and material properties lead to differing energy deposition predictions.
Conclusions:
- Computational Human Models play a critical role in determining the safety of MRI for patients with CIEDs.
- Accurate CHM selection is essential for reliable risk assessment and the safe use of MRI in patients with these devices.
Related Concept Videos
01:13Voltage
4.3K
The movement of electrons in a conductor requires some form of energy or work, usually provided by an external force, like a battery. This force is called the electromotive force or voltage. The voltage between two points, referred to as points "a" and "b," in an electric circuit is the energy (or work) needed to move a unit charge from point "a" to point "b," and this relationship is expressed mathematically as
4.3K
01:13Induced-fit Model
89.2K
Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being consumed or permanently changed. They reduce the activation energy needed to convert the reactants into products. Enzymes are proteins, that usually work by binding to a substrate—a reactant molecule that they act upon.
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical...
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical...
89.2K
02:46Calculating the Equilibrium Constant
38.0K
The equilibrium constant for a reaction is calculated from the equilibrium concentrations (or pressures) of its reactants and products. If these concentrations are known, the calculation simply involves their substitution into the Kc expression.
For example, gaseous nitrogen dioxide forms dinitrogen tetroxide according to this equation:
For example, gaseous nitrogen dioxide forms dinitrogen tetroxide according to this equation:
38.0K
02:49Calculating Standard Free Energy Changes
24.9K
The free energy change for a reaction that occurs under the standard conditions of 1 bar pressure and at 298 K is called the standard free energy change. Since free energy is a state function, its value depends only on the conditions of the initial and final states of the system. A convenient and common approach to the calculation of free energy changes for physical and chemical reactions is by use of widely available compilations of standard state thermodynamic data. One method involves the...
24.9K
02:45Calculating pH Changes in a Buffer Solution
58.7K
A buffer can prevent a sudden drop or increase in the pH of a solution after the addition of a strong acid or base up to its buffering capacity; however, such addition of a strong acid or base does result in the slight pH change of the solution. The small pH change can be calculated by determining the resulting change in the concentration of buffer components, i.e., a weak acid and its conjugate base or vice versa. The concentrations obtained using these stoichiometric calculations can be used...
58.7K
01:24Numerical Calculations
1.2K
In engineering applications, the representation of the numerical value is critical. Presenting or reporting the answer is one of the essential parts of engineering practices. Numerical calculations are performed using handheld calculators or computers since numerically accurate answers are always preferred.
The solution to a problem is obtained using different methods. While manually solving algebraic symbols is one of the most common methods, the graphical method is often preferred. Computers...
The solution to a problem is obtained using different methods. While manually solving algebraic symbols is one of the most common methods, the graphical method is often preferred. Computers...
1.2K