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| Custom electric heating element developed for keeping mice warm during MRIs. |
Compatibility between MRI machines and resistive, electric heaters has been a challenge to manufacturers of heating devices. MRI's and electric heaters don't like each other because of the electromagnetic field given off by DC and standard AC voltages. That E/M field disturbs the image resolution and quality of the MRI.
In research and lab testing, mice and other rodents are examined via MRI technology. In order for the rodents to be compliant with the testing procedure, the mice are given anesthesia which lowers their body temperatures and can send them into hypothermia. In the past, this situation was corrected by warming the air around the animal sufficiently to warm their body. Air heating requires a significant amount of valuable space, so a different heating source that would both not conflict with the MRI output and also provide a more compact, economical solution was required.
While DC voltages and standard AC voltage caused problems with the MRI, the solution turns out to be a copper wire element, embedded in heating blanket, and powered by AC voltage in a frequency ranging between 10-100 kHz.
In research and lab testing, mice and other rodents are examined via MRI technology. In order for the rodents to be compliant with the testing procedure, the mice are given anesthesia which lowers their body temperatures and can send them into hypothermia. In the past, this situation was corrected by warming the air around the animal sufficiently to warm their body. Air heating requires a significant amount of valuable space, so a different heating source that would both not conflict with the MRI output and also provide a more compact, economical solution was required.
While DC voltages and standard AC voltage caused problems with the MRI, the solution turns out to be a copper wire element, embedded in heating blanket, and powered by AC voltage in a frequency ranging between 10-100 kHz.
Conclusion
High frequency electrical heating provides a simple means by which stable body temperatures can be maintained in the mouse. The space requirement for the heating apparatus around the mouse is minimized and the system can be extended to use arbitrarily shaped resistor systems. Image and spectral quality are not adversely affected by the presence of the AC used in the heater so MRI performance is not compromised. As such a new MRI-compatible mouse heating system has been developed and validated.
To read the entire article, An MRI-Compatible High Frequency AC Resistive Heating System for Homeothermic Maintenance in Small Animals, visit this link.