MRI, Radiotranslucent, and Radio-opaque Compatibility

BIOPAC definitions

Items have been tested with a 7T Siemens MAGNETOM, with SC72 gradient set, a maximum gradient amplitude of 70 mT/m, and a slew rate of 200 mT/m/ms. Tested sequences include EPI/DTI/MPRAGE. Studies include a 32-channel Nova Medical head coil. Proper operation was observed and no safety concerns were noted during these described circumstances.

• MR Safe – an item that poses no known hazards in all MRI environments. Using the terminology, “MR Safe” items are non-conducting, non-metallic, and non-magnetic items such as a plastic Petri dish. An item may be determined to be MR Safe by providing a scientifically based rationale rather than test data.
  • BIOPAC’s MR Safe items have no specific MR conditions for use, as these items are constructed of only non-conductive, non-metallic, and non-magnetic parts
• MR Conditional – an item that has been demonstrated to pose no known hazards in a specified MR environment with specified conditions of use. “Field” conditions that define the MR environment include static magnetic field strength, spatial gradient magnetic field, dB/dt (time rate of change of the magnetic field), radio frequency (RF) fields, and specific absorption rate (SAR). Additional conditions, including specific configurations of the item (e.g., the routing of leads used for a neurostimulation system), may be required
  • All MRI Conditional items must be used with the associated, supporting, MECMRI type cabling system.  Furthermore, any conductive leads placed across subject should be thermally insulated, from bare skin, via clothing or towel – as additional safety precaution.
• Radiotranslucent – products that have no metal at all in the applied part; these are best-suited for MRI applications.

Cable and Lead Notes

Do not coil or twist leads, simply run parallel to the subject and the bore, up to the point of subject attachment, where the leads make a right angle to be attached to the point of interest.

X-ray Notes

MR Safe or Conditional does not refer to the capability of an applied part to be used in an x-ray machine. Radio-opaque implies that the applied part is easily visible in an x-ray machine so it can be manipulated via the x-ray viewer. Radiotranslucent in this context implies that the applied part is only partially or not visible in the x-ray viewer.

Safety Notes

Caution is required whenever employing electrode leads and electrodes in an MRI environment.

IMPORTANT! See Safety Guidelines for recording  biopotential measurements in the MRI environment.

Under certain conditions, single fault and otherwise, low impedance conduction through the subject represents a potential hazard due to currents that may be induced in loops placed in the time-varying MRI field gradients and RF fields, and due to body movement in the static MRI field. Low impedance conduction can result in significant heating at the electrode/skin junction, because this point is often the part of the signal path with the highest impedance. Sufficient heating at the electrode/skin junction could result in burns.

For more information:

• Read the Associated Application Notes listed below.
• See the “Magnetic Resonance Imaging” section of a BIOPAC Hardware Guide (available at Support > Manuals, or under the software Help menu, or on the software CD).
• Read Methodological Issues in EEG-correlated Functional MRI Experiments (Lemieux L, Allen PJ, Krakow K, Symms MR, Fish DR; International Journal of Bioelectromagnetism 1999; 1: 87-95).
• See MRI Recommended Reading

BIOPAC Systems, Inc. products (including instruments, components, accessories, electrodes and electrode leads) are designed for educational and research applications. BIOPAC does not condone the use of its products for clinical medical applications. Products provided by BIOPAC are not intended for the diagnosis, mitigation, treatment, cure or prevention of disease.