MRI SAFETY: THE CONTEXT, NOT THE TERMINOLOGY—Continued

Text Box: EXAMPLE: Old FDA Standard – MR Safe “MR Safe: [device] will not present an additional hazard or risk to a patient undergoing an MRI procedure using an MR system operating with a static magnetic field of 1.5 Tesla or less.”

Left Arrow Callout: In context this statement: Old FDA Standard – “MR Safe”

Left Arrow Callout: In context this statement: New ASTM Standard – “MR Safe”

Text Box: EXAMPLE: MR Safe New Standard MR Safe: Flouroplastic. Material is non-conducting or a nonmagnetic item and poses no known hazards in all MR environments.

Text Box: EXAMPLE: MR Conditional: New Standard Non-clinical testing has demonstrated that [Device] is MR Conditional. It can be scanned safely under the following conditions: Static Magnetic field of 3 Tesla or less. Spatial gradient field 720 gauss/cm or less. Maximum whole-body averaged specific absorption rate (SAR) of 2.0 W/kg for 15 minutes of scanning. In non-clinical testing the [device] produced a temperature rise of less than 2.0 °C. at a maximum MR system reported, whole body averaged specific absorption rate (SAR) of 2 W/kg for 15 minutes of MR scanning in a [static field strength] [Model] [MR Manufacturer] [software version] scanner.

Left Arrow Callout: In context this statement: New ASTM Standard – “MR Conditional”

Text Box: Because of those few manufacturers who did use the term “MR Safe” per the FDA recommendation prior to the change to ASTM standards, we now have a situation where the term “MR Safe” (Old FDA Standard) in information provided by those manufacturers, does not mean “MR Safe” (New ASTM Standard) even though the two terms are spelled identically! In these cases the difference must be resolved by determining the context in which the information was given.

Text Box: The fastest growing segment of the MRI business is the addition of 3T scanners. Pressure from the 3T market growth is forcing manufacturers to furnish 3T MR safety information. Therefore, the fastest growing area of MR safety documentation revisions is the addition of “MR Conditional” information, particularly that which is related to 3T magnets. However, because the change to the new ASTM standards is not being enforced retrospectively, the array of existing and confusing MR safety terms will remain in the marketplace for some time. Prior to a scan technologists must identify the implant, find the manufacturer’s MR safety information, and evaluate it against their facility’s scanning conditions. While we can sympathize with MRI technologists and radiologists, who are looking for the terms “Safe,” ”MRI Safe,” and/or “MR Safe” to provide a simple go or no-go scan decision, due diligence requires that the context, in which the safety status information was given, be evaluated as well. Particularly for 3T facilities, “MR Safe” (old FDA Standard) does not have the same definition as “MR Safe” (new ASTM Standard)!

In an effort to provide clarification to this issue, MagResource, first and only site to do so, displays the new ASTM Standard F2503-05 symbols in its search results to graphically identify manufacturers’ information complying with the new ASTM standards.

MagResource MRI Implant Safety Database

New ASTM Standard

Old FDA Standard

MR Safe

Indicates no known hazards in all MRI environments

The device, when used in the MRI environment, has been demonstrated to present no additional risk to the patient or other individual, but it may affect the quality of the diagnostic information. The MRI conditions in which the device was tested should be additionally specified.