Letters to the Editor
Thank you for the article in the March/April 2012 issue of SN on the work of Committee F04 on Medical and Surgical Materials and Devices, and standard F2503, Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment.
While this standard has done much toward standardizing the world's identification of safety parameters of items in the MR environment, there are some significant challenges yet to overcome.
There are actually two substantially different versions of the term "MR Safe" in circulation. Prior to 2005, the term meant "safe, as long as you adhere to a defined set of conditions." From 2005 onward, if safety were dependent upon specific conditions of use, that formerly "MR Safe" device was labeled "MR Conditional." Post-2005, "MR Safe" means safe under any MR conditions, so without urging users or manufacturers of pre-2005 "MR Safe" labeled materials to update the labeling, the exact same phrase (invoking two entirely different standards) may be concurrently used.
The testing criteria used to define safe conditions of use (MR Conditional), don't define safety thresholds, but rather identify whether or not an item is safe under the specific test conditions of a single MRI scanner. This means that the information on an MR Conditional label may be so specific that it only applies to the scanning conditions of a single model of MRI scanner.
Unless a medical device seeks FDA approval specifically for use in conjunction with an MRI exam, there is no requirement that devices or support materials that are critical to a safe MRI environment be tested or labeled in accordance with the ASTM International standards.
I don't offer these critiques as an indictment of the F2503 standard or the work of Committee F04, but rather as a challenge to the very title of the article, "Promoting Safe Use of MRI Technology." Effective promotion of MRI safety demands ongoing effort of each of us, from working with the industry on vocabulary changes, to review and refinement of testing and labeling criteria, to integration with industry/regulatory requirements.
–Tobias Gilk, Radiology Design Specialists, Kansas City, Mo.