In Reply

On behalf of the American Society of Anesthesiologists Task Force on Magnetic Resonance Imaging, we appreciate the efforts of Dr. Gorlin and coauthors to publicize the phenomenon of vertigo and other physical effects that may be experienced by healthcare professionals who work in the magnetic resonance imaging (MRI) environment. They note that these effects are neither widely known nor commonly experienced by anesthesia professionals, even among those who spend a great deal of time providing anesthesia care for patients undergoing MRI. Although there is a lack of strongly supportive evidence, we believe that these experiences may well be related to the strength of the static magnetic field, designated by the tesla number of the scanner, and movement of the individual (or more specifically one’s head movement) within that field near its central region. Nurses routinely working with patients lying within 1.5- and more so 3-tesla scanners have reported associated health complaints.¹  Leaning inside the scanner bore to locate the pulse oximeter, find an IV injection port, or assess a patient’s airway may be the kind of activity that could produce this sensation. It may be that anesthesiologists do not encounter these effects as much because they are less apt to engage in this activity to the extent as do the nurses with whom we work. Despite the decades-long recognition of MRI-associated vertigo and other neurobehavioral effects, no long-term deleterious consequences have been documented to date.² 

Awareness of this phenomenon and prudent caution to avoid sudden head movement in the area of the scanner bore would appear to be common sense advice; however, at this time, the accumulated evidence needed for such a recommendation is not available. Admittedly, protocols at some research MRI facilities where 7-tesla and higher static field magnets are in operation prohibit technicians from working alone in the scanner as a precaution against the effects of disabling vertigo and its untoward consequences. At present, we cannot recommend without more compelling evidence that “anesthesia providers be instructed to stay as far away from the scanner as possible” or that “clinicians should avoid leaning directly into the bore of the MRI scanner.” Finally, having “back-up personnel available in the event that a provider experiences intense vertigo that impairs his or her ability to safely care for patients” cannot be recommended without evidence that such resources are justified. Although we do agree that this phenomenon may occur more often in the future as higher field strength magnets evolve from the research arena into clinical imaging, the American Society of Anesthesiologists process of practice parameter development will require convincing evidence to make appropriate recommendations regarding neurobehavioral and cognitive effects of MRI. The task force does intend to address this issue in a future update of the Practice Advisory.