The FDA issued a safety alert on March 31 announcing that it had received a small number of adverse events that it believes are associated with CT imaging of insulin pumps, cardiac implantable electronic devices (pacemakers and implantable cardioverter defibrillators) and neurostimulators.

“Our current understanding is that when a CT scanner directly irradiates the circuitry of certain implantable or wearable electronic medical devices (i.e. when the device is visible in the resulting CT image), it can cause sufficient electronic interference to affect the function and operation of the medical device,” the FDA said.

However, the agency said there was an “extremely low” probability that the interference could cause clinically significant adverse events.

Further, operators can avoid interference by making sure the medical device is outside the CT scanner’s primary X-ray beam.

The FDA noted the clinical benefits of a medically indicated CT exam outweigh the possibility of an adverse event.

“CT continues to be the preferred tomographic imaging technology for patients with implantable or wearable medical devices,” the FDA said. “CT is safer for patients with devices of unknown [MRI] safety status. You should be aware that an MR Conditional device is only safe within the MR environment that matches its conditions of safe use. Any device with an unknown MRI safety status should be assumed to be MR Unsafe.”