FDA Guidance on Medical Apps Clears Path for Mobile Imaging

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 - David Hirschorn, MD
David Hirschorn, MD

Mobile computing—via smart phones, tablets and, increasingly, wearable devices like smart watches—is increasing exponentially. In 2013 alone, mobile web traffic grew by 81%; average usage of smart phones increased by 50%. 1 By the end of this year, experts predict that there will be more mobile devices than humans on the planet. The mobile revolution is clearly in full swing. But what does it mean for imaging?

In a session at RSNA 2013, David Hirschorn, MD, director of radiology informatics at Staten Island University and Hospital and member of the ACR’s IT and Informatics Committee, set out to answer that question. He began by specifying that, because of the privacy issues associated with medical data, any discussion regarding mobile imaging must begin with an examination of the FDA’s rules on the subject. “The FDA was surprised when someone first wrote medical software for mobile devices,” he said. “They had to come out with a guidance for medical apps, which was recently finalized.”

FDA Guidance

The FDA was in a difficult position because, for the first time, it was being asked to issue guidance on a product that was not itself a medical device. “The manufacturers aren’t making medical devices, they’re making phones,” Hirschorn said. “And the programmers are making web-based apps. They’re making no statements about the devices they will be displayed on—they could be anything.”

The closed nature of Apple’s operating systems gave the agency the in it needed to approach regulation of mobile imaging software; unlike open-source platforms such as Android, Apple’s iOS is not device-agnostic. “When you write software for iOS, it’s hard to argue that you don’t know what hardware it will run on,” Hirschorn said. “So the FDA said that it could hold programmers responsible for that, and in January of 2010 they said to put marketing of these apps on hold for a year to give them time to answer some questions.”

The FDA regulates software and devices according to three classes. In Classes I and II, products can be released without FDA approval but are subject to scrutiny from the agency and can be taken off the market at its behest. In Class III, on the other hand, products require pre-market approval. “The FDA’s initial response was that these apps should be subject to pre-market approval,” Hirschorn said. 

In July of 2011, the agency released a draft version of guidance on mobile medical apps. Regarding imaging apps, “They said they can pose risks,” Hirschorn said. “For example, interpretation of images could be adversely affected by smaller screen size, lower contrast ratio and uncontrolled ambient light. All of those things are very reasonable concerns.”

App Versus Device

In September of 2013, the FDA finalized its  guidance2 on mobile medical apps. The spirit of the draft version remained, although the agency took the opportunity to get more granular in the final version. “They clarified things a little further, because if you’re a vendor putting a product out, you want to do the right thing from the beginning,” Hirschorn said.  

The guidance primarily concerns itself with determining under what circumstances consumer technology can be considered a medical device. “What makes the platform—that’s the phone or tablet—into a mobile medical application is if it used as an accessory to a regulated medical device, or if it transforms the platform into a regulated medical device,” Hirschorn explained. “With the intended use of mobile imaging apps for diagnosis, they make the platform into a device. Anything used to help diagnose the patient is a device.”

Specifically, the FDA calls out the following categories of mobile medical apps as subject to its regulatory oversight: mobile apps that are extensions of medical devices; mobile apps that transform the mobile platform into a regulated medical device; and mobile apps that become regulated medical devices by performing patient-specific activities like analysis, diagnosis and recommending treatments. “If I take some earbuds and a microphone and plug them into my phone and say, ‘Look, I have a great amplifier for hearing heart sounds,’ that is now a stethoscope, and it’s under their purview,” Hirschorn said by way of example. 

To further illustrate its point, the FDA includes in the guidance a handy list of examples of mobile apps that do not constitute medical devices. These include electronic copies of reference materials like medical textbooks; mobile apps intended for physician