Computer Diagnosis

by Food and Drug Administration (FDA)

When Paul A. Mongerson of Marathon, Fla., had severe abdominal pains in 1980, a battery of tests showed he had an elevated blood level of the enzyme lipase, which could indicate cancer of the pancreas. Though the diagnosis was not confirmed by other tests, his doctor recommended surgery.

"I'm an engineer by training, so I made up a matrix, charting my symptoms and test results, the possible diseases that could cause my symptoms, and what other symptoms would be present with those diseases," Mongerson recalls. "My conclusion was that I could not have cancer of the pancreas, and the fifth doctor I consulted, at Mt. Sinai in New York, agreed with me."

Eventually the pain disappeared, and he was found to have a condition known as pseudolipase, which results in abnormally high readings for the enzyme in tests. Mongerson said he thinks he might have bruised his pancreas while working around the house.

"I said at that time, 'what I did is just what a computer would do.' Medicine has gone about as far as it can without computers. There's a limit to how much the mind can retain, even with the degree of specialization that we've seen in medicine," Mongerson said. "The field of knowledge is so big the human mind is incapable of grasping it all — but a computer could help."

So Mongerson formed a foundation that provided financial assistance to physicians working to develop computer diagnosis systems. Today, medical diagnostic software puts entire medical libraries a mouse-click away. The Food and Drug Administration already regulates some diagnostic software, and as the number of programs expands, so does FDA's review.

Anthony Voytovich, M.D., chief of staff at John Dempsey Hospital in Connecticut, who has worked with computerized diagnosis programs for more than a decade, said it's important to keep their function in perspective.

"These programs are kind of like those Nordic Track machines. You can't put a machine like that in your bedroom and suddenly look like a million bucks; it's going to take a lot of sweat," Voytovich said. "When these programs were first put out there, a lot of people thought they would replace the physician, but they can't do that anymore than a high-speed drill will replace the dentist. They're a tool — a very effective tool that makes the physician's job much easier, but a tool nonetheless."

Diagnostic software is enjoying increasingly wider use each year. Computers are helping in the general practitioner's office, where they can identify even exotic diseases the physician has never seen. In the laboratory, they might help find a precancerous cell from a pap smear or a lump in breast tissue.

The programs are particularly good at prompting physicians with possibilities they might not otherwise envision. G. Octo Barnett, M.D., of Harvard Medical School's Laboratory of Computer Science, who developed the diagnostic software DXplain (2,200 diseases and 5,000 symptoms in its knowledge base), told of a physician in Texas seeing an adolescent boy with a skin rash and high fever. The computer suggested Rocky Mountain spotted fever, which the physician had not considered. He learned the boy had been hiking in Colorado recently, and subsequent tests confirmed the diagnosis.

Jerome P. Kassirer, M.D., editor of the New England Journal of Medicine, wrote in an editorial June 23, 1994, about the use of a computer program in the case of an 18-year-old man who had symptoms of a heart attack. The software also suggested cocaine abuse, which had not been considered, but which could have been a cause.

A study at the University of California San Diego Medical Center, focusing on emergency room patients experiencing chest pain, found computers accurately diagnosed 97 percent of heart attacks, compared with 78 percent for physicians.

Closer Look

FDA is now taking a closer look at medical diagnostic programs. Harvey Rudolph, Ph.D., acting deputy director of the Office of Science and Technology in the Center for Devices and Radiological Health, said FDA's policy has been that as long as the programs provided for "competent human intervention," they would not be actively regulated.

"In effect, the stand-alone diagnostic software programs used by physicians are considered decision support systems, and are exempt from regulation," Rudolph said. "The programs are based on well-known, well-established data, and the person using the software is expected to be competent to interpret the results."

FDA has always regulated computer software that modifies data entered by a user to control a medical device, or modifies data from a medical device to present it to a user. This includes, for instance, software that scans biopsied cells for signs of cancer.

But as the use of computers in diagnosis grows, the line between the different types of software blurs. Currently, FDA has applications on file for premarket approval of programs that would, for instance, help in reading diagnostic images such as mammograms.

Later this year, FDA plans to publish a Federal Register notice about its proposed policy for assessing and regulating various software, said Jurriaan Strobos, M.D., who is also an attorney and heads the policy research staff in FDA's Office of Policy.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.