Computer Diagnosis : Part 3

by Food and Drug Administration (FDA)

(Page 3 of 3)

Doctor Still Needed

The programs' limitations preclude them from replacing the physician.

Barnett, who developed DXplain, contended that only the physician can comprehend the "gestalt" of the disease, or diseases, producing the symptoms.

If a patient has only one disease, DXplain would stand a good chance of coming up with the correct diagnosis, Barnett said. "If they come in with two or three different diseases, though, it gets beyond the competence of any of the expert systems." In those cases, a physician's intuition, years of experience, and ability to make leaps of logic are the patient's best hope for unraveling the underlying diseases.

Nor can the computer consider the patient's personality, stresses, and other factors, or judge how those might interplay.

And, Barnett said, only physicians can quantify the disease, taking into account the myriad factors to determine its course in a particular patient. Is the pain radiating down the left arm from angina? Is it late- or early-stage disease? How severe is it? Will it get worse?

Still, Barnett and others agree, diagnostic software can prompt consideration of diseases a physician might never have seen or remembered described since medical school.

Computers are particularly effective for calculations needed for diagnosis. Susan Madden, a spokeswoman for Western Psychological Services in Los Angeles, said computers are commonly used in psychological assessments, to determine, for example, the potential of a patient for suicide, depression and anxiety, or substance abuse.

"The clinician using one of these programs doesn't have to calculate the scores or write an interpretive report on their own," Madden said. "It frees them up to do more clinical work."

Help for Technicians

More recently, computer diagnosis has been used to supplement the skills of medical technicians.

For instance, a technologist reviewing pap smears is expected to recognize a few abnormalities out of 100,000 cells — the equivalent of finding a couple of typographical errors in a large novel. A good technician might look at 90 slides a day. Estimates are that as many as many as 5 in 100 of the slides contain abnormalities that are missed, according to an article on the pap test in the Feb. 3, l989, issue of the Journal of the American Medical Association.

But Papnet, a computer program under a premarket review by FDA, developed by Neuromedical Systems Inc. in Suffern, N.Y., can screen one slide every five minutes, and work round the clock if necessary. The computer program identifies the 1,000 most suspect cells under magnification, then does a secondary screening where it stores magnified colored images of the 128 most suspect cells. A technologist can review them later and determine which require a pathologist's review.

A retrospective study by a team at Johns Hopkins University found Papnet identified suspect cells on slides from women whose undetected abnormalities had later gone on to develop lesions.

"It has the potential to detect abnormalities much earlier," said Laurie J. Mango, M.D., medical director and vice president at Neuromedical Services. "The most accurate pap smear will always be one that's read in two independent ways. In that sense, this will always be a complementary screen. But this is also a task that's particularly suited to computers because it's so repetitive."

The company is also investigating whether the program can be modified to screen cell samples from the respiratory tract and esophagus.

Other programs are being developed to digitize the information from mammograms and detect abnormalities. Stephen Feig, M.D., of Thomas Jefferson University Hospital in Philadelphia, said digital enhancement was found to increase a radiologist's detection of abnormalities on mammograms, from 85 to 92 percent in one study, and from 81 to 90 percent in another.

"It's not going to substitute for a radiologist, because no computer yet comes close to the human brain in terms of judgment, so determining whether something is benign or malignant is beyond its capabilities. But it might be of great value to a radiologist in that it would bring attention to potential abnormalities that he or she might not appreciate on a mammogram," Feig said. "Of course, it might also pick up abnormalities that are not there, but a radiologist could quickly rule them out."

Systems Integration

There is also an effort under way to integrate different computer systems. For instance, some electrocardiograms now come with a computer analysis attached to the printout, which notes some things the physician might want to consider based on the test results.

Jerome H. Grossman, M.D., chairman of the New England Medical Center in Boston, said the programs can also be used to reduce unnecessary treatment or tests.

Grossman, who is also chairman of the Federal Reserve Bank of Boston, said he has seen major changes in the way banks do business, to drive down costs by reducing duplication of services, or services too costly to justify.

"Health care is in the final stages of a similar transformation," Grossman said. "There is a real market for efficiency and value in health care. We have a marketplace that never existed before."

And, he predicted, there will be a continual sophistication of the software, integrating all the different information systems so that information on a patient's medical record is automatically considered by the diagnostic software, and the outcome of treatment, good or bad, is automatically fed back into the system to guide future decisions.

In the meantime, there are gradual refinements of existing software programs, and each year they become a little better at helping physicians figure out what is wrong with each patient who comes through the door.

About the Author

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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.