BusinessWeek: July 19, 1993

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WATCHING THE BRAIN AT WORK

For Albert Taxin, the first hint of trouble came one steamy day last July. The 52-year-old owner of Philadelphia's venerable Bookbinder's restaurant collapsed while jogging. His physician wrote it off as heat stroke, but then it happened again, and again. Finally, neurosurgeons found a malignant brain tumor--and the nightmare began. Doctor after doctor refused to operate, fearing that surgery would leave Taxin an invalid. The tumor had displaced the motor cortex, the part of the brain that controls movement, and the doctors were unsure of its exact location. Eventually, one neurosurgeon sent Taxin to Scripps Clinic & Research Foundation in La Jolla, Calif., for an experimental brain scan known as magnetic source imaging (MSI).

That has added years to his life, Taxin figures. MSI tracks the tiny electrical signals that are generated as the brain and muscle tissue go about their routine business. So unlike current technologies, which just show a structural picture, MSI scans show the precise functions of different parts of the brain. When a patient moves a finger, for example, an array of MSI sensors placed around the skull detects increased electrical activity where the movement originates. The system's computer then generates an image that pinpoints the brain region that controls the motion. Seeing the exact location of the tumor and the function of adjacent tissues enabled Taxin's neurosurgeon to proceed. "When I showed him the pictures," Taxin recalls, "he said: 'Let's go out and celebrate--I can operate.'"

Doctors from more than a score of medical centers in the U.S. are referring patients to the two facilities that now offer MSI, Scripps and the Veterans Administration hospital in Albuquerque. Today, MSI is used mainly to map the brain before surgery. But researchers believe it will also help them understand brain activity affecting everything from epilepsy and Parkinson's disease to psychiatric disorders. "This will revolutionize psychiatry and behavioral neurology," says Dr. Christopher C. Gallen, a psychiatrist and neurologist at Scripps. Adds Dr. Rudolfo Llinas, chairman of the physiology and biophysics department at New York University Medical Center: "I can imagine the day when people will come in once a year to see how their brain is doing, just like they go to the dentist to get their teeth checked."

FINE-TUNING. The prospect of a new, multibillion-dollar medical-imaging market has business excited, too--though the market won't take off until insurers start picking up the tab. So far, Biomagnetic Technologies Inc., a tiny San Diego company that is collaborating with medical centers in the U.S., Japan, and Europe, is the only company that has Food & Drug Administration approval for its scanner--a $2.5 million system. But the major medical-imaging companies all have similar programs under way. Siemens has installed three systems in Europe, and Philips and General Electric are developing prototypes of their own. Startups in Canada, Italy, and Finland are fine-tuning the technology. And the Japanese government and 16 companies, including Hitachi, Toshiba, and Shimadzu, have a $50 million consortium to build a prototype of a more sophisticated scanner by 1996.

MSI takes advantage of the fact that every electrical signal creates a magnetic field around it. In the body, the difficulty is that such magnetic fields are infinitesimally small--a billionth of the earth's gravitational pull in the case of the brain. "It's like listening for the footsteps of an ant in the middle of a rock concert," says Scripps's Gallen.

By the mid-1970s, scientists had shown that sensitive instruments called magnetometers could pick up magnetic fields from the heart and brain. At the same time, the government was designing ultrasensitive magnetometers for monitoring underground nuclear explosions and finding enemy submarines. The instruments do so using a low-temperature superconducting wire coil--known as a superconducting quantum interference device, or SQUID.

The idea of using the technology in medicine got a boost in 1982, when University of California at Los Angeles researchers did the first experiments showing that a biomagnetometer could precisely locate the faulty brain tissue that triggers epileptic seizures. Other external methods of monitoring the body's electrical activity--such as electroencephalographs--can- not determine the exact location because electrical signals are distorted as they pass through bone and tissue.

To zero in on the magnetic fields, which aren't distorted as they pass through the body, BTI's biomagnetometer is pressed against part of the skull for a few seconds. Sensors in the instrument--which looks like an X-ray machine--collect data from 37 points. Then the patient's head is moved slightly and the process is repeated. A complete scan takes nearly an hour and requires a room shielded against stray electrical signals. The computer-generated image is overlaid on a conventional magnetic resonance imaging (MRI) scan. This composite shows both tumors and other structures--from the MRI--and the sensory and motor functions.

INSURERS UNSURE. For MSI to become commonplace, it must win over insurers and Medicare. "MSI scanners are giving us information that wasn't available before, so it's difficult to put a dollar value on it," says Dr. Thomas A. Waltz, Scripps's president and a neurosurgeon himself. "It probably adds to costs, but it should [also] significantly add to the success of surgeries." The one-hour scan costs $1,200, roughly the same as an MRI. During development, BTI has underwritten the scans' cost. But now, Scripps has started billing patients for the service in an attempt to persuade insurance companies to begin reimbursing patients on a case-by-case basis. "I'm optimistic," says Gerald Cohen, manager of applications development for GE Medical Systems in New Berlin, Wis., "but reimbursement agencies keep raising the bar."

Some doctors believe insurers will eventually pay for the procedure to avoid the risk of much higher costs. "It has eliminated to a large extent some of the devastating consequences of neurosurgery," says Dr. William W. Orrison Jr., chief of neuroradiology at the University of New Mexico and Veterans Administration hospitals in Albuquerque. "It doesn't take many unintentional paralyses to pay for this."

Better yet, researchers are on the verge of proving MSI's ability to pinpoint the brain's language center, another area that surgeons desperately want to avoid. And they are close to demonstrating its value in epilepsy surgery. About a quarter of epileptics can be helped by surgery to remove the tissue that triggers their attacks, but very few operations are done today. The actual surgery averages $7,000, but the week or more of monitoring with electrodes implanted in the brain to find the origin of the epilepsy can easily top $40,000. That cost could be eliminated using an MSI scan, says Scripps's Galen.

Scientists are also using MSI to try to figure out the pattern of brain signals that indicate dyslexia or attention disorders in children. Today, it's difficult for a psychiatrist to know whether such biological problems are at the root of some childhood troubles--or whether they're caused by social situations such as drug or child abuse. Researchers are also trying to discern the differences between schizophrenia and manic-depressive syndrome, two conditions that are often confused but require a different set of drugs to treat. Physicians want an objective way to identify these and other disorders for two reasons: to more accurately diagnose the condition and to better gauge the effect of treatments. "What we want to know is whether brain function is improving," says Orrison. "Now, about all we can do is ask, 'Do you feel better?'"

Long before MSI is commonplace in psychiatry, however, it will be solving the mysteries of brain-caused physical problems. The next use is likely to be diagnostic scans after head injuries and strokes. Currently, physicians often must rely on telltale physical symptoms--such as partial paralysis after a stroke--and then must wait several days or more to see whether patients improve. Because it monitors electrical activity, MSI will be able to tell immediately whether brain tissue is working or not.

Orrison knows that firsthand. In a basketball game with his 9-year-old son last year, the Albuquerque radiologist ran into a wall. The mishap gave him a terrible headache, made his eyes overly sensitive to light, and kept him from sleeping. At work the next day, he scanned himself. The MRI was completely normal--there was no structural damage. But the MSI scan showed dramatic changes--a slowing of the electrical activity--exactly where he had hit his head. "It made a real believer out of me," he says. A day later, a second MSI scan showed no brain dysfunction. And all of Orrison's symptoms were gone.

Larry Armstrong in La Jolla, Calif., with Jonathan B. Levine in Paris and Neil Gross in Tokyo
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