New Imaging Technology Gains Stature in Hospitals
It was as quiet as a chapel in the lab, deep within the labyrinth-like corridors of UCLA Medical Center. No one could hear the march of science, but it was there nevertheless.
Ashleigh, a 23-month-old cancer victim from Bakersfield, dozed while Dr. Rosalind B. Dietrich silently studied a panel of television monitors that looked more like a broadcast studio than one of the newest modes of medical photography.
It has been 15 years since a researcher in New York first published a scientific paper suggesting a new method for detecting tumors without the radiation of X-rays or the need for injections or other invasive procedures.
It’s been nearly nine years since the first experimental machine was built in Brooklyn and three years since the first unit was installed in Southern California, at Huntington Memorial Hospital in Pasadena.
Research Began in ‘40s
Now, as a toddler slept, a vast field of progressive research dating to the 1940s was being applied in a fundamental way to help save her life.
The technology is known as “nuclear magnetic resonance” or “magnetic resonance imaging.” Radiologists like Dietrich say it has shown tremendous potential in diagnosing a number difficult-to-detect diseases besides cancer, especially those involving the brain and spine.
Experts in the field say the new technology, which became available in the late 1970s, has been slow to catch on, but it’s gaining acceptance. That’s partly because some medical insurers, including Medicare, began about six months ago to reimburse hospitals for certain types of NMR scans, which cost about $550 per person.
Medical insurance coverage helps in two ways, according to Dr. William G. Bradley, a leading authority on the technology and director of NMR imaging at the Huntington Medical Research Institute in Pasadena.
“It removes the financial burden from the patient so they don’t have to pay for it themselves,” Bradley said, “and it legitimizes the procedure, because the insurance companies wouldn’t pay for it if it wasn’t legitimate, right?”
About 335 magnetic resonance units have been installed throughout the United States, about 66 of them in California, according to Ellen Speros of the American College of Radiology.
“The greatest concentration of these units without any doubt is in Southern California,” said Dr. David B. Hinshaw Jr., director of the MRI unit at Loma Linda University Medical Center. His hospital uses a portable unit, but is installing a new unit at a cost between $1.5 million and $2 million as part of a hospital expansion.
Bradley, who celebrated the third anniversary of his NMR unit on May 12th, attributes the slow acceptance to high cost and the conservative instincts of doctors and hospitals in dealing with new technology.
“If they have a $1 million CAT scanner that’s working just fine, they’re a little reluctant to install a $2-million NMR scanner,” Bradley said.
Among the most widely promoted features of magnetic resonance imaging are that it does not use radiation and it does not require injections or any other “invasive” surgical procedures. The patient simply lies still within the magnetic resonance machine.
In the Bakersfield child’s case, Dietrich said doctors had found a tumor adjacent to her kidney and spine when the girl was just 7 months old.
Other Studies
Before coming to UCLA, Dietrich said, she’d had regular X-rays and those involving injections of high-contrast material; diagnostic ultrasound tests; a myelogram, which involves the injection of a high-contrast material into the spine; and a CAT scan, which uses a computer to analyze relatively high doses of radiation shot through the body.
“MRI told us everything that all the other studies had shown, and it showed it better,” said Dietrich, an assistant professor of pediatric radiology at UCLA. “Using the MRI, we’ve saved her from a lot of radiation and a lot of invasive procedures.”
Magnetic resonance was used to follow the girl’s progress through chemotherapy and Dietrich said it now indicates the cancer has disappeared.
According to one of her colleagues, Dr. William N. Hanafee, Dietrich, 32, is one of the pioneers in the field of magnetic resonance imaging.
Hanafee, a head and neck radiologist, is an enthusiastic promoter of the new technology, and he said the fact that researchers as young as Dietrich are doing important work is an indication of just how new the field is.
Hanafee explained that the new medical imaging technology depends on something that chemists have known for decades--that molecules are slightly magnetic and that different types of molecules vibrate at different frequencies, or energy levels.
In the 1970s, Raymond Damadian, a medical research at the Downstate Medical Center of the State University of New York, realized the usefulness of this knowledge.
For one thing, the molecules that make up a human body line up like little bar magnets when a person is put inside a big magnetic field. Moreover, when an ordinary radio signal is transmitted into the body in the magnet, it jangles the alignment of the molecules so that their frequencies can be analyzed by a computer. And because these frequencies vary, the computer can distinguish between different tissue, bone and fat, or almost anything else.
“If you take plain water and put it into the unit, you get a certain signal,” Hanafee said. “If you freeze it, you get a different signal and if you add ordinary table salt to the water you get still another signal.”
Hanafee said Damadian realized it would be possible to distinguish healthy tissue from cancerous tissue because a tumor doesn’t have the same chemistry as normal tissue.
“If it’s diseased fat or diseased muscle it gives off a different signal,” Hanafee said.
The result has been dramatically detailed pictures of internal organs.
“Magnetic resonance is the most sensitive modality for the brain and spine,” Bradley said. For example, it has proved to be a definitive diagnostic tool for multiple sclerosis.
But it also has been useful in detecting brain tumors, strokes, herniated discs and a variety of damaged nerve tissue. Bradley said a recent study at the Huntington Institute found that out of 400 patients, magnetic resonance imaging detected brain lesions in 30% that had not been detected using CAT scans or other types of diagnostic imaging.
New techniques are even more promising, Bradley added, saying a new process involving the injection of a paramagnetic substance “makes brain tumors light up like light bulbs.”
