SCANNING FOR HEALTH

This MRI scan shows a herniated cervical disk in a patient's neck. The herniated disk is visible as the dark bulge indicated above. (IMAGE COURTESY OF SOUTHEAST MISSOURI HOSPITAL)

Rick Ross and Mary Craven, both registered technologists of radiology and magnetic resonance imaging, performed an MRI on a patient's hand at Southeast Missouri Hospital.

Dr. George Pjura, a staff neurologist at St. Francis Medical Centerr, explained magnetic resonance images of a child's skull. The MRI provides several images of the body at different depths.

An elderly woman had been diagnosed with cerebellar infarctions -- decay in the blood vessels leading into a region of the brain.

When she developed bilateral blindness -- loss of vision in both eyes -- doctors suspected the infarctions had worsened, further impeding the flow of blood into the brain.

A cathetered angiogram -- an X ray of the blood vessels themselves -- would have confirmed the diagnosis, said Dr. David Anderson, a Cape Girardeau neuroradiologist, but the procedure could have been dangerous for the patient.

Instead, doctors were able to perform a magnetic resonance angiogram and get the same image without making the woman undergo the trauma of catheterization, Anderson said.

The MRI (magnetic resonance imaging) didn't require radiation, contrast dye or needles -- big pluses for an elderly woman already in distress, he said.

Better technology, and in turn, lower costs, mean doctors can use MRIs more and more often in place of more invasive procedures like angiograms.

For the patient, the process is simple. The patient lies on the scanning table, which is drawn into a magnetic chamber, where the diagnostic image is actually made.

During the procedure, the patient must lie absolutely still to help cut the risk of blurred images.

How does an MRI work?

"That's one of the most complex things you could ask," said Dr. Daniel Harris, a Cape Girardeau neuroradiologist.

Essentially, the magnetic field into which the patient is drawn is bombarded with radio frequencies. The radio frequencies realign protons in the atoms making up the patient's body, and the information from that realignment is converted into a gray scale photo image by computer.

MRIs offer several advantages over other diagnostic images -- X rays and CT scans -- for several reasons.

First and foremost, the images are more complete and more accurate.

"CT scans differentiate real well between soft tissue and bone," said Linda Wibbenmeyer, MRI lead technician at St. Francis Medical Center. "The MRI lets you differentiate between a lot of different layers of soft tissue. You can see where the skin is and where the muscle is."

In some instances, an MRI scan may let doctors tell a cancerous tumor from a non-cancerous tumor -- without the need for a biopsy.

The MRI can also eliminate the need for other diagnostic procedures, which cuts down on discomfort, inconvenience and expense for patients.

"The main scope of MRIs are for any kind of brain pathology," Harris said. "The other main area that it's used for is in the spine. You can image anywhere in the body essentially. They're fairly common to look for knees and shoulders for orthopedic scans, looking for tears in the cartilage. With a CAT scan, you can't even see the cartilage" in a knee.

St. Francis Medical Center and Southeast Missouri Hospital in Cape Girardeau both house MRI scanners.

A new MRI was installed at St. Francis in June, and Southeast completed an upgrade of its MRI and installed a new camera designed for heart imaging earlier this year.

The MRI's magnetic field and radio frequencies have not been shown to have harmful effects on patients, doctors say, and the procedure itself is painless.

But some patients do become claustrophobic when they're drawn into the magnetic chamber itself.

"We may give them some Valium or something to help them relax," Harris said.

Patients can also listen to music during the procedure "to kind of occupy their wondering minds," Wibbenmeyer said.

Some hospitals use soothing scents to help patients in their MRI units relax during the procedure.

"We have been talking about that. Cucumber is the main one that really helps ease the anxiety," Wibbenmeyer said.