Detecting Asthma - Radiologists Develop Asthma Imaging Method

January 1, 2009 — Radiologists developed a new method for viewing the lungs of asthma sufferers. The method uses a polarized helium-3 gas--making it visible during an MRI. The patient inhales the helium-3 and undergoes an MRI, where doctors can see how far the atoms in the gas can travel in the lungs. This gives an image of what airways are blocked and what parts of the lungs ventilate. The black areas of the image indicate portions of the lung where air does not reach--areas where the helium-3 atoms could not travel.

Asthma makes breathing difficult for more than 22 million Americans. There's no cure, but new research is looking at asthma patients in a whole new way.

A little exercise is all it takes to remind Quinn Taylor of the asthma he has lived with since childhood. "I can feel a little bit of tightness in my chest just from kicking around the soccer ball," Taylor said.

Today, Taylor is volunteering to test a new imaging technique that helps radiologists see inside his lungs like never before.

"We get a better feel for what's going on within the lungs, something that is not really possible with other techniques at this point," said Eduard de Lange, M.D., a radiologist at the University of Virginia in Charlottesville, Va.

The new method combines MRI scans with a harmless gas called helium-3. It's not the helium found in balloons, but a special gas that is visible inside the lungs when inhaled during an MRI scan.

"We can see what parts of the lungs are blocked, [which] airways are blocked and which parts of the lungs ventilate," Dr. de Lange said.

The images show in the healthy lung how helium-3 atoms move and completely fill the lungs. In asthma patients, areas of the lungs are blocked so the atoms may not fill the lung at all.

Doctors hope the technique will help develop new ways to prevent, treat and cure asthma. Thanks to volunteers like Taylor, others may soon breathe easier.

ASTHMA OR ALLERGIES? Asthma is a chronic disease affecting the airways that carry air in and out of the lungs. The inside walls of the airways become inflamed and thus narrower so less air can flow through the lung tissues. This in turn causes wheezing, coughing, tightness in the chest, and trouble breathing. Asthma is linked to allergies, although not everyone with asthma has allergies. People with allergies tend to react more strongly to the presence of allergens such as animal dander, dust mites, pollen or mold, as well as cigarette smoke and air pollution.

HOW MRI WORKS: Magnetic resonance imaging uses radio frequency waves and a strong magnetic field instead of X-rays to provide clear and detailed pictures of internal organs and tissues. These radio waves are directed at protons in hydrogen atoms -- one of the most abundant atoms in the human body, because of the body's high water content. The waves "excite" the protons, and when they "relax," they emit strong radio signals. A computer can turn those signals into a high-contrast image showing differences in the water content and distribution in various bodily tissues.

The American Association of Physicists in Medicine contributed to the information contained in the TV portion of this report. 

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.