| 
(HealthDay News) – One of the major problems with determining
the severity of asthma and other lung diseases has been scientists'
inability to see how well the small passages of the lungs
are working. That problem is on its way to resolution, literally.
A new magnetic resonance imaging (MRI) technique that uses
specially treated helium to light up the lungs' airways may
be the way to decide types of asthma treatment.
The technique, called dynamic hyperpolarized 3He (helium)
imaging, is the first method able to provide clear resolution
of the smaller lung airways. It could help doctors better
understand and treat asthma and other chronic obstructive
pulmonary diseases (COPD). Helium is an inert gas that can
be inhaled directly into the lungs with no adverse reaction.
Hyperpolarized helium lights up when viewed through an MRI.
Researchers at Brigham and Women's Hospital in Boston had
six healthy adult volunteers, aged 22 to 40, inhale one breath
of hyperpolarized helium gas at the same time that they were
undergoing an MRI. The images using this method showed contrast
of both distal airways (those smaller passages of the lung
leading away from the main branches) and the lung periphery.
Results appeared in the May 2003 issue of Radiology.
"Other non-radioactive techniques have only been able
to image lung peripheries. Dynamic hyperpolarized helium MR
imaging offers a completely noninvasive and safe method of
studying the airways," principal investigator Mitchell
S. Albert said in a news release at the time the research
was published.
"Our new technique provides information on ventilation,
while depicting structure and function of the airways. Other
non-radioactive imaging modalities do not provide this type
of information," Albert added.
If the hyperpolarized helium/MRI method can be used to help
determine asthma treatment, it also could be used as a diagnostic
tool for other COPD diseases. And there are many. According
to the U.S. government's National Heart, Lung, and Blood Institute,
chronic obstructive pulmonary disease is the fourth leading
cause of death in the United States and in the world.
Here is the institute's description of how various activities
such as cigarette smoking can lead to COPD:
Cigarette smoking is the most common cause of COPD. Most
people with COPD are smokers or former smokers. Breathing
in other kinds of lung irritants, like pollution, dust, or
chemicals over a long period of time may also cause or contribute
to COPD.
At the end of each airway branch are many small, balloon-like
air sacs. In healthy people, each airway is clear and open,
the air sacs are small and dainty, and both are elastic and
springy. When you breathe in, each air sac fills up with air,
like a small balloon, and when you breathe out, the balloon
deflates and the air goes out.
In COPD, the airways and air sacs lose their shape and become
floppy. Less air gets in and less air goes out because:
| • |
The airways and air
sacs lose their elasticity (like an old rubber band); |
| • |
The walls between many
of the air sacs are destroyed; |
| • |
The walls of the airways
become thick and inflamed (swollen); |
| • |
Cells in the airways make more mucus
(sputum) than usual, which tends to clog the airways.
|
COPD develops slowly, and it may be many years before you
notice symptoms like feeling short of breath. Most of the
time, COPD is diagnosed in middle-aged or older people.
Chronic obstructive pulmonary disease has no cure, but there
are treatments that can help, according to the institute.
Bronchodilators
Your doctor may recommend medications called bronchodilators
that work by relaxing the muscles around the airways. They
help open the airways quickly and make breathing easier. Bronchodilators
can be either short-acting or long-acting.
| • |
Short-acting bronchodilators
last about 4 to 6 hours and are used only when needed.
|
| • |
Long-acting bronchodilators
last about 12 hours or more and are used every day.
|
Most bronchodilator medications are inhaled so they go directly
into the lungs, where they are needed. There are many kinds
of inhalers, and it is important to know how to use an inhaler
correctly.
If you have mild COPD, your doctor may recommend that you
use a short-acting bronchodilator. You then will use the inhaler
only when needed.
If you have moderate or severe COPD, your doctor may recommend
regular treatment with one or more inhaled bronchodilators.
You may be told to use one long-acting bronchodilator. Some
people may need to use a long-acting bronchodilator and a
short-acting bronchodilator. This is called combination therapy.
Inhaled Glucocorticosteroids (Steroids)
Inhaled steroids are used for some people with moderate or
severe COPD. Inhaled steroids work to reduce airway inflammation.
Your doctor may recommend that you try inhaled steroids for
six weeks to three months to see if the medication helps with
your breathing problems.
On the Web
The American
College of Allergy, Asthma & Immunology has information
on screening for asthma. To learn more about asthma, visit
the National
Heart, Lung, and Blood Institute.
SOURCES:
Article, Radiology, May 2003; |
Radiological Society of North America, news release, April
29, 2003;
Articles, National Heart, Lung, and Blood Institute, updated
April 18, 2004
Publication date: May 31, 2004
Copyright © 2004 ScoutNews, LLC. All rights reserved.
Author: Barry Hoffman
|
