More Proof Secondhand Smoke Damages Lungs
Modified MRI Detects Changes Suggestive of Emphysema Long Before Symptoms Occur
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Smoking Bans
Some breathe deeply while others fume as tough anti-smoking rules catch on.
Their study also suggests that the modified magnetic resonance imaging (MRI) technique used to detect the lung damage may be able to spot emphysema long before symptoms occur.
The researchers used global helium-3 diffusion MRI to study the lungs of 13 current or former smokers and 45 people who had never smoked. Of the nonsmokers, 22 had heavy exposure to secondhand smoke, meaning they lived with a smoker or worked in a bar for at least a decade. None had symptoms of lung disease.
The modified MRI detected signs of early lung damage in 67 percent of smokers and 27 percent of nonsmokers with heavy exposure to secondhand smoke, says researcher Chengbo Wang, Ph.D., of the Children's Hospital of Philadelphia.
In contrast, only 4 percent of nonsmokers who had never smoked and had fewer than 10 years of exposure appeared to have signs of early lung damage, he says.
The research was presented here at the annual meeting of the Radiological Society of North America (RSNA).
Modified MRI Detects Lung Damage
Wang tells WebMD that it's long been thought that prolonged exposure to secondhand smoke can cause lung damage and emphysema, but doctors lacked a way to prove it.
"Previous methods of detection weren't sensitive enough," he says.
Helium-3 diffusion MRI offers more detailed images of the lungs than previous techniques, he says.
It works like this: first, helium gas is polarized with a laser; this makes it more visible on MRI.
Then, while lying in a conventional MRI scanner, a person inhales the energized helium. In just six seconds, the scanner collects images showing how the helium gas distributes in the tiny air sacs called alveoli in the lung.
Prolonged exposure to cigarette smoke causes the walls of the air sacs to break down and the air sacs to become bigger and bigger - early signs of emphysema, Wang says.
As a result, helium travels much further in people with enlarged air sacs than in people with healthy alveoli, he explains.
"Using helium MRI, we were able to detect microscopic changes suggestive of emphysema in smokers and people exposed to secondhand smoke," Wang says.
RSNA spokeswoman Katarzyna Macura, M.D., Ph.D., of Johns Hopkins Medical Institutions in Baltimore, tells WebMD that the modified MRI needs to be studied in larger numbers of people before it's ready for prime time.
"Accessibility and cost are the two big issues that need to be addressed," she says. "Before any recommendations can be made, we need solid data and proof that what we are seeing [on the scan reflects lung changes indicative of emphysema]."
By Charlene Laino
Reviewed by Louise Chang
©2005-2006 WebMD, Inc. All rights reserved.



I am guessing it is because of the deprivation of o2 to your brain from all of your smoking and/or disregard for the validity of the obvious in that smoke - no matter where it originates - is a toxin to our bodies...
Duh - let me think here ... what the most frequent cause of death is when fires occur - yes - people get burnt - but their lungs give out due to smoke inhalation and it only takes common sense to see the validity of all of this.
Your brain has obviously been so washed by the tobacco companies that you will fight to the bitter end to say that second hand smoke can''t cause problems for anyone who has to breathe it in (let alone those "die-hard" smokers - which I am guessing you are with your stupid comment.
Hey - did you even ever think that coughing is our bodys'' way of telling us that it is rejecting and trying to protect itself from such health destroying pathogens contained in smoke of any kind...
It is pure common sense - and why it has not been possible to prove scientifically is only because there are too many people like you who continue to demonstrate so much arrogance ...
The argument will be made with no questions about it... If these brilliant scientists would just put some common sense about the deaths from any fires and the cause of death to smoke inhalation - (duh - second hand smoke of any kind)...