Clowns and party-goers suck helium from balloons to make their voices squeaky, but soon seemingly healthy smokers could inhale it to explore such conditions as emphysema and asthma.

A new test devised by University of Wisconsin-Madison scientists starts with smokers breathing in a liter of the harmless gas, mixed with nitrogen, through a straw and finishes with an MRI that can detect how far the gas has penetrated into the tiny air cavities of the lungs.

"Our technique is potentially more sensitive than established [imaging] techniques," Fain said. "This is the first time structural changes have been shown in the lungs of asymptomatic smokers."

Seeing deeper

The helium approach could help doctors see more deeply into the lungs of smokers, explore whether some patients may be genetically predisposed to lung damage and spot smoking-associated diseases much sooner to evaluate if treatments are working.

"Spotting lung change at an early stage allows us to evaluate the efficacy of lung therapies as well as better understand the mechanisms underlying the disease," medical physicist Sean Fain told LiveScience.

Fain is the lead author on an article on the helium approach recently published in the journal Radiology.

MRIs usually rely on tracking differences in water content, rather than helium, which produce high-contrast images of the body's soft tissues.

Fain and his colleagues used a machine called a gas polarizer to manipulate an isotope of helium with light so it shows up in MRIs.

The study was paid for by the company, GE Healthcare, that makes the gas polarizer, but Fain and his colleagues are not employees or consultants for the company and had full control of the data.

Why it matters

Smoking is the most common cause of emphysema, and cigarettes can contribute to the onset of asthma and bronchitis.

With emphysema, the lung's alveoli — the tiny sacs where oxygen goes into the blood stream and carbon dioxide comes out — break down.

Previous work using helium with MRIs showed that the gas moved more freely in the lungs of patients with emphysema.

Fain and his colleagues tested this technique on eight non-smokers and 11 healthy smokers with no obvious lung damage.

Their results indicate that the helium approach is more sensitive to lung damage than a CT scan, which is the common approach now used to image the lungs.

Also, CT scans expose patients to potentially harmful radiation if repeated, according to Eduard E. de Lange of the University of Virginia Health Sciences System, who wrote an article in the same issue of Radiology to accompany and support Fain's work.

The helium approach would avoid this risk.

"This approach will allow us to look at lung micro-structures that are on the scale of less than a millimeter," Fain said.

The approach could be useful for non-smokers too, as everyone's lung structure breaks down over time as a result of aging. But smoking and other environmental processes speed up the breakdown considerably.

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