R.K. Radhakrishnan

Study gives an impetus to States in the U.S.

Helium-3 diffusion MRI helps detect changes in small airways

CHICAGO: Are you a smoker? If so, you should look around before you light one. It’s about the smoke that comes out of the cigarette and the smoke you exhale. It’s bad for people around you, says a study.

Researchers at the University of Virginia School of Medicine in Charlottesville and The Children’s Hospital of Philadelphia in Pennsylvania have identified structural damage to the lungs caused by second hand cigarette smoke.

The results were presented at the 93rd meeting of the Radiological Society of North America (RSNA) here on Monday.

Even without the study’s findings, all public buildings, including restaurants and bars, in the United States are smoke-free because second hand smoke is seen as a public health threat.

Even in biting cold, die-hard smokers have to step out for a smoke. In some buildings, such as the entrance of the Hotel Hyatt at the Chicago RSNA convention centre, there is a sign that asks you to stand 15 feet away from the door if you are smoking!

The study gives an impetus to States in the U.S. that are considering law on second hand smoke.

“It’s long been hypothesised that prolonged exposure to second hand smoke may cause physical damage to the lungs but previous methods of analysing lung changes were not sensitive enough to detect it,” says Chengbo Wang, magnetic resonance physicist, Radiology Department, Children’s Hospital of Philadelphia.

Now here is the science: Dr. Wang and his colleagues T.A. Altes, G.W. Miller, E.E. de Lange, K. Ruppert, J.F. Mata, and G.D. Cates used a long-time-scale, global helium-3 diffusion magnetic resonance imaging (MRI) to study the lungs of 43 volunteers. (Seven current and former smokers and 36 people who had never smoked. Eighteen of them had a high level of exposure to second hand smoke.)

A RSNA release says that Helium-3 diffusion MRI differs from the conventional MRI in that, the patient inhales a specially prepared helium gas prior to imaging and the scanner is adjusted to collect images showing this helium gas in tissue. MR measures how far the helium atoms move, or diffuse, inside the lungs during a specific time period —1.5 seconds in this study.

Detecting changes

Using this method, radiologists and physicists can detect changes deep in the small airways and sacs in the lungs, which can break down, become enlarged and develop holes after prolonged exposure to cigarette smoke.

Helium-3 diffusion MRI identifies this damage by measuring the increased distance the helium atoms move.

“With this technique, we are able to assess lung structure on a microscopic level,” Dr. Wang said.

“These findings suggest that breathing second hand smoke can injure your lungs.”