The researchers gave 15 people a tracing chemical that sticks to inflammation on the lungs and makes it visible on CT scans.

In cancer treatment, for example, a doctor may inject a tracer that binds to tumor tissue and scan a person to find signs they could soon develop the disease.

Researchers, who published their findings last week in the Journal of Nuclear Medicine, found no difference in lung inflammation between non-smokers and cigarette users.

The true impact e-cigarettes have on the lungs is still being researched by health officials, but early data shows the devices could have devastating long-term.

Medically known as bronchiolitis obliterans, it occurs when the chemical forms scar tissue in the lungs and blocks the flow of air.

Another recent study found the devices can cause DNA damage comparable to that of cigarettes - opening users up to developing cancer in the future.