TUESDAY, Nov. 30 (HealthDayNews) -- A test known as end-expiratory high-resolution computed tomography (CT) helped identify a condition called air trapping in 25 of 29 World Trade Center rescue and recovery workers with a mysterious ailment referred to as "WTC cough."

Researchers from the Mount Sinai School of Medicine in New York City presented their findings Nov. 30 at the Radiological Society of North America annual meeting in Chicago.

Air trapping, often seen in smokers and elderly people, is caused by obstructed lung airways and causes shortness of breath, wheezing, or dry cough. It's viewed as a variant of asthma and treated with steroids and bronchodilators.

The 29 rescue and recovery workers had respiratory complaints that couldn't be clearly identified by routine pulmonary function tests. They were then evaluated using standard CT and end-expiratory CT. The diagnosis of air trapping in 25 of the 29 workers was made by end-expiratory CT, which detected lung abnormalities that weren't caught by standard CT.

End-expiratory CT is performed after patients expel their breath, while standard chest CT is done while the patient holds his or her breath.

More information

The American Medical Association has information about lung disease.