Lung Injury Induced by Secondhand Smoke Exposure Detected With Hyperpolarized Helium-3 Diffusion MR

PurposeTo determine whether helium-3 diffusion MR can detect the changes in the lungs of healthy nonsmoking individuals who were regularly exposed to secondhand smoke. Materials and MethodsThree groups were studied (age: 59 9 years): 23 smokers, 37 exposure-to-secondhand-smoke subjects, and 29 control subjects. We measured helium-3 diffusion values at diffusion times from 0.23 to 1.97 s. ResultsOne-way analysis of variance revealed that the mean area under the helium-3 diffusion curves (ADC AUC) of the smokers was significantly elevated compared with the controls and to the exposure-to-secondhand-smoke subjects (P < 0.001 both). No difference between the mean ADC AUC of the exposure-to-secondhand-smoke subjects and that of the controls was found (P = 0.115). However, application of a receiver operator characteristic-derived rule to classify subjects as either a control or a smoker, based on ADC AUC, revealed that 30% (11/37) of the exposure-to-secondhand subjects were classified as smokers indicating an elevation of the ADC AUC. ConclusionUsing helium-3 diffusion MR, elevated ADC values were detected in 30% of nonsmoking healthy subjects who had been regularly exposed to secondhand smoke, supporting the concept that, in susceptible individuals, secondhand smoke causes mild lung damage. J. Magn. Reson. Imaging 2014;39:77-84. (c) 2013 Wiley Periodicals, Inc.