Objective: To examine cardiovascular consequences of electronic cigarette (EC) use by evaluating their effect on the entire atherosclerotic cascade of young adults (18-30 years old) using noninvasive combined positron emission tomography (PET)/magnetic resonance imaging (MRI) and comparing EC use with age matched smokers of traditional cigarettes and nonsmoking controls.
Background: EC use is popular among youth, touted as a safer alternative to smoking and promoted as a tool to aid in smoking cessation. EC cardiovascular safety however is not well established.
Methods: Carotid PET/MRI was obtained to look at vascular inflammation(18-fluorodeoxyglucose(FDG)-PET) and plaque burden (multi-contrast MRI of vessel wall)  from 60 young adult subjects (20 purely electronic cigarette users, 20 traditional smokers and 20 nonsmokers).  
Results: Groups were reasonably well balanced  in terms of age, gender, demographics, cardiovascular risk and most biomarkers. There were no differences in vascular inflammation as measured by 18-FDG-PET target to background ratios (TBR) between EC users, traditional cigarette smokers and nonsmokers. However, measures of plaque burden such as wall area, normalized wall index, and wall thickness measured from MRI indicated that both traditional smokers and EC users were significantly higher compared to nonsmokers.
Conclusions: Young adult EC users, smokers and nonsmokers have similar levels of vascular inflammation; but smokers and EC users have significantly more plaque burden compared to matched nonsmokers. These results indicate that electronic cigarette use may have adverse cardiovascular consequences and are possibly not as safe as previously considered.

05 - VAPING SAFER THAN SMOKING BUT NOT WITHOUT CARDIOVASCULAR RISK: A PET/MRI STUDY