PURPOSE To determine the normal size and wall thickness of the ascending thoracic aorta (AA) and its relationship with cardiovascular risk factors in a large population-based study. MATERIALS AND METHODS The mean AA luminal diameter was measured in 3573 Multi-Ethnic Study of Atherosclerosis (MESA) participants (age: 45–84 years), using gradient echo phase contrast cine MRI. Multiple linear regression models were used to evaluate the associations between risk factors and AA diameter. The median and upper normal limit (95th percentile) was defined in a “healthy” subgroup as well as AA wall thickness. RESULTS The upper limits of body surface area indexed AA luminal diameter for age categories of 45–54, 55–64, 65–74, and 75–84 years are 21, 22, 22, and 28 mm/m2 in women and 20, 21, 22, 23 mm/m2 in men, respectively. The mean AA wall thickness was 2.8 mm. Age, gender and body surface area were major determinants of AA luminal diameter (~+1 mm/10 years; ~+1.9 mm in men than women; ~+1 mm/ 0.23 m2; p<0.001). The AA diameter in hypertensive subjects was +0.9 mm larger than in normotensives (p<0.001). CONCLUSION AA diameter increases gradually with aging for both genders, among all race/ethnicities. Normal value of AA diameter is provided.

Background Whereas low lung function is known to predict mortality in the general population, the prognostic significance of emphysema on computed tomography (CT) in persons without chronic obstructive pulmonary disease (COPD) remains uncertain. Objective To determine whether greater emphysema-like lung on CT is associated with all-cause mortality among persons without airflow obstruction or COPD in the general population. Design Prospective cohort study. Setting Population-based, multiethnic sample from 6 US communities. Participants 2965 participants ages 45-84 years without airflow obstruction on spirometry. Measurements Emphysema-like lung was defined on cardiac CT as the number of lung voxels less than -950 Hounsfield Units, and was adjusted for the number of total imaged lung voxels. Results Among 2965 participants, 50.9% of whom never smoked, there were 186 deaths over a median of 6.2 years. Greater emphysema-like lung was independently associated with increased mortality (adjusted hazard ratio [HR]1.14 per one-half of the interquartile range, 95% CI 1.04-1.24, P=0.004), adjusting for potential confounders including cardiovascular risk factors and the forced expiratory volume in one second. Generalized additive models supported a linear association between emphysema-like lung and mortality without evidence for a threshold. The association was of greatest magnitude among smokers, although multiplicative interaction terms did not support effect modification by smoking status. Limitations Cardiac CT scans did not include lung apices. The number of deaths was limited among subgroup analyses. Conclusions Emphysema-like lung on CT was associated with all-cause mortality among persons without airflow obstruction or COPD in a general population sample, particularly among smokers. Recognition of the independent prognostic significance of emphysema on CT among patients without COPD on spirometry is warranted. Primary Funding Source NIH/NHLBI.

).q RSNA, 2015 Purpose:To evaluate age-related left ventricular (LV) remodeling during longitudinal observation of a large cohort of asymptomatic individuals who were free of clinical cardiovascular disease at baseline. Materials and Methods:The applicable institutional review boards approved this study, and all participants gave informed consent. Cardiac magnetic resonance (MR) imaging was used to identify longitudinal changes in LV structure and function in 2935 participants who underwent baseline and follow-up cardiac MR imaging in the Multi-Ethnic Study of Atherosclerosis. Participants were free of clinical cardiovascular disease at baseline. Participants who experienced an incident coronary heart disease event were excluded. Data were analyzed with multivariable mixed-effects regression models in which the outcome was cardiac MR imaging measurement, and the covariates included follow-up time and cardiac risk factors. Results:Participants were aged 54-94 years at follow-up, and 53% of the participants were women. Median time between baseline and follow-up cardiac MR imaging was 9.4 years. Over this period, LV mass increased in men and decreased slightly in women (8.0 and 21.6 g per decade, respectively; P , .001). In both men and women, LV enddiastolic volume decreased (29.8 and 213.3 mL per decade, respectively; P , .001), stroke volume decreased (28.8 and 28.6 mL per decade, respectively; P , .001), and mass-to-volume ratio increased (0.14 and 0.11 g/mL per decade, respectively; P , .001). Change in LV mass was positively associated with systolic blood pressure and body mass index and negatively associated with treated hypertension and high-density lipoprotein cholesterol level. In men, the longitudinal LV mass increase was in contrast to a cross-sectional pattern of LV mass decrease. Conclusion:As patients age, the LV responds differently in its mass and volume between men and women, although both men and women experience increased concentric LV remodeling with age. In men, the opposition of longitudinal and cross-sectional changes in LV mass highlights the importance of longitudinal study.q RSNA, 2015

Background The clinical significance of magnetic resonance imaged (MRI) plaque characteristics in the superficial femoral artery (SFA) is not well established. We studied associations of the ankle brachial index (ABI) and leg symptoms with MRI-measured plaque area and percent lumen area in the SFA in participants with and without lower extremity peripheral arterial disease (PAD). Methods and Results Four hundred twenty-seven participants (393 with PAD) underwent plaque imaging of the first 30 millimeters of the SFA. Twelve 2.5 millimeter cross-sectional images of the SFA were obtained. Outcomes were normalized plaque area, adjusted for artery size (0–1 scale, 1=greatest plaque), and lumen area, expressed as a percent of the total artery area. Adjusting for age, sex, race, smoking, statins, cholesterol, and other covariates, lower ABI values were associated with higher normalized mean plaque area (ABI < 0.50:0.79; ABI 0.50 to 0.69:0.73; ABI 0.70 to 0.89:0.65; ABI 0.90 to 0.99:0.62; ABI 1.00 to 1.09:0.48; ABI 1.10–1.30:0.47 (P trend <0.001)) and smaller mean percent lumen area (P trend<0.001). Compared to PAD participants with intermittent claudication, asymptomatic PAD participants had lower normalized mean plaque area (0.72 vs. 0.65, p=0.005) and larger mean percent lumen area (0.30 vs. 0.36, p=0.01), adjusting for the ABI and other confounders. Conclusions Lower ABI values are associated with greater MRI-measured plaque burden and smaller lumen area in the first 30 millimeters of the SFA. Compared to PAD participants with claudication, asymptomatic PAD participants have smaller plaque area and larger lumen area in the SFA.