• Department of Radiology, Mayo Clinic Florida, 4500 San Pablo Road, Jacksonville, FL, 32224. Electronic address: mccomb.barbara@mayo.edu.
• Houston Methodist Hospital and Research Institute, Houston, TX, 77030. Electronic address: rfmunden@houstonmethodist.org.
• Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Box G-S121-7, 121 S. Main Street, Providence, RI, 02912. Electronic address: fduan@stat.brown.edu.
• Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Box G-S121-7, 121 S. Main Street, Providence, RI, 02912. Electronic address: amanda.m.jain@gmail.com.
• Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA, 19111. Electronic address: ctuite@fccc.edu.
• Department of Radiology, Wake Forest Health Sciences Center, Medical Center Boulevard, Winston-Salem, NC, 27157. Electronic address: cchiles@wakehealth.edu.

Purpose
Establish normative reference values for thoracic aortic diameter (AD) in participants in the National Lung Screening Trial (NLST).

Methods
Thoracic AD on 322 prevalence CTs was recorded at the sinotubular junction (STJ), mid-ascending (MA), transverse arch (TA), mid-descending (MD), and diaphragmatic hiatus (DH).

Results
Mean AD (cm) and upper limits of normal for men and women were recorded for at each location. Smoking did not correlate with AD. Age, gender and body surface area (BSA) were the most significant factors.

Conclusions
Thoracic AD reference values are reported. They do not correlate with smoking, but did for age, gender, BSA.