title: Assessment of the thoracic aorta by multidetector computed tomography: age- and sex-specific reference values in adults without evident cardiovascular disease.
abstract: BACKGROUND
  Dilatation of the aortic root and other segments of the thoracic aorta is important in the pathogenesis of aortic regurgitation and of aortic dissection. Although echocardiographic criteria exist to detect aortic root dilation, comparably standardized methods have not been developed to detect enlargement of the remainder of the thoracic aorta. Nongated axial chest computed tomography (CT), traditionally used to evaluate aortic size, does not account for the obliquity, systolic expansion, and nonaxial motion of the aorta during the cardiac cycle. Reference values for aortic diameters in anatomically correct double-oblique short axis images have not been established with the use of electrocardiogram (ECG)-gated 64-detector row multidetector CT (MDCT).
  
  
  OBJECTIVE
  To establish reference values for thoracic aortic diameters MDCT in healthy normotensive nonobese adults without evident cardiovascular disease.
  
  
  METHODS
  A total of 103 (43% women, age 51 +/- 14 years) consecutive normotensive, nonobese adults free of cardiac or aortic structural disease or arrhythmia underwent MDCT examination to determine aortic dimensions.
  
  
  RESULTS
  End-diastolic diameter 95% confidence intervals were 2.5-3.7 cm for the aortic root, 2.1-3.5 cm for the ascending aorta, and 1.7-2.6 cm for the descending thoracic aorta. Aortic diameters were significantly greater at end systole than end diastole (mean difference 1.9 +/- 1.2 mm for ascending and 1.3 +/- 1.8 for descending thoracic aorta, P < 0.001). Aortic root and ascending aortic diameter increased significantly with age and body surface area.
  
  
  CONCLUSIONS
  This study establishes age- and sex-specific ECG-gated MDCT reference values for thoracic aortic diameters in healthy, normotensive, nonobese adults to identify aortic pathology by MDCT. MDCT measurements of the thoracic aorta should use ECG-gated double-oblique short-axis images for accurate quantification.
authors.affiliation: Department of Medicine, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10021 USA.
authors.forename: Fay Y
authors.initials: FY
authors.lastname: Lin
authors.forename: Richard B
authors.initials: RB
authors.lastname: Devereux
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Roman
authors.forename: Joyce
authors.initials: J
authors.lastname: Meng
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Jow
authors.forename: Avrum
authors.initials: A
authors.lastname: Jacobs
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Weinsaft
authors.forename: Leslee J
authors.initials: LJ
authors.lastname: Shaw
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
authors.forename: Amanda
authors.initials: A
authors.lastname: Gilmore
authors.forename: Tracy Q
authors.initials: TQ
authors.lastname: Callister
authors.forename: James K
authors.initials: JK
authors.lastname: Min
mesh_terms: D000367:Age Factors; D000792:Angiography / Q000379:methods*; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013902:Radiography, Thoracic / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*