Thoracic and abdominal aortic dimension in 70-year-old men and women--a population-based whole-body magnetic resonance imaging (MRI) study.
OBJECTIVE
The aim of this population-based study was to determine the optimal dividing-line between normal aorta and aneurysm for different aortic segments in 70-year-old men and women by means of whole-body magnetic resonance imaging.


METHODS
Two hundred thirty-one subjects (116 men), randomly recruited from a population-based cohort study, were included. The smallest outer diameter (dia) was measured on the axial survey scan on six predefined aortic segments: (1) ascending aorta, (2) descending aorta, (3) supraceliac aorta, (4) suprarenal aorta, (5) largest infrarenal abdominal aorta, and (6) aortic bifurcation. Relative aortic dia were calculated by dividing a given aortic dia by the suprarenal aortic dia. The dividing-line between normal aorta and aneurysm at different aortic segments was estimated by taking the mean dia +2 SD and/or mean ratio of the aortic segment to the suprarenal aorta +2 SD.


RESULTS
The mean dia of the six segments were 4.0 cm (SD 0.4), 3.2 cm (0.3), 3.0 cm (0.3), 2.8 cm (0.3), 2.4 cm (0.5), and 2.3 cm (0.3) in men. The corresponding dia in women were 3.4 cm (0.4), 2.8 cm (0.3), 2.7 cm (0.3), 2.7 cm (0.3), 2.2 cm (0.3), and 2.0 cm (0.2). The mean ratio to the suprarenal aorta was 1.4 (SD 0.2) for the ascending aorta, 1.2 (0.1) for the descending aorta, and 0.9 (0.2) for the infrarenal aorta in men. The corresponding ratios in women were 1.3 (0.2), 1.0 (0.1), and 0.8 (0.1).


CONCLUSIONS
For men the suggested dividing-line (dia and ratio) between normal aorta and aneurysm for the ascending aorta is 4.7 cm dia and 1.8 ratio, for the descending aorta 3.7 cm dia and 1.5 ratio, and for the infrarenal aorta is 3.0 cm dia and 1.1 ratio. The corresponding dividing-lines for women are 4.2 cm dia and 1.7 ratio, 3.3 cm dia and 1.3 ratio, and 2.7 cm dia and 1.0 ratio.
Wanhainen
Anders
A
Department of Surgical Sciences, Section of Vascular Surgery, University Hospital Uppsala, Uppsala, Sweden. andwan@algonet.se
Themudo
Raquel
R
Ahlström
Håkan
H
Lind
Lars
L
Johansson
Lars
L
D000368:Aged; D001012:Aorta, Abdominal / Q000473:pathology*; D001013:Aorta, Thoracic / Q000473:pathology*; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology*; D017545:Aortic Aneurysm, Thoracic / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D011159:Population Surveillance; D012737:Sex Factors; D051598:Whole Body Imaging