Aortic dimension nomograms for adults and children are available at http://www.marfan.org/marfan/2576/Aortic-Root-Dilatation-Nomogram
It is important to note that nomograms developed from echo do not exactly apply to CT or MRI, and vice versa, due to differences in these techniques.
Generally accepted upper limit for LVIDd is 5.5cm, IVSd 1.2cm, and peak RVSP 35 mm Hg or mean 25 mm Hg at rest or mean 30 mm Hg with exercise. However, PASP >40 mm Hg is present in 6% of otherwise normal individuals older than 50 years. (Barst, R. J. Diagnosis and differential assessment of pulmonary arterial hypertension. J Am Coll Cardiol, 2004; 43:40-47.)
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