dilated aorta or aneurysm

1.  When you say that a dilated aorta is not the same as an aneurysm, is that because of the size?  Is it considered one only when it hits 4.0 cm?   Please explain the criteria to me.

2.  Can you also explain where on the aorta these areas are? I understand ascending and descending but don't know where the proximal, mid or distal are.

                                              Ascending               Descending
Proximal Thoracic Aorta           3.8 cm x 3.7 cm       2.1 cm x 2.3 cm
Mid  Aorta                               3.3 cm x 3.5 cm       2.1 cm x 2.2 cm
Distal Aorta                             3.2 cm x 3.4 cm       2.0 cm x 2.0 cm

Thanks

[CCFCardio MD2]

Dilated just means the aorta is slightly larger than what is usually considered normal.  Aneurysmal actually refers to thinning of the aorta wall which causes dilation of that area of the vessel as it is weaker.  4cm is the typical cutoff for considering an aortic root dilated or slightly enlarged.  It doesn't require immediate treatment, just a little more monitoring.  

Proximal typically means from the aortic valve to the innominate artery, mid is typically involving the vessels off the aortic arch, and distal typically refers to the aorta after the L subclavian artery.  

Please stay in touch with your cardiologist or cardiothoracic surgeon for monitoring of your aorta.  Right now your dimensions are not concerning.

Best of luck.