Aortic Arch

I am a 66 year old female.I was diagnosed in April 07 with a dilated aortic arch of 4.1.  The following Jan of 08 it measured 3.7.  Both tests were done by CT scan.  Was the first measurement wrong or has it shrunk?  What % of patients go on to need surgery after diagnosis? Do any just stay the same for a lifetime or do they always grow?  I am controlling BP, pulse and lipids and doing moderate exercise?

[Cleveland Clinic]

It is unlikely that it shrunk that much, much more likely is that the first CT was erroneously read. Ask the person who ordered the test what hapenned to cause this marked change. The aneurysms do tend to grow with time, but this rate can be slowed by treating hypertension and decreasing one's pulse. At this point you don't need surgery unless the aneurysm grows very quickly or to over 5-5.5 cm.