I find medical self defense essential these days. You may want to look up these current diagnostic guidelines:

"An ascending aorta (AAo) measurement of 4.1 cm is generally classified as "dilated," not a true medical aneurysm.
According to the official American College of Cardiology / American Heart Association (ACC/AHA) Joint Guidelines for aortic disease, an ascending thoracic aorta between 4.0 cm and 4.4 cm is considered enlarged or dilated. It typically does not officially cross the threshold into a "true aneurysm" until it reaches 4.5 cm or larger."

The recommendation from my doc for watch and wait is reliant at the beginning on having two scans 6 mos apart, which do not show significant growth. Then 6 mos - 1yr scans for long term observation. But if a first scan showed 4.1 and 6 mos later it had increased more than 0.1-0.2 in that amount of time, that would indicate need for immediate follow up. I am doing echocardiogramss rather than having more contrast injections or radiation so frequently. Also, being on Losartan or some of the other BP control meds not only keeps my blood pressure down but has protective effects on AO tissue and is part of my watch and wait plan.