Hi, as a fellow engineer, the growth was not 4.1 of course but to 4.1 from ?, the aorta on average is around 3cm +/- so your growth may have been about 1 cm which is significant. The main path in my mind is to continue periodical follow ups and measures following the exact same procedure (CT Scan) so that a true growth rate can be determined.

My recommendation is you find a cardiologist who is an aortic diseases specialist, not all of them are and it makes a big difference. The cardiologist will set the periodicity of your follow ups and measures and will give you recommendations. At 4.1 cm you are far from needing repair, especially since you are tall (size of aneurysm to body size is one of the variables they take into account among many others, growth rate is another) but it is paramount to determine true growth rate.

Hope that helps