Why Is My Surgeon Replacing My Aortic Root?

I forgot to ask a very important question when I met with my surgeon, Dr. Wheatley. His treatment plan calls for the replacement of my aortic valve, root and ascending aorta. This means that I will need a Bentall Procedure, where the coronary arteries are grafted onto the dacron replacement lower aorta. Since the measurements of my lower aorta do not seem to indicate that is is aneurysmal, I'm wondering why it needs to be replaced. One reason could be Annuloaortic ectasia...a dilation of the proximal ascending aorta and aortic annulus. Here are three views of the aorta...the first is a healthy aorta, the second is one with annuloaortic ectasia, and the last is mine. Look at the difference at the level of the annulus (circled in images 1 & 2), where the aorta joins the heart, then compare that to mine in image 3.