not sure what vessel is that. There are celiac, mesenteric and various branches such as gastric, hepatic, splenic, renal aneurysms. If the one you have is feeding the omentum (epiloic) at this size is safe to observe and risk of rupture is very low.as a vascular surgeon I advice follow up and observation with a repeat CTA in 6 months, if progression ie over 19-20 mm embolization is safe and carries low risk even if it’s feeding a gastric portion. But your AME may insist on therapy before. Make sure your interventional radiologist is experienced. There are specific guidelines for visceral artery aneurysms published by the (american) society of vascular surgery
They are the two arteries which outline the greater curvature of your stomach.
Trivial to endovascularly treat ananeeurisms there, but really easy to bleed to death if one blows it off...