From what I can remember, there are three aortic sinus's. The left, the right and the posterior and they are all in the descending aorta, just above the aortic valve. The left sinus is where the left coronary artery is joined, the right sinus has the right coronary artery. The posterior has no coronary artery attached. I believe they are all classed as 'dilated'.
The sinus valsalva is the right aortic sinus. Did you read this on a medical report or something?
I'm not sure if they are referring to the right coronary artery being dilated at the aortic sinus.