Sinuses of Valsalva diameter

Immediately above the aortic valve are the aortic sinuses, which are also called the sinuses of Valsalva. Normally there are three sinuses corresponding to the three aortic valve cusps: right, left, and noncoronary.The sinuses bulge slightly above the valve, and the coronary arteries typically arise from the left and right sinuses. The sinuses taper superiorly, where they meet the ascending aorta at the sinotubular junction (or “sinotubular ridge”). 

Normative reference value of sinuses of Vasalva: 29-40 mm (18±2mm/m²)

Note : Measurements of the aortic root may be challenging,  Burman et al. compared cusp-commissure dimensions in the sinus planes with the corresponding cusp-cusp measurements; they found that cusp-commissure dimensions in the sinus planes were 2–3 mm smaller than cusp-cusp measurements but corresponded more closely with reference echocardiographic aortic root measurements in the Framingham Heart Study.