Look up reference values— adjusted for age, gender, and body size— for the aortic root (aortic valve and sinus of Valsalva) using data published in the American Journal of Cardiology, 2012.
Devereux RB, de Simone G, Arnett DK, Best LG, Boerwinkle E, Howard BV, Kitzman D, Lee ET, Mosley TH Jr, Weder A, Roman MJ.Am J Cardiol. 2012 Oct 15;110(8):1189-94.