title: Roentgenographic method for measurement of the cross-sectional area of the aortic valve.
mesh_terms: D001021:Aortic Valve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging; D006328:Cardiac Catheterization; D006350:Heart Valve Prosthesis; D006801:Humans; D008433:Mathematics; D011859:Radiography