Differences in aortic valve area measured with CT planimetry and echocardiography (continuity equation) are related to divergent estimates of left ventricular outflow tract area.
Halpern EJ, Mallya R, Sewell M, Shulman M, Zwas DR. Differences in aortic valve area measured with CT planimetry and echocardiography (continuity equation) are related to divergent estimates of left ventricular outflow tract area. AJR Am J Roentgenol. 2009 Jun; 192(6):1668-73.