 In echocardiography the aortic valve area is calculated using the velocity time integral (VTI) which is the most accurate method and preferred.The flow through the LVOT, or LV stroke volume (in cm3), can be calculated by measuring the LVOT diameter (in cm), squaring that value, multiplying the value by 0.78540 giving a cross sectional area of the LVOT (in cm2) and multiplying that value by the LVOT VTI (in cm), measured on the spectral Doppler display using pulsed-wave Doppler.From these, it is easy to calculate the area (in cm2) of the aortic valve by simply dividing the LV stroke volume (in cm3) by the AV VTI (in cm) measured on the spectral Doppler display using continuous-wave Doppler.