Diagnostic Value of Cardiac MRI in Aortic Valve Stenosis in Comparison with Echocardiography

Accurate assessment of the orifice area and/or the pressure gradient is an important factor for determining whether surgery is necessary or not. Transthoracic Echocardiography (TTE) is the method of choice to determine the severity of aortic valve stenosis. By using Doppler ultrasound, the maximum velocity over the valve is measured and used to calculate the peak pressure gradient. However, ultrasound examination has its limitations, e.g. noise can obscure the measurement in obese or emphysematous patients or if the orientation of the heart and valve make accurate ultrasound imaging impossible. Also, in some cases of severe stenosis, the pressure gradient measured by Doppler ultrasound overestimates the actual pressure gradient. Furthermore, direct measurement of the orifice dimension is not accurate and reproducible in cases of severe stenosis [3] .