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Echocardiography in M-mode
Last reviewed: 04.07.2025
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Echocardiography in M-mode
Despite the advantages of 2D imaging, M-mode echocardiography (M for motion ) remains a fast and simple technique. Unlike 2D technology, ultrasound signals are transmitted and received along a single beam, recording the movements of the heart structures. The desired beam position is verified by simultaneously obtaining a 2D image. Changes in wall thickness and chamber size and the pattern of movement of the valve structures are visualized and measured with very high temporal resolution. Two examples of M-mode examinations are given below.
Doppler and color duplex echocardiography
Using Doppler and color duplex modes, cardiac blood flow can be visualized and quantified. This is necessary for the evaluation of heart valves when insufficiency or stenosis is suspected. In addition, cardiac output can be assessed by measuring blood flow in the aorta and pulmonary trunk and identifying blood flow abnormalities associated with congenital heart defects. For Doppler and color duplex sonography to be effective, the results of traditional 2D scanning must be taken into account.
Atrioventricular valves
The apical acoustic window, especially when using the four-chamber plane, is optimal for visualizing blood flow through the atrioventricular valves. Normal blood flow has the following color pattern: after closure of the semilunar valves, the atrioventricular valves open in the early phase of diastole; blood flows along the pressure gradient between the atria and relaxed ventricles across the entire width of the open valve lumen. Rapid blood flow through the mitral valve appears as a cloud of red pixels with a central blur (red-blue). This causes a redistribution of blood flow in the left ventricle, with blood slowly moving along the left ventricular outflow tract toward the aortic valve (blue pixels). Contraction of the atria initiates the second phase of ventricular filling. Following this, the atrioventricular valves close and systole begins. If the valves are intact, there is no regurgitant blood flow in the region of their cusps. In this case, only blue color can be determined in the outflow tract of the left ventricle towards the aortic valve. The red area reflects the entry of blood into the left atrium from the pulmonary veins.
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