Parasternal long axis (PLAX) view – echocardiogram – split screen images
Split screen display with side by side display of 2-D (2 dimensional) and Colour Doppler imaging in echocardiography from parasternal long axis view.
Left panel shows the 2-D image with mitral valve open. Structure nearest to the transducer in the PLAX view is the right ventricular free wall (RVFW). There may be a thin echo free space anterior to it due to pericardial pad of fat. Beneath that the outflow region of the right ventricle is partially seen, but not the pulmonary valve or sub pulmonary region. Next comes the interventricular septum (IVS), which is continuous proximally with the anterior wall of aorta (Ao). Posterior wall of aorta appears as the anterior boundary of the left atrium in this view (LA). Aortic valve is seen in the closed position here (AoV), but parts of it are not visualised as it is a thin structure and the echo beam is going parallel to its closed position. Left ventricular outflow tract (LVOT) is seen apical to the aortic valve, bounded posteriorly by anterior mitral leaflet (AML) and anteriorly by the interventricular septum. Left ventricular body (LV) is seen apical to the LVOT. Posterior mitral leaflet (PML) almost strikes the left ventricular posterior wall (PW) when the valve is fully open. Pericardium is seen with great echo density as there is transition from myocardial echodensity to the pericardium. The interface seems to reflect the ultrasound beams very much. Hence it may not be always accurate to assess to pericardial thickness by echocardiography. Computed tomography may be a better modality for assessing pericardial thickening in suspected constrictive pericarditis. Nyquist limit of the colour Doppler system in this image is seen below the colour bar on the right side as 77 cm/s. When the velocity of flow being imaged is above this limit, there will be aliasing with colour wrap around to that of opposite direction. Here the mitral flow is seen as red with transducer on anterior chest wall because the flow comes from the left atrium which is the posterior most cardiac chamber.