Cardiac ultrasound

Left ventricle dimensions measured on the 2D image


On the screen:
1) Display the parasternal long axis view (PLAX)
2) Make sure you transect the LV so it appear largest
3) Freeze a full cine loop covering a whole heart cycle
4) Use the trackball to scroll to diastole (just before the aortic valve opens)
5) Activate the measurement button (machine dependent)
6) Measure as perpendicular to the septum and posterior wall as possible
7) Measure only the free of the tip of the mitral leaflets
8) Repeat for systole when convenient

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Measurement points for dimensions of the interventricular septum (1-2), left ventricle (2-3) and posterior wall (3-4)
Yellow arrow indicate the moderator band that should not be measured

M-mode: Presentation on the ultrasound screen


The image below is a typical greyscale M-mode recording of the left ventricle in the parasternal long axis view with:

– The 2D reference image on top (red box)

– The M-mode recording at the bottom (yellow box)

Because M-mode is a one dimensional display it has a very high time (temporal) resolution

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Building of the M-mode image


It is important to understand that M-mode provides no spatial information beyond the width of one ultrasound beam

Conversion of M-mode data to area or volume estimates should be done with caution

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The top image shows a 2D long axis view with a cursor line (white)
The middle image displays the actual part of the heart which is depicted in the M-mode image
The bottom image displays the corresponding M-mode recording

M-mode recordings in the PLAX view


To collect the echocardiographic M-mode data in the parasternal long axis view (FATE position 3) the cursor line alternately transects:

– The left ventricle (1 red line)
– The anterior mitral leaflet (2 green line)
– The aorta and left atrium (3 blue line)

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Understanding the M-mode image


The image below shows a typical M-mode recording of the left ventricle in the parasternal long axis view with:

– 2D reference image on top (red box)

– M-mode recording at the bottom (yellow box)

Notice that the greyscale value is the same so that the white in the 2D image remains white in the M-mode recording and vice versa

Because the ultrasound is emitted from the top of the sector (red box) the anatomical structures close to the transducer are displayed at the top of each box and deeper structures are displayed closer to the bottom of each box (yellow and red)

As time is depicted along the horizontal axis dynamical changes can be observed

In this case 4 cardiac cycles are displayed

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Eyeballing


Eyeballing is a simple visual qualitative method to evaluate the overall function of the heart chambers

All imaging views can be used for the eyeballing and combined information from different views is recommended

The result of eyeballing the 4 basic FATE views below is normal ventricular function of all chambers

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