TRANSTHORACIC CARDIAC ULTRASOUND
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| Plate 3-12 TRANSDUCER POSITIONS IN ECHOCARDIOGRAPHIC EXAMINATION |
Understanding cardiac ultrasound (US) requires knowing cardiac anatomy and physiology. In addition, performing echocardiography requires considerable experience to develop the necessary technical skills. Cardiac US records reflected sound waves from blood tissue interfaces within the heart and great vessels, thus visualizing the complex cardiac anatomy and providing a remarkably detailed image of heart motion and structure during all phases of the cardiac cycle (see Plate 3-12). Transthoracic cardiac US is one of the most useful diagnostic tests available.
The most common
echocardiogram is a two dimensional (2D) image of cardiac anatomy in different
planes, similar to angiography. The 2D echocardiogram provides a detailed
picture of spatial relations of the cardiac chambers and valves. One weakness
is that the image is somewhat difficult to quantitate. A major limitation is
too much lung between the transducer and the heart, making it difficult to
obtain good images in patients with chronic obstructive pulmonary disease.
Parameters that can be measured with US include the following:
1.
Ventricular chamber size and wall thickness
2.
Ventricular function
3.
Mitral valve: motion, valve thickness, prolapse, calcification, vegetations
4.
Aortic valve: thickness, extent of motion, calcification, vegetations,
number of cusps, aortic root size
5.
Left atrium: size, presence of clots, tumors
6.
Pericardial effusion
7.
Congenital cardiac malformations
