Echocardiography
The echocardiogram is an ultrasound of the heart. Using standard ultrasound techniques, two-dimensional slices of the heart can be imaged.The standard echocardiogram is also known as a trans-thoracic echocardiogram, or TTE. In this case, the echocardiography transducer (or probe) is placed on the chest wall (or thorax) of the subject, and images are taken through the chest wall.
Another method to perform an echocardiogram is to insert the echocardiography transducer within the patient's esophagus, and record pictures from there. This is known as trans-esophageal echocardiography, or TEE. The advantage of TEE over TTE are that better pictures can be produced, since there is less tissue between the transducer and the structures that are being imaged. Also, certain structures of the cardiovascular system are not ammenable to adequate imaging via TTE, including the aorta, the pulmonary artery, the valves of the heart, and the left and right atria. These structures are usually well visualized on trans-esophageal echocardiography.
In addition to creating two-dimensional pictures of the cardiovascular system, the echocardiogram can also produce accurate assessment of the direction of blood flow and the velocity of blood and cardiac tissue at any arbitrary point. This allows assessment of cardiac valve areas and function, any abnormal communications between the left and right side of the heart, any leaking of blood through the valves (valvular regurgitation), and calculation of the cardiac output.
Echocardiography was the first medical application of ultrasound.