Cardiac echo
sonography is a diagnostic tool.
Cardiac echo sonography is the technique of using high-frequency sound waves to obtain pictures of the heart. Images of the heart obtained through echo sonography are known as an echocardiogram. There are different types of echocardiograms, with each type having a particular diagnostic strength. Echocardiograms are the best way of diagnosing many heart problems, and have the added benefit of being very safe.
Principles of Echo Sonography
Cardiac echo sonography uses a device called a transducer that sends waves of high-frequency sound into a region of the body. Sound moves at different speeds through materials of different density, and when encountering tissue of a different density the change in speed causes some of the sound to be reflected back to the transducer. The amount of sound that is reflected back indicates the new density and the time taken for the sound to return indicates the depth. These two pieces of information can be used to assemble a picture of the slice of the body through which the sound wave is moving.
Types of Echocardiograms
A two-dimensional (2D) echocardiogram is the most basic. It uses the principles described above to obtain images of slices of the heart as it is beating. A skilled interpreter can use these images to get a sense of the three-dimensional structure of the heart. A three-dimensional (3D) echo-cardiogram is more sophisticated. It uses an array of transducers sending out multiple waves that a computer will combine to create 3D images of the heart. Doppler echocardiograms use the principle that the sound reflected back from a moving object will return with a different frequency, depending upon the speed and direction the object is moving. Doppler echocardiograms can measure the velocity and direction of the blood flowing through the heart.
Uses of Echocardiograms
Both 2D and 3D echocardiograms are both extremely useful for measuring the size and motion of various parts of the heart. They are also effective in detecting masses in the heart and changes in heart valves, although a 3D echocardiogram usually produces superior images of these problems. Doppler echocardiograms are used to detect unusual patterns of blood flow (such as blood flowing backward through a valve) or unusually high pressure gradients in the heart (such as occur when valves are not opening properly).
Administration of Echocardiograms
Echocardiograms can either be performed through the external chest wall (transthoracic) or from inside the esophagus (transesophageal). Transesophageal echocardiograms can provide clearer images of certain parts of the heart that lie deeper in the chest. Transthoracic echocardiograms are more convenient for the patient and are often administered in a doctor's office. Transesophageal echocardiograms require numbing of the esophagus and light sedation and are usually administered in a hospital or clinic setting.
Safety of Echocardiograms
Echocardiograms are a popular diagnostic tool because they provide a lot of information about the heart with little risk to the patient. Unlike imaging techniques utilizing radiation, sound waves do not damage DNA or hurt cells. Echocardiograms are safe even for pregnant women. Transesophageal echocardiograms are a bit more invasive then transthoracic echocardiograms, but even with transesophageal ones complications are virtually unknown.
Tags: Cardiac echo, Doppler echocardiograms, echo sonography, reflected back, Transesophageal echocardiograms
