Transthoracic echocardiogram
In this case, the probe (or ultrasonic transducer) is placed on the chest or abdomen of the subject to get various views of the heart.
Pronunciation of "TTE" and "TEE" are similar, and full use of "transthoracic" or "transesophageal" can minimize any verbal miscommunication.
Other structures visible on TTE include the aorta, the pericardium, pleural effusions, ascites, and inferior vena cava.
TTE in adults is also of limited use for the structures at the back of the heart, such as the left atrial appendage.
Transesophageal echocardiography may be more accurate than TTE because it excludes the variables previously mentioned and allows closer visualization of common sites for vegetation and other abnormalities.
[citation needed] "Bubble contrast TTE" involves the injection of agitated saline into a vein, followed by an Echocardiographic study.
It can be accomplished by either exercising on a bike or treadmill, or by medicine given through an IV along with a contrast agent to make the bodily fluids show up brighter.
Examination involves using an echo probe at various positions or windows to obtain views of the heart (thus capturing images/videos for later playback while formally "reading" the study to come up with the findings).
Examination is usually done while lying flat and tilted onto the left side to bring the heart into better view.
Ultrasound gel is used to improve the acoustic windows and increase quality of the captured images.
For example, critically ill patients often have "bedside ultrasounds" performed to assess particular questions the treating team has about their status.
Often, this may include examination of other organ systems such as lungs for effusions or the focused assessment with sonography for trauma.
Extremes in body sizes (obesity and cachexia) limit the acoustic windows and degrade the image quality of TTEs.
This structure is known to form clots in atrial fibrillation and the LAA is rarely seen on TTE but readily seen on TEE.
Cardioversion of atrial fibrillation in someone not on anticoagulation would require TEE to best visualize the LAA to rule out a thrombus.
It is not, for example, able to determine perfusion of the myocardium, which would require a metabolic imaging modality such as PET or SPECT stress testing.
A two-dimensional plane is formed by sweeping the ultrasound waves to obtain an image that varies with angle and depth.
Color doppler can also show blood flow in abnormal locations such as with septal defects (ASD or VSD).
Using color doppler in this way gives better visualization of the changes in flow with time due to the higher frame rate with M-mode.
For example, the aortic valve area can be estimated using the continuity equation by measuring the velocity time integral (VTI) of the aortic valve & LV outflow tract; the VTI is calculated by tracing the flow on the spectral doppler curve.
This can be used to measure motion of the septal and lateral mitral annulus to suggest diastolic heart failure.
The long axis is an imaginary line from the apex of the heart through the center of the tricuspid/mitral valve (depending on ventricle of reference).
The classic "hockey stick" shape of rheumatic mitral stenosis can be appreciated in this view.
Quantitative echo utilizes a number of equations to calculate aspects of the heart structure and function.
