Physics and Instrumentation
Click here to play video Effect of transducer frequency on image The effects of different transducer frequencies on image quality and appearance are demonstrated. In panel A, a 3.0 MHz transducer is used to record a short-axis view. In panel B, the same image is recorded using a 5.0 MHz transducer.|NV";
Click here to play video Effect of gain long-axis images demonstrate the effect of gain on the appearance on the echocardiographic image. In panel A, gain is adjusted appropriately to allow recording of all relevant information. In panel B, too much gain is utilized, distorting the image, reducing resolution and increasing noise.|NV";
Click here to play video Example of reverberations|f02_030a.jpg|v02_030a.mov|Reverberation artifacts are demonstrated. In panel A, the source of the artifact is the posterior pericardium, which is a very strong reflector. This creates the illusion of a second structure behind the heart. In this case, the second line of echoes (far arrows) is twice the distance from the transducer as the actual pericardial echoes. In panel B, a second lumen appears just distal to the descending aorta (DA) in this subcostal view. The illusion of a second vessel was apparent with two-dimensional imaging (*, panel B) and color Doppler (panel C). LV = left ventricle; RV = right ventricle|NV";
Click here to play video Example of reverberations Reverberation artifacts are demonstrated. In panel A, the source of the artifact is the posterior pericardium, which is a very strong reflector. This creates the illusion of a second structure behind the heart. In this case, the second line of echoes (far arrows) is twice the distance from the transducer as the actual pericardial echoes. In panel B, a second lumen appears just distal to the descending aorta (DA) in this subcostal view. The illusion of a second vessel was apparent with two-dimensional imaging (*, panel B) and color Doppler (panel C). LV = left ventricle; RV = right ventricle|NV";
Click here to play video Example of shadowing The concept of shadowing is demonstrated and compared to reverberations. In panel A, a St. Jude mitral prosthesis (MV) is present. The echo-free space beyond the sewing ring (*) represents shadowing behind the strong echo-reflecting sewing ring. The cascade of echoes directly beyond the prosthetic valve itself that extend into the left ventricle (LV) represent reverberations. In panel B, a shot gun pellet within the heart (arrow) casts a series of reverberations into the left ventricle. Ao = aorta; LA = left atrium.|NV";
Click here to play video Near field clutter This apical two-chamber view demonstrates an artifact called near field clutter (arrows). This is the result of high amplitude oscillations emitted by the transducer and is a common source of misinterpretation. LA = left atrium; LV = left ventricle|NV";