Transesophageal Echocardiogram (TEE), Harmonics and Contrast Echocardiogram

In this chapter, three ways by which we can obtain more information by increasing the Frequency and hence the Resolution of the images obtained by Echocardiogram are discussed. The first one namely Trans Esophageal Echocardiogram gets better resolution by altering the route, which takes the Transducer Probe closer to the Heart and avoids intervening structures which impede the Ultrasound beam. The Second one, namely, Harmonics, can be used in both Trans Thoracic and Trans Esophageal Echocardiogram, which provides images at twice the Fundamental Frequency, and reduces side lobes and grating lobes which enhances Resolution (Axial) resulting in better images. Thirdly, we discuss about the Contrast Echocardiogram which helps us in several ways: Contrast images use the principle of Contrast Harmonic Frequency, which is a multiple of Fundamental Frequency and results in better resolution. Secondly, Contrast Agents better define cardiac borders and thus give more accurate information about Ventricular Volumes which translates into more accurate Ejection Fraction determination. They are better in diagnosing space occupying lesions in the Heart, may it be clot or tumor etc. The properties of the Contrast Agents can be altered to better suit our needs: For example, the ones that do not cross the Pulmonary Vasular Bed to reach the left side help us diagnose conditions like Atrial Septal Defect, Ventricular Septal Defect, Arterio Venous Fistula, Aorto Pulmonary Window etc. The ones that cross the Pulmonary Vascular Bed help us evaluate the Left Atrium and Left Ventricle better as mentioned above. Schematic diagrams enlighten the versatility of the Trans Esophageal Echocardiogram in terms of Views and Angles. After reading this chapter, one would be knowledgeable about the uses of all three of these enhancements.