Two-dimensional transthoracic echocardiogram (2D TTE) with and without harmonic imaging

The long axis precordial view in a technically difficult subject is shown in panel A. The transducer of the instrument insonates tissues at a center line carrier frequency of 3 MHz and receives the resulting reflected signals at the same or fundamental frequency. Harmonic imaging from the same subject is shown in panel B; the instrument insonates tissues at 1.8 MHz and detects their first harmonic reflections at 3.6 MHz. The fundamental frequency reflections are not used. Note that this technique improves the visualization of the walls and valves by creating surfaces that appear to be more continuous. This technique is particularly helpful in stress echocardiography.