Prediction of nonlinear acoustic effects at biomedical frequencies and intensities

Use of the Second Harmonic in Strain Imaging: A Phantom Study

“…The frequency domain of the receiving signals contains additional harmonic frequencies at integer multiples of the fundamental frequency. Muir et al [4] and Carstensen et al [5] first reported that B-mode scanners might produce large enough signal amplitude to cause the nonlinear effects. They ran a series of experiments with medical ultrasound transducers to support their predictions.…”

The role of tissue harmonic imaging in fetal echocardiography

“…Harmonics are generated by tissue itself due to propagation of the fundamental transmitted band. When a transducer transmits a band of frequencies of, say, 2 MHz, the return energy will be in multiple frequency bands, the first of which corresponds to the transmitted fundamental band and is due to tissue interfaces and heterogeneities, whereas the second harmonic (in this case at 4 MHz) is produced by the tissue itself 1,2 . Tissue harmonics increase with depth, being virtually absent at the skin level and increase up to the point where tissue attenuation makes them decrease.…”

An Update on Diagnostic Imaging Techniques in Veterinary Practice

“…Clinical use of this technology is an area of intense research activity especially in fetal anomaly scanning (Benacerraf et al, 2005;Benoit and Chaoui, 2004;Krakow et al, 2003) but there are also popular uses that have been shown to improve fetal-maternal bonding (Ji et al, 1997) (Tranquart et al, 1999). Images are derived from the higher frequency, especially second harmonic sound, as the ultrasound pulse passes through the body tissue (Muir and Carstensen, 1980;Staritt et al, 1985Staritt et al, , 1986. In THI, the conventional echoes generated from the tissues are eliminated and only harmonic frequencies are used to form the image (Tranquart et al, 1999).…”