From Philips Medical Systems;
'The Philips iU22 system combines Intelligent Design, including breakthroughs in ergonomics, with Intelligent Control, providing new levels of automation, to give you revolutionary performance and workflow.'

The earliest introduction of vascular ultrasound contrast agents (USCA) was by Gramiak and Shah in 1968, when they injected agitated saline into the ascending aorta and cardiac chambers during echocardiographic to opacify the left heart chamber. Strong echoes were produced within the heart, due to the acoustic mismatch between free air microbubbles in the saline and the surrounding blood.

From GE Healthcare.;
'The System of Choice for General Imaging
Imagine a leading-edge ultrasound system so versatile that it can meet the demands of virtually any clinical setting. With the LOGIQ® 9, you'll have a high-performance system capable of multi-dimensional imaging for a full range of clinical applications - from abdominal to breast to vascular imaging. And an ergonomic design that improves scanning comfort and clinical work flow. Now, imagine what LOGIQ® 9 could do for you and your patients.'

(PII) Pulse inversion imaging (also called phase inversion imaging) is a non-linear imaging method specifically made for enhanced detection of microbubble ultrasound contrast agents. In PII, two pulses are sent in rapid succession into the tissue; the second pulse is a mirror image of the first. The resulting echoes are added at reception. Linear scattering of the two pulses will give two echoes which are inverted copies of each other, and these echoes will therefore cancel out when added.
Linear scattering dominates in tissues. Echoes from linear scatterers such as tissue cancel, whereas those from gas microbubbles do not. Non-linear scattering of the two pulses will give two echoes which do not cancel out completely due to different bubble response to positive and negative pressures of equal magnitude. The harmonic components add, and the signal intensity difference between non-linear and linear scatterers is therefore increased. The resulting images show high sensitivity to bubbles at the resolution of a conventional image.
In harmonic imaging, the frequency range of the transmitted pulse and the received signal should not overlap, but this restriction is less in pulse inversion imaging since the transmit frequencies are not filtered out, but rather subtracted. Broader transmit and receive bandwidths are therefore allowed, giving shorter pulses and improved axial resolution, hence the alternative term wideband harmonic imaging. Many ultrasound machines offer some form of pulse inversion imaging.

See also Pulse Inversion Doppler, Narrow Bandwidth, Dead Zone, Ultrasound Phantom.

From Siemens Medical Systems;
'This high-performance, multi-specialty system supports and improves your daily ultrasound routine. Embedded DICOM creates the integrated foundation for a complete connectivity solution while MultiHertz™ multiple frequency imaging and Tissue Harmonic Imaging (THI) expands the clinical versatility of the system. Advanced applications such as stress echo, SieScape™ panoramic imaging, and transesophageal imaging can be seamlessly integrated.'