(THI) Tissue harmonic imaging (also called native harmonic imaging) is a signal processing technique which addresses ultrasound limitations like penetration and resolution. Tissue harmonic imaging reduces noise and clutter by improving signal to noise ratio and resolution. The signal penetration in soft tissue increases as the transmit frequency is decreased, by simultaneous decreased image resolution. As an ultrasound wave propagates through the target media a change occurs in the shape and frequency of the transmitted signal. The change is due to the normal resistance of tissue to propagate sound energy. This resistance and the resulting signal change is called a harmonic oscillation.
For harmonic imaging the input frequency doubles the output frequency, for example a transmit frequency of 3.0 MHz. which would provide maximum penetration will return a harmonic frequency of 6.0 MHz. The returning higher frequency signal has to only travel one direction to the probe. The advantages of high frequency imaging and the one-way travel effect are decreased reverberation, beam aberration, and side lobes, as well as increased resolution and cystic clearing.

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.'

From Siemens Medical Systems;
The new gold standard in echocardiography is defined by Native Tissue Harmonic Imaging (NTHI) and DELTA Differential Echo Amplification−two powerful technologies that were first introduced on Acuson's Sequoia™ echocardiography system. Now they have migrated to the Aspen™ Advanced system.

Specifications for this system will be available soon.

From Siemens Medical Systems;
'Conventional ultrasound systems are unable to compensate for the unique acoustic signature of individual patients. But there is nothing conventional about the new ACUSON Sequoia™ C512 echocardiography system with Sequoia™ matched response technology.'

From ALOKA Co., Ltd.;
'A Platform for Digital, Pure-Beam Imaging The high-performance, ALOKA ProSound SSD-3500 utilizes advanced ProSound technologies including:
Fully digital beam former A wide dynamic range, 12-bit A/D converter Multi beam processing.
The SSD-3500 also helps you achieve more efficient examinations. Its ergonomic, user-friendly design enables you to customize the system according to your specific application needs.'