Imaging contrast agent and tissue at higher harmonics

A major step is realized in ultrasound imaging with the introduction of 2nd harmonic (2H) technology. 2H showed significant enhancement in image quality when used in native mode. When combined with contrast agent (CA), 2H increased the discrimination between perfused and non-perfused tissue, usually termed contrast to tissue ratio (CTR). This improvement is due to the strong nonlinear scattering exhibited by byca compared to tissue. We demonstrate in this study that for tissue and CA imaging, substantial advantages can be achieved over 2H if imaging is performed at higher harmonic frequencies, termed here SuperHarmonic (SH). The SH is a single nonlinear component created from a combination of frequencies ranging from the 3H up to 5H. A special a wide frequency band array transducer was developed specifically for SH imaging. The array was connected to a Vivid5 system. In vitro and patient studies were carried out for contrast SH imaging and for tissue SH imaging. The results showed that for specific scanning settings higher harmonics proved to be generated in a sufficient amount. They increase CTR and improve the image quality further compared to 2H alone.