HARMONIC US FOR HEPATOBILIARY DISEASE

Prof Byung Ihn Choi MD, Department of Radiology, Seoul National University Hospital, Seoul, South Korea

Harmonic imaging is a new ultrasonographic imaging method that exploits the effect of nonlinear propagation on the acoustic signal as it travels through the human body
or tissue. It produces ultrasonographic images by using second harmonic signals generated by tissue itself during this nonlinear propagation of insonated acoustic energy1-4. The resultant advantages are improved lateral resolution, reduced side lobe artifact, and increased signal-to-noise ratio3. Two methods are available for harmonic imaging: tissue harmonic imaging (THI), which is conventionally used; and pulse inversion harmonic imaging (PIHI), a newer method.