The New Paradigm for Understanding,Teaching,and Testing Sonographic Principles

Abstract

Two alternative fundamental principles of operation are present in the array of sonographic equipment commercially available currently. Principle 1 has been the operating principle for over 50 years. Recently, Principle 2 has appeared. In Principle 1, there is a one-to-one correspondence between the echo stream from an emitted ultrasound pulse and its displayed scan line, ie, physical beam-forming is directly coupled with displayed scan lines. In Principle 2, fewer pulses are required and focusing is not necessary, and yet the entire image is in focus (ie, excellent detail resolution) and with higher frame rates (improved temporal resolution). This “virtual beam-forming” is accomplished through massive, parallel, high-speed computational postprocessing. The resulting images are similar to what extremely thin, laser-like physical ultrasound beams would produce. However, such beams cannot be physically produced in the frequency range required for imaging depths appropriate for human anatomic imaging. Virtual beam-forming significantly improves nearly every aspect of sonographic, anatomic imaging and Doppler motion detection and presentation.