SURF Imaging denotes Second Order UltRasound Field Imaging, and is a new method for ultrasound imaging being developed at the Department of Circulation and Imaging. Conventional ultrasound imaging transmits a band-limited pulse as shown in Figure 1. Such a pulse is transmitted in many directions, and the received echoes are used to form an image. In SURF Imaging, two pulses are transmitted simultaneously in the same direction (see Figure 2); a standard imaging pulse, and manipulation pulse. This is here denoted a SURF pulse. Typically, the frequency difference between the two pulses is a factor 7-10, e.g. an imaging pulse of 10 MHz and a manipulation pulse of 1 MHz. The low-frequency manipulation pulse affects both the propagation and scattering properties of the high-frequency imaging pulse due to the fact that both these properties become dependent of the manipulation pulse pressure. This opens up a range of new possibilities for ultrasound imaging.
Figure 1: Regular ultrasound pulses
By placing the imaging pulse in different phases of the manipulation pulse, and varying the number of SURF pulses transmitted, different methods of imaging may be realized. One such method can for example be to first place the imaging pulse in a compression phase of the manipulation pulse, second in rarefaction phase. By combining the received signals and using adapted signal processing, such a pulsing scheme may be used as an ultrasound contrast detection method .
Figure 2: SURF pulses
SURF Imaging has a strong potential within the following fields of medical ultrasound:
The research group of professor Bjørn Angelsen has been working extensively since 2002 on the SURF Imaging method, starting with the PhD of Dr. Rune Hansen. The follow link shows the publications and presentations from the group on this matter.
