title: Harmonic source wavefront aberration correction for ultrasound imaging.
abstract: A method is proposed which uses a lower-frequency transmit to create a known harmonic acoustical source in tissue suitable for wavefront correction without a priori assumptions of the target or requiring a transponder. The measurement and imaging steps of this method were implemented on the Duke phased array system with a two-dimensional (2-D) array. The method was tested with multiple electronic aberrators [0.39π to 1.16π radians root-mean-square (rms) at 4.17 MHz] and with a physical aberrator 0.17π radians rms at 4.17 MHz) in a variety of imaging situations. Corrections were quantified in terms of peak beam amplitude compared to the unaberrated case, with restoration between 0.6 and 36.6 dB of peak amplitude with a single correction. Standard phantom images before and after correction were obtained and showed both visible improvement and 14 dB contrast improvement after correction. This method, when combined with previous phase correction methods, may be an important step that leads to improved clinical images.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Dianis
authors.forename: Olaf T
authors.initials: OT
authors.lastname: von Ramm
mesh_terms: D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D013997:Time Factors; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*