Phase-insensitive and phase-sensitive quantitative imaging of scattered ultrasound using a two-dimensional pseudo-array

A two-dimensional receiving array was used to measure both phase-insensitively and phase-sensitively the average power and power spectrum of a backscattered (160°) ultrasonic field. The effects of introducing phase-distorting media in front of the receiving array on the phase-insensitively and phase-sensitively derived quantitative energy measurements were investigated under conditions of planar, spherical, and correlation focusing. A transmitting transducer was found at the surface of a glass-bead phantom and a two-dimensional pseudoarray receiver was achieved by translating an apodized planar transducer in a 13×13 grid pattern. Phase-insensitive determination of average power exhibited a maximum 0.9-dB variation for measurements made with all combinations of phase-distorting media and focusing schemes, whereas the corresponding phase-sensitively derived values varied by as much as 9.4 dB