Arrangement to calculate and image Doppler frequency shifts, to determine blood flow

摘要

The arrangement uses an emitted coded impulse and pulse compression for the received signal. Use of different coding for transmitted and received pulses permits different types of signal sensitivities to be obtained for different circumstances, e.g. for small but deep sample volumes, or for better spatial resolution. The arrangement has an ultrasound transducer array (2) comprising several transducer elements (18). A bipolar pulser (20) connected to the transducer array pulses selected transducer elements, to form a transmission aperture with a coded pulse sequence during first and second transmission releases, which are focused in the same focus position. The coded pulse sequence is a function of a transmission code with a base pulse sequence. Detector channels (26) connected to the transducer array receive first and second signal sequences from selected transducer elements, which form a detector aperture, corresponding to the first and second transmission releases. Devices (30) form first and second summed signals, corresponding the signal sequences. A decoding filter (32) compresses the summed signals, to form compressed pulse sequences. Processing devices provide a set of Doppler frequency shift data, which depend on the two compressed pulse sequences. A device displays a spectral line, which is a function of the Doppler frequency shift data. An Independent claim is given for a method for using the arrangement.