US 6,210,332 B1 · Method and apparatus for flow imaging using coded excitation

Abstract

In performing flow imaging using coded excitation and wall filtering, a coded sequence of broadband pulses (centered at a fundamental frequency) is transmitted multiple times to a particular transmit focal position, each coded sequence constituting one firing. On receive, the receive signals acquired for each firing are supplied to a finite impulse response filter which both compresses and bandpass filters the receive pulses, e.g., to isolate a compressed pulse centered at the fundamental frequency. The compressed and isolated signals are then high pass filtered across firings using a wall filter. The wall-filtered signals are used to image blood flow and contrast agents.

Claims62

Dependent claims

An imaging system comprising:

a transducer array having a multiplicity of transducer elements for transmitting wave energy centered at a fundamental frequency in response to electrical activation and for transducing returned wave energy into electrical signals;
a transmitter coupled to said transducer array and programmed to activate a plurality of said transducer elements to transmit focused wave energy encoded with a transmit code during first and second transmit events;
a receiver programmed to respectively form first and second receive signals from electrical signals produced by said plurality of transducer elements subsequent to said first and second transmit events respectively;
a wall filter programmed with first and second sets of filter coefficients to compress and bandpass first and second fundamental signal components of said first and second receive signals respectively and selectively pass frequencies corresponding to wave energy reflectors moving at a velocity above a predetermined threshold, the wall filter forming a flow signal derived at least in part from the compressed and bandpassed first and second fundamental signal components and the selectively passed frequencies;
and
a subsystem for displaying an image having an image portion which is a function of at least said flow signal.

3 more elements

An imaging system comprising:

a transducer array having a multiplicity of transducer elements for transmitting wave energy centered at a fundamental frequency in response to electrical activation and for transducing returned wave energy into electrical signals;
a transmitter coupled to said transducer array and programmed to activate a plurality of said transducer elements to transmit focused wave energy encoded with a first Golay code of a Golay code pair during first and third transmit events and transmit focused wave energy encoded with a second Golay code of said Golay code pair during second and fourth transmit events;
a receiver programmed to respectively form first through fourth receive signals from electrical signals produced by said plurality of transducer elements subsequent to said first through fourth transmit events respectively;
a wall filter programmed with first through fourth sets of filter coefficients to decode and bandpass first through fourth fundamental signal components of said first through fourth receive signals respectively and selectively pass frequencies corresponding to wave energy reflectors moving at a velocity above a predetermined threshold, said wall filter forming a flow signal derived at least in part from said decoded and bandpassed first through fourth fundamental signal components and the selectively passed frequencies;
and
a subsystem for displaying an image having an image portion which is a function of at least said flow signal.

3 more elements

A method of operating an imaging system comprising a multiplicity of transducer elements for transmitting wave energy in response to electrical activation and transducing returned wave energy into electrical signals, and a display monitor for displaying an image having an image portion which is a function of a flow image signal, said method comprising the steps of:

(a) activating transducer elements of said array to transmit focused wave energy encoded with a transmit code during first and second transmit events;
(b) forming first and second receive signals from electrical signals produced by said transducer elements subsequent to said first and second transmit events respectively;
(c) compressing, bandpassing and wall filtering first and second fundamental signal components of said first and second receive signals respectively to form a flow signal;
(d) forming a flow image signal derived at least in part from said flow signal;
and
(e) applying said flow image signal to said display monitor.

3 more elements

(a) activating transducer elements of said array to transmit focused wave energy encoded with a first Golay code of a Golay code pair during first and third transmit events and to transmit focused wave energy encoded with a second Golay code of said Golay code pair during second and fourth transmit events;
(b) forming first through fourth receive signals from electrical signals produced by said transducer elements subsequent to said first through fourth transmit events respectively;
(c) decoding, bandpassing and wall filtering first through fourth fundamental signal components of said first through fourth receive signals respectively to form a flow signal;
(d) forming a flow image signal derived at least in part from said flow signal;
and
(e) applying said flow image signal to said display monitor.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for flow imaging using coded excitation

Life of this patent

Method and apparatus for flow imaging using coded excitation

Life of this patent

Abstract

Claims62