Method and apparatus for removing artifacts from an ultrasonically generated image of a small cavity

Claim 1

A method of imaging a cross section of a small cavity such as a coronary vessel using an imaging apparatus having a transducer, wherein the transducer flexes in response to a received electrical pulse so as to emit an ultrasonic wave into an ambient environment of the array within the small cavity, the method comprising the steps of: a. inserting the transducer into a first area of the cavity; b. delivering an electrical pulse to the transducer in order to generate an ultrasonic wave in the ambient environment of the array; c. detecting a ringdown signal generated by a damped oscillation of the transducer in response to its excitation by the electrical pulse; d. storing the ringdown signal as a reference waveform; e. inserting the transducer into a second area of the cavity having a diameter smaller than that of the first section; f. emitting ultrasonic waves into the second area by mechanically exciting the transducer in response to electrical pulses; g. generating an echo waveform in response to echoes of the emitted waves that are reflected off inner walls of the second section and impinge upon the transducer; h. subtracting the reference waveform from the echo waveform for the purpose of creating an imaging waveform stripped of the ringdown signal; and i. generating a visual image using a plurality of the imaging waveforms.

Claim 2

A method of imaging a cross section of a small cavity such as a coronary vessel using an imaging apparatus having a transducer, wherein the transducer flexes in response to a received electrical pulse so as to emit an ultrasonic wave into an ambient environment of the array within the small cavity, the method comprising the steps of: a. inserting the transducer into a first area of the cavity; b. delivering an electrical pulse to the transducer in order to generate an ultrasonic wave in the ambient environment of the array; c. detecting a ringdown signal generated by a damped oscillation of the transducer in response to its excitation by the electrical pulse; d. storing the ringdown signal as a reference waveform; e. inserting the transducer into a second area of the cavity having a diameter smaller than that of the first section; f. emitting ultrasonic waves into the second area by mechanically exciting the transducer in response to electrical pulses; g. generating an echo waveform in response to echoes of the emitted waves that are reflected off inner walls of the second section and impinge upon the transducer; h. subtracting the reference waveform from the echo waveform for the purpose of creating an imaging waveform stripped of the ringdown signal; and i. generating a visual image using a plurality of the imaging waveforms.

Claim 9

A method of imaging a cross section of a small cavity such as a coronary vessel, the method employing an imaging apparatus including a transducer, wherein the transducer flexes in response to a received electrical pulse so as to emit ultrasonic waves in an ambient environment of the transducer within the small cavity, the method comprising the steps of: a. positioning the transducer within a reference collection environment; b. emitting ultrasonic waves into the reference collection environment by exciting the transducer in response to an electrical pulse; c. detecting a ringdown signal generated by a damped oscillation of the transducer in response to the electrical pulse; d. storing the ringdown signal as a linear reference waveform; e. inserting the transducer into a small cavity to be imaged; f. emitting ultrasonic waves into the small cavity by exciting the transducer in response to an electrical pulse; g. detecting an echo waveform generated by echoes of the ultrasonic waves as they are reflected off surfaces of the small cavity and impinge upon the transducer; h. subtracting the reference waveform from the echo waveform so as to generate an imaging waveform; i. amplifying the imaging waveform such that the entire waveform remains linear; and j. processing the linear imaging waveform with other linear imaging waveforms in order to create a visual image of the small cavity.

Claim 10

A method of imaging a cross section of a small cavity such as a coronary vessel, the method employing an imaging apparatus including a transducer, wherein the transducer flexes in response to a received electrical pulse so as to emit ultrasonic waves in an ambient environment of the transducer within the small cavity, the method comprising the steps of: a. positioning the transducer within a reference collection environment; b. emitting ultrasonic waves into the reference collection environment by exciting the transducer in response to an electrical pulse; c. detecting a ringdown signal generated by a damped oscillation of the transducer in response to the electrical pulse; d. storing the ringdown signal as a linear reference waveform; e. inserting the transducer into a small cavity to be imaged; f. emitting ultrasonic waves into the small cavity by exciting the transducer in response to an electrical pulse; g. detecting an echo waveform generated by echoes of the ultrasonic waves as they are reflected off surfaces of the small cavity and impinge upon the transducer; h. subtracting the reference waveform from the echo waveform so as to generate an imaging waveform; i. amplifying the imaging waveform such that the entire waveform remains linear; and j. processing the linear imaging waveform with other linear imaging waveforms in order to create a visual image of the small cavity.

Claim 12

An apparatus for imaging a cross section of a small cavity such as a coronary vessel, the apparatus including in combination: a probe having a transducer element; a source of an electrical pulse for exciting the transducer element to emit ultrasonic waves in an ambient environment of the transducer element within the small cavity; a receiver for detecting electrical signals generated by mechanical oscillations of the transducer element after excitation of the transducer element by the electrical pulse; a first buffer for storing the electrical signals as an echo waveform, comprising N bytes; a second buffer for storing the electrical signals as a reference waveform, comprising M bytes of non-zero data, where N>M; means for subtracting the reference waveform from the echo waveform in order to provide an imaging waveform stripped of any repeatable noise patterns; and an imaging device responsive to the imaging waveform for generating a visual image.

Claim 13

An apparatus for imaging a cross section of a small cavity such as a coronary vessel, the apparatus including in combination: a probe having a transducer element; a source of an electrical pulse for exciting the transducer element to emit ultrasonic waves in an ambient environment of the transducer element within the small cavity; a receiver for detecting electrical signals generated by mechanical oscillations of the transducer element after excitation of the transducer element by the electrical pulse; a first buffer for storing the electrical signals as an echo waveform, comprising N bytes; a second buffer for storing the electrical signals as a reference waveform, comprising M bytes of non-zero data, where N>M; means for subtracting the reference waveform from the echo waveform in order to provide an imaging waveform stripped of any repeatable noise patterns; and an imaging device responsive to the imaging waveform for generating a visual image.

Claim 14

An apparatus for imaging a cross section of a small cavity such as a coronary vessel, the apparatus including in combination: a prove having a transducer element; a source of an electrical pulse for exciting the transducer element to emit ultrasonic waves in an ambient environment of the transducer element within the small cavity; a receiver for detecting electrical signals generated by the mechanical flexing of the transducer element after excitation of the transducer element by the electrical pulse; a first buffer for storing as a reference waveform electrical signals which are free of signals caused by echoes of the ultrasonic waves, where the reference waveform is substantially entirely linear; means for subtracting the reference waveform from electrical signals that include signals caused by echoes of the ultrasonic waves in order to generate an echo waveform; a second buffer for storing the echo waveform; means responsive to the second buffer for generating visual images.

Claim 15

An apparatus for imaging a cross section of a small cavity such as a coronary vessel, the apparatus including in combination: a prove having a transducer element; a source of an electrical pulse for exciting the transducer element to emit ultrasonic waves in an ambient environment of the transducer element within the small cavity; a receiver for detecting electrical signals generated by the mechanical flexing of the transducer element after excitation of the transducer element by the electrical pulse; a first buffer for storing as a reference waveform electrical signals which are free of signals caused by echoes of the ultrasonic waves, where the reference waveform is substantially entirely linear; means for subtracting the reference waveform from electrical signals that include signals caused by echoes of the ultrasonic waves in order to generate an echo waveform; a second buffer for storing the echo waveform; means responsive to the second buffer for generating visual images.