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EP0123427A2
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Ultrasonic medium characterization
Assignee: Fujitsu Ltd
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Filing: 1984-03-22
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Granted: —
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Expires: 2004-03-22
Abstract
Abstract A method for ultrasonic living body tissue characterization using a transducer (3) and processor (9). The method includes the steps of transmitting an ultrasonic pulse into the tissue (4) and receiving a reflected pulse, calculating the normalised power frequency spectrum of the reflected pulse, determining the frequency at which the maximum value for the power spectrum occurs, determining the high and low half powerfrequencies, calculating the upper and lower frequency ratios of the maximum value frequency and the half power frequencies, and determining the power exponent of the frequency of the reflection coefficient. The frequency exponent of the reflection coefficient is used to calculatethe attenuation slope of the ultrasonic wave. The attenuation slope or the reflection power exponent is used to generate a tomographic image of the living tissue characteristics for visual non-invasive tissue diagnosis. The attenuation slope and/or the reflection power exponent tomographic image or the others can be combined with a reflection intensity tomographic image or the others to produce other diagnostic images.
Inventors
- 👤 Hirohide C/O Fujitsu Limited Patent Dept. Miwa
- 👤 John M. Reid
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 13:49
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/895; G01S15/8954; G01S7/00; G01S7/52; G01S7/52017; G01S7/52023; G01S7/52025; G01S7/52036
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
135 words
An ultrasonic medium characterization method, comprising the steps of: a) transmitting a pulse into the medium and receiving a reflected pulse waveform from within the medium; b) calculating the power frequency spectrum of the reflected pulse waveform; . c) normalising the calculated power frequency spectrum; d) determining a maximum frequency f m at which a maximum value of the normalised power frequency spectrum occurs; e) determining a high fraction frequency f + higher than fm at which the value of the normalised power frequency spectrum is a fraction of the maximum value; f) determining a low fraction frequency f lower than f m at which the value of the normalised power frequency is the fraction of the maximum value; and g) determining a medium characteristic dependent upon f m , f and f - .
Claim 2
Dependent Claim
135 words
An ultrasonic medium characterization method, comprising the steps of: a) transmitting a pulse into the medium and receiving a reflected pulse waveform from within the medium; b) calculating the power frequency spectrum of the reflected pulse waveform; . c) normalising the calculated power frequency spectrum; d) determining a maximum frequency f m at which a maximum value of the normalised power frequency spectrum occurs; e) determining a high fraction frequency f + higher than fm at which the value of the normalised power frequency spectrum is a fraction of the maximum value; f) determining a low fraction frequency f lower than f m at which the value of the normalised power frequency is the fraction of the maximum value; and g) determining a medium characteristic dependent upon f m , f and f - .
Claim 3
Dependent Claim
66 words
A method as claimed in claim 1, wherein step g comprises calculating a reflection power exponent n characteristic of the medium or of a region of the medium to which the reflected pulse waveform relates from where 1 x is the said fraction, y + = f + /f m and y - = f /f m , and y ± means either y or y_.
Claim 4
Dependent Claim
110 words
A method as claimed in claim 1, wherein the step g comprises the step of scanning a table of possible values of n, a reflection power exponent whose actual value is characteristic of the medium or of a region of the medium to which the reflected pulse waveform relates, corresponding to respective possible values of y - y , + - where y + = f + /f m and y - = f - /f m , and comparing a measured value of y + - y - with the table values until a match is found, the corresponding value of n then being taken as the actual value.
Claim 5
Independent Claim
16 words
A method as claimed in any preceding claim, wherein the said fraction is equal to one-half.
Claim 6
Independent Claim
22 words
A method as claimed in any preceding claim, wherein step b is performed using a Fast Fourier Transform on the reflected pulse.
Claim 7
Independent Claim
41 words
A method as claimed in any preceding claim, wherein step c comprises the steps of: ci) generating a measuring system power spectrum; and cii) dividing the calculated power frequency spectrum by the measuring system power spectrum or subtracting the log spectra.
Claim 8
Independent Claim
92 words
A method as claimed in any preceding claim, wherein the medium being characterized has a number of regions therein, through which the said pulses pass, which may be numbered 1 to i, where i is an integer, and wherein step g comprises: calculating at least one of attenuation slopes β i and β (z) for each such region from where ΔT is the time difference between pulse reflections from the boundaries between regions i+i and i and between regions i and i-1, and C is the velocity of sound in the medium.
Claim 9
Dependent Claim
68 words
A method as recited in claim 7, when read as appended to claim 2 or 3, comprising performing steps a-g a plurality of times in respect of reflected pulse waveforms related to different locations or regions of the medium; and generating at least one of an attenuation slope and a reflection power exponent n tomographic image representing an attenuation slope and/or reflection power exponent image of the medium.
Claim 10
Dependent Claim
71 words
A method as claimed in claim 8, wherein each reflected pulse waveform related to a different location or region has a reflection intensity, and wherein the method further comprises the steps of: generating a reflection intensity tomographic image in dependence upon the reflection intensity of the reflected pulses; and combining the-reflection intensity tomographic image with at least one of the attenuation slope β and the reflection power exponent n tomographic images.
Claim 11
Dependent Claim
51 words
A method as claimed in claim 7 or 8, further comprising the steps of: calculating the linear integration of (attenuation slope) along a path from the n value; reconstructing a 0 and/or n tomographic image by applying an algorithm well-known in X-ray computer tomography to the linear integrations for various projections.
Claim 12
Independent Claim
60 words
A method as claimed in any preceding claim, further comprising the steps of: k) performing steps a-g a plurality of times in respect of reflected pulse waveforms related to different locations or regions of the medium; and 1) reconstructing the β and/or n image by applying the algorithm well-known in X-ray computer tomography to the linear integrations for various projections.
Claim 13
Independent Claim
15 words
A method as claimed in any preceding claim, wherein the medium is living body tissue.
Claim 14
Independent Claim
182 words
A system for ultrasonic characterization of a medium, comprising a transducer or transducers for transmitting pulses into the medium and for receiving reflected pulse waveforms from the medium, and a processor, the system being operable for: a) transmitting a pulse into the body tissue and receiving a reflected pulse waveform from within the body tissue; b) calculating the power frequency spectrum of the reflected pulse waveform with the processor; c) normalising the calculated power frequency spectrum with the processor; d) determining a maximum frequency f m at which a maximum value of the normalised power frequency spectrum occurs with the processor; e) determining a high fraction frequency f + higher than f m at which the value of the normalised power frequency spectrum is a fraction of the maximum value with the processor; f) determining a low fraction frequency f lower than f m at which the value of the normalised power frequency is the fraction of the maximum value with the processor; and g) determining a medium characteristic dependent upon f m , f + and f - with the processor.
Claim 15
Independent Claim
182 words
A system for ultrasonic characterization of a medium, comprising a transducer or transducers for transmitting pulses into the medium and for receiving reflected pulse waveforms from the medium, and a processor, the system being operable for: a) transmitting a pulse into the body tissue and receiving a reflected pulse waveform from within the body tissue; b) calculating the power frequency spectrum of the reflected pulse waveform with the processor; c) normalising the calculated power frequency spectrum with the processor; d) determining a maximum frequency f m at which a maximum value of the normalised power frequency spectrum occurs with the processor; e) determining a high fraction frequency f + higher than f m at which the value of the normalised power frequency spectrum is a fraction of the maximum value with the processor; f) determining a low fraction frequency f lower than f m at which the value of the normalised power frequency is the fraction of the maximum value with the processor; and g) determining a medium characteristic dependent upon f m , f + and f - with the processor.
Claim 16
Dependent Claim
30 words
A system as claimed in claim 13, wherein the processor is operable in step g to calculate a reflection power exponent n in accordance with the method of claim 2.
Claim 17
Dependent Claim
85 words
A system as claimed in claim 13, wherein the processor has a look-up table of possible values of n, a reflection power exponent whose actual value is characteristic of the medium or of a region of the medium to which the reflected echo pulse waveform relates, corresponding to respective possible values of y - y , + where y + = f + /f m and y - =f-/f m , and is operable in step g in accordance with the method of claim 3.
Claim 18
Dependent Claim
26 words
A system as claimed in claim 13, 14 or 15 wherein the processor is operable in step g in accordance with the method of claim 7.
References Cited (Backward Citations)
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