Method of estimating tissue attenuation using wideband ultrasonic pulse and apparatus for use therein

Claim 3

The method as defined by claim 1 wherein said measure of amplitude is the natural logarithm of amplitude of said reflected wave.

Claim 4

The method as defined by claim 2 wherein said step of estimating center frequency estimates mean frequency.

Claim 5

The method as defined by claim 3 wherein said step of obtaining tissue attenuation is based on the relationship d[1n|S(f.sub.p)|]/d1=α.sub.o f.sub.p where S(f p )=power spectrum l=depth in the tissue α o =tissue attenuation coefficient f p =mean center frequency of the spectrum in the tissue between two levels.

Claim 6

The method as defined by claim 3 wherein the step of estimating average frequency includes counting zero crossings of the spectrum between the two levels.

Claim 7

Apparatus for use in estimating tissue attenuation of ultrasound energy comprising: means for transmitting a wideband ultrasonic pulse into said tissue, means for receiving said pulse as reflected by said tissue and generating an electrical signal in response thereto, an amplifier interconnected to receive and amplify said electrical signal, means interconnected to receive said amplified electrical signal and provide a measure of amplitude of said amplified electrical signal for two different levels in said tissue and for producing a first signal indicative of variation between said signals, means for determining the center frequency of said electrical signal corresponding to said reflected pulse between said two different levels and providing a second signal indicative thereof, and means responsive to said first and second signals for estimating the said tissue attenuation of ultrasound energy.

Claim 8

Apparatus for use in estimating tissue attenuation of ultrasound energy comprising: means for transmitting a wideband ultrasonic pulse into said tissue, means for receiving said pulse as reflected by said tissue and generating an electrical signal in response thereto, an amplifier interconnected to receive and amplify said electrical signal, means interconnected to receive said amplified electrical signal and provide a measure of amplitude of said amplified electrical signal for two different levels in said tissue and for producing a first signal indicative of variation between said signals, means for determining the center frequency of said electrical signal corresponding to said reflected pulse between said two different levels and providing a second signal indicative thereof, and means responsive to said first and second signals for estimating the said tissue attenuation of ultrasound energy.

Claim 9

Apparatus as defined by claim 6 wherein said means for transmitting and said means for receiving comprise a wide band ultrasonic transducer.

Claim 10

Apparatus as defined by claim 6 wherein said means for determining center frequency comprises a zero crossing detector.

Claim 11

Apparatus as defined by claim 6 wherein said center frequency is a mean center frequency.

Claim 12

Apparatus as defined by claim 6 wherein said center frequency is an average center frequency.

Claim 13

Apparatus as defined by claim 6 wherein said amplifier is logarithmic.