Ultrasound diagnosis apparatus, method for operating ultrasound diagnosis apparatus, and computer-readable recording medium

A method comprising:

• analyzing, by a processor comprising hardware, frequency of an ultrasound signal obtained by an ultrasound probe comprising an ultrasound transducer configured to transmit ultrasound to a subject and receive the ultrasound reflected from the subject, thereby to calculate a frequency spectrum of the ultrasound signal for each reception depth;
• retrieving, from a noise level data storage, noise level data in accordance with a frequency and a reception depth;
• comparing the noise level data with data of the frequency spectrum, thereby to set a frequency band of the frequency spectrum for calculation;
• calculating a second-order change rate in the frequency band of the frequency spectrum, (θ2/∂f∂L) F(f, L) or (∂2/∂L∂f) F(f, L), or a second-order change rate of a function defined by using the frequency band of the frequency spectrum, (∂2/∂f∂L)ψ(f, L) or (∂2/∂L∂f)ψ(f, L), wherein F(f, L) is the data of the frequency spectrum, ψ(f,L) is the function defined by using F(f, L) as ψ(f,L)=F(f, L)−F(f, 0), by:
• as a first operation, performing, by the processor, partial differential operation or regression analysis to approximate a result of the operations using distance as a variable, in the frequency spectrum or in the function defined by using the frequency spectrum, and as a second operation, performing, by the processor, another partial differential operation or another regression analysis to approximate a result of the operations, using frequency as a variable, on a result of the first operation;
• or
• as a first operation, performing, by the processor, partial differential operation or regression analysis to approximate a result of the operations using a frequency as a variable, in the frequency spectrum or in the function defined by using the frequency spectrum, and as a second operation, performing, by the processor, another partial differential operation or another regression analysis to approximate a result of the operations, using distance as a variable, on a result of the first operation;
• estimating, by the processor, an attenuation rate of the ultrasound signal, per unit distance and per unit frequency, in a predetermined region within a scanning region of the ultrasound transducer using the second-order change rate;
• generating B-mode image data for an ultrasound image to be displayed by converting amplitude of the ultrasound signal into brightness;
• and
• generating combined image data for a combined image including the ultrasound image and the attenuation rate, using the attenuation rate and using the B-mode image data.

A non-transitory computer-readable recording medium with an executable program stored thereon, the program causing a computer to execute:

• analyzing frequency of an ultrasound signal obtained by an ultrasound probe comprising an ultrasound transducer configured to transmit ultrasound to a subject and receive the ultrasound reflected from the subject, thereby to calculate a frequency spectrum of the ultrasound signal for each reception depth;
• retrieving, from a noise level data storage, noise level data in accordance with a frequency and a reception depth;
• comparing the noise level data with data of the frequency spectrum, thereby to set a frequency band of the frequency spectrum for calculation;
• calculating a second-order change rate in the frequency band of the frequency spectrum, (θ2/∂f∂L) F(f, L) or (∂2/∂L∂f) F(f, L), or a second-order change rate of a function defined by using the frequency band of the frequency spectrum, (∂2/∂f∂L)ψ(f, L) or (∂2/∂L∂f)ψ(f, L), wherein F(f, L) is the spectrum data, ψ(f, L) is the function defined by using F(f, L) as ψ(f, L)=F(f, L)−F(f,0), by:
• as a first operation, performing partial differential operation or regression analysis to approximate a result of the operations using distance as a variable, in the frequency spectrum or in the function defined by using the frequency spectrum, and as a second operation, performing another partial differential operation or another regression analysis to approximate a result of the operations, using frequency as a variable, on a result of the first operation;
• or
• as a first operation, performing partial differential operation or regression analysis to approximate a result of the operations using frequency as a variable, in the frequency spectrum or in the function defined by using the frequency spectrum, and as a second operation, performing another partial differential operation or another regression analysis to approximate a result of the operations, using distance as a variable, on a result of the first operation;
• estimating an attenuation rate of the ultrasound signal, per unit distance and per unit frequency, in a predetermined region within a scanning region of the ultrasound transducer using the second-order change rate;
• generate B-mode image data for an ultrasound image to be displayed by converting amplitude of the ultrasound signal into brightness;
• and
• generate combined image data for a combined image including the ultrasound image and the attenuation rate, using the attenuation rate and using the B-mode image data.