Subject information acquisition apparatus
First Claim
1. A subject information acquisition apparatus for transmitting, through a reference layer, an elastic wave to a subject, receiving, through the reference layer, the elastic wave reflected from inside the subject, and acquiring information inside the subject, the subject information acquisition apparatus comprising:
- a conversion device configured to receive the elastic wave and convert the elastic wave into an electrical signal; and
a memory and processor which function as each unit comprising;
a measuring unit configured to measure strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer interposed between the conversion device and the subject by using the electrical signal; and
a calculation unit configured to calculate a viscosity coefficient (TO) of the subject by using a viscosity coefficient and an elastic modulus of the reference layer, the strain of the subject, and the strain of the reference layer,whereinthe pressure applied to the subject and the reference layer is periodic pressure application including releasing the pressure, andthe calculation unit calculates the viscosity coefficient (η
) of the subject by using an area of a hysteresis loop drawn with strain values of the subject and strain values of the reference layer which are generated by the periodic pressure.
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Abstract
Viscoelastic characteristics in a subject are imaged by a simple method. A viscoelasticity measurement reference layer whose elastic modulus and viscosity coefficient are known is included between an ultrasonic wave transmitting/receiving probe and the subject and distributions of elastic modulus and viscosity coefficient inside the subject are calculated from a change over time of strain generated in the viscoelasticity measurement reference layer and the subject according to a pressure applied to the subject which changes over time and known elastic modulus and viscosity coefficient of the viscoelasticity measurement reference layer.
5 Citations
24 Claims
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1. A subject information acquisition apparatus for transmitting, through a reference layer, an elastic wave to a subject, receiving, through the reference layer, the elastic wave reflected from inside the subject, and acquiring information inside the subject, the subject information acquisition apparatus comprising:
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a conversion device configured to receive the elastic wave and convert the elastic wave into an electrical signal; and a memory and processor which function as each unit comprising; a measuring unit configured to measure strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer interposed between the conversion device and the subject by using the electrical signal; and a calculation unit configured to calculate a viscosity coefficient (TO) of the subject by using a viscosity coefficient and an elastic modulus of the reference layer, the strain of the subject, and the strain of the reference layer, wherein the pressure applied to the subject and the reference layer is periodic pressure application including releasing the pressure, and the calculation unit calculates the viscosity coefficient (η
) of the subject by using an area of a hysteresis loop drawn with strain values of the subject and strain values of the reference layer which are generated by the periodic pressure. - View Dependent Claims (2, 3, 4, 5)
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6. A subject information acquisition apparatus for transmitting, through a reference layer, an elastic wave to a subject, receiving, through the reference layer, the elastic wave reflected from inside the subject, and acquiring information inside the subject, the subject information acquisition apparatus comprising:
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a conversion device configured to receive the elastic wave and convert the elastic wave into an electrical signal; and a memory and processor which function as each unit comprising; a measuring unit configured to measure strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer interposed between the conversion device and the subject by using the electrical signal, the reference layer having a viscosity coefficient and an elastic modulus; and a calculation unit configured to calculate a viscosity coefficient (TO) of the subject by using the viscosity coefficient and the elastic modulus of the reference layer, the strain of the subject, and the strain of the reference layer, wherein the calculation unit calculates the viscosity coefficient (η
) of the subject by using a delay time between the change over time of the strain value of the subject and the change over time of the strain value of the reference layer which are generated by the application of the pressure. - View Dependent Claims (7, 8)
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9. A subject information acquisition apparatus for transmitting, through a reference layer, an elastic wave to a subject, receiving, through the reference layer, the elastic wave reflected from inside the subject, and acquiring information inside the subject, the subject information acquisition apparatus comprising:
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a conversion device configured to receive the elastic wave and convert the elastic wave into an electrical signal; and a memory and processor which function as each unit comprising; a measuring unit configured to measure strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer interposed between the conversion device and the subject by using the electrical signal; and a calculation unit configured to calculate a stress applied to the subject by using a viscosity coefficient of the reference layer, a Young'"'"'s modulus of the reference layer, and the strain of the reference layer, according to the following equation; - View Dependent Claims (10, 11, 12)
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13. A subject information acquisition method for acquiring information on inside of a subject by using echo signals from the subject, the method comprising:
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transmitting, through a reference layer, an elastic wave to the subject; receiving, through the reference layer, the elastic wave reflected in the subject; measuring strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer; and calculating a viscosity coefficient (η
) of the subject by using a viscosity coefficient and an elastic modulus of the reference layer, the strain of the subject, and the strain of the reference layer,wherein the pressure applied to the subject and the reference layer is periodic pressure application including releasing the pressure, and calculating the viscosity coefficient (η
) of the subject is performed by using an area of a hysteresis loop drawn with strain values of the subject and strain values of the reference layer which are generated by the periodic pressure. - View Dependent Claims (14, 15, 16, 17)
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18. A subject information acquisition method for acquiring information on inside of a subject by using echo signals from the subject, the method comprising:
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transmitting, through a reference layer, an elastic wave to the subject; receiving, through the reference layer, the elastic wave reflected in the subject; measuring strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer; and calculating a viscosity coefficient (η
) of the subject by using a viscosity coefficient and an elastic modulus of the reference layer, the strain of the subject, and the strain of the reference layer,wherein calculating the viscosity coefficient (η
) of the subject is performed by using a delay time between the change over time of the strain value of the subject and the change over time of the strain value of the reference layer which are generated by the application of the pressure. - View Dependent Claims (19, 20)
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21. A subject information acquisition method for acquiring information on inside of a subject by using echo signals from the subject, the method comprising:
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transmitting, through a reference layer, an elastic wave to the subject; receiving, through the reference layer, the elastic wave reflected in the subject; measuring strain of the subject and strain of the reference layer which are generated when a pressure is applied to the subject and the reference layer; and calculating a stress applied to the subject by using a viscosity coefficient of the reference layer, a Young'"'"'s modulus of the reference layer, and the strain of the reference layer, according to the following equation; - View Dependent Claims (22, 23, 24)
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Specification