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EP-4205665-B1 - ULTRASONIC DIAGNOSTIC DEVICE AND METHOD FOR CONTROLLING ULTRASONIC DIAGNOSTIC DEVICE

EP4205665B1EP 4205665 B1EP4205665 B1EP 4205665B1EP-4205665-B1

Inventors

  • NOGUCHI, MASAFUMI

Dates

Publication Date
20260506
Application Date
20210727

Claims (13)

  1. An ultrasound diagnostic apparatus (1) comprising: an ultrasound probe (2); an image acquisition unit (22) that generates an ultrasound image (U) by performing transmission and reception of an ultrasound beam with respect to a subject using the ultrasound probe (2); and an initial condition setting unit (25) that sets a basic sound speed value V1 (m/s) for generating the ultrasound image (U) of a breast (B) of the subject by V1 = [R1*V11 + (100-R1) × V12]/100 using a ratio R1 (%) of the mammary glands which is calculated by analyzing a radiation image (S) in which the breast (B) is imaged, and wherein V11 (m/s) is a mammary gland sound speed value determined for the mammary glands, and V12 (m/s) is a fat sound speed value determined for fat, wherein the image acquisition unit (22) generates the ultrasound image (U) of the breast using the basic sound speed value.
  2. The ultrasound diagnostic apparatus (1) according to claim 1, wherein the ratio of the mammary glands is a ratio of a volume of the mammary glands in a breast region (A) with respect to a volume of the breast (B) in the breast region (A).
  3. The ultrasound diagnostic apparatus (1) according to claim 1, wherein the ratio of the mammary glands is a ratio of a volume of the mammary glands in a mammary gland region (M) with respect to a volume of the breast (B) in the mammary gland region (M).
  4. An ultrasound diagnostic apparatus (1) comprising: an ultrasound probe (2); an image acquisition unit (22) that generates an ultrasound image (U) by performing transmission and reception of an ultrasound beam with respect to a subject using the ultrasound probe (2); and an initial condition setting unit (25) that sets a basic sound speed value for generating the ultrasound image (U) of a breast (B) of the subject on the basis of a ratio of mammary glands in the breast (B), which is calculated by analyzing a radiation image (S) in which the breast (B) is imaged, wherein the image acquisition unit (22) generates the ultrasound image (U) of the breast (B) using the basic sound speed value, and the ratio of the mammary glands is represented by a ratio R1 of a volume of the mammary glands in a mammary gland region (M) with respect to a volume of the breast (B) in the mammary gland region (M), and a ratio R2 of a thickness of a mammary gland layer (L2) in the mammary gland region (M) with respect to a breast thickness (T1) in the mammary gland region (M) obtained by tomosynthesis.
  5. The ultrasound diagnostic apparatus (1) according to claim 4, wherein the initial condition setting unit (25) sets a basic sound speed value V1 (m/s) by V1 = (R1/R2) × V11 + (1 - R1/R2) × V12 using the ratio R1 (%) of the volume of the mammary glands, the ratio R2 of the thickness of the mammary gland layer (L2), a mammary gland sound speed value V11 (m/s) determined for the mammary glands, and a fat sound speed value V12 (m/s) determined for fat.
  6. The ultrasound diagnostic apparatus according to any one of claims 1 to 5, further comprising: an extraction unit (26) that extracts a fat layer (L1) and a mammary gland layer (L2) by analyzing the ultrasound image (U) of the breast (B).
  7. The ultrasound diagnostic apparatus (1) according to claim 6, wherein the image acquisition unit (22) generates the ultrasound image (U) using the basic sound speed value for the mammary gland layer (L2) extracted by the extraction unit (26).
  8. The ultrasound diagnostic apparatus (1) according to claim 6, wherein the image acquisition unit (22) generates the ultrasound image (U) using the fat sound speed value different from the basic sound speed value for the fat layer (L1) extracted by the extraction unit (26).
  9. The ultrasound diagnostic apparatus (1) according to any one of claims 6 to 8, wherein the extraction unit (26) extracts a muscle layer (L3) by analyzing the ultrasound image (U) of the breast (B), and the image acquisition unit (22) generates the ultrasound image (U) using a muscle sound speed value that is different from the basic sound speed value and the fat sound speed value and is determined for muscle, for the extracted muscle layer (L3).
  10. The ultrasound diagnostic apparatus (1) according to any one of claims 1 to 9, further comprising: an input device (30) for inputting the ratio of the mammary glands calculated by analyzing the radiation image (S), wherein the initial condition setting unit (25) sets the basic sound speed value using the ratio of the mammary glands input via the input device (30).
  11. The ultrasound diagnostic apparatus (1) according to any one of claims 1 to 9, further comprising: an input device (30) for inputting the radiation image (S); and a mammary gland ratio calculation unit that calculates the ratio of the mammary glands by analyzing the radiation image (S) input via the input device (30), wherein the initial condition setting unit (25) sets the basic sound speed value using the ratio of the mammary glands calculated by the mammary gland ratio calculation unit.
  12. A control method of an ultrasound diagnostic apparatus (1), the control method comprising: setting a basic sound speed value V1 (m/s) for generating an ultrasound image (U) of a breast (B) of a subject by V1 = (100 - R1) × V12]/100 using a ratio R1 (%) of the mammary glands which is calculated by analyzing a radiation image (S) in which the breast (B) is imaged, wherein V11 (m/s) is a mammary gland sound speed value determined for the mammary glands, and V12 (m/s) is a fat sound speed value determined for fat; and generating the ultrasound image (U) of the breast (B) using the basic sound speed value.
  13. A control method of an ultrasound diagnostic apparatus (1), the control method comprising: setting a basic sound speed value for generating an ultrasound image (U) on the basis of a ratio of mammary glands in a breast (B) of a subject, which is calculated by analyzing a radiation image (S) in which the breast (B) is imaged; and generating the ultrasound image (U) of the breast (B) using the basic sound speed value, wherein the ratio of the mammary glands is represented by a ratio R1 of a volume of the mammary glands in a mammary gland region (M) with respect to a volume of the breast (B) in the mammary gland region (M), and a ratio R2 of a thickness of a mammary gland layer (L2) in the mammary gland region (M) with respect to a breast thickness (T1) in the mammary gland region (M) obtained by tomosynthesis.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasound diagnostic apparatus, and a control method of the ultrasound diagnostic apparatus which are for examining a breast of a subject. 2. Description of the Related Art In the related art, observation of the inside of a subject is performed by generating an ultrasound image representing tomogram of the subject using an ultrasound diagnostic apparatus. In a case where the ultrasound image is generated, first, an ultrasound beam is transmitted from a transducer array consisting of a plurality of ultrasonic transducers to the inside of the subject, the ultrasound beam is reflected in the subject, and an ultrasound echo is received in the transducer array. The ultrasound image is generated by correcting the difference in propagation time until the ultrasonic wave emitted from the ultrasonic transducer returns to the same ultrasonic transducer via a reflection point in the subject, for an echo signal received by each ultrasonic transducer of the transducer array, and then adding each echo signal. The propagation time of the ultrasonic wave is calculated on the basis of the length of the path of the ultrasonic wave and the sound speed in a medium in the subject. The difference between the value of the sound speed used in the calculation and the value of the actual sound speed in the medium is known to cause degradation in the resolution of the ultrasound image. In the human body, the sound speed is about 1550 m/s in the liver and the like, is 1420 m/s in fat, and has different values depending on the tissues. Therefore, in order to improve the resolution of the ultrasound image, for example, as disclosed in JP2015-136449A, a technique of changing the sound speed value used for the calculation in the fat layer and the other layers has been developed. Richard G. Barr et al. "Speed of Sound Imaging: Improved Image Quality in Breast Sonography", Ultrasound Quarterly, Raven Press, New York, USA, vol. 25, no. 3, 1 September 2009, XP009149006, ISSN: 0894-8771 presents a study with the purpose of blindly evaluating breast ultrasound images corrected for the speed of sound in breast tissue and comparing them to standard images. SUMMARY OF THE INVENTION The examination of the breast of the subject is performed by using the ultrasound diagnostic apparatus. It is generally known that the breast includes a fat layer, a mammary gland layer, and a muscle layer. Among these, in the mammary gland layer, mammary glands and fat are mixed, and the ratio of fat in the mammary gland layer varies depending on the subject due to individual differences, an increase of fat with age, and the like. Thus, as in the technique disclosed in JP2015-136449A, even in a case where a constant sound speed value is applied to the mammary gland layer, the applied sound speed value is not necessarily an optimal value, and the ultrasound image that clearly shows the mammary gland layer may not be obtained. Even in a case where an optimal sound speed value for the mammary gland layer is tried to be calculated by calculating the presence ratio of the mammary gland and fat in the mammary gland layer from the ultrasound image, since the entire mammary gland layer is depicted in the ultrasound image with high brightness regardless of the ratio of mammary glands in the mammary gland layer, it is difficult to calculate the presence ratio of the mammary gland and fat in the mammary gland layer from the ultrasound image. The present invention has been made in order to solve such a problem in the related art, and an object of the present invention is to provide an ultrasound diagnostic apparatus and a control method of the ultrasound diagnostic apparatus which can improve the resolution of the ultrasound image of the mammary gland layer. According to a first aspect of the present invention, an ultrasound diagnostic apparatus is provided as claimed in claim 1. According to a second aspect of the present invention, an ultrasound diagnostic apparatus is provided as claimed in claim 4. The initial condition setting unit sets a basic sound speed value V1 (m/s) by V1 = [R1 × V11 + (100 - R1) × V12]/100 using a ratio R1 (%) of the mammary glands, a mammary gland sound speed value V11 (m/s) determined for the mammary glands, and a fat sound speed value V12 (m/s) determined for fat. The ultrasound diagnostic apparatus can further include an extraction unit that extracts a fat layer and a mammary gland layer by analyzing the ultrasound image of the breast. In this case, the image acquisition unit can generate the ultrasound image using the basic sound speed value for the mammary gland layer extracted by the extraction unit. Alternatively, the image acquisition unit can generate the ultrasound image using the fat sound speed value different from the basic sound speed value for the fat layer extracted by the extraction unit. The extraction unit can extract a muscle layer by analyzin