JP2010005271A - Fatty tissue detecting method and fatty tissue detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fatty tissue detecting method and a detecting device for easily detecting the fatty tissue of a subject by reflection-type ultrasonic wave measurement. <P>SOLUTION: The fatty tissue detecting method includes: a measurement process for measuring an ultrasonic echo signal during non-irradiation, which is received from the measurement region of the subject when near-infrared light is not radiated, and an ultrasonic echo signal after light irradiation, which is received from the measurement region after the near-infrared light is radiated (a); an ultrasonic velocity change calculation process for calculating ultrasonic velocity change data before/after light irradiation in the measurement region, based on the ultrasonic echo signal during non-irradiation and the ultrasonic echo signal after light irradiation (b); and a fatty region detection process for detecting the region as the fatty region, where the ultrasonic velocity indicates a negative change after the light irradiation concerning the calculated ultrasonic velocity change data (c). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for detecting adipose tissue inside an object such as a living body, and more particularly to a method for detecting adipose tissue using ultrasonic velocity change calculation data.

  Myocardial infarction, cerebral infarction, diabetes and the like are called lifestyle-related diseases. One of the risk factors for these lifestyle-related diseases is visceral fat obesity. Efforts are being made to diagnose a person with a high risk of lifestyle-related diseases due to built-in fat obesity as metabolic syndrome and prevent the disease from the viewpoint of preventive medicine. And in order to diagnose whether it is a metabolic syndrome, the visceral fat test | inspection which measures a visceral fat by image diagnosis is performed.

  In addition, when a lump is found in breast cancer screening, it is necessary to examine whether the lump is simply a mass of fat and is benign, or not a malignant tumor. In that case, if it can be easily detected whether or not the lump is adipose tissue, it will be helpful in determining benign and malignant.

Thus, it may be necessary to examine whether the tissue of the region of interest in the living body is fat. In that case, adipose tissue can be detected by image diagnosis using an X-ray CT apparatus. However, there is a problem of radiation exposure on the subject when the X-ray CT apparatus is used.
Therefore, as a safer image diagnostic method that does not cause the problem of radiation exposure, a fat inspection by ultrasonic tomography that obtains a tomographic image using ultrasonic waves has been proposed (see Non-Patent Document 1).

Generally, the speed of sound propagating in water is 1524 m / sec, and the speed of sound in fat is 1412 m / sec (however, when the temperature is 37 ° C.). Ultrasonic sound velocity propagating through moisture-rich muscles and internal organs (intestines, kidneys), and ultrasonic wave velocity propagating through standoffs (eg, polymer gel materials) used between the transceiver and the body surface Is 1500 m / sec or more. On the other hand, since the sound velocity of the ultrasonic wave propagating in the fat tissue is 1500 m / sec or less, the sound velocity of the tissue constituting the measurement site (for example, the abdomen) of the subject is measured, and the sound velocity is a constant value (1500 m If it can be determined whether it is equal to or less than / second), the abdominal fat distribution can be detected from the sound speed data.
According to the ultrasonic tomography disclosed in the above-mentioned document, the visceral fat is measured using the difference in sound speed for each substance.
That is, when measuring visceral fat in the abdominal section of the subject, an ultrasonic wave transmitter and a wave receiver are placed facing each other with the abdomen interposed therebetween, and the propagation time by the ultrasonic transmission signal is measured.

  In ultrasonic tomography, propagation time data by transmission measurement is information that depends on the sound velocity of the abdominal tissue through which the ultrasonic wave has passed and the thickness of the abdominal tissue through which the ultrasonic wave has passed. Therefore, it is necessary to obtain only the sound speed by separating the thickness and the sound speed included in the propagation time data. Therefore, in the above ultrasonic tomography, the transmitter and the receiver facing each other are moved around the abdomen, and the transmission propagation time from a plurality of directions is obtained, and the complicated CT algorithm similar to the X-ray CT is used. By performing tomography calculation, the sound speed information is extracted excluding the thickness information.

  On the other hand, while using a normal reflection type ultrasonic diagnostic apparatus, a mechanism for irradiating the measurement area with light is provided, and the speed change of the ultrasonic echo signal is calculated when light is not irradiated and after light irradiation. It has been proposed to obtain a tomographic image of an ultrasonic velocity change distribution in a measurement region by light irradiation (a tomographic image of a light absorption distribution) (see Patent Document 1).

  The tomographic image of the ultrasonic velocity change (the tomographic image of the light absorption distribution) represents the tomographic image of the temperature change in the measurement region due to the absorption of the irradiated light. That is, when light is irradiated into the living body, a temperature distribution is generated in the living body according to the light absorption characteristics of each part. Since the sound velocity of the ultrasonic wave propagating in the living body changes depending on the temperature, by calculating the sound velocity change of the ultrasonic echo signal before and after the light irradiation for each part and tomographic imaging, A tomographic image of ultrasonic velocity change distribution, temperature change distribution, or light absorption distribution is displayed.

FIG. 8 is a diagram illustrating a device configuration for displaying a tomographic image of a light absorption distribution described in Patent Document 1. In FIG. The subject 100 is irradiated with light by a light source 40 composed of an infrared laser. On the emission side of the light source 40, a shutter 42 for intermittently irradiating the subject 100 with light is provided. The shutter 42 is controlled to be opened and closed by the light absorption analysis unit 60.
Transmission / reception of ultrasonic waves is performed by the array-type probe 50. The array-type probe 50 is excited by a drive signal from the transmission / reception unit 52 to emit an ultrasonic signal, and the transmission / reception unit 52 receives a reception signal (ultrasonic echo signal) from within the subject in response to the ultrasonic signal. return. The scanning probe 54 scans the array probe by sequentially switching transducers that transmit and receive waves.
The received signal of the array type probe 50 is input to the B-mode signal processing circuit 56 and the light absorption analysis unit 60. The B-mode signal processing circuit 56 performs normal B-mode tomographic image formation processing on the received signal to form a tomographic image in the array type probe scanning range, and writes it in a DSC (digital scan converter) 58. Further, the light absorption analysis unit 60 analyzes the received signal to form an image of the light absorption distribution (that is, ultrasonic velocity change distribution) in the array type probe scanning range. This ultrasonic velocity change is obtained by calculating the phase change (waveform shift amount) of the echo signal before and after the light irradiation.

  A control procedure for obtaining a light absorption distribution image by the above apparatus will be described below. First, the light absorption analysis unit 60 closes the shutter 42 and outputs a received signal (received signal for a B-mode image) of the probe 50 in a state where the subject 100 has no temperature rise due to light absorption for one scan. Remember. At this time, the light absorption analysis unit 60 distinguishes and stores the received signal for each scanning line (beam) based on the scanning information from the scanning control unit 54. Next, the light absorption analysis unit 60 opens the shutter 42 to irradiate the subject 100 with light, and a time during which a detectable temperature rise occurs in each part of the subject (this is obtained and set in advance by experiments). After the elapse of time, the received signal of the probe 50 is again acquired for one scan. Then, the light absorption analysis unit 60 compares the received signals before and after the light absorption for each scanning line, and analyzes the change in the sound velocity of the ultrasonic wave from the phase change. The analysis result is written in the DSC 58. The DSC 58 displays a light absorption distribution image (that is, an ultrasonic velocity change distribution) that is an analysis result of the light absorption analysis unit 60 on the display device 62. At this time, the light absorption distribution image may be displayed in color by being superimposed on the B-mode image. For example, since the light absorption distribution corresponds to the temperature rise of each part of the subject, a warm color is used so that the higher the absorption rate (the larger the phase difference before and after irradiation), the higher the lightness. By taking such a form, an image that can be easily grasped intuitively by an image diagnostician can be obtained.

  In this way, different from the ultrasonic echo signal intensity (reflection intensity) (B-mode image), it is possible to display a distribution of different physical quantities called a distribution of light absorption characteristics (that is, an ultrasonic velocity change distribution). A multifaceted understanding of the organization is possible.

Also, when analyzing the ultrasonic velocity change from the ultrasonic echo signal before and after the light irradiation, the envelope of the signal waveform of each ultrasonic echo signal is extracted, and each ultrasonic wave before and after the light irradiation is based on the envelope data By extracting the signal section of interest in the signal waveform of the echo signal, by determining the ultrasonic velocity change based on the signal in the signal section of interest of the non-irradiation ultrasonic echo signal and the post-irradiation ultrasonic echo signal, It has been proposed to display a tomographic image of an accurate ultrasonic velocity change without the influence of artifacts (see Patent Document 2).
Proceedings of Symposium on Ultrasonic Electronics, Vol.28, (2007), pp.339-340 14-16 November. 2007 JP 2001-145628 A JP 2008-80101 A

According to the fat detection method by ultrasonic tomography described in Non-Patent Document 1 described above, built-in fat can be measured by transmission-type ultrasonic propagation velocity measurement. However, in order to perform transmission-type ultrasonic propagation velocity measurement, it is necessary to place ultrasonic transmitters and receivers around the measurement region (abdomen) and perform measurements from multiple directions. In addition, the analysis after the measurement also requires an arithmetic processing using the CT algorithm, and is complicated.
In addition, it is necessary to maintain acoustic coupling between the ultrasonic transducer and the body surface during measurement, and a medium for acoustic coupling (for example, water) is provided around the entire measurement region (abdomen) of the subject. Bag) must be attached, which is a heavy burden on the subject. Furthermore, in order to increase the measurement accuracy, it is necessary to accurately move the positions of the ultrasonic transmitter and receiver, and the control mechanism for that purpose is also complicated.

  Therefore, it is desired to detect fat using a reflection type ultrasound diagnostic apparatus instead of a transmission type. Accordingly, an object of the present invention is to provide a detection method and a detection apparatus for adipose tissue capable of detecting the adipose tissue of a subject using a normal ultrasonic diagnostic apparatus.

In general, as described above, the velocity of ultrasonic waves propagating in water and fat is 1524 m / sec underwater and 1412 m / sec under fat at 37 ° C. It is as follows.
Water: +2 m / sec / ° C
Fat: -4 m / sec / ° C

In other words, the muscles containing a lot of water and the internal organs (intestines and kidneys) increase in ultrasonic velocity as the temperature rises, whereas the fat velocity decreases the ultrasonic velocity, and the polarity of the ultrasonic velocity changes. Invert.
Therefore, in the present invention, the change in the ultrasonic velocity when the temperature of the measurement region is changed, not the detection of the fat region (Non-patent Document 1) using the ultrasonic propagation velocity by the method in the transmission ultrasonic tomography. The fat region is detected by using this.

From the measurement area, that is, the fat detection method of the present invention made in order to solve the above-described problem, (a) non-irradiation ultrasonic echo from the measurement area of the subject when the near infrared light is not irradiated. A measurement process for measuring a signal and a post-irradiation ultrasonic echo signal from the measurement region after irradiation with near infrared light; and (b) a non-irradiation ultrasonic echo signal and a post-light irradiation ultrasonic echo signal. An ultrasonic velocity change calculating step for calculating an ultrasonic velocity change before and after the light irradiation in the measurement region, and (c) the ultrasonic velocity change negative after the light irradiation in the calculated ultrasonic velocity change data. A fat region detecting step of detecting the region as a fat region.

According to the present invention, in the first measurement step, the non-irradiation ultrasonic echo signal received from the measurement region of the subject when the near infrared light is not irradiated, and the measurement region after the near infrared light irradiation After receiving the light received from the ultrasonic wave, the ultrasonic echo signal is received by the ultrasonic probe.
Subsequently, in the ultrasonic velocity change calculation step, the ultrasonic velocity change before and after the light irradiation in the measurement region is calculated based on the non-irradiation ultrasonic echo signal and the post-irradiation ultrasonic echo signal.

This ultrasonic velocity change is obtained from the following relationship.
FIG. 9 is a schematic view showing a non-irradiation ultrasonic echo signal and a post-irradiation ultrasonic echo signal.
The ultrasonic velocity at the time of non-irradiation is V, and the ultrasonic velocity after light irradiation is V ′. Further, τ is the time when the ultrasonic signal propagates between certain boundaries during non-irradiation, and τ−Δτ is the propagation time of the ultrasonic signal after irradiating light between the same boundaries (constant distance). That is, it is assumed that the pulse interval is shifted by Δτ due to a temperature change so as to be shortened.
At this time,
V · τ = V ′ · (τ−Δτ) (1)
Is established,
Therefore, the ultrasonic velocity change can be calculated by the following equation from the time change of the pulse interval in the two echo signals.
V ′ / V = τ / (τ−Δτ) (2)

Next, in the fat region detection step, a region in which the ultrasonic velocity shows a negative change after light irradiation is detected as a fat region from the calculated ultrasonic velocity change data.
That is, by determining whether the ultrasonic velocity ratio obtained by the expression (2) is larger or smaller than 1, if smaller than 1, the region is a fat region where the ultrasonic velocity change with respect to the temperature change is negative. Detect as.

In addition, the fat detection device of the present invention, which has been made from another point of view, emits near-infrared light to the measurement region, transmits an ultrasonic signal to the measurement region, and receives an ultrasonic echo signal from the measurement region. Ultrasonic wave transmission / reception mechanism, non-irradiation ultrasonic echo signal received from the measurement area when not irradiating near-infrared light, and post-irradiation super-wave received from the measurement area after irradiation with near-infrared light An ultrasonic velocity analysis unit that calculates the ultrasonic velocity change for the light irradiation to the measurement region based on the acoustic echo signal, and a region in which the ultrasonic velocity changes negatively after the light irradiation in the calculated ultrasonic velocity change data A fat region detection unit that detects a fat region, and a tomographic image relating to the distribution of ultrasonic velocity change based on the ultrasonic velocity change data, and an image display control unit that displays the detected fat region West There.
According to the present invention, the fat region of the subject can be detected by realizing the above-described fat detection method.

According to the fat detection method and fat detection apparatus of the present invention, fat detection can be performed using a reflection type ultrasonic diagnostic apparatus that is normally used instead of a transmission type.
In addition, it is not necessary to perform a calculation by a complicated CT algorithm performed in sound velocity measurement using a transmission ultrasonic device.
Furthermore, it is not necessary to attach a medium for acoustic coupling (for example, a water bag) to the entire circumference of the measurement region (abdomen) of the subject, the apparatus becomes simple and the burden on the subject is reduced.

(Device configuration)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a fat detection apparatus according to an embodiment of the present invention.
The fat detection device 1 includes an array probe 2, a probe 5 including an infrared laser light source 3, a transmission / reception unit 6, a scanning control unit 7, an ultrasonic velocity change analysis unit 8 (light absorption analysis unit), and envelope data extraction. A control system 11 (computer device) including a unit 14, an interest signal section extraction unit 15, a fat region detection unit 16, a B-mode signal processing unit 9, a DSC 10 (digital scan converter (image display control unit)), and a display device 12. It has.

  While the probe 5 is pressed against the subject 100, an ultrasonic signal is transmitted from the array probe 2 and near infrared light of 700 nm to 1000 nm is irradiated from the infrared laser light source 3. The infrared laser light source 3 is controlled to be turned on by the ultrasonic velocity change analysis unit 8.

The array-type probe 2 has a plurality of transducers arranged in one direction, and each transducer is excited by a drive signal from the transmission / reception unit 6 to generate an ultrasonic signal. An ultrasonic echo signal from the inside of the subject is returned to the transmission / reception unit 6. The scanning control unit 7 scans a plurality of (for example, 345) ultrasonic signals by sequentially switching transducers that transmit and receive waves. FIG. 2 is a diagram illustrating an example of a reception waveform of an ultrasonic echo signal of one scanning line. A large amplitude signal is generated at the boundary between tissues.
A reception signal (ultrasonic echo signal) of the array type probe 2 is input to the B-mode signal processing circuit 9 and the ultrasonic velocity analysis unit 8. The B-mode signal processing circuit 9 performs a well-known B-mode tomographic image forming process on the received signal to form a tomographic image in the beam scanning range and writes it in the DSC 10. FIG. 3 is a diagram illustrating an example of a B-mode image formed from ultrasonic signals of 345 scanning ultrasonic beams.

  On the other hand, the ultrasonic velocity analysis unit 8 analyzes the received signal (ultrasonic echo signal) to form an image of the distribution of ultrasonic velocity changes in the ultrasonic beam scanning range. At that time, the envelope data The extraction unit 14 and the interest signal section extraction unit 15 are controlled.

  The envelope data extraction unit 14 performs a process of executing an envelope process for extracting an envelope for the echo signal waveform of each ultrasonic beam after light irradiation when the received signal is not irradiated. The envelope processing calculation itself is performed using known software. FIG. 4A shows an example of envelope data, which is extracted from the ultrasonic echo signal shown in FIG.

  The interest signal section extraction unit 15 performs a process of extracting an interest signal section for calculating a change in ultrasonic velocity from the entire extracted envelope data. That is, a section including a signal peak on the envelope data is extracted as a signal section of interest. At this time, a processing time may be shortened by setting a threshold value in advance, extracting only signal peaks equal to or higher than the threshold value, and removing small peaks as artifacts.

  Specifically, the process of extracting the interest signal section from the envelope data is performed as follows. As shown in FIG. 5 (a), comparison is made with respect to each data (set as M = ± 160 points in FIG. 3) within a predetermined section M centered on one maximum point j on the envelope data. When the central maximum point is the maximum value in the predetermined interval M, the predetermined interval M centering on the maximum point j is extracted as one of the interest signal intervals. If the central maximum point j ′ is not the maximum value in the predetermined section M as shown in FIG. 5B, the section M is not extracted as an interest signal section and the next maximum point is not extracted. Move the section so that becomes a new center, and repeat the same operation. For example, in the example of FIG. 4, four sections are extracted by this method. Except for the interest signal section, it is processed as an artifact.

And the ultrasonic velocity change analysis part 8 is based on the part (colored part of FIG.4 (b)) of the ultrasonic echo signal corresponding to each extracted interest signal area at the time of non-irradiation and after light irradiation. The waveform shift amount (Δτ) in each ultrasonic echo signal is calculated (actually, the number of shifted sampling points (ΔM) is counted as the waveform shift amount Δτ). Further, the ultrasonic propagation time (τ) between the tissue boundaries is calculated (the number of sampling points between the peaks of two adjacent signal sections of interest is counted as time (τ)).
For example, the same analysis is performed for the interest signal sections of all the ultrasonic beams of 345 ultrasonic scanning lines, and the propagation time (τ) and the waveform shift amount (Δτ) are calculated.
And based on Formula (2), the ultrasonic velocity ratio (V '/ V) of each site | part is calculated. Further, the ultrasonic velocity change analysis unit 8 forms an ultrasonic velocity change image based on the calculation result of the ultrasonic velocity ratio, and writes it into the DSC 10.

  The fat region detection unit 16 determines a portion having this value smaller than 1 as a fat region based on the calculated ultrasonic velocity ratio (V ′ / V) of each portion. Then, the fat region image is written in the DSC 10 so as to be displayed on the display device in a predetermined color (for example, blue).

(Measurement operation)
Next, an example of measurement operation by the optical tomography apparatus 1 will be described with reference to the flowchart of FIG.
The probe 5 is set toward the measurement region of the subject and measurement is started. A control signal for irradiating light to the infrared laser light source 3 is sent (S11). As a result, the subject 100 is irradiated with light from the infrared laser light source 3.

Then, after a lapse of a predetermined time from the start of irradiation, the scanning control unit 7 sequentially sends a signal to the transmission / reception unit 6 to drive the array-type probe 2 and transmit a pulsed ultrasonic signal and the subject 100. An ultrasonic echo signal which is a received signal from the receiver is received (S12). Here, the predetermined time from the start of light irradiation to the start of transmission / reception of ultrasonic waves is a time required for each part of the subject 100 to absorb sufficient light energy, and is measured in advance through experiments or the like, and the control system 11 is not shown. Set in the storage unit. The scanning control unit 7 refers to this and adjusts the transmission / reception timing.
And the waveform of the ultrasonic echo signal (reception signal) acquired in the light irradiation state is memorize | stored as an ultrasonic echo signal after light irradiation (S13).

When storage of the received waveform of the ultrasonic echo signal after light irradiation ends, a control signal for stopping light irradiation is sent (S14). Thereby, the light irradiation with respect to the subject 100 is stopped.
When the temperature of the subject 100 is sufficiently lowered after a lapse of a predetermined time from the stop of the irradiation, the scanning control unit 7 sends a signal to the transmission / reception unit 6 to drive the array probe 2 and transmit an ultrasonic signal. At the same time, an ultrasonic echo signal is received from the subject 100 (S15). And the waveform of the ultrasonic echo signal (reception signal) acquired in the light irradiation stop state is stored as the non-irradiation ultrasonic echo signal (S16).

  Subsequently, envelope data is extracted for the ultrasonic echo signals after the light irradiation and at the time of non-irradiation (S17). Further, a signal peak equal to or greater than a predetermined threshold is extracted on the envelope data, and an interest signal section is extracted based on the signal peak (S18). Subsequently, the ultrasonic wave propagation time (τ) and the waveform shift amount (Δτ) are calculated from the interest signal interval with respect to the ultrasonic echo signals after the light irradiation and at the time of non-irradiation. A change in ultrasonic velocity (ultrasonic velocity change ratio (V ′ / V)) is calculated (S19).

  Subsequently, based on the calculated ultrasonic velocity change ratio (V ′ / V) of each part, a part having this value smaller than 1 is determined as a fat region.

  Then, the distribution of the ultrasonic velocity change of the analysis result is imaged and displayed on the display device (S20). At this time, the fat region is displayed in a predetermined color (for example, blue) and is clearly separated from the other parts.

(Measurement example)
FIG. 7 is a diagram showing an example of a tomographic image taken using the fat detection apparatus 1 of the present invention, FIG. 7A is a diagram for explaining a measurement target sample, FIG. 7B is a B-mode image thereof, FIG. 7C is an ultrasonic velocity change image.

  The sample to be measured is composed of agar containing intralipid, which is a light scattering substance, and a piece of beef tallow containing carbon powder serving as a fat region is embedded in a part thereof. The carbon powder serves to efficiently heat the beef tallow pieces during light irradiation, and functions as a contrast agent. For reference, carbon powder agar is embedded in the same size as beef tallow pieces.

This sample was irradiated with laser light of 809 nm for about 15 seconds (0.1 W / cm ² ) to collect ultrasonic velocity change data.
Although the B-mode image in FIG. 7B is almost indistinguishable, in the ultrasonic velocity change image according to the present invention in FIG. 7C, the fat region can be clearly displayed in blue.

  The present invention can be used as a fat detection method and a fat detection apparatus for detecting a fat region in an object.

The block diagram which shows the structure of the fat detection apparatus which is one Embodiment of this invention. The figure which shows an example of the received waveform of one ultrasonic echo signal. The figure which shows an example of the B mode image formed from 345 ultrasonic signals. The figure which shows an example of an envelope. The figure explaining the extraction example of an interest area. The flowchart which shows the measurement operation | movement procedure by the fat detection apparatus which is one Embodiment of this invention. The figure which shows the example of a tomographic image image | photographed using the fat detection apparatus of this invention. The figure which shows the apparatus structure for displaying the tomographic image of the conventional light absorption distribution. The schematic diagram which shows the ultrasonic echo signal at the time of non-irradiation and the ultrasonic echo signal after light irradiation.

Explanation of symbols

1: Fat detection device 2: Array type probe 3: Infrared laser light source 5: Probe 8: Ultrasonic velocity change analysis unit 10: DSC (image display control unit)
12: Display device 14: Envelope data extraction unit 15: Interest signal section extraction unit 16: Fat region detection unit

Claims (3)

A method for detecting adipose tissue,
(A) Non-irradiation ultrasonic echo signal received from the measurement region of the subject when the near infrared light is not irradiated, and after the light irradiation received from the measurement region after the near infrared light irradiation A measurement process for measuring ultrasonic echo signals;
(B) an ultrasonic velocity change calculating step for calculating an ultrasonic velocity change before and after light irradiation in the measurement region based on the non-irradiation ultrasonic echo signal and the post-light irradiation ultrasonic echo signal;
(C) A method of detecting adipose tissue comprising a fat region detection step of detecting, as a fat region, a region in which the ultrasonic velocity changes negatively after light irradiation in the calculated ultrasonic velocity change data.   A light source that emits near-infrared light to the measurement region, an ultrasonic transmission / reception mechanism that transmits ultrasonic signals to the measurement region and receives ultrasonic echo signals from the measurement region, and no infrared light Velocity of light irradiation to the measurement region based on the non-irradiation ultrasonic echo signal received from the measurement region and the post-irradiation ultrasonic echo signal received from the measurement region after the near infrared light irradiation An ultrasonic velocity change analyzing unit for calculating a change, a fat region detecting unit for detecting a region where the ultrasonic velocity shows a negative change after light irradiation in the calculated ultrasonic velocity change data as a fat region, and an ultrasonic velocity change A fat detection apparatus comprising: an image display control unit that displays a tomographic image related to a distribution of ultrasonic velocity changes based on data and displays a detected fat region.   The fat detection device according to claim 2, wherein the image display control unit color-displays a region where the ultrasonic velocity shows a negative change after light irradiation.