JPH06339478A - Method and device for ultrasonically evaluating osteoporosis - Google Patents

Abstract

PURPOSE:To make it easy to determine the stage of osteoporosis by transmitting an ultrasonic wave to the bone, computing the velocity at which the wave is transmitted through the bone, calculating the area ratio of the trabeculae, drawing a chart, and displaying in different colors portions which differ from the chart to an image taken at a healthy person of the same age and sex. CONSTITUTION:An ultrasonic wave is transmitted to and received from the calcaneus or patella of an examinee by using probes 5a, 5b each connected to an ultrasonic transceiver 8, and the signal received is input to a computer main body 1 via a filter 9, an amplifier 10 and an A/D converter 11. The velocities at which the ultrasonic wave propagates through the medulla, ossein, and medullary space, Va, Vb, Vc, respectively, are computed and the trabecular density Eu of the spongy tissues within the bone is calculated from the velocities of propagation by using the formula: Eu=[(1/ Vb)-(1/Vc)]/[-(1/Va)-(1/Vc)]. Next, the area ratio Au of the trabeculae is calculated from the formula: Au=Eu*Eu. Thereafter, a chart that meets the area ratio Au of the trabeculae is drawn and compared with an image taken at a healthy person of the same age and sex as the examinee, and portions differing from the chart to the image are displayed in different colors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for evaluating the progress of osteoporosis using ultrasonic waves.

[0002]

2. Description of the Related Art The rapid increase in the number of people with an illness called osteoporosis, which makes it easier for people to fracture their bones in their normal daily lives as the elderly population increases, has become a major problem in the medical field. Osteoporosis is a disease in which the amount of calcium and other components in the bone decreases, resulting in a decrease in bone mass, which easily causes cracking and damage due to reduced strength.
It is said that about 30% of people over the age of 0 and about 10% of men are applicable. If osteoporosis is detected at an early stage, it is possible to effectively prevent the progression of osteoporosis by various treatments. Therefore, early detection by regular examination is important. For this reason, conventionally, bone mineral content (BMC) by X-ray radiation or gamma radiation
The measurement was used to predict and evaluate the degree of progression of osteoporosis.

However, radiation is extremely harmful to the living body, and is intended for people aged about 50 to 60 years or older, who are predicted to have a high possibility of osteoporosis, and for women after closing the diameter. It was evaluated while taking risks.
Therefore, a device for evaluating osteoporosis using ultrasonic waves, which is harmless to the human body, has also been proposed.

For example, a method is proposed in which the sound velocity inside the bone and the attenuation rate are obtained from the received signal that is transmitted by transmitting ultrasonic waves to the patient (subject), and these are used as an evaluation index for the condition of the bone. (For example, Japanese Patent Publication No. 1-503199, Japanese Patent Laid-Open No. 2-1)
04337, Tokuhyo 4-541519, etc.). However, as shown in FIG. 15, the vertical axis shows the index called the stiffness calculated by the computer from the information obtained by the transmission of ultrasonic waves, while the horizontal axis shows the age. , An average curve of a healthy person is drawn, on the other hand, the measurement result of the patient (subject) is plotted on it, and how far is this patient (subject) from the normal person? As a result, it was determined whether the patient (subject) was normal, was in a state of caution, or was in a state in which treatment must be started immediately.

[0005]

However, from the viewpoint of the patient (subject), what is displayed on the screen of the computer is certainly far from the reference curve shown by the healthy person. Even if I could understand what it was, I was not convinced even when I heard the explanations from doctors and public health nurses about how the condition was related to the degree of progression of the disease of osteoporosis. Therefore, the present invention enables a patient (subject) to recognize the progressing state of osteoporosis from his / her own eyes on the screen of a computer. Subject)
On the other hand, it is an object of the present invention to provide an osteoporosis evaluation method and a device thereof, which include a computer screen displaying internal information of the bone, which makes it extremely easy to explain the progress state of osteoporosis.

[0006]

The present invention takes advantage of the fact that ultrasonic waves propagate at different speeds in bone (solid) and bone marrow (liquid) in hard tissue, and the length ratio of solid to liquid is utilized. Then, the area ratio of the part occupied by the bone is obtained from the measurement in at least two right-angled directions, or the measurement at two or more positions on the same plane (the positions are moved as when ironing), and the bone area is calculated in advance. (Cancellous bone) The equivalent cancellous bone shape based on the quantified (trabecular area ratio) parameter that represents the characteristics of the shape is displayed. That is, when evaluating osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to the calcaneus or patella of the subject to determine the transmission propagation velocity inside the bone. Then, the trabecular area ratio is calculated from the trabecular line density of the cancellous bone inside the bone by a predetermined calculation formula from the obtained propagation velocity. Next, using the fractal dimension corresponding to this trabecular bone linear density, a drawing program satisfying this trabecular bone area ratio is performed using a predetermined drawing program by a computer. This drawn image and at least gender of male and female,
The state of progression of osteoporosis was evaluated by comparing with the images of the cancellous bones of healthy persons of almost the same age.

[0007]

First, for example, when assessing the degree of progression of osteoporosis in a human, an ultrasonic probe consisting of a pair of transmitter and receiver is applied to the calcaneus to measure the propagation time through the bone. Next, the propagation velocity is calculated from the measured propagation time, and computer processing is performed based on this ultrasonic propagation velocity data by a predetermined calculation formula, and a graphic equivalent to the shape of the cancellous bone in the calcaneus is displayed on the computer display screen. Represent. This display image is color-coded by displaying only the thin bones in red, as compared with an average healthy person. On the other hand, when the treatment is started after it is evaluated as osteoporosis and the effect of the treatment gradually appears, the increased portion of the trabecular bone is changed to a different color by making it bluer. By visually recognizing the color-coded regions, the patient (subject) can specifically grasp the progress of the disease and, conversely, the effect of the treatment.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an apparatus for carrying out the present invention will be specifically described with reference to the drawings. In FIG. 1, 1 is a CPU, R
Computer body including OM and RAM, 2 is a CRT which is a display, 3 is a printer, 4 is a key for input
A board 5 is a measuring unit equipped with a footrest on which a subject's foot is placed and an ultrasonic probe connected to an ultrasonic transceiver, and 6 is an FD device of an external storage device.

FIG. 2 shows an electrical circuit configuration diagram of the connection between a computer and a measuring unit including an ultrasonic probe connected to an ultrasonic transmitter / receiver, and the ultrasonic probes 5a and 5b are relays, respectively. It is connected to the ultrasonic transmitter / receiver 8 via the substrate 7. The electric pulse signal from the ultrasonic probe 5a is converted into an ultrasonic signal by the piezoelectric element and transmitted to the ultrasonic probe 5b. In the ultrasonic probe 5b, the ultrasonic signal is again converted into an electric signal by the piezoelectric element. The ultrasonic transmitter / receiver 8 is connected to an A / D converter 11 via a filter 9 and an amplifier 10. The filter 9 removes low frequency and high frequency components from the RF signal of the ultrasonic transmitter / receiver 8 and The A / D converter 11 converts the signal from the amplifier 10 into a digital signal and sends the data to the CPU of the computer main body 1. Further, the CPU of the computer main body 1 performs arithmetic processing based on the signal from the ultrasonic transmitter / receiver 8 to estimate the trabecular area ratio and trabecular shape of the cancellous bone. Furthermore, the ultrasonic transmitter / receiver 8 is connected to the CPU of the computer main body 1, while the CPU is the CRT 2, the printer 3 and the FDD.
It is also connected to the device 6 and outputs the results of the arithmetic processing to these devices or stores and holds them.

FIG. 3 shows an external view of a main part of the measuring section 5 equipped with an ultrasonic probe connected to an ultrasonic transmitter / receiver. The footrest 21 is bent in a substantially right-angled direction and includes a surface 21a that supports the sole of the foot and a surface 21b that supports the legs, and is fixed to the base 22. The ultrasonic probe 5a is fixed to the side of the base 22, while the other ultrasonic probe 5b is fixed.
Is loosely attached to the groove 22a provided on the base 22, and the handle 23
Is attached so as to be movable laterally along the groove 22a. In FIG. 4, inside a thin-walled cylindrical cassette 30, a synthetic resin film-shaped storage bag 31 loaded with water and a gel-like liquid is fixed in a laterally spherical protruding state. Has been done. The cassette 30 is screwed onto the outer peripheral surfaces of the heads of the ultrasonic probes 5a and 5b.
Instead of the bag 31 containing water or the like, a pad made of silicon may be attached.

[0012] Now, in measuring with ultrasonic waves to evaluate osteoporosis, first, as shown in FIG. 5, when the foot of the subject is placed on the footrest 21 of the measuring unit 5, the heel part is superposed. It hits the side surface of the storage bag 31 of the cassette 30 screwed to the sound wave probe 5a. Then, attach the other ultrasonic probe 5b to the handle 2
When it is moved in the lateral direction by the operation of 3, the storage bag 31 of the cassette 30 screwed to the ultrasonic probe 5b hits the other side surface of the heel portion, and the heel portion is just sandwiched. Here, ultrasonic waves are transmitted from the ultrasonic probe 5a and received by the other ultrasonic probe 5b. The signal of the ultrasonic probe 5b is sent to the ultrasonic transmitter / receiver 8 via the relay substrate 7 as shown in FIG. 2, and here, first, the time during which the ultrasonic wave passes through the inside of the bone is measured. Then, the signal from the ultrasonic transmitter / receiver 8 is filtered by the filter 9, the amplifier 10 and the A / D converter 11
Is sent to the computer main body 1 via. Since the distance between the ultrasonic probes 5a and 5b is known in advance in the computer main body 1, from the measured ultrasonic wave transmission time,
The velocity of propagation of ultrasonic waves through the bone is calculated.

The trabecular bone linear density is calculated from the calculated propagation velocity by the following equation.

[Equation 9] However, Vb: Ultrasonic wave propagation velocity in bone Va: Ultrasonic bone marrow propagation velocity (1500 m / s) Vc: Ultrasonic bone substance propagation velocity (3000 m / s) Here, trabecular linear density is one-dimensional (length The ratio of the portion containing bone matter (solid) to the bone marrow (liquid) and bone matter (solid) in the direction). That is, in general, the heel and knee are composed of soft tissue (skin and flesh) and hard tissue (bone).
, Of which hard tissue (bone part) is cortical bone, cancellous bone (mixed trabecular bone and bone marrow) and bone marrow (liquid).
It is composed of three parties. Since ultrasonic waves actually penetrate the entire heel part (solid part and liquid part), here
Ultrasonic velocity means the average velocity of these. by the way,
Since the cancellous bone occupies almost 95% of the calcaneus,
Since osteoporosis first appears in the cancellous bone, it is the optimal site for its evaluation. Next, the trabecular bone area ratio is obtained from the obtained trabecular bone linear density. Au (trabecular bone area ratio) = Eu * Eu --- (second formula) Here, the trabecular bone area ratio includes the bone material (solid) portion with respect to bone material (solid) and bone marrow (liquid) in a certain area. Say the percentage that will be given. This is for displaying the two-dimensional (planar) image as the internal information of the bone by arithmetic processing of the data measured by the ultrasonic waves by the computer.

FIG. 6 shows an example in which the ultrasonic measuring unit is a knee instead of the heel shown in FIG.
In this case, the pair of ultrasonic probes 5a and 5b are applied in the horizontal direction (X-X direction) and the vertical direction (Y-Y direction) orthogonal to the horizontal direction for measurement. From the obtained ultrasonic wave propagation velocity, the trabecular bone linear densities (Eu) are obtained in the X direction and the Y direction by the above-described first calculation formula. Next, the trabecular bone area ratio (trabecular bone surface density) is calculated from the trabecular bone linear density. Au (trabecular bone area ratio) = Eux * Euy --- (3rd formula)

Next, using a predetermined drawing program by a computer, drawing is performed to satisfy the above-mentioned trabecular bone area ratio, and the fractal dimension is obtained from this drawing image. That is, the geometric pattern of the cancellous bone inside the bone is two-dimensional (planar).
Next, the method of artificially drawing the shape will be described.
First, the underlying square (eg 240 * 240)
Pixel) and make P * Q elliptical pilot holes in it.
Here, the center coordinates of the prepared hole are points on a zigzag lattice, as shown in FIG. This is to eliminate extreme variations in trabecular thickness in the final cancellous bone image. next,
It is considered to be similar to the shape of the cancellous bone geometric pattern by generating n osteoclasts grown in m stages on the surface of the bone. That is, it is assumed that an elliptical hole smaller than the basic pilot hole is made around a position slightly eccentric from the center coordinates of the pilot hole, and the black-painted portion is torn as shown in FIG. In FIG. 8, the hatched portion represents the trabecular bone portion). At this time, the size and number of prepared holes, or m, n
The fractal dimension is affected by the value of. The trabecular shape of the cancellous bone thus human-engineered is shown in FIG. 9 (in this figure, the shaded portion represents the bone marrow, while the white portion represents the trabecular bone). Next, FIG. 10 shows the relationship between the trabecular area ratio (apparent density) of cancellous bone and the fractal dimension obtained from the human engineering drawing.
Shown in A.

On the other hand, the relationship between the trabecular bone area ratio of the cancellous bone of natural bone (human bone) and the fractal dimension is separately obtained in advance. In other words, when the geometrical pattern of cancellous bone of natural bone (human bone) is two-dimensionally (planarly) arranged in fractal dimension with respect to the trabecular area ratio, the fractal dimension is taken on the vertical axis and When the trabecular bone area ratio is taken on the axis, all the cancellous bones overlap on one curve as shown in FIG. 10B. From this, it was possible to express the following approximate expression between the trabecular bone area ratio S and the fractal dimension D. D = 1 + S to the 0.4th power (however, S: trabecular bone area ratio) --- (4th formula)

By comparing the fractal dimension and trabecular bone area ratio obtained by this relational expression with the trabecular bone area ratio and fractal dimension of the subject, if both the trabecular bone area ratio and the fractal dimension substantially match. The image (see FIG. 9) displayed using the predetermined drawing program by the computer is identified as the image of the cancellous bone of the bone of the subject. That is, when comparing the actual shape of the cancellous bone and the shape of the cancellous bone by drawing, when the trabecular bone area ratio and fractal dimension are almost the same,
This is because the two figures are very similar figures. Therefore, considering that the shape of the cancellous bone drawn by the computer represents one of the shapes of the cancellous bone that represents this trabecular bone area ratio, conversely, by obtaining the trabecular bone area ratio by ultrasonic measurement, etc. By obtaining the fractal dimension, it is possible to derive a figure representing the shape of the cancellous bone at that trabecular area ratio.

The progressed state of osteoporosis was evaluated by comparing the images identified as described above with the images of the cancellous bones of the healthy persons having at least the same sex and age of men and women. That is, information on cancellous bones according to age of men and women of normal persons is prepared in advance as standard data, and this is stored in the ROM of the computer body 1 (FIG. 1).
1). Here, instead of the data for each age, information indicating the proportion of the trabecular bone area ratio in stages may be prepared as standard data (see FIG. 12). Incidentally, FIG. 11 and FIG.
In 2, the white part represents bone marrow, while the black part represents trabecular bone.

Evaluation Example 1 The subject is a 65-year-old woman, and the measured ultrasonic wave propagation velocity is 1.
It was 680 m / s. The trabecular bone area ratio at this time is 21.5% as calculated by the above-mentioned first and second equations by the computer main body 1, and the fractal dimension at this time is 1.54 by the fourth equation. It was On the other hand, the ultrasonic wave propagation velocity and trabecular area ratio of the healthy female, age 65, were 1790 m / s and 27%, respectively, and the defractal dimension was 1.59. A computer image of the cancellous bone of the calcaneus of this subject is shown in Figure 13A, while that of a healthy person is shown in Figure 13B. The images of both the subject and the healthy person are displayed on the same display screen, and the image of the subject is compared with the image of the healthy person, and the reduced portion of the trabecular bone is color-coded (in the figure, Since it is painted black, the subject was evaluated as having advanced osteoporosis (the white part in FIG. 13 represents the trabecular bone, and the shaded part represents the bone marrow). ). Evaluation Example 2 FIG. 14 shows an example of a case in which a patient evaluated to have osteoporosis started treatment for one year. FIG. 14A shows one year ago, FIG. 14B shows half a year ago, and FIG. 14C shows an example of the case of the current measurement. Compared to the first one, the increased portion of the trabecular bone is color-coded (blackened portion in the figure), so that the effect of treatment can be immediately discriminated (see FIG. 14).
Then, the white part represents the trabecular bone, and the shaded part represents the bone marrow).

As described above, according to the present invention, ultrasonic waves are transmitted to the calcaneus or patella to determine the transmission propagation velocity inside the bone, and based on this propagation velocity information, a computer process is performed to determine the cancellous bone inside the bone. Although an example of displaying the image of the bone is described, the present invention is not limited to this example, and instead of the propagation velocity of the ultrasonic wave, the present invention calculates by a computer based on the transmission attenuation rate information of the amplitude of the ultrasonic wave. An image of the cancellous bone inside the bone is processed and displayed, or a computer is operated based on information that takes into account both the ultrasonic transmission speed and the attenuation rate of the transmitted amplitude, and the inside of the bone is processed. Of course, it can also be applied to displaying an image of the cancellous bone.

[0020]

As described above, according to the present invention, the subject is an image displaying the state of the geometric pattern of the cancellous bone of his / her bone, which is arithmetically processed by the computer from the data obtained by the ultrasonic measurement, and the healthy subject. Compared with the bone quality image, the amount of trabecular bone loss is displayed in different colors, so you can see the progress of osteoporosis specifically with your own eyes, and the person evaluated as osteoporosis. However, since the portion where the trabecular bone increases due to the change over time after the treatment is started is displayed in different colors, the effect of the treatment can be recognized at a glance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an apparatus for evaluating osteoporosis according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an electric circuit of the device shown in FIG.

FIG. 3 is a schematic perspective view of a measuring unit including an ultrasonic probe.

FIG. 4 is a cross-sectional view of essential parts showing the relationship between an ultrasonic probe and a storage bag.

FIG. 5 is an explanatory diagram when ultrasonic waves are transmitted to the calcaneus for measurement.

FIG. 6 is an explanatory diagram when ultrasonic waves are transmitted to the patella and measured.

FIG. 7 is an explanatory diagram in the case of drawing the shape of cancellous bone by computer support.

FIG. 8 is an explanatory diagram in the case of drawing the shape of cancellous bone by computer support.

FIG. 9 is an explanatory diagram showing the shape of cancellous bone artificially drawn by computer assistance.

FIG. 10 is a graph showing the relationship between trabecular area ratio of cancellous bone and fractal dimension.

FIG. 11 is an explanatory diagram showing a planar shape of a cancellous bone according to age of a healthy person.

FIG. 12 is an explanatory diagram showing the proportion of trabecular bone area ratio of cancellous bone in stages.

FIG. 13 is an explanatory diagram showing a trabecular bone area ratio of a cancellous bone of a subject and a trabecular bone area ratio of a cancellous bone of a healthy subject.

FIG. 14 is an explanatory diagram showing changes with time of trabecular area ratio of cancellous bone of the same person.

FIG. 15 is an explanatory diagram of evaluation results used for conventional ultrasonic evaluation.

[Explanation of symbols]

 1 Computer Main Body 2 CRT 5 Ultrasonic Measuring Unit 5a, 5b Ultrasonic Probe 8 Ultrasonic Transceiver

Claims (6)

[Claims] 1. When evaluating the progressing state of osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to the calcaneus or patella of the subject to determine the transmission propagation velocity inside the bone, and then From the obtained propagation velocity, using a predetermined drawing program by the computer while calculating the trabecular bone area ratio from the trabecular bone linear density of the cancellous bone in the bone by the following calculation formula,
A drawing that satisfies this trabecular area ratio was performed, and the progress of osteoporosis was evaluated by comparing this drawn image with the image of the cancellous bone of a healthy person of at least the same sex and age. A method for evaluating osteoporosis by ultrasonic waves, which is characterized in that [Equation 1] However, Vb: ultrasonic wave propagation speed in bone Va: ultrasonic wave bone marrow propagation speed (1500 m / s) Vc: ultrasonic wave bone quality propagation speed (3000 m / s) 2. When evaluating osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to the calcaneus or patella of the subject to determine the transmission velocity inside the bone, and then this is calculated. From the propagation velocity, the trabecular area ratio is calculated from the trabecular bone linear density of the trabecular bone in the bone by the following calculation formula, and the fractal dimension corresponding to this trabecular linear density is used, and the predetermined drawing program by the computer Using this method, a drawing that satisfies this trabecular area ratio was performed, and this drawn image was compared with the image of the cancellous bone of a healthy person of at least the gender and age of almost the same condition to determine the osteoporosis A method for evaluating osteoporosis using ultrasonic waves, characterized in that the progress state is evaluated. [Equation 3] However, Vb: Ultrasonic bone propagation velocity Va: Ultrasonic bone marrow propagation velocity (1500 m / s) Vc: Ultrasonic bone bone velocity (3000 m / s) 3. When evaluating osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to the calcaneus or patella of the subject to determine the transmission velocity inside the bone. The trabecular area ratio is calculated from the trabecular line density of the trabecular bone in the bone by the following calculation formula from the propagation velocity, and the trabecular area ratio is calculated using a computer-specified drawing program. Then, the fractal dimension is obtained from this drawing image, and on the other hand, the relation between the trabecular bone area ratio of the cancellous bone of the natural bone (human bone) and the fractal dimension is obtained in advance, and this relational expression and the trabecular bone of the subject are set. If the area ratio and the fractal dimension are collated and both the trabecular bone area ratio and the fractal dimension substantially match, the image displayed using the predetermined drawing program by the computer is an image of the cancellous bone of the subject. Certified as By ultrasonic waves, the certified image is compared with the image of the cancellous bone of a healthy person of at least the sex and age of men and women to evaluate the progression of osteoporosis. Evaluation method of osteoporosis. [Equation 5] However, Vb: Ultrasonic bone propagation velocity Va: Ultrasonic bone marrow propagation velocity (1500 m / s) Vc: Ultrasonic bone bone velocity (3000 m / s) 4. When evaluating osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to the calcaneus of the subject to determine the transmission propagation speed inside the bone, and then the determined propagation speed. From the velocity, the trabecular bone linear density of the cancellous bone inside the bone is calculated from the velocity, and the calculated trabecular bone linear density is squared to obtain the trabecular bone area ratio. A computer image equivalent to the rate was displayed, and this image was compared with a bone quality image of a healthy person who had at least the same sex and age as men and women, and the part in which the trabecular bone of the subject had decreased was color-coded and displayed. An ultrasonic evaluation method for osteoporosis, which is characterized in that [Equation 7] 5. When evaluating osteoporosis using ultrasonic waves, ultrasonic waves are transmitted to a patella of a subject in a substantially horizontal direction and in two directions substantially orthogonal to the patella, and the ultrasonic waves propagate through the bone. Velocity is calculated respectively, and then the trabecular linear density of the trabecular bone in the bone is calculated from the calculated propagation velocity by the following formula, and the calculated trabecular linear density is respectively multiplied to the trabecular bone. The area ratio is obtained, and then a computer image equivalent to this trabecular bone area ratio is displayed, and this image is compared at least with the bone quality image of a healthy person of the same sex and age condition of the male and female to compare the bone of the subject. A method for evaluating osteoporosis by ultrasonic waves, which is characterized in that the part where the beam is reduced is displayed in different colors. [Equation 8] 6. An ultrasonic transmitting / receiving means for transmitting ultrasonic waves to the calcaneus or patella of a subject, and propagation speed information of ultrasonic waves transmitted through the inside of the bone by the ultrasonic transmitting / receiving means to determine the cancellous bone inside the bone. A means for calculating the trabecular bone area ratio, a means for drawing an image equivalent to the trabecular bone area ratio of the subject obtained by the calculating means, and means for displaying the drawn image on a display,
Separately, from the standard data of the trabecular bone area ratio of the cancellous bone of the calcaneus or patella based on the sex and age of the male and female of the healthy person prepared in advance, the data of the trabecular bone area ratio under the same conditions as the subject, sex and age Means for displaying the images of both the subject and the healthy subject on the same screen as the display for displaying the drawing image of the trabecular bone area ratio of the subject, and for displaying the different portions of the two in different colors An apparatus for evaluating osteoporosis by ultrasonic waves, which comprises: