KR101197923B1 - Measuring method and device of cortical bone thickness by using pulse-echo ultrasound - Google Patents

Abstract

The present invention relates to a method of measuring cortical bone thickness using pulse-echo ultrasound. The present invention provides a technique for calculating the thickness of the cortical bone of the bone by using the time difference in which the detected echo ultrasound is received by detecting the echo ultrasonic waves reflected by the time difference by injecting the ultrasonic pulse to the bone. According to the present invention, it is possible to accurately diagnose osteoporosis at an early stage by measuring the thickness of cortical bone by applying ultrasound to the tibia. It also has the advantage of not irradiating harmful radiation to the human body. In addition, the measurement method is simple and the measurement time is short, and the result can be quickly known.

Description

Cortical bone thickness measurement method using pulse-eco ultrasound and its apparatus {MEASURING METHOD AND DEVICE OF CORTICAL BONE THICKNESS BY USING PULSE-ECHO ULTRASOUND}

The present invention relates to a method of measuring cortical bone thickness using pulse-echo ultrasound.

Osteoporosis is defined as a systemic bone disease in which bone fractures easily occur due to bone loss due to bone loss and microstructure destruction of bone tissue. In addition, severe osteoporosis will cause the appearance of gums. Estrogen, a hormone that increases calcium absorption and prevents calcium from escaping from bone, is particularly pronounced in women because it suddenly decreases after menopause. Osteoporosis can also be caused by.

Diagnosis of such osteoporosis includes simple X-ray imaging, dual energy X-ray absorptiometry, quantitative ultrasound technology, and quantitative computed tomography. .

X-ray diagnosis of osteoporosis can be used to diagnose bone loss due to osteoporosis at a relatively low cost. However, at least 30% or more of the bone loss occurs after the diagnosis is possible to diagnose osteoporosis early, and there is a problem that can be harmful to the human body due to irradiation.

Dual-energy X-ray absorptiometry is similar to simple X-ray imaging. It is a method of measuring bone density per unit area of vertebrae using low energy and high energy radiation. Irradiation can have a harmful effect on the human body.

Quantitative ultrasound technology is a method for diagnosing osteoporosis using ultrasound, and compared to X-ray osteoporosis diagnosis, there is little risk to the human body, and there is an advantage in that it is easy to use and inexpensive. Quantitative ultrasound technology diagnoses osteoporosis by indirectly measuring bone density by penetrating ultrasound through the calcaneus (elbow bone) of the human body consisting of cancellous bone.

Quantitative computed tomography (CT) is a device capable of comparing and quantifying the bone density of patients by installing and photographing an assistive device in which a reference material showing progressively high density from low density is installed in an existing tomography camera installed in many hospitals. However, there are disadvantages in that the measurement time is long, the accuracy is low in the elderly, and the radiation dose is large.

In the past, osteoporosis was diagnosed by showing the findings on X-rays only after a fracture of the thigh, radial or spine occurred or after severe bone loss occurred. In the case of late diagnosis of osteoporosis, most of the treatment effects could not be expected even if the treatment was started. Therefore, the prevention of osteoporosis has been emphasized, and the development of appropriate diagnostic techniques for early detection of osteoporosis was required.

In addition, it is possible to diagnose osteoporosis using the above methods, but there is a problem that it is harmful to the human body or difficult to accurately diagnose osteoporosis. In addition, the bone density of the cortical bone, which is the first occurrence of fracture, cannot be measured accurately. The diagnosis is limited.

The present invention has been made in order to solve the above-mentioned problems and to provide a technology capable of accurately diagnosing osteoporosis without harmful effects on the human body by not irradiating radiation.

In order to achieve this object, in one aspect of the present invention, a cortical bone thickness measurement method using pulse-echo ultrasound includes: a step of injecting ultrasound pulses into a bone; Detecting the echo ultrasonic waves reflected from the bone at a time difference; And calculating a thickness of the cortical bone of the bone by using a time difference at which the echo ultrasound detected in the step B is received. Characterized in that it comprises a.

And a step D for outputting a result calculated in the step C; And further comprising:

At this time, the frequency of the ultrasonic pulse of step A is characterized in that 2MHz ~ 10MHz.

In addition, the operation in the step C is the following equation

(Where Δt is the time until the ultrasound pulse is transmitted in step A and the echo ultrasound is received in step B, and v is the traveling speed of the ultrasound in the cortical bone.).

The echo ultrasound detected in the step B is characterized in that the ultrasonic wave is first reflected after the ultrasonic pulse incident in the step A.

And cortical bone thickness measurement apparatus using pulse-eco ultrasound is incident portion for injecting ultrasound to the bone; A detector for detecting echo ultrasonic waves reflected from the bone at a time difference; And a calculating unit calculating a thickness of the cortical bone of the bone by using a time difference at which the echo ultrasonic waves sensed by the detecting unit are received. Characterized in that it comprises a.

In addition, an output unit for outputting a result calculated by the operation unit; And further comprising:

At this time, the frequency of the ultrasonic pulse incident the incident portion is characterized in that 2MHz ~ 10MHz.

The calculation in the operation unit is the following equation

(Where Δt is the time from transmitting the ultrasonic pulse at the incidence portion to receiving the echo ultrasonic wave at the sensing portion and v is the traveling speed of the ultrasonic waves in the cortical bone).

The echo ultrasonic wave detected by the sensing unit is characterized in that the ultrasonic wave is first reflected after the ultrasonic pulse incident from the incident unit.

As described above, according to the present invention, it is possible to accurately diagnose osteoporosis at an early stage by measuring the thickness of cortical bone by applying ultrasound to the cortical bone of tibia.

It also has the advantage of not irradiating harmful radiation to the human body.

In addition, the measurement method is simple and the measurement time is short, and the result can be quickly known.

1 is a block diagram showing an apparatus for measuring cortical bone thickness using pulse-echo ultrasound according to an embodiment of the present invention.
Figure 2 shows an example of the use of the cortical bone thickness measurement apparatus using pulse-eco ultrasound in accordance with an embodiment of the present invention.
3 is a flowchart illustrating a cortical bone thickness measurement method using pulse-echo ultrasound according to an embodiment of the present invention.
Figure 4 illustrates the appearance of echo ultrasound reflected at the interface between the cortical bone and bone marrow in the embodiment of the present invention.
FIG. 5 is a graph illustrating a time at which the reflected echo ultrasound is received in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, but the well-known technical parts will be omitted or compressed for brevity of description.

In the embodiment of the present invention, a pulse-echo method is used to measure the thickness of the cortical bone constituting the outer shell of long bone such as tibia.

Ultrasound refers to an area of sound having a frequency of 20 kHz to 20,000 kHz or more, which is a frequency range that can be heard by a human. Ultrasonic waves are inherently the same as sound waves in the audible range, but because they are large in frequency, short in wavelength, and have strong vibrations at the top, they are not seen in normal sound. Medical ultrasound usually uses from 1 MHz to 20 MHz and can vary in power and range depending on the purpose.

The principle of ultrasonography is based on the fact that solids are excellent mediators of ultrasound. In the same principle as a fish finder or radar, ultrasonic waves generated by a transducer and transmitted into the material are reflected back to the transducer by reflecting from a material boundary or internal defect, ie, a gap, penetration of another material, or disconnection.

The ultrasonic transducer contains piezoelectric crystals (materials whose properties change in shape and size when electricity is applied and conversely, when they change shape and size), which are formed of numerous dipoles arranged in a geometric form. If an instantaneous voltage is applied, the thickness of the crystals changes (vibrates), generating ultrasonic waves. When a short pulse of ultrasound is emitted into the body, the pulse travels through the tissue at a constant rate until it meets any reflective surface in the body. When hitting the reflective surface, part of the ultrasonic wave is reflected toward the sound source, which is an echo. The rest continues until it meets the next reflecting surface.

The interaction of ultrasound with tissues can be roughly classified into reflection, refraction, and absorption, of which reflection is the basis of ultrasound. Reflection, or echo generation, occurs at the interface between tissues of different properties (called the ultrasonic interface), creating an interface even with very small differences in density. Water, blood cells, fat, hepatocytes, bile, bile duct walls and connective or fibrous tissues all have different densities to create interfaces.

Mature bone is composed of cortical bone, spongy bone, periosteum, endosteum, and the like. If you look at the cross section of the bone, there are a lot of fine pores, and a little rougher than the outside, the inner bone is called spongy bone, and the hard outer part is called cortical bone.

In the embodiment of the present invention to measure the cortical bone thickness of the tibia, which can increase the accuracy of the measurement compared to the conventional spongy bone density of the calcaneus. In addition, the accuracy of diagnosis of osteoporosis can be improved by measuring the thickness of cortical bone, which is the site where the fracture actually occurs.

< Description of the device >

1 is a block diagram showing an apparatus for measuring cortical bone thickness using pulse-echo ultrasound according to an embodiment of the present invention.

As shown in FIG. 1, the cortical bone thickness measuring apparatus using pulse echo echo according to an exemplary embodiment of the present invention includes an incident part, a sensing part, a calculating part, and an output part.

At the incident portion, ultrasonic waves are incident into the tibia. At this time, the incidence portion is preferably in close contact with the tibia so as to make accurate measurements. In an embodiment of the present invention, an ultrasonic wave having a frequency of 2 MHz to 10 MHz is used to measure the thickness of thin cortical bone among ultrasonic waves of 1 MHz to 20 MHz that are generally used for diagnosis.

The detector detects echo ultrasonic waves from which ultrasonic waves incident from the incident portion are reflected. In this case, the echo ultrasound refers to the reflected ultrasound which is first detected after the ultrasound incident. The reason for this is as follows. Ultrasound incident on the tibia proceeds by reflecting or transmitting at various interfaces inside the tibia as shown in FIG. 4 (Δt, t ₁ , t ₂ ). This is because the value to be obtained in the embodiment of the present invention is a signal reflected by the density difference between the cortical bone and bone marrow, the interface where the incident ultrasonic waves first meet.

The calculator calculates the thickness of the cortical bone using the reflected echo to diagnose osteoporosis or predict the fracture rate. At this time, the following [Equation 1] is used for the calculation.

Where Δt is the time from the ultrasound incidence to the detection of the echo ultrasound, and v is the velocity of the ultrasound in the cortical bone. In the embodiment of the present invention, it is assumed that the traveling speed of the ultrasound in the cortical bone is 4000m / s. The speed of the ultrasonic wave is determined according to the nature and density of the medium irrespective of the frequency. Table 1 shows the speed at which the ultrasonic wave proceeds in various media.

Rate of progress of ultrasound in different media medium Speed (m / s) air  330 Water (20 ℃) 1480 lead 2400 aluminum 6422 Adipose tissue 1450 Soft tissue 1540 brain 1541 liver 1549 blood 1570 The lens of the eye 1620 skull 4080 Teflon 1340

The output unit outputs the information calculated by the operation unit to an external device. In other words, it is connected to an external oscilloscope to detect the reception time of the detected echo reflected from the interface between the cortical bone and bone marrow through the oscilloscope.

Information output from the output unit is Δt, arithmetic results, osteoporosis determination results, and the like. The determination of osteoporosis is somewhat controversial, but is usually based on criteria set out by the World Health Organization (WHO). That is, it is evaluated by the difference in the measured value (T-score) compared to the average bone density of healthy adults (20-29 years old) who have secured the maximum bone density. Osteoopenia is determined when the T-score shows low bone density from -1 to -2.5, and osteoporosis is determined when the bone density is lower than -2.5.

< Description of the method >

3 is a flowchart illustrating a cortical bone thickness measurement method using pulse-echo ultrasound according to an embodiment of the present invention. A description will be given with reference to FIGS. 1 and 2, but for convenience.

1.Step of entering <S301>

In step S301, the ultrasonic wave is incident to the inside of the tibia, and at this time, it is preferable to make an accurate measurement by closely contacting the incident portion perpendicular to the tibia. In the embodiment of the present invention, ultrasonic waves having a frequency of 2 MHz to 10 MHz are used.

2. Detection step <S302>

In step S302, the ultrasonic wave incident to the tibia detects echo ultrasonic waves reflected from the interface by the density difference between the cortical bone and the bone marrow in the tibia.

3. Operation step <S303>

In step S303, the thickness of the cortical bone is calculated using echo ultrasound detected in step S302 to diagnose osteoporosis or predict fracture rate. In this case, Equation 1 is used for the calculation.

4. Output stage <S304>

In step S304, the information calculated in step S303 is output to an external device. The output information is Δt, arithmetic results, osteoporosis determination results and the like.

According to this embodiment of the present invention, by measuring the thickness of the cortical bone using the time from the ultrasound to the tibia to detect the echo ultrasound, it is possible to accurately diagnose osteoporosis early.

As described above, the detailed description of the present invention has been made by the embodiments with reference to the accompanying drawings. However, since the above-described embodiments have only been described with reference to preferred examples of the present invention, the present invention is limited to the above embodiments. It is not to be understood that the scope of the present invention will be understood by the claims and equivalent concepts described below.

100: cortical bone thickness measurement apparatus using pulse-eco ultrasound
110: incident part 120: detection part
130: calculator 140: output unit
200: oscilloscope
C: Cortical bone M: Bone marrow

Claims (10)

Contacting an incident part for injecting ultrasonic waves into the tibia so as to be perpendicular to the tibia, and injecting ultrasonic pulses into the tibia in a frequency band between 2 MHz and 10 MHz;
Step B for detecting the echo echo first reflected after the ultrasonic pulse incident in step A; And
Calculating a thickness of the cortical bone of the tibia by using a time difference at which the echo ultrasound detected in the step B is received; Including,
The operation in the step C is characterized by using the following equation
[Mathematical Expression]

(Where Δt is the time from transmitting the ultrasonic pulse in the A stage to receiving the echo ultrasonic wave, which is the first detected ultrasonic wave in the B stage, and v is the speed of the ultrasonic wave in the cortical bone.)
Cortical bone thickness measurement method using pulse echo echo ultrasound. The method of claim 1,
A D step of outputting a result calculated in the C step; &Lt; RTI ID = 0.0 &gt;
Cortical bone thickness measurement method using pulse echo echo ultrasound. delete delete delete An incidence portion that is in close contact with the tibia and is incident on the inside of the tibia to inject ultrasonic pulses in a frequency band between 2 MHz and 10 MHz;
A detector configured to detect echo ultrasonic waves reflected first after the ultrasonic pulse is incident on the incident portion; And
A calculating unit calculating a thickness of the cortical bone of the tibia using a time difference at which the echo ultrasonic waves sensed by the detecting unit are received; Including,
The calculation in the operation unit is characterized by using the following equation
[Mathematical Expression]

(Where Δt is the time until the ultrasonic wave is transmitted from the incidence part to receive echo ultrasonic wave, which is the first detected ultrasonic wave in the detection part, and v is the speed of the ultrasonic wave in the cortical bone)
Cortical bone thickness measurement apparatus using pulse echo echo ultrasound. The method according to claim 6,
An output unit for outputting a result calculated by the operation unit; &Lt; RTI ID = 0.0 &gt;
Cortical bone thickness measurement apparatus using pulse echo echo ultrasound. delete delete delete

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