JP5346555B2 - Ultrasound diagnostic device with arteriosclerosis risk display function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus accurately determining a risk of arteriosclerosis through multiple observation by displaying the IMT (Intima Media Thickness) together with the elasticity index of a blood vessel. <P>SOLUTION: The ultrasonic diagnostic apparatus includes: an ultrasonic probe 101 for transmitting ultrasonic waves to a subject and outputting receiving signals by receiving ultrasonic echo reflected from the subject; a receiving circuit 115 for generating image data representing ultrasonic images related to the blood vessel of the subject; an IMT calculating means 123 for measuring the IMT of the blood vessel based on the image data generated by the receiving circuit; an elasticity index measuring means 131 for calculating the elasticity index of the blood vessel based on the image data generated by the receiving circuit: and a display means 105 for displaying the two-dimensional coordinate system with the IMT displayed in a first coordinate axis and the value indicating the elasticity index of the blood vessels displayed in a second coordinate axis. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention provides an ultrasonic diagnosis having a function of displaying a measurement result of an intima media thickness (IMT) of a blood vessel and an elasticity index together so that an arteriosclerosis risk can be easily determined. Relates to the device.

In recent years, there has been a rapid increase in the number of patients treated for cardiovascular diseases such as ischemic diseases such as cerebral infarction, myocardial infarction or angina. In order to prevent these diseases, it is important to detect signs of arteriosclerosis early and improve lifestyle, and the Ministry of Health, Labor and Welfare has introduced a system such as mandatory metabolic syndrome screening.
As a method for noninvasively measuring the arteriosclerotic state, pulse wave velocity (PWV) and intima-media complex thickness (IMT) measurement by carotid artery echo are common, and clinical The diagnostic value is also revealed.

  IMT is the thickness of the arterial wall having a three-layer structure composed of an intima, an intima and an adventitia. The length to the boundary with the outer membrane). Recent studies have shown that the intima-media complex becomes thicker and plaques are formed as arteriosclerosis progresses. Here, the plaque is a portion where the blood vessel wall bulges inward. There are various plaque tissues such as thrombus, fatty or fibrous tissue, and the exfoliated plaque causes carotid artery stenosis, cerebral infarction, cerebral ischemia, and the like.

  IMT can be measured by ultrasonography (carotid ultrasound). That is, the ultrasonic probe is brought into contact with the neck of the subject (patient), and ultrasonic waves are transmitted from the ultrasonic probe. Ultrasound is reflected at the surface of the structure in the subject (an interface between different tissues), so that the resulting ultrasound echo is received by the ultrasound probe, and an ultrasound image is generated based on the received signal. Is done. Here, the IMT in the carotid artery is measured because the carotid artery is a blood vessel branching portion between the external carotid artery connected to the facial artery and the internal carotid artery connected to the cerebral artery, or a blood intake portion into the carotid artery. This is because plaque is easily formed in a region where the direction of flow changes, and becomes a site where arteriosclerosis occurs frequently.

  FIG. 9 shows an example of an ultrasonic image showing a blood vessel wall in a normal state, and FIG. 10 shows an example of an ultrasonic image showing a blood vessel wall whose film thickness is increased by plaque. The IMT can be obtained by determining the boundary of the blood vessel wall from the generated ultrasonic image and measuring the thickness using calipers or the like. Furthermore, the examiner (operator such as a doctor) diagnoses the degree of arteriosclerosis based on the IMT, and estimates the vascular condition of the whole body including the heart and brain based on the result.

FIG. 11 is a graph showing the relationship between IMT and the risk of stroke shown by O'Leary DH et al. IMT has a clear correlation with the stroke risk rate, and it can be seen that the stroke risk rate increases rapidly when the IMT is 1.1 mm or more.
However, IMT is an index indicating only the morphological change of the carotid artery, and does not represent the dynamic characteristics of the blood vessel. Therefore, it is not appropriate to evaluate the degree of arteriosclerosis alone.

  On the other hand, the pulse wave velocity (PWV) measures the time of heart contraction, detects the carotid artery pulse wave and femoral artery pulse wave from the body surface, and determines the propagation time from the heart contraction to the generation of the pulse wave. The calculated speed is a parameter that represents the stiffness of the artery. The progression of arteriosclerosis can be quantitatively diagnosed using PWV, and the age of blood vessels can also be estimated. With the emphasis on preventive medicine, PWV has attracted attention as a new preventive medical index that represents the dynamic properties of blood vessels.

In recent years, diagnostic devices that easily measure PWV from the pulse waves of the arms and ankles are commercially available. Furthermore, an instrument is also provided that displays a cardiac ankle vascular index (CAVI) that presents a stiffness parameter β, which is the vascular elasticity itself, by measuring PWV.
FIG. 12 is a graph showing changes in the stiffness parameter β by age, presented by Hiroshi Furudate et al. It can be seen that the stiffness parameter β increases as the age increases regardless of gender.
Furthermore, methods for obtaining elasticity indices such as stiffness parameter β, blood vessel diameter change rate, and elastic modulus by calculating the displacement of the blood vessel wall from the carotid artery echo have been developed and are expected to be applied to diagnosis.

  Patent Document 1 discloses a method for determining a blood vessel age only from a moving image of dilation / contraction deformation. The disclosed method is, for example, the difference between the vascular diameter difference between the maximum dilation and the maximum contraction of the arterial vasculature divided by the vascular diameter at the time of maximum expansion divided by the time lag as the arteriosclerosis coefficient. Collect and store comparison information based on the correlation with the arteriosclerosis coefficient, calculate the arteriosclerosis coefficient of the subject and express the percentage of the average arteriosclerosis coefficient at the same age as a percentage The age standard ratio is used, and the diagnosis result of the subject is displayed based on the age standard ratio. By comparing the degree of arteriosclerosis with an average person of the same age, there is an effect of improving the awareness of the risk of developing arteriosclerosis and increasing the willingness to improve lifestyle habits. FIG. 13 is a graph showing the correlation between arteriosclerosis coefficient and age, which is a parameter indicating the mechanical properties of arterial blood vessels, disclosed in Patent Document 1. From this graph, the age dependence of the arteriosclerosis coefficient is clearly observed.

  In Patent Document 2, a tomographic image of a blood vessel is created with ultrasonic waves, the displacement of the blood vessel wall is calculated on the measurement line, the blood flow velocity is calculated with a sample gate based on the measurement line, and the wave intensity is calculated from this. An apparatus for calculating a city WI is disclosed. The WI serves as an index for discriminating which of the forward pulse wave from the heart to the periphery and the reflected pulse wave from the periphery to the heart is dominant, and the pressure and blood flow at a local site in the artery. It is obtained as a product of a change in speed at a predetermined time or a product of a time differential value of blood pressure at a local site and a time differential value of blood flow velocity. WI can be used as a blood vessel elasticity index for evaluating blood vessel properties, heart function, and the like.

Further, Patent Document 3 discloses an ultrasonic diagnostic apparatus that obtains local blood pressure using the stiffness parameter β. The stiffness parameter β is a coefficient relating to a change in blood pressure in the blood vessel and a change in blood vessel cross-sectional area or blood vessel diameter, and is a blood vessel elasticity index representing the hardness of the blood vessel.
It is recognized that the IMT indicating the morphological change of the blood vessel and the parameter (elasticity index) indicating the hardness of the blood vessel have a positive correlation with arteriosclerosis, but they do not always coincide with each other. That is, there are patients whose blood vessel dynamic changes are not smooth even if the IMT is thin, and conversely, there are patients whose blood vessel dynamic changes are large even if the IMT is thick. For this reason, there is a problem that the risk of developing arteriosclerosis cannot be estimated correctly, even if only the diagnosis of IMT or the diagnosis of only the elastic index indicating the dynamic properties of the blood vessels is required, and both must be observed in a composite manner. .
Japanese Patent No. 3882084 Japanese Patent No. 3464185 Japanese Patent No. 4091365

  Therefore, in view of the above points, an object of the present invention is to provide an ultrasound diagnostic apparatus capable of accurately determining the risk of developing arteriosclerosis through combined observation by displaying IMT and a blood vessel elasticity index together. To do.

  In order to solve the above problem, an ultrasonic diagnostic apparatus according to one aspect of the present invention transmits an ultrasonic wave toward a subject and outputs a reception signal by receiving an ultrasonic echo reflected from the subject. Generated by the ultrasonic probe, image data generating means for generating image data representing an ultrasonic image related to the blood vessel of the subject, based on the reception signal output from the ultrasonic probe, and generated by the image data generating means A value indicating an elasticity index of the blood vessel based on the image data generated by the IMT measuring means for measuring the IMT (intima-media complex thickness) of the blood vessel based on the image data and the image data generating means Elastic index measuring means, and display means for displaying a two-dimensional coordinate system in which IMT is represented on the first coordinate axis and a value indicating the elasticity index of the blood vessel is represented on the second coordinate axis.

  According to one aspect of the present invention, since the IMT of a blood vessel and the elasticity index of the blood vessel obtained based on image data representing an ultrasound image related to the blood vessel are displayed together in a two-dimensional coordinate system, the IMT and the elasticity of the blood vessel are displayed. It is possible to accurately determine the risk of developing arteriosclerosis by observing multiple indicators.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, the same referential mark is attached | subjected to the same component and description is abbreviate | omitted.
FIG. 1 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to the first embodiment of the present invention, FIG. 2 is a flowchart showing the procedure of a measurement method, and FIGS. FIG. 5 is a diagram illustrating a change state of a blood vessel wall, and FIGS. 6 and 7 are diagrams illustrating examples of display screens.

  The ultrasonic diagnostic apparatus according to the first embodiment includes an ultrasonic probe that transmits and receives ultrasonic waves, and an ultrasonic diagnostic apparatus main body. The ultrasonic diagnostic apparatus main body controls transmission / reception of ultrasonic waves and generates image data representing an ultrasonic image based on the received signal, and further, the intima-media complex thickness (IMT) of the blood vessel and the blood vessel It has a function of measuring an elasticity index indicating dynamic properties and displaying the IMT and the elasticity index on a display. The main body of the ultrasonic diagnostic apparatus has a function of storing arteriosclerosis risk comparison information serving as a material used for diagnosis, a display for displaying a diagnosis result, and a sphygmomanometer for measuring blood pressure.

  The ultrasonic probe 101 is a probe used in contact with a subject, such as a convex type, a linear scan type, or a sector scan type. The ultrasonic probe 101 includes a plurality of ultrasonic transducers constituting a one-dimensional or two-dimensional transducer array. These ultrasonic transducers transmit an ultrasonic wave toward the subject based on an applied drive signal, and output a reception signal by receiving an ultrasonic echo reflected from the subject.

  Each ultrasonic transducer is, for example, a piezoelectric ceramic represented by PZT (Pb (lead) zirconate titanate) or a polymer piezoelectric element represented by PVDF (polyvinylidene difluoride). It is constituted by a vibrator in which electrodes are formed at both ends of a piezoelectric material (piezoelectric body). When a pulsed or continuous wave voltage is applied to the electrodes of such a vibrator, the piezoelectric body expands and contracts. By this expansion and contraction, pulsed or continuous wave ultrasonic waves are generated from the respective vibrators, and an ultrasonic beam is formed by combining these ultrasonic waves. Each vibrator expands and contracts by receiving propagating ultrasonic waves and generates an electrical signal. These electric signals are output as ultrasonic reception signals.

The ultrasonic diagnostic apparatus main body includes a transmission / reception control unit 111, a transmission circuit 113, a reception circuit 115, a tomographic image formation unit 117, a display processing unit 119, an IMT measurement line setting unit 121, an IMT calculation unit 123, A measurement tracking unit 125, a blood vessel wall displacement calculation unit 127, a blood pressure measurement unit 129, a β calculation unit 131, and an arteriosclerosis risk determination unit 133 are provided.
In addition, a sphygmomanometer 103 and a display 105 are provided as peripheral devices of the ultrasonic diagnostic apparatus main body, the blood pressure measurement unit 129 captures the measurement result from the sphygmomanometer 103, and the display processing unit 119 controls the display on the display 105. To do. The arteriosclerosis risk comparison information 107 used in the arteriosclerosis risk determination unit 133 can be supplied from a storage device provided in the ultrasonic diagnostic apparatus main body.

The transmission / reception control unit 111 sequentially sets the transmission direction of the ultrasonic beam and the reception direction of the ultrasonic echo of the ultrasonic probe 101 via the transmission circuit 113 and the reception circuit 115, and according to the set transmission direction. A transmission control function for selecting a transmission delay pattern and a reception control function for selecting a reception delay pattern according to the set reception direction.
Here, the transmission delay pattern is a pattern of delay time given to the drive signal of each ultrasonic transducer in order to form an ultrasonic beam in a desired direction by ultrasonic waves transmitted from a plurality of ultrasonic transducers, The reception delay pattern is a pattern of delay time given to a reception signal in order to extract ultrasonic echoes from a desired direction by ultrasonic waves received by a plurality of ultrasonic transducers. A plurality of transmission delay patterns and a plurality of reception delay patterns are stored in the storage device, and are selected and used according to the situation.

  The transmission circuit 113 includes a plurality of channels, and generates a plurality of drive signals applied to the plurality of ultrasonic transducers. At that time, based on the transmission delay pattern selected by the transmission / reception control unit 111, each delay time can be given to the plurality of drive signals. The transmission circuit 113 may adjust the delay amounts of the plurality of drive signals and supply the ultrasonic probe 101 so that the ultrasonic waves transmitted from the plurality of ultrasonic transducers form an ultrasonic beam. Alternatively, a plurality of drive signals configured so that ultrasonic waves transmitted at a time from a plurality of ultrasonic transducers reach the entire imaging region of the subject may be supplied to the ultrasonic probe 101.

The reception circuit 115 includes a plurality of channels, receives a plurality of analog reception signals output from the plurality of ultrasonic transducers, amplifies them, and converts them into digital reception signals. Further, based on the reception delay pattern selected by the transmission / reception control unit 111, each delay time is given to a plurality of reception signals, and the reception focus processing is performed by adding the reception signals. By this reception focus processing, a sound ray signal (sound ray data) in which the focus of the ultrasonic echo is narrowed is formed.
Next, the sound ray data is subjected to envelope detection processing by low pass filter processing or the like, and depending on the distance according to the depth of the reflection position of the ultrasonic wave by STC (Sensitivity Time gain Control). Correct the attenuation.

The sound ray data thus processed is sequentially stored in a cine memory having a memory capacity for accumulating a plurality of frames of sound ray data. The receiving circuit 115 has an image data generation function, inputs sound ray data directly supplied in the live mode, and inputs sound ray data supplied from the cine memory in the freeze mode. Preprocessing processes such as log (logarithmic) compression and gain adjustment are performed on the data to generate image data, which is output to the tomographic image forming unit 117 or the IMT measurement line setting unit 121.
The tomographic image forming unit 117 converts the image data of the ultrasonic image supplied from the receiving circuit 115 into image data according to a normal television signal scanning method (raster conversion), and performs necessary image processing such as gradation processing. And transmitted to the display processing unit 119.

  On the other hand, the IMT measurement line setting unit 121 sets a ROI (region of interest) in the ultrasonic image represented by the image data supplied from the receiving circuit 115 and can determine the IMT boundary position in the depth direction in the ROI. A number of lines (sound lines) are sequentially selected, and image data in the selected lines is extracted. Fig. 3 shows the boundary between the adventitia and media in the anterior wall of the blood vessel and the boundary between the intima and the vascular cavity, and the boundary between the blood vessel and the intima in the posterior wall of the blood vessel and the boundary between the media and the adventitia It is a conceptual diagram explaining having set to the IMT measurement line. FIG. 4 is a conceptual diagram illustrating a case where a state in which plaque is formed inside the rear wall is detected. It can be seen that a part of the boundary between the posterior wall vascular cavity and the intima is raised toward the vascular cavity side.

  When the IMT measurement line setting unit 121 supplies the image data extracted for the selected line to the IMT calculation unit 123, the IMT calculation unit 123 automatically measures the IMT of the blood vessel after verifying the reliability of the image data. . For this reason, the IMT calculation unit 123 generates reference data by performing image processing such as noise suppression processing using a low-pass filter or a median filter on the extracted image data. The reference data generated from the image data is stored in a predetermined storage device in association with the patient information and examination information, or the age and sex of the patient. Further, typical reference data may be stored in advance according to the age and sex of the patient.

  Further, reference data stored in the storage device or reference data generated from the extracted image data is selected as reference data to be actually used in accordance with the operator's operation or the automatic operation procedure of the apparatus. An evaluation region (region in the depth direction) for evaluating the reliability of IMT measurement is set from the ROI set for the image, and the reliability of IMT measurement in the set region is calculated. For example, after aligning the depth direction positions of the image data and the reference data in the set evaluation area, along the predetermined number of lines in the depth direction in the set area, the difference between the image data and the reference data The reliability of IMT measurement can be calculated by integrating the absolute values of the two or obtaining the variance value of the difference. Further, the reliability of the IMT measurement is determined by comparing the calculated reliability value of the IMT measurement with a threshold value.

  When it is determined that the reliability of the IMT measurement in the set evaluation region is good, the IMT calculation unit 123 automatically performs the IMT of the blood vessel using the image data obtained in the selected line in the evaluation region. measure. In carotid ultrasonography, a blood vessel diameter and a max (maximum) IMT are measured, and a mean (average) IMT is calculated to accurately determine the size of deposits such as plaque. This meanIMT is obtained, for example, by obtaining maxIMT and IMT at positions A and B 1 cm on both sides thereof and calculating an average value {maxIMT + IMT (A) + IMT (B)} / 3 of these three points. The IMT thus determined is transmitted to the arteriosclerosis risk determination unit 133.

  In addition, the IMT measurement line with high IMT measurement reliability set by the IMT measurement line setting unit 121 may be a reference line used for automatic tracking of the blood vessel wall displacement waveform and the blood vessel diameter by the measurement line tracking unit 125. it can. The measurement line tracking unit 125 sets a specific point of the set IMT measurement line as a tracking target, performs image processing on the image data, automatically identifies and tracks the line, and tracks changes in the blood vessel wall position. There are various methods for tracking a measurement line, such as a tomographic pattern matching method, a zero cross point method, a tissue Doppler method, and a phase difference tracking method, but it goes without saying that any method may be used.

In the image data, since the blood vessel cavity generally has a low signal level, it is likely to cause tracking failure. Therefore, an object that has been moved substantially parallel to the outer membrane side from the IMT measurement line may be used as a tracking target. Thus, by setting the tracking start line based on the IMT measurement line, the measurement time can be shortened, and the load on the doctor or the like can be reduced.
Furthermore, Dd / Ds can also be measured by drawing a line between the systolic position and the diastolic position of the blood vessel. The vascular wall displacement calculation unit 127 calculates a systolic blood vessel diameter Ds and a diastolic blood vessel diameter Dd based on the vascular wall displacement waveform.

FIG. 5 is a drawing showing changes in the blood vessel wall along the time axis. The blood vessel diameter D has a maximum value Ds during the systole and a minimum value Dd during the diastole. The blood vessel wall displacement calculation unit 127 tracks the change in the blood vessel diameter D from the image data, obtains the maximum blood vessel diameter Ds and the minimum blood vessel diameter Dd, and transmits them to the β calculation unit 131.
On the other hand, the blood pressure P measured by the cuff sphygmomanometer 103 takes the maximum value Ps and the minimum value Pd corresponding to the contraction and dilation of the heart, respectively, so that it can be easily read from the maximum value and the minimum value of the blood pressure indication values. it can. These blood pressure data are automatically or manually input to the blood pressure measurement unit 129 and further transmitted to the β calculation unit 131.

The β calculation unit 131 calculates the stiffness parameter β from β = {Log (Ps / Pd)} / (Ds / Dd−1) and transmits it to the arteriosclerosis risk determination unit 133.
The arteriosclerosis risk determination unit 133 determines the arteriosclerosis risk by considering the input stiffness parameter β and the IMT provided from the IMT calculation unit 123 in combination. Here, as shown in FIG. 6, a two-dimensional coordinate system is prepared in which IMT is represented on the first coordinate axis and stiffness parameter β is represented on the second coordinate axis, and the degree of arteriosclerosis risk is classified into large, medium and small on the IMT-β plane. A method of recognizing the risk of arteriosclerosis by displaying the state of the patient's blood vessel on the IMT-β plane can be adopted.

The arteriosclerosis risk is determined by evaluating the results measured for a large number of subjects and stored in the storage device as the arteriosclerosis risk comparison information 107, and the arteriosclerosis risk determination unit 133 determines the determination at the time of determination. Use it by removing it from the storage device.
The arteriosclerosis risk comparison information 107 may set information classified according to blood vessel age as shown in FIG. The blood vessel age is determined by adopting an average index value for the age group from the measurement results of a large number of subjects. Moreover, you may follow the index value in the boundary which can determine with a healthy person.
The formed two-dimensional coordinate system graph is supplied to the display processing unit 119.

The display processing unit 119 generates display image data based on the image data supplied from the tomographic image forming unit 117 and the graph of the two-dimensional coordinate system input from the arteriosclerosis risk determination unit 133. Note that the display processing unit 119 may be provided with an image processing function for performing image processing such as linear gradation processing including gain adjustment and contrast adjustment, and nonlinear gradation processing including γ correction. Further, a D / A converter is provided, and the display image data is converted into an analog image signal and output to the display 105. The display 105 is, for example, a raster scan type LCD display, and based on the image signal analog-converted by the display processing unit 119, a moving image or still image of an ultrasonic image, or two-dimensional coordinates in which IMT and β are plotted. Display graphs and so on.
Doctors and subjects can intuitively determine the risk of developing arteriosclerosis from the combined state of vascular morphological information (IMT) and elasticity index (stiffness parameter β) using the two-dimensional coordinate graph displayed on the display 105. It can be recognized accurately.

Next, the operation of the ultrasonic diagnostic apparatus according to the first embodiment of the present invention will be described based on the flowchart of FIG.
First, in step S1, it is confirmed that the moving image of the carotid tomogram displayed on the display 105 has been stably acquired, and the freeze button is pressed. Then, a moving image from about several beats before pressing the freeze button (about 3 seconds) to the present is stored in the memory, and the first frame stored is displayed on the screen of the display 105 (step S2).

Further, the maximum blood pressure obtained with the cuff type sphygmomanometer is input manually or online as the systolic pressure Ps and the minimum blood pressure is used as the diastolic pressure Pd (step S3).
As shown in FIG. 3, the IMT measurement line setting unit 121 sets an IMT measurement line in the tomographic image (step S4). The measurement tracking unit 125 tracks the IMT measurement line using the first image to the image at the time when the freeze button is pressed (step S5), and obtains the blood vessel wall displacement waveform as shown in FIG. The vascular wall displacement calculation unit 127 calculates the systolic blood vessel diameter Ds and the diastolic blood vessel diameter Dd from the vascular wall displacement waveform (step S6).

In step S <b> 7, the β calculation unit 131 determines that the following expression β = {Log (Ps / Pd)} / (Ds / Dd−1)
Is used to calculate the stiffness parameter β. Note that the value of β is preferably an average value on the sound ray line obtained by subtracting the IMT measurement line, but there is no significant influence even if it becomes a specific one sound ray line due to constraints such as calculation time.

  On the other hand, the IMT calculation unit 123 takes in the image data obtained in the IMT measurement line set in step S4, and automatically measures the IMT of the blood vessel (step S8). In order to accurately determine the size of plaque and other deposits, for example, an average value {maxIMT + IMT (A) + IMT (B)} / 3 is calculated for three points of maxIMT and IMT at positions A and B 1 cm on both sides thereof. The meanIMT obtained in this way is used.

The IMT thus obtained and the stiffness parameter β obtained by the β calculation unit 131 are plotted with respect to the first coordinate axis and the second coordinate axis, respectively, to obtain a two-dimensional display (step S9).
Finally, in step S10, the arteriosclerosis risk determination unit 133 compares the combination of IMT and β with the arteriosclerosis risk comparison information 107, and evaluates the arteriosclerosis risk of the vascular state of the subject. The evaluation blood vessel is displayed on the display 105 in the form of a graph shown in FIG. In the example shown in FIG. 6, the IMT and the elasticity index of the blood vessel are displayed in a two-dimensional coordinate system in which the stiffness parameter β, which is the elasticity index of the carotid artery related to the subject and the elasticity index of the blood vessel, is displayed with a high risk of developing atherosclerosis. Since the two-dimensional coordinates are combined and displayed, the risk of developing arteriosclerosis can be determined more accurately than the diagnosis of only IMT or the diagnosis of only β, and can be easily communicated to doctors and subjects Become.

  The graph of FIG. 6 shows, for example, the two-dimensional coordinate plane in which the risk of developing arteriosclerosis is classified into large, medium, and small ranks and the region representing the rank is displayed in different colors such as red, yellow, and blue. It is preferable to plot the coordinates represented by IMT and β so that the onset risk of the subject can be easily understood. Generally, if the elasticity index is small even if IMT is large, and if the IMT is small even if the elasticity index is large, the risk of arteriosclerosis is small. Therefore, the risk classification zone is displayed in a ring surrounding the origin.

  In addition, expressing the arteriosclerosis risk as a blood vessel age is also effective for enhancing the recognition of the onset risk. FIG. 7 shows average IMT and β with respect to age calculated from IMT and β data collected for a large number of subjects, and displays the area for each age group. Find the blood vessel age by plotting the IMT and β coordinates of the subject. For example, “Your blood vessel age is 80 years. It is possible to raise the risk compared to the actual age.

Next, a second embodiment of the present invention will be described. In the first embodiment, the stiffness parameter β is used as a blood vessel elasticity index, but the same can be said by using a blood vessel diameter change, elastic modulus, and WI (wave intensity). The second embodiment uses an elastic modulus as a blood vessel elasticity index.
FIG. 8 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to the second embodiment. Since only the β calculation unit 131 in FIG. 1 is replaced with the elastic modulus calculation unit 132, the other components are not changed. Therefore, the same components are denoted by the same reference numerals, and description thereof is omitted.

In the case of the second embodiment using the elastic modulus as the elasticity index of the blood vessel, the measurement line tracking unit 125 also tracks the IMT measurement line at the boundary between the anterior wall and the lining of the posterior wall and the media, and the IMT of one heartbeat. The maximum value Td and the minimum value Ts are obtained, and the following equation E = (Ps−Pd) / {(Td−Ts) / Td}
Further, the elastic modulus E is obtained. In this case, since the measurement location of the elastic modulus E is automatically limited to the inside of the IMT, there is an advantage that it becomes stable elastic modulus data without dependency on the measurement location and can be easily compared with other measurement data.

When a more advanced algorithm is used, the elastic modulus of each region may be measured by dividing the inner membrane IMT measurement line and the outer membrane-media boundary IMT measurement line.
As described above, the operation of the measurement processing unit shown in FIG. 8 is different from that of the first embodiment, and the other points are the same as those of the first embodiment.

In the case of an embodiment using WI (wave intensity) as a blood vessel elasticity index, the product of the time derivative of blood pressure P and the time derivative of blood flow velocity U is calculated by replacing the modulus calculator with the WI calculator. You just have to do it. The blood flow velocity U can be obtained in the carotid artery with a Doppler measuring instrument using an ultrasonic probe.
In the case of an embodiment that uses a change in blood vessel diameter as a blood vessel elasticity index, only the procedure around the sphygmomanometer is excluded from the above, and there is no other change. The change in blood vessel diameter can be obtained from an ultrasonic image of the blood vessel.

  In the above embodiment, the transmission / reception control unit 111, the tomographic image generation unit 117, the display processing unit 119, the IMT measurement line setting unit 121, the IMT calculation unit 123, the measurement line tracking unit 125, the blood vessel wall displacement calculation unit 127, and the blood pressure measurement unit 129. , Β calculation unit 131, elastic modulus calculation unit 132, arteriosclerosis risk determination unit 133, and the like are configured by a central processing unit (CPU) and software for causing the CPU to perform various processes. You may comprise with a circuit or an analog circuit. The software is stored in a storage unit (not shown).

  The present invention generates ultrasonic image data by transmitting an ultrasonic wave toward a subject and receiving an ultrasonic echo reflected from the subject, and has a function of measuring IMT of a blood vessel. In the ultrasonic diagnostic apparatus, the risk of developing arteriosclerosis can be more accurately and highly recognizable to the subject.

1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. It is a flowchart which shows the procedure of the measuring method which concerns on the 1st Embodiment of this invention. It is a conceptual diagram explaining the condition which sets an IMT measurement line from an ultrasonic image. It is a conceptual diagram explaining the condition which sets an IMT measurement line when a plaque exists in an ultrasonic image. It is a diagram explaining the change state of the blood vessel wall obtained by tracking. It is drawing which shows the display screen which displayed the combination coordinate of IMT and (beta) on the two-dimensional coordinate which displayed the degree of the arteriosclerosis risk zone. It is drawing which shows the display screen which displayed the combination coordinate of IMT and (beta) on the two-dimensional coordinate which displayed the blood vessel age in the zone. It is a flowchart which shows operation | movement of the ultrasonic diagnosing device which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the procedure of the measuring method which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of the ultrasonic image which shows the blood vessel wall at the time of normal. It is a figure which shows the example of the ultrasonic image which shows the blood vessel wall from which the film thickness became large by the plaque. It is a graph showing the relationship between IMT and stroke risk rate. It is a graph which shows the change according to the age of the stiffness parameter β. It is a graph showing the correlation of the arteriosclerosis coefficient which shows the mechanical property of an arterial blood vessel, and age.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Ultrasonic probe 103 Blood pressure meter 105 Display 107 Arteriosclerosis risk comparison information 111 Transmission / reception control part 113 Transmission circuit 115 Reception circuit 117 Tomographic image formation part 119 Display processing part 121 IMT measurement line setting part 123 IMT calculation part 125 Measurement tracking part 127 Blood vessel wall displacement calculation unit 129 Blood pressure measurement unit 131 β calculation unit 132 Elastic modulus calculation unit 133 Arteriosclerosis risk determination unit

Claims (9)

An ultrasonic probe that transmits an ultrasonic wave toward the subject and outputs a reception signal by receiving an ultrasonic echo reflected from the subject; and
Image data generating means for generating image data representing an ultrasonic image related to a blood vessel of a subject based on a reception signal output from the ultrasonic probe;
IMT measurement means for measuring IMT (intima-media complex thickness) of blood vessels based on the image data generated by the image data generation means;
Elasticity index measuring means for obtaining a value indicating the elasticity index of the blood vessel based on the image data generated by the image data generating means;
Display means for displaying a two-dimensional coordinate system in which the IMT is represented on a first coordinate axis and a value indicating the elasticity index of the blood vessel is represented on a second coordinate axis;
An ultrasonic diagnostic apparatus comprising: Furthermore, it comprises a data storage device for storing atherosclerosis risk comparison data,
The ultrasonic diagnostic apparatus according to claim 1, wherein the atherosclerosis risk comparison data is displayed on the two-dimensional coordinate system to facilitate determination of the atherosclerosis risk.   The ultrasonic diagnostic apparatus according to claim 1, wherein a value indicating the elasticity index of the blood vessel is a stiffness parameter β.   The ultrasonic diagnostic apparatus according to claim 1, wherein the value indicating the elasticity index of the blood vessel is a blood vessel diameter change rate.   The ultrasonic diagnostic apparatus according to claim 1, wherein the value indicating the elasticity index of the blood vessel is an elastic modulus.   The ultrasonic diagnostic apparatus according to claim 1, wherein the value indicating the elasticity index of the blood vessel is WI (wave intensity).   The elasticity index measuring means obtains the elasticity index of the blood vessel by a tracking start line set based on an IMT measurement line determined by the IMT measurement means in the image data. Ultrasonic diagnostic equipment.   The ultrasonic diagnostic apparatus according to claim 7, wherein the tracking start line is the IMT measurement line.   The ultrasonic diagnostic apparatus according to claim 7, wherein the tracking start line is obtained by translating the IMT measurement line in the inner-middle membrane in the outer membrane direction.