JP2021137480A - Cardiac function parameter calculation method, method for cardiac functional evaluation, calculation program, and diagnosis system - Google Patents

Abstract

To provide a new evaluation/diagnosis technology for a cardiac function.SOLUTION: Left ventricular volume acceleration a in a cardiac contraction process is divided by left ventricular volume velocity b to obtain a value of a/b.SELECTED DRAWING: None

Description

The present invention relates to a technique for diagnosing cardiac function.

So far, based on the echocardiogram, the stroke volume, which is given as the difference between the end-diastolic volume (EDV) of the left ventricle and the end-systolic volume (ESV), is given. SV) and ejection fraction (EF) obtained by dividing SV by EDV have been clinically used as parameters that best represent left heart function (Non-Patent Documents 1 to 4).
However, these parameters were not always sufficient indicators to know the functional state of the myocardium because they did not include the time factor of cardiac contraction, which is a very important factor for the pumping function of the heart. In response to this problem, the present inventor has proved that the change in the volume of the left ventricle during the ejection period can be replaced with a quadratic curve as a function with time, and proposes a new parameter (Non-Patent Document 5).

^{In Non-Patent Document 5, the left chamber volume (D 3} ) at time (t) at three or more time points in the ejection period is calculated based on the image data acquired by using the echocardiographic M mode method, and time-left chamber. It is stated that a volume curve was created. Hereinafter, a specific description will be given.

In the study of Non-Patent Document 5, three time points of the time of the ejection start point (t ₀ ), the time of the ejection end point (t _l ), and the time of the T wave start point located at the intermediate point (t _k ) are set. setting a plurality of times (t) including, determined based on echocardiographic left ventricular volume (D ³⁾ at each time, determines the following coordinates in the phase out ejection.
^{_{(t 0, D 0 3)}} , ···, (t k, D k 3), ··· (t l, D l 3)

Then, in order to express the change in left chamber volume during the ejection period as a time function, time (t ^{) was set on the horizontal axis and left chamber volume (D 3} ) was set on the vertical axis, and the measurement was performed from the echocardiogram. When each coordinate was plotted and curve fitting was performed by the nonlinear least squares method, it was proved that it could be optimized for a quadratic function. That is, the time-left chamber volume curve can be expressed by the following equation.
f (t) = at ² + bt + c
In this equation, t is time, and f (t) represents ^{the left chamber volume (D 3) corresponding to that time.}

This expression, the above-mentioned third coordinate ^{_{(t 0, D 0 3)}} , (t k, D k 3), (t l, D l 3) following ternary simultaneous equations are obtained as substitutes.
f (t ₀ ) = c = D ₀ ^{3
_{f (t k) = at k}} 2 + bt k + c = D k 3
f (t _l ) = at _l ² + bt _l + c = D _l ³
By solving this simultaneous equation, the values of a, b, and c can be obtained.

Here, a represents the amount of change in the left chamber volume velocity per unit time, that is, the left chamber volume acceleration (cm ³ / s ² ).
Further, b represents the amount of change in the left chamber volume per unit time, that is, the left chamber volume velocity (cm ³ / s).
Further, as is clear from the above equation, c represents the ^{left ventricular volume (cm 3) at the start point (extrusion start point) of cardiac contraction.}

Am. J. Physiol. , 238, H126-Hl33, 1980. Circulation, 58, 77-89, 1978. Circ. Res. , 28, 49-61, 1971. Am. J. Cardiol. , 42,895-903.1978. Nippon Medical School, Vol. 55, No. 6 (1988)

An object of the present invention is to provide a new evaluation / diagnosis technique for cardiac function.

As a result of diligent research, the present inventor found that the value of a / b obtained by dividing the left ventricular volume acceleration a by the left ventricular volume velocity b is very useful as a new index for evaluating cardiac function. And completed the present invention.
The present invention that solves the above problems is as follows.

[1] A method for calculating a cardiac function parameter, comprising a step of obtaining a value of a / b by dividing the left ventricular volumetric acceleration a in the cardiac contraction process by the left ventricular volumetric velocity b.

[2] A method for calculating cardiac function parameters, comprising the following steps (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation process that generates ternary simultaneous equations by substituting into.
(B) A solving step of solving the three-dimensional simultaneous equations to obtain at least the values of a and b.
(C) A division step of obtaining the value of a / b by dividing a by b.

[3] The above three time points are
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
The calculation method according to [2], which is characterized by the above.

[4] Calculate the value of a / b by the calculation method according to any one of [1] to [3], and compare it with the following indexes (1-1) and / or (1-2). This is a cardiac function evaluation method for evaluating the cardiac function of a subject.
[index]
(1-1) When the value of a / b is positive, it is an index indicating that the cardiac function is deteriorated.
(1-2) When the absolute value of the a / b value is less than 1, it is an index indicating that the cardiac function is deteriorated.

[5] The value of a / b is calculated by the calculation method according to any one of [1] to [3], and one or 2 selected from the following (2-1) to (2-4). A cardiac function evaluation method that evaluates a subject's cardiac function by comparing it with an index of more than one species.
[index]
(2-1) When the value of a / b is -1.5 or less, it is an index indicating that the cardiac function is in an extremely good state.
(2-2) When the value of a / b is larger than -1.5 and -1.0 or less, it is an index that the cardiac function is slightly deteriorated.
(2-3) When the value of a / b is larger than -1.0 and 0 or less, it is an index indicating that cardiac function is mildly to moderately deteriorated.
(2-4) When the value of a / b is positive, it is an index indicating that the cardiac function is highly deteriorated.

[6] A program comprising a computer functioning as a means for obtaining a value of a / b by dividing the left ventricular volumetric acceleration a by the left ventricular volumetric velocity b in the process of cardiac contraction.

[7] A program that causes a computer to function as the means of the following (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation means that generates ternary simultaneous equations by substituting into.
(B) A solving means for solving at least the values of a and b by solving the three-dimensional simultaneous equations.
(C) A division means for obtaining the value of a / b by dividing a by b.

[8] The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
The program according to [7].

[9] A collecting unit that collects two-dimensional or three-dimensional image data related to cardiac contraction, and
It is equipped with an information processing unit that calculates cardiac function parameters based on the image data.
The information processing unit has means for calculating the left chamber volume acceleration a, the left chamber volume velocity b, and the value of a / b obtained by dividing a by b, based on the image data. , Cardiac function diagnostic system.

[10] A collecting unit that collects two-dimensional or three-dimensional image data related to cardiac contraction, and
It is equipped with an information processing unit that calculates cardiac function parameters based on the image data.
A cardiac function diagnosis system, wherein the information processing unit includes the following means (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation means that generates ternary simultaneous equations by substituting into.
(B) A solving means for solving at least the values of a and b by solving the three-dimensional simultaneous equations.
(C) A division means for obtaining the value of a / b by dividing a by b.

[11] The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
[10] The cardiac function diagnostic system according to [10].

[12] The cardiac function diagnostic system is an ultrasonic diagnostic apparatus.
The cardiac function diagnostic system according to any one of [9] to [11], wherein the collecting unit is an ultrasonic probe and the image data is an echo diagram.

[13] A collection process for collecting two-dimensional or three-dimensional image data including the heart, and
A left chamber volume information calculation step for calculating left chamber volume information regarding the left chamber volume based on the image data is provided.
The left chamber volume information is
Left chamber volumetric acceleration a and
Left chamber volume velocity b and
The value of a / b obtained by dividing a by b and
A method for diagnosing cardiac function, which comprises.

[14] A collection process for collecting two-dimensional or three-dimensional image data including the heart, and
A left chamber volume information calculation step for calculating left chamber volume information regarding the left chamber volume based on the image data is provided.
A method for diagnosing cardiac function, wherein the left chamber information calculation step includes the following steps (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation process that generates ternary simultaneous equations by substituting into.
(B) A solving step of solving the three-dimensional simultaneous equations to obtain at least the values of a and b.
(C) A division step of obtaining the value of a / b by dividing a by b.

[15] The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
[14] The method for diagnosing cardiac function.

[16] The heart according to any one of [13] to [15], wherein the collecting step is an ultrasonic inspection step of applying ultrasonic waves to an object and imaging the echoes thereof. How to diagnose the function.

[17] The method for diagnosing cardiac function according to any one of [13] to [16], wherein when the value of a / b is positive, it is diagnosed that the cardiac function is deteriorated.

[18] The method for diagnosing cardiac function according to any one of [13] to [17], wherein when the absolute value of a / b is less than 1, it is diagnosed that the cardiac function is deteriorated. ..

[19] The cardiac function according to any one of [13] to [18], which is diagnosed as having extremely good cardiac function when the value of a / b is -1.5 or less. Diagnostic method.

[20] When the value of a / b is larger than -1.5 and -1.0 or less, it is judged that the cardiac function is slightly deteriorated, and it is in any one of [13] to [19]. The described method for diagnosing cardiac function.

[21] When the value of a / b is larger than -1.0 and 0 or less, it is judged that the cardiac function is mildly to moderately deteriorated, and any one of [13] to [20]. The method for diagnosing cardiac function described in.

[22] The method for diagnosing cardiac function according to any one of [13] to [21], wherein when the value of a / b is positive, it is determined that the cardiac function is highly deteriorated.

According to the method for calculating cardiac function parameters of the present invention, new parameters that are very useful for diagnosing cardiac function can be calculated.
According to the cardiac function evaluation method of the present invention, the cardiac function of a subject can be evaluated with high accuracy.
According to the program of the present invention, it is possible to provide a computer capable of calculating new parameters that are very useful for diagnosing cardiac function.
According to the cardiac function diagnostic system of the present invention, the cardiac function of a subject can be evaluated with high accuracy.
According to the diagnostic method of the present invention, the cardiac function of a subject can be diagnosed with high accuracy.

It is a block diagram which shows the cardiac function diagnosis system of this invention.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments described below.

[Calculation method of cardiac function parameters]
The method for calculating the cardiac function parameter of the present invention includes a step of obtaining the value of a / b by dividing the left chamber volume acceleration a by the left chamber volume velocity b.

The left chamber volumetric acceleration a and the left chamber volumetric acceleration b may be obtained by any method. It is preferably obtained based on the following formula representing the time-left chamber volume curve described in Non-Patent Document 5.
f (t) = at ² + bt + c

In this equation, t represents the ejection period, that is, the time in the cardiac contraction process from the start point to the end point of the cardiac contraction. As the time t, it is preferable to use a value calculated with the start point of cardiac contraction as the starting point, that is, the time of the start point of cardiac contraction as 0 seconds.

In the present invention, the time (t) at at least three time points in the ejection period and the left chamber volume (f (t)) at the time point corresponding to the time (t) are substituted into the above equation.
Assuming that the times at the above three time points are t ₁ , t ₂ , and t ₃ , respectively, and the left chamber volumes corresponding to the respective times are f (t ₁ ), f (t ₂ ), and f (t ₃ ), the above-mentioned Substituting into the equation of, the following three-dimensional simultaneous equations are obtained.
f (t ₁ ) = at ₁ ² + bt ₁ + c
f (t ₂ ) = at ₂ ² + bt ₂ + c
f (t ₃ ) = at ₃ ² + bt ₃ + c

By solving this ternary simultaneous equation, the values a to c can be obtained. Although three values a to c can be obtained, in the present invention, it is sufficient to obtain only the values a and b.
Then, by dividing a by b to obtain the value of a / b, a cardiac function parameter useful for evaluating left ventricular function can be obtained.

The left chamber volume (f (t)) may be obtained at at least any three time points during the ejection period. In a preferred embodiment of the present invention, the left ventricular volume (f (f) t)) is used in the calculation.
As an arbitrary intermediate point, a time point of about 1/3 from the start point of the cardiac contraction period is desirable.

That is, it is preferable to use the left chamber volume (f (t)) of the following (1) to (3) for the calculation.
(1) Left ventricular volume at the starting point of cardiac contraction (t is 0 seconds) (so-called left ventricular end-diastolic volume (LVEDV))
(2) Left ventricular volume at any midpoint during ejection (3) Left ventricular volume at the end of cardiac contraction (so-called left ventricular end-system volume (LVESV))

(1) Each time the three time points of _{~ (3) t 0, t} m, is _{t l,} the left ventricular volume corresponding to each time _{f (t 0), f (} t m), f ( Substituting into the above equation, assuming that it is t _{l), the following ternary simultaneous equations are obtained.}
f (t ₀ ) = c
^{_{f (t m) = at m}} 2 + bt m + c
f ( _tl ) = at _l ² + bt _l + c
By solving this ternary simultaneous equation, the values a to c can be obtained (c is LVEDV itself). The value of a / b is calculated by dividing the obtained value of a by the value of b.

Any known method may be used to calculate the left chamber volume.
For example, a method of calculating the left chamber volume from an M-mode echo diagram or a 2D echo diagram can be mentioned. Examples of the method for obtaining the left chamber volume from the M-mode echo diagram include the Pombo method, the Teichholz method, and the Gibson method. Examples of the method of obtaining by the 2D echo method include a single plane area-length method and a modified Simpson method (disk method).
Another method is to reconstruct the ventricular cavity shape three-dimensionally using CT or MRI.

A / b, which is a cardiac function parameter calculated by the method of the present invention, is an extremely effective index. By using a / b for the evaluation / diagnosis of cardiac function, it is possible to distinguish a person with cardiac dysfunction among those having a normal left ventricular ejection fraction (EF). Therefore, it becomes possible to detect patients who will develop heart failure sooner or later.

[Cardiac function evaluation method]
The present invention also relates to a cardiac function evaluation method. The cardiac function evaluation method of the present invention uses the cardiac function parameters calculated by the above-mentioned calculation method, that is, the values of a / b.

In the case of normal cardiac function, the value of the left ventricular volume acceleration a is positive, but the value of a / b is negative in the normal state because the left ventricular volume velocity b decreases the contraction velocity.
However, in cases where cardiac dysfunction is predicted, the left ventricular volume acceleration a may show a negative value. In this case, the values of a / b are positive, and the quadratic curve of time-left chamber volume is an upward curve.
Further, when the absolute value (| b |) of the left chamber volume acceleration a and the left chamber volume velocity b is compared, most of them have a relationship of a> | b |. That is, the absolute value of a / b is larger than 1. However, in some cases where cardiac function is reduced, the relationship a << b | occurs, and in this case, the absolute value of a / b is smaller than 1.

From this, the following matters can be understood from the values of a / b.
(1-1) When the value of a / b is positive ... Cardiac function is considerably deteriorated, which is close to heart failure.
(1-2) When the absolute value of the a / b value is less than 1 ... A state in which cardiac function is deteriorated.

That is, the cardiac function of the subject can be evaluated by comparing the calculated value of a / b with the following indexes (1-1) and / or (1-2).
(1-1) When the value of a / b is positive, it is an index indicating that the cardiac function is deteriorated.
(1-2) When the absolute value of the a / b value is less than 1, it is an index indicating that the cardiac function is deteriorated.

In addition, when the findings based on the examples described later are also examined, the cardiac function can be classified into the following four stages based on a / b.

(1) When the value of a / b is -1.5 or less ... Extremely good cardiac function (2) When the value of a / b is greater than -1.5 and -1.0 or less ... -Slightly reduced cardiac function (3) When the value of a / b is greater than -1.0 and 0 or less ... A state in which cardiac function is mildly to moderately reduced.
(4) When the value of a / b is positive ... A state in which cardiac function is highly deteriorated.

Based on this four-step classification, the cardiac function of the subject can be evaluated by comparing the value of a / b with one or more indexes selected from the following (1) to (4). can.

(1) When the value of a / b is -1.5 or less, it is an index indicating that the cardiac function is in an extremely good state.
(2) When the value of a / b is larger than -1.5 and -1.0 or less, it is an index that the cardiac function is slightly deteriorated.
(3) When the value of a / b is larger than -1.0 and 0 or less, it is an index indicating that cardiac function is mildly to moderately deteriorated.
(4) When the value of a / b is positive, it is an index indicating that the cardiac function is highly deteriorated.

[Cardiac function diagnostic system]
The matters described in the item of "calculation method of cardiac function parameters" can also be applied to the embodiment of the cardiac function diagnostic system of the present invention.

The cardiac function diagnostic system of the present invention includes a collecting unit that collects two-dimensional or three-dimensional image data including the heart, and an information processing unit that calculates cardiac function parameters based on the image data (FIG. 1).

Specific forms of the cardiac function diagnostic system include an ultrasonic diagnostic device, a computed tomography device (CT device), and a magnetic resonance tomography device (MRI). Are suitable.
In the form of an ultrasonic diagnostic apparatus, the collecting unit serves as a means for transmitting and receiving ultrasonic waves (that is, an ultrasonic probe).
In the form of a computed tomography apparatus, the collecting unit includes, for example, an X-ray generating means and an X-ray detecting means.
In the form of a magnetic resonance tomography (MRI), the collecting unit includes, for example, a static magnetic field generating means, a gradient magnetic field generating means, and an NMR signal detecting means.

The two-dimensional or three-dimensional image data collected by the collecting unit may be still image data or moving image data. In the present invention, since it is necessary to calculate the left chamber volume during the ejection period at at least three time points, it is preferable to use moving image data.

When the cardiac function diagnostic system of the present invention is realized as an ultrasonic diagnostic apparatus, the image data is data related to an echo diagram.
When the cardiac function diagnosis system of the present invention is realized as a computed tomography apparatus, the image data is data related to a CT image.
When the cardiac function diagnostic system of the present invention is realized as a magnetic resonance tomography apparatus, the image data is data related to an MRI image.

The cardiac function diagnosis system of the present invention may have an image generation unit that processes image data primaryly collected from the collection unit and constructs an image (FIG. 1).
Further, a display for displaying an image constructed by the image generation unit may be provided (FIG. 1).

The cardiac function diagnostic system of the present invention includes an information processing unit that calculates cardiac function parameters based on image data.
The information processing unit controls the entire processing of the cardiac function diagnosis system. Specifically, the information processing unit processes information based on various setting requests input from the operator via the input interface, various control programs read from the storage unit, and various data.
Further, the processing unit controls the display image stored in the storage unit to be displayed on a display, a touch monitor in the input interface, or the like.
This information processing unit has means for calculating the left chamber volume acceleration a, the left chamber volume velocity b, and the value of a / b obtained by dividing a by b, based on the image data.

The information processing unit preferably includes means for calculating the left chamber volume as the basis for calculating the left chamber volume acceleration a and the left chamber volume velocity b. Further, in order to calculate the volume of the left chamber, the length of the long axis of the left chamber may be calculated.
When the cardiac function diagnostic system is configured as an ultrasonic diagnostic apparatus, the calculation of the left ventricular volume can be performed by any known method such as the Pombo method, the Teichholz method, the Gibson method, the single plane area method, or the modified Simpson method (disk method). It may be carried out by the method of.

More specifically, a means for calculating the time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction. It is preferable to provide.
Then, the time (t) and the left chamber volume (f (t)) at these three time points are set.
f (t) = at ² + bt + c
It is preferable to provide simultaneous equation generation means for generating ternary simultaneous equations by substituting each of them into (Fig. 1).

The generation of the three-dimensional simultaneous equations by the simultaneous equation generation means may be performed by referring to ^{the equation (f (t) = at 2 + bt + c) stored in the storage unit in advance.}

Further, it is preferable to provide a solving means for solving at least the values of a and b by solving the ternary simultaneous equations generated by the simultaneous equation generating means (FIG. 1). Of course, it may be configured to solve c.

The information processing unit includes a division means for obtaining the value of a / b by dividing the value of a by the value of b (FIG. 1).

The left chamber volume (f (t)) calculated by the information processing unit may be acquired at least at any three time points during the ejection period. In a preferred embodiment of the present invention, the left ventricular volume (f (f) t)) is used in the calculation.

It is also preferable that the information processing unit has means for calculating other cardiac function parameters such as the left chamber stroke volume (SV) and the left ventricular ejection fraction (EF) in addition to a / b.
Various cardiac function parameters calculated by the information processing unit may be configured to be displayed on the display.

The cardiac function diagnostic system of the present invention may include an input interface (Fig. 1). It is preferable that the input interface is used to make a request to the information processing unit.

The cardiac function diagnosis system of the present invention may include a storage unit for storing image data and the like acquired so far. Further, as described above, it is preferable that the information processing unit stores in advance the formula (f (t) = at2 + bt + c) that is the basis for calculating a / b in the storage unit.
The storage unit can be realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, or an optical disk.

[program]
The present invention also relates to a program for causing a computer to execute each step of the above-described method for calculating cardiac function parameters. As for the specific embodiment of the program of the present invention, the matters described in the item of "Calculation method of cardiac function parameters" can be applied.

The program may be stored in a recording medium. Using this recording medium, for example, the program can be installed on a computer. Here, the recording medium in which the program is stored may be a non-transient recording medium such as a CD-ROM.

By storing the program of the present invention in the storage unit, the above-mentioned cardiac function diagnosis system may be configured.
The program of the present invention is preferably configured to execute each step in the information processing unit in the above-mentioned cardiac function diagnosis system.

[Test Example 1]
Echocardiography was performed on two groups of subjects aged 64 years or younger (under64y) and 65 years or older (over65y), and various cardiac function parameters shown in Table 1 were calculated. Table 1 summarizes the unit of each parameter, the average of the calculated values, the SD (standard deviation), the number of subjects (number), and the p-values for the two groups.

As shown in Table 1, regardless of which cardiac function parameter was used for examination, a decrease in cardiac function was observed predominantly in the group aged 65 years or older as compared with the group aged 64 years or younger. .. From this result, it was proved that the left heart function declined in the elderly.
Looking at a / b, it was -1.321 in the group aged 64 years or younger, whereas it was -0.935 in the group aged 65 years or older. That is, while a> | b | holds in the group aged 64 or younger, this is reversed in the group aged 65 or over and becomes a << b |. As described above, the effectiveness of comparing the absolute values of a and b, that is, evaluating the cardiac function using whether or not the absolute value of the a / b value is less than 1 is proved.

[Test Example 2]
Pimobendan or digoxisin, which are therapeutic agents for heart failure, were administered to subjects with subjective symptoms of tiredness and shortness of breath. Echocardiography was performed before and after administration of the therapeutic agent, and various cardiac function parameters shown in Tables 2 and 3 were calculated. Tables 2 and 3 summarize the unit of each parameter, the average of the calculated values, the SD (standard deviation), the number of subjects (number), and the p-values before and after administration.

As shown in Tables 2 and 3, significant improvement in cardiac function was confirmed by administration of pimobendan or digoxisin, which are therapeutic agents for heart failure. There were also many subjects who were aware of the improvement in cardiac function.
Before the administration, the value of a was negative, so the value of a / b was positive, but after the administration, the value of a turned positive, and the value of a / b became negative. From this, it is proved that the cardiac function can be evaluated extremely effectively by the index of whether the value of a / b is positive or negative.
In addition, after administration of the therapeutic agent for heart failure, as is clear from the parameters other than a / b, the cardiac function is in an extremely good state. The value of a / b at this time is −1.5 or less. From this, it can be said that when the value of a / b is −1.5 or less, the cardiac function is in an extremely good state.

From the results of Test Example 1 and Test Example 2, it can be said that the following four-stage index can be set based on the value of a / b.
(1) When the value of a / b is -1.5 or less ... Extremely good cardiac function (2) When the value of a / b is greater than -1.5 and -1.0 or less ... -Slightly reduced cardiac function (3) When the value of a / b is greater than -1.0 and 0 or less ... A state in which cardiac function is mildly to moderately reduced.
(4) When the value of a / b is positive ... A state in which cardiac function is highly deteriorated.

The present invention can be applied to cardiac function diagnosis.

Claims (12)

A method for calculating a cardiac function parameter, comprising a step of obtaining a value of a / b by dividing the left ventricular volumetric acceleration a by the left ventricular volumetric velocity b in the cardiac contraction process. A method for calculating cardiac function parameters, comprising the following steps (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation process that generates ternary simultaneous equations by substituting into.
(B) A solving step of solving the three-dimensional simultaneous equations to obtain at least the values of a and b.
(C) A division step of obtaining the value of a / b by dividing a by b. The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
The calculation method according to claim 2, wherein the method is characterized by the above. By calculating the value of a / b by the calculation method according to any one of claims 1 to 3 and comparing it with the following indexes (1-1) and / or (1-2), the subject Cardiac function evaluation method for evaluating cardiac function.
[index]
(1-1) When the value of a / b is positive, it is an index indicating that the cardiac function is deteriorated.
(1-2) When the absolute value of the a / b value is less than 1, it is an index indicating that the cardiac function is deteriorated. The value of a / b is calculated by the calculation method according to any one of claims 1 to 3, and one or more indexes selected from the following (2-1) to (2-4) are used. A cardiac function evaluation method for evaluating the cardiac function of a subject by comparison.
[index]
(2-1) When the value of a / b is -1.5 or less, it is an index indicating that the cardiac function is in an extremely good state.
(2-2) When the value of a / b is larger than -1.5 and -1.0 or less, it is an index that the cardiac function is slightly deteriorated.
(2-3) When the value of a / b is larger than -1.0 and 0 or less, it is an index indicating that cardiac function is mildly to moderately deteriorated.
(2-4) When the value of a / b is positive, it is an index indicating that the cardiac function is highly deteriorated. A program comprising a computer functioning as a means for obtaining a value of a / b by dividing the left ventricular volumetric acceleration a by the left ventricular volumetric velocity b in the process of cardiac contraction. A program that causes a computer to function as the means of the following (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
A generation means that generates ternary simultaneous equations by substituting into.
(B) A solving means for solving at least the values of a and b by solving the three-dimensional simultaneous equations.
(C) A division means for obtaining the value of a / b by dividing a by b. The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
7. The program according to claim 7. A collection unit that collects 2D or 3D image data related to cardiac contraction,
It is equipped with an information processing unit that calculates cardiac function parameters based on the image data.
The information processing unit has means for calculating the left chamber volume acceleration a, the left chamber volume velocity b, and the value of a / b obtained by dividing a by b, based on the image data. , Cardiac function diagnostic system. A collection unit that collects 2D or 3D image data related to cardiac contraction,
It is equipped with an information processing unit that calculates cardiac function parameters based on the image data.
A cardiac function diagnosis system, wherein the information processing unit includes the following means (A) to (C).
(A) The time (t) at at least three time points and the left ventricular volume (f (t)) at the three time points in the process of cardiac contraction from the start point to the end point of the subject's cardiac contraction are expressed by the following equations, respectively. ,
f (t) = at ² + bt + c
Simultaneous equation generation means that generates ternary simultaneous equations by substituting into.
(B) A solving means for solving at least the values of a and b by solving the three-dimensional simultaneous equations.
(C) A division means for obtaining the value of a / b by dividing a by b. The above three time points
The starting point of cardiac contraction,
Any midpoint from the start to the end of cardiac contraction, and the end of cardiac contraction,
10. The cardiac function diagnostic system according to claim 10. The cardiac function diagnostic system is an ultrasonic diagnostic apparatus.
The cardiac function diagnostic system according to any one of claims 9 to 11, wherein the collecting unit is an ultrasonic probe, and the image data is an echo diagram.

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