JP2016002130A - Electrocardiographic waveform detector, electrocardiographic waveform detecting method, electrocardiographic waveform detecting program, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrocardiographic waveform detector capable of detecting a detection object waveform in an ECG signal with a small calculation quantity.SOLUTION: An electrocardiographic waveform detector 1 comprises: a first integration part 20 for calculating a first integral value for a first period of an ECG signal acquired; a second integration part 30 for calculating a second integral value for a second period of the ECG signal; and a detection part 40 for detecting a specific detection object waveform in the ECG signal by using the first integral value and the second integral value.

Description

  Embodiments described herein relate generally to an electrocardiogram waveform detection apparatus, an electrocardiogram waveform detection method, an electrocardiogram waveform detection program, and an imaging apparatus.

  An electrocardiograph is a device that attaches electrodes to a living body and measures a potential difference between the electrodes. Information measured by an electrocardiograph is called an electrocardiogram (ECG) and is widely used in the medical field. Examples of information obtained from an electrocardiogram include a P wave (P-wave), an R wave (R-wave), a QRS complex wave (QRS complex), and a T wave (T-wave). These waveforms are used for diagnosis of various heart diseases, and are also used for a synchronization signal of a medical diagnostic apparatus capable of performing electrocardiogram synchronous imaging. Therefore, automatic waveform detection is important for industrial applications.

Bert-Uwe Kohler et al. “The Principles of Software QRS Detection,’ ”IEEE Engineering in Medicine and Biology, pp. 42-57, January / February 2002.

  There is a demand for an electrocardiogram waveform detection apparatus, an electrocardiogram waveform detection method, an electrocardiogram waveform detection program, and an imaging apparatus that can detect a detection target waveform in an ECG signal with a small amount of calculation.

  The electrocardiogram waveform detection apparatus according to the embodiment includes a first integration unit that calculates a first integration value for the first period of the acquired ECG signal, and a second integration value for the second period of the ECG signal. A second integration unit for calculating, and a detection unit for detecting a specific detection target waveform in the ECG signal using the first integration value and the second integration value.

The figure which shows an ECG signal typically. The figure which shows the electrocardiogram waveform detection apparatus of 1st Embodiment. The figure explaining the determination method of the parameter used for a detection process. The figure which shows the hardware constitutions of an electrocardiogram waveform detection apparatus. The flowchart which shows the process example of an electrocardiogram waveform detection apparatus. The figure explaining a period for integration contrasted with the attention time on an ECG signal. The figure which shows the electrocardiogram waveform detection apparatus of 2nd Embodiment. The figure explaining operation | movement of the electrocardiogram waveform detection apparatus comprised with three detectors. The figure explaining operation | movement of the electrocardiogram waveform detection apparatus comprised with six detectors. The figure which shows the electrocardiogram waveform detection apparatus of 3rd Embodiment. The figure explaining operation | movement of the electrocardiogram waveform detection apparatus of 3rd Embodiment. The figure which shows the electrocardiogram waveform detection apparatus of 4th Embodiment. The figure explaining operation | movement of the electrocardiogram waveform detection apparatus of 4th Embodiment. The figure which shows an electrocardiogram synchronous imaging device. The figure which shows the structural example of an electrocardiogram waveform detection apparatus. The figure which shows the structural example of an electrocardiogram waveform detection apparatus. The figure which shows the structural example of an electrocardiogram waveform detection apparatus.

  Embodiments of an electrocardiogram waveform detection apparatus, an electrocardiogram waveform detection method, an electrocardiogram waveform detection program, and an electrocardiogram synchronization imaging apparatus according to embodiments will be described with reference to the accompanying drawings. Note that in the following embodiments, the same reference numerals are assigned to the same operations, and duplicate descriptions are omitted as appropriate.

(First embodiment)
FIG. 1 is a diagram schematically showing an ECG signal (a signal corresponding to the shape of an electrocardiogram is called an ECG signal) that is a detection target of the electrocardiogram waveform detection apparatus 1 according to the present embodiment. As shown in FIG. 1, the ECG signal has specific waveforms such as a P wave, an R wave, a QRS composite wave (a composite wave of a Q wave, an R wave, and an S wave), and a T wave.

  When the electrocardiogram waveform detection device 1 detects, for example, an R wave, the electrocardiogram waveform detection device 1 outputs a heartbeat synchronization signal (synchronization signal) to the electrocardiogram synchronization imaging device (imaging device) 200. Examples of the electrocardiographic imaging apparatus 200 that can image in synchronization with the heartbeat include a CT (Computed Tomography) apparatus and an MRI (Magnetic Resonance Imaging) apparatus. For example, the electrocardiogram synchronous imaging apparatus 200 uses an imaging method (electrocardiographic synchronous imaging method) that determines the start timing of data collection with reference to an R wave generation position. The electrocardiogram-synchronized imaging apparatus 200 acquires a heartbeat synchronization signal corresponding to the position of the R wave, and determines a data collection start timing based on the acquired heartbeat synchronization signal.

  For example, the case of an MRI apparatus will be described as an example. In an MRI apparatus, various non-contrast MRA (Magnetic Resonance Angiography) such as FBI (Fresh Blood Imaging) method and Time-SLIP (Time-Spatial Labeling Inversion Pulse) method are used. ) Method is used. In data collection by the FBI method, the MRI apparatus collects diastolic images and systolic images by controlling the timing of data collection on the basis of, for example, a heartbeat synchronization signal, and calculates a difference image between them to obtain an artery. Can be obtained.

  Further, in data collection by the Time-SLIP method, the MRI apparatus can obtain an image of blood flow by controlling the timing of applying a labeling pulse and the timing of data collection with reference to a heartbeat synchronization signal, for example. . As described above, the MRI apparatus controls the data collection timing and the application timing of various pulses using the heartbeat synchronization signal generated from the ECG signal as a reference. In addition, the MRI apparatus performs imaging based on the heartbeat synchronization signal in other imaging, such as various imaging for the heart and the like, imaging using a contrast agent, and the like.

  For example, the heartbeat synchronization signal is also used when imaging the heart using the segmented method, or when imaging the heart in a specific cardiac phase. The heartbeat synchronization signal is also used when data of a basic cross-sectional image (for example, a left ventricular short axis image) of the heart is acquired in synchronization with the heartbeat synchronization signal, for example, in the diastole. Further, volume data including the entire heart is collected in synchronization with the heartbeat synchronization signal, for example, in the diastole. Then, image processing such as volume rendering and MIP is performed on the collected volume data.

  Also in the CT apparatus, imaging synchronized with the heartbeat synchronization signal is performed. For example, an imaging method is known in which a cardiac phase period with a large fluctuation in heart size is obtained from a heartbeat synchronization signal, and X-ray irradiation is stopped during the cardiac phase period with a large fluctuation, thereby reducing the exposure dose. Yes.

  FIG. 2 is a block diagram illustrating a configuration of the electrocardiogram waveform detection device 1 according to the first embodiment and a configuration of a device connected to the electrocardiogram waveform detection device 1. The electrocardiograph 100 generates an ECG signal and sends it to the electrocardiogram waveform detection apparatus 1. The electrocardiogram waveform detection apparatus 1 generates a heartbeat synchronization signal from the ECG signal and sends it to the electrocardiogram synchronization imaging apparatus 200.

  The electrocardiograph 100 includes electrodes 101a and 101b, an amplifier 110, and an AD converter 120. The electrodes 101a and 101b are attached to the human body. The amplifier 110 amplifies a weak potential difference between the electrodes 101a and 101b. The AD converter 120 converts the analog signal amplified by the amplifier 110 into a digital signal.

  The electrocardiograph 100 illustrates two electrodes 101a and 101b, but the number of electrodes is not limited to two. For example, in order to obtain a 12-lead electrocardiogram, a configuration including four electrodes attached to the limbs and six electrodes attached to the chest may be used. Further, instead of a method of obtaining a potential difference between two points on the body, a method of recording a potential difference between a predetermined reference and an electrode mounting point may be used.

  The electrocardiographic waveform detection apparatus 1 includes an input unit 10, a first integration unit 20, a second integration unit 30, and a detection unit 40. The first integration unit 20, the second integration unit 30, and the detection unit 40 constitute a detector 50.

  The input unit 10 acquires an ECG signal from the AD converter 120. The first detection unit 20 calculates an integral value (first integral value) for the first period of the acquired ECG signal. The second detection unit 30 calculates an integral value (second integral value) for the second period. The detection unit 40 detects a specific detection target waveform in the ECG signal using the first integration value and the second integration value. More specifically, the detection unit 40 obtains a difference between the first integral value and the second integral value, and compares this difference with a predetermined reference value (threshold value) to detect a detection target waveform.

  The length of each period of the first period and the second period, the interval between the first period and the second period, and the reference value are determined in advance as appropriate values.

  Appropriate values for the period length, interval, and reference value of the first period and the second period are, for example, while changing each of the above values parametrically for a large number of ECG signals actually acquired from the human body. This can be determined by simulation.

  For example, a detection range corresponding to the detection target waveform is set for the ECG signal, and the period length, interval, and reference value of the first period and the second period are changed parametrically within the detection range. Then, each value is determined so that the detection target waveform can be detected with the highest possible detection performance. In other words, the lengths, intervals, and reference values of the first period and the second period are tuned so that the detection target waveform can be detected with high detection performance. Here, high detection performance means that the probability (correct detection rate) of correctly detecting the detection target waveform is high and the probability (false detection rate) of detecting a waveform other than the detection target waveform is low.

  For example, when the detection target waveform in the ECG waveform is a waveform indicated by a solid line in FIG. 3, a detection range corresponding to the detection target waveform is set, and the first period and the second period are set in the detection range. The period length, interval, and reference value of the period are changed parametrically, and each value is tuned and determined so that the detection target waveform can be detected with the highest possible detection performance.

  The period length, interval, and reference value of the first period and the second period determined in this way are stored in an appropriate storage unit of the present apparatus, and the first integration unit 20 and the second integration unit are stored. Provided to the unit 30 and the detection unit 40.

  When detecting the detection target waveform, the detection unit 40 generates an electrocardiogram synchronization signal. In addition, the detection unit 40 sends the generated electrocardiogram synchronization signal to the electrocardiogram synchronization imaging apparatus 200.

  Each part of the electrocardiogram waveform detection apparatus 1 may be configured by hardware such as an application specific integration circuit (ASIC) or a field-programmable gate array (FPGA), or may be realized by software processing. Further, a combination of hardware and software processing may be realized. When realized by software processing, the operation of each part of the electrocardiogram waveform detection apparatus 1 can be realized by causing the computer 300 illustrated in FIG. 4 to execute a predetermined program.

  A computer 300 illustrated in FIG. 4 includes an input / output interface 301, a processor 302, a communication interface 303, a RAM (Random Access Memory) 304, a nonvolatile memory 305, and a disk drive 306.

  The non-volatile memory 305 is a storage device such as a hard disk or a flash memory, and stores various programs and data. The processor 302 is stored in the nonvolatile memory 305. The processor 302 reads a program for realizing the operation of each unit of the electrocardiogram waveform detection apparatus 1 from the nonvolatile memory 305 to the RAM 304 and executes it. In addition, a program stored in a recording medium such as a magnetic disk, an optical disk, or a USB memory may be read from the disk drive 306 or the input / output interface 301. Alternatively, it may be downloaded from an external server via the communication interface 303.

  FIG. 5 is a flowchart showing an outline of processing of the electrocardiogram waveform detection apparatus 1. In step ST100, the input unit 10 of the electrocardiogram waveform detection apparatus 1 inputs an ECG signal as a time series signal. The ECG signal is, for example, a signal sampled at a constant period (for example, at 1 millisecond).

  In step ST102, the first detection unit 20 calculates an integral value (first integral value) for the first period. In step ST104, the second detection unit 30 calculates an integration value (second integration value) for the second period. The order of step ST102 and step ST104 may be reversed. Moreover, the process of step ST102 and the process of step ST104 may be performed simultaneously.

  In step ST106, the detection unit 40 obtains a difference value by subtracting the first integration value and the second integration value. Further, the detection unit 40 detects the detection target waveform by comparing the obtained difference value with a reference value held in advance.

  In step ST108, the detection unit 40 outputs detection information. The detection information is, for example, “+1” or “−1”. If a detection target waveform is detected, “+1” is output, and otherwise “−1” is output. When the detection target waveform is detected, a heartbeat synchronization signal is output to the electrocardiogram synchronization imaging apparatus 200.

  6 compares the first period, which is the integration target period of the first detection unit 20, and the second period, which is the integration target period of the second detection unit 30, with the time of interest on the ECG signal. FIG. If the time required for the detection process of the detection unit 40 is ignored, at the time when both the first integrated value and the second integrated value are obtained (at the end of the second period in FIG. 5), the waveform to be detected is detected. The detection result of the detection unit 40 is obtained. Therefore, the end time of the second period becomes the attention time.

  In order to detect the detection target waveform from the ECG signal input in time series, as shown in FIG. 5, while shifting the time of interest with respect to the time series of the ECG signal, steps ST102 to ST108 in FIG. What is necessary is just to repeat a process.

  As described above, the electrocardiogram waveform detection apparatus 1 according to the first embodiment detects a detection target waveform by two integration operations, one difference, and one comparison process. That is, the detection target waveform can be detected with a very small amount of calculation.

(Second Embodiment)
FIG. 7 is a block diagram showing a configuration of the electrocardiographic waveform detection apparatus 1b according to the second embodiment. The electrocardiographic waveform detection apparatus 1b according to the second embodiment includes a plurality of detectors 50 and an integrated detection unit 60 that integrates detection information output from each of the plurality of detectors 50.

  In the example shown in FIG. 7, it has N detectors 50 from # 1 to #N, and accordingly, the number of first integrating units 20, second integrating units 30, and detecting units 40 is also increased. There are N each.

  The operation of each detector 50 is the same as that of the first embodiment described above. That is, each detection unit 40 compares the difference value between the first integration value output from the first integration unit 20 and the second integration value output from the second integration unit 30 with the reference value. For example, when the difference value exceeds the reference value, “+1” is output as detection information of the detection target waveform, and when the difference value does not exceed the reference value, “−1” is output.

  The integrated detection unit 60 performs predetermined weighting on the detection information “+1” or “−1” output from each detector 50. Then, the respective pieces of weighted detection information of the detectors 50 are added to generate weighted addition values for “+1” and “−1”. Further, the weighted addition value is compared with a predetermined integration reference value to obtain final integrated detection information. Here, the integrated reference value is a threshold value applied to the weighted addition value. For example, it may be determined that a predetermined detection target waveform has been detected when the integrated reference value as the threshold is zero and the weighted addition value is positive.

  The weighting value and the integrated reference value used in the integrated detection unit 60 are determined in advance and held in the integrated detection unit 60 in the same manner as the length and interval of the integration period used in each detector 50 and the reference value. . Weighting values and integrated reference values are also determined by performing simulations while changing parametrically a large number of ECG signals actually obtained from the human body so that the detection target waveform can be detected with the highest possible detection performance. It has been tuned to.

  FIGS. 8A and 8B illustrate the operation of an example in which three detectors of “detector 1”, “detector 2”, and “detector 3” are used as the plurality of detectors 50. FIG. FIG. In the example shown in FIG. 8A, three periods, “period A”, “period B”, and “period C”, are set in chronological order.

  The detector 1 is a detector that calculates the difference between the integral value A in the period A and the integral value B in the period B. A high difference value is obtained when an R wave arrives in period B, and a low difference value is obtained otherwise. Therefore, the difference value is compared with the held reference value (threshold value) (compared with “0.37” in the example shown in FIG. 8B), and if the difference value exceeds (or falls below) the reference value. It can be assumed that an R wave has been detected.

  The detector 3 is a detector that calculates a difference between the integral value B in the period B and the integral value C in the period C. Similar to the detector 1, a high difference value is obtained when an R wave arrives in the period B, and a low difference value is obtained otherwise. Therefore, the difference value is compared with the held reference value (threshold value) (compared with “0.33” in the example shown in FIG. 8B), and if the difference value is above (or below) the reference value. It can be assumed that an R wave has been detected. The detector 1 obtains a difference result after the end of the period B, whereas the detector 3 obtains the difference result after the end of the period C. For this reason, the time when the detection result of the R wave is obtained by the detector 3 is later than that of the detector 1.

  The detector 2 uses only the integral value of period B. The detector 2 can be used as an auxiliary detector for adjusting the reference value of the detector 1 or the detector 3, for example. For example, the detector 2 is operated while shifting the time of interest, and the detector 2 exceeds the reference value (in the example shown in FIG. 8B, “0.61”) held in a separately defined interval. In this case, it is considered that the peak value of the above value represents the magnitude of the R wave, so that the reference values of the detector 1 and the detector 3 are used as the peak value. By making it proportional to the value, the reference values of the detector 1 and the detector 3 can be adaptively changed according to the strength of the signal of the target living body.

  As shown in FIG. 8B, the integrated detection unit 60 uses, for example, a weight “0.4” for the detection information of the detector 1 and a weight “0. 3 ”and a weight“ 0.2 ”are set for the detection information of the detector 3, respectively. Then, each detection information (for example, a value of “+1” or “−1”) output from the detector 1, the detector 2, and the detector 3 is weighted and added with the above weight, and the weighted addition value Is calculated. Thereafter, the weighted addition value and the integrated reference value are compared to obtain final integrated detection information.

  In the electrocardiographic waveform detection apparatus 1b of the second embodiment, at least one of the first period and the second period for the ECG signal is different in each of the plurality of detectors. For example, in the above example, the first period of the detector 1 is the period A, and the second period is the period B. Further, the first period of the detector 3 is the period B, and the second period is the period C. In this way, each detector detects the detection target waveform using information of different integration periods, and further integrates these detection results by weighted addition, compared with the case where detection is performed by one detector. Thus, the detection target waveform can be detected with higher detection performance. That is, the probability (correct detection rate) of correctly detecting the detection target waveform can be improved, and the probability (false detection rate) of detecting a waveform other than the detection target waveform can be reduced.

  The detection performance can be further enhanced by increasing the number of detectors. FIG. 9 is a diagram illustrating the operation of an example in which six detectors “detector 1” to “detector 6” are configured as the plurality of detectors 50. As the integration period, four periods “period A” to “period D” are set.

  Now, the integrated values of “period A” to “period D” are referred to as “integrated value A” to “integrated value D”. At this time, as shown in the “difference processing” column in the center of the table of FIG. 9D, for example, the detector 1 calculates the difference between the “integrated value A” and the “integrated value B”, and the detector 2 The difference between “integrated value A” and “integrated value C” is calculated, and detector 3 calculates the difference between “integrated value A” and “integrated value D”. Further, for example, the detector 4 calculates a difference between “integrated value B” and “integrated value C”, and the detector 5 calculates a difference between “integrated value B” and “integrated value D”. For example, the detector 6 calculates the difference between the “integral value C” and the “integral value D”.

  FIGS. 9A to 9C show a relative positional relationship with respect to the ECG signals in “period A” to “period D”. 9A and 9B, the relative positional relationship between the “period A” and “period D” with respect to the ECG signals is the same. In either case, there is an R wave at a position of “period B”, “period A” is at a position before the R wave, and “period C” is at a position after the R wave. And “period D”. However, FIG. 9A is a diagram for a state in which noise is not mixed in the ECG signal, and FIG. 9B is a diagram corresponding to a state in which noise is mixed in the ECG signal.

  On the other hand, in FIG. 9C, the relative positional relationship with respect to the ECG signals in “period A” to “period D” is different from the positional relationships shown in FIGS. 9A and 9B. That is, in FIG. 9C, the positional relationship with respect to the ECG signal in “period A” to “period D” is shifted to the front with respect to FIGS. 9A and 9B. .

  The state of FIG. 9A is referred to as “reference”, the state of FIG. 9B is referred to as “noise mixing”, and the state of FIG. 9C is referred to as “time shift”. The magnitudes of the differential outputs of “detector 1” to “detector 6” in each state are shown in the three “differential output” columns on the right side of the table of FIG. Here, “++” indicates that the difference output is a large positive value, and “−−” indicates that the difference output is a large negative value. “+” Indicates that the differential output is a small positive value, and “−” indicates that the differential output is a small negative value.

  In the example shown in FIG. 9D, the differential outputs of “detector 1” to “detector 6” with respect to the “reference” state are “−−”, “+”, “ “−”, “++”, “+”, “−”. In the electrocardiographic waveform detection apparatus 1b of the second embodiment, a reference value (threshold value) is set for each detector based on a large number of ECG signals collected in advance so that each detector can detect these differential outputs. Tuned in advance. Then, using the determined reference value (threshold value), a comparison determination is performed for each difference output, and detection information of, for example, “+1” (with detection) or “−1” (without detection) is obtained. Thereafter, the detection information output from each detector is weighted and added by the integrated detection unit 60, and compared with the integrated reference value. The weight used in the integrated detection unit 60 and the integrated reference value are also tuned based on a large number of ECG signals collected in advance.

  In this way, by integrating the output results of a plurality of detectors, it is possible to obtain higher detection performance than that determined by a single detector.

  On the other hand, the differential outputs of “detector 1” to “detector 6” in the “noisy” state are “−”, “+”, “−”, “+”, “+” in order from “detector 1”. “+” And “−”. When these are compared with the respective differential outputs in the “reference” state, the absolute values of the differential outputs are different, but the positive and negative signs show a similar tendency in each of the detectors 1 to 6. This means that when the detection information of each detector is integrated, the integrated detection information in the “noise mixed” state and the integrated detection information in the “reference” state show similar tendencies. In other words, by integrating the detection information of a plurality of detectors, a detection process that is less susceptible to noise becomes possible.

  On the other hand, the differential outputs of “detector 1” to “detector 6” in the “time shift” state are “−”, “−”, “+”, “+”, “+” in order from “detector 1”. “+” And “+”. That is, each difference output shows a tendency that not only the absolute value but also its sign greatly differs from the “reference” state. That is, when only the output of one specific detector is compared (for example, when the output of the detector 1 is compared), there are those with the same sign, but when the overall signs of the six detectors are compared, the “reference” The state and the “time shift” state are totally different. In the case of “time shift”, that is, when the target time of the detection target waveform is different and the waveform of the ECG signal at the target time is different from the detection target waveform in the “reference” state, this different waveform is used. This means that the probability of erroneous detection is reduced as compared with the case of determining with only one detector.

(Third embodiment)
According to the second embodiment using a plurality of detectors, the overall detection performance is improved. On the other hand, since each detector performs two integral calculations, the total integral calculation amount increases in proportion to the increase in the number of detectors.

  Therefore, the electrocardiogram waveform detection apparatus 1c according to the third embodiment is provided with means for reducing the total amount of integral calculation. FIG. 10 is a block diagram showing a configuration of an electrocardiographic waveform detection apparatus 1c according to the third embodiment. The difference from the second embodiment (FIG. 7) is that an accumulating unit 70 is provided between each detector 50 c and the input unit 10. The processing performed by the first integration unit 20c and the second integration unit 30c of each detector 50c is also different from that of the second embodiment.

  The accumulating unit 70 sequentially accumulates ECG signals acquired from the subject in time series according to the time series, and calculates a cumulative value. The first integrating unit 20c refers to the accumulating unit 70, and calculates the difference between the accumulated value at the start of the first period and the accumulated value at the end of the first period as the first integrated value. Similarly, the second integration unit 30c refers to the accumulation unit 70, and uses the difference between the accumulation value at the start of the second period and the accumulation value at the end of the second period as the second integration value. calculate.

  FIG. 11 is a diagram for explaining the operation concept of the third embodiment. FIG. 11A illustrates the ECG signal acquired in time series and a plurality of integration target periods corresponding thereto as periods A to F. FIG. 11B illustrates the accumulated value of the ECG signal calculated by the accumulating unit 70. When the ECG signal is positive as in the P wave, R wave, and S wave regions, the accumulated value continues to increase, and in some negative regions such as the Q wave and S wave, the accumulated value slightly decreases.

  For example, when calculating the integration value B of the period B, the first integration unit 20c or the second integration unit 30c is the difference between the accumulated value at the start of the period B and the accumulated value at the end of the period B. And the calculated difference is defined as an integral value B. Integration values for other periods can be obtained in the same manner.

  As described above, in the third embodiment, the two values (the start of the integration period) obtained by referring to the accumulated value without performing the actual integration calculation in the first integration unit 20c or the second integration unit 30c. The integrated value can be obtained by simply subtracting the cumulative value at the time and the end). For this reason, the amount of calculation required for the integral calculation can be reduced. This effect of reducing the amount of calculation becomes more prominent as the number of detectors increases.

  Further, even when the first and second integration period lengths and the intervals of the integration periods are different between the detectors, there is no need to change the processing content itself of the integration calculation.

  Note that the above-described third embodiment may be applied to a configuration in which the detector 50 is one (first embodiment).

(Fourth embodiment)
The electrocardiographic waveform detection apparatus 1d of the fourth embodiment has means different from the third embodiment as means for reducing the total amount of integral calculation. FIG. 12 is a block diagram showing a configuration of an electrocardiographic waveform detection apparatus 1d according to the fourth embodiment. The difference from the third embodiment (FIG. 10) is that a holding unit 80 is provided between each detector 50d and the input unit 10 instead of the accumulating unit 70. The processing performed by the first integration unit 20d and the second integration unit 30d of each detector 50d is also slightly different from that of the third embodiment.

  The holding unit 80 operates as a so-called queue and temporarily holds time-series sample values of the ECG signal. In addition, when the first integration unit 20d of the fourth embodiment acquires a new sample value for the first period, the sample value at the start of the first period held in the holding unit 80 Is subtracted from the first integral value, and the acquired new sample value is added to the first integral value to update the first integral value. In addition, when the second integration unit 20d of the fourth embodiment acquires a new sample value for the second period, the sample value at the start of the second period held in the holding unit 80 Is subtracted from the second integral value, and the acquired new sample value is added to the second integral value to update the second integral value.

  FIG. 13 is a diagram for explaining an operation concept of the electrocardiographic waveform detection apparatus 1d according to the fourth embodiment. Now, it is assumed that the integration period A is a period from the sample time t = −7 to t = 0, and the integration value A corresponding to this period is the total value of the eight sample values in the period. At this time, the holding unit 80 is assumed to hold at least sample values from t = −7 at the start of the integration period A to the current t = 0.

  Here, when a new sample value t = + 1 of the ECG signal is input, the holding unit 80 adds the new sample value to the queue.

  On the other hand, when the first integration unit 20d (or the second integration unit 30d) calculates the integration value B corresponding to the integration period B shifted by one sample with respect to the integration period A, from the integration value A, By subtracting the sample value at the start of the integration period A (that is, the sample value of t = −7), the newly acquired sample value of t = + 1 is added to the integration value A to obtain the integration value B. . That is, in calculating the integral value B, instead of integrating all sample values in the integration period B, one sample value is added to the previous integral value A, and one sample value is subtracted. The integration value B can be obtained only by doing this.

  If such processing is repeated each time a new sample value is input, a large number of integration values corresponding to a large number of integration periods having different relative positional relationships with respect to the ECG signal are calculated with a small amount of calculation. be able to.

  In addition, when there are two different integration units such as the first integration unit 20d and the second integration unit 30d, or corresponding to the plurality of detectors 50d, the first integration unit 20d and the second integration unit Even when there are a plurality of units 30d, the same holding unit (queue) 80 can be shared.

  Thus, the fourth embodiment can also reduce the amount of calculation required for the integral calculation, and this effect of reducing the amount of calculation becomes more prominent as the number of detectors increases.

  Note that the fourth embodiment described above can also be applied to the configuration in which the detector 50 is one (first embodiment).

  In each of the above-described embodiments, the example in which the electrocardiographic waveform detection device 1 is configured separately from the electrocardiogram synchronous imaging device 200 has been described. The electrocardiogram waveform detection apparatus 1 may be an internal configuration of the electrocardiogram synchronous imaging apparatus 200.

  FIG. 14 is a diagram illustrating an example in which the electrocardiogram synchronous imaging apparatus 200a includes the electromagnetic waveform detection apparatus 1. In addition to the electrocardiographic waveform detection device 1 that generates a heartbeat synchronization signal, the ECG synchronization imaging device 200a collects data obtained by imaging a subject in synchronization with the heartbeat synchronization signal, and the subject from the collected data. An image generation unit 220 for generating the image.

  In each of the above-described embodiments, the example in which the electrocardiographic waveform detection apparatus 1 is configured separately from the electrocardiograph 100 is shown. The electrocardiograph 100 may be the internal configuration of the electrocardiogram waveform detection apparatus 1.

  FIGS. 15 to 17 are diagrams showing an example in which the electrocardiographic waveform detection apparatus 1 includes an electrocardiograph 100.

  The ECG waveform detection apparatus 1 shown in FIG. 15 inputs the ECG signal received from the AD converter 120 to the input unit 10 by wire.

  The electrocardiographic waveform detection apparatus 1 illustrated in FIG. 16 further includes a transmission unit 130 and a reception unit 132. The transmission unit 130 and the reception unit 132 can perform wireless communication with each other. The receiving unit 132 receives an ECG signal that the transmitting unit 130 transmits wirelessly. According to this configuration, wiring to the outside can be eliminated from the electrocardiograph 100 attached to a patient lying on the inside of the bore of the electrocardiogram synchronous imaging apparatus 200.

  The electrocardiographic waveform detection apparatus 1 shown in FIG. 17 further includes a storage unit 140 and a reading unit 142. The storage unit 140 stores the ECG signal in a portable recording medium such as a CD, DVD, or USB memory. The reading unit 142 reads a recording medium. The reading unit 142 sends the read ECG signal to the input unit 10.

  The various processing procedures described above are not necessarily limited to the illustrated processing procedures. Processing procedures that can be executed in parallel may be executed in parallel, and processing procedures that do not depend on the order may be executed by changing the order.

  According to at least one embodiment described above, the detection target waveform in the ECG signal can be detected with a small amount of calculation.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ECG waveform detection apparatus 10 Input part 20 1st integration part 30 2nd integration part 40 Detection part 50 Detector 60 Integrated detection part 70 Accumulation part 80 Holding part 100 Electrocardiograph 200 ECG synchronous imaging device

Claims (9)

A first integrator that calculates a first integral value for a first period of the acquired ECG signal;
A second integrator for calculating a second integral value for the second period of the ECG signal;
A detection unit for detecting a specific detection target waveform in the ECG signal using the first integration value and the second integration value;
An electrocardiographic waveform detection apparatus comprising: The detection unit detects the detection target waveform by comparing a difference between the first integration value and the second integration value with a predetermined reference value;
The electrocardiographic waveform detection apparatus according to claim 1. An accumulator that sequentially accumulates the ECG signals acquired in time series according to the time series to calculate a cumulative value;
Further comprising
The first integration unit calculates a difference between the accumulated value at the start of the first period and the accumulated value at the end of the first period as the first integrated value,
The second integration unit calculates a difference between the accumulated value at the start of the second period and the accumulated value at the end of the second period as the second integrated value;
The electrocardiographic waveform detection apparatus according to claim 1 or 2. The ECG signal is a time-series sample value,
A holding unit that temporarily holds the time-series sample values;
When the first integration unit acquires a new sample value for the first period, the first integration unit uses the sample value at the start of the first period held in the holding unit as the first integration. While subtracting from the value, the acquired new sample value is added to the first integral value to update the first integral value;
When the second integration unit acquires a new sample value for the second period, the second integration unit uses the sample value at the start of the second period held in the holding unit as the second integration. Subtracting from the value while adding the acquired new sample value to the second integral value to update the second integral value;
The electrocardiographic waveform detection apparatus according to claim 1 or 2. A plurality of the detection units;
Integrated detection unit that calculates integrated detection information using detection information obtained from each of the plurality of detection units, and weight values set for each of the plurality of detection units;
Further comprising
At least one of the first period and the second period for the ECG signal is different in each of the plurality of detection units.
The electrocardiographic waveform detection apparatus according to any one of claims 1 to 4. A first integrator that calculates a first integral value for a first period of the acquired ECG signal;
A second integrator for calculating a second integral value for the second period of the ECG signal;
A detection unit that detects a specific detection target waveform in the ECG signal using the first integration value and the second integration value, and generates a synchronization signal;
A data collection unit for collecting data obtained by imaging the subject in synchronization with the synchronization signal;
An image generation unit that generates an image of the subject from the collected data;
An imaging apparatus comprising: The imaging apparatus is an MRI apparatus;
The imaging device according to claim 6. Calculating a first integral value for a first period of the acquired ECG signal;
Calculating a second integral value for a second period of the ECG signal;
Detecting a specific waveform to be detected in the ECG signal using the first integrated value and the second integrated value;
ECG waveform detection method. On the computer,
Calculating a first integral value for a first period of the acquired ECG signal;
Calculating a second integral value for a second period of the ECG signal;
Detecting a specific waveform to be detected in the ECG signal using the first integral value and the second integral value;
ECG waveform detection program to execute.

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