CN113796849A - A device for image data acquisition across cardiac cycles - Google Patents

Abstract

The invention discloses an image data acquisition device across cardiac cycles, wherein the device comprises: a comparison device, which determines a comparison result between an actual heart rate and a heart rate threshold, and determines a cycle coefficient when image data acquisition is performed based on the comparison result; a cycle determination device, based on The period coefficient determines the number of cardiac cycles included in each acquisition cycle when the image data is acquired, and determines the time length of each cardiac cycle when the image data is acquired based on the actual heart rate; the delay determination means, according to the actual heart rate, the adjustment factor and the reversal time to determine the pulse preparation time, and determine the trigger delay time based on the inversion time and the pulse preparation time; the time determination device determines the start of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time. a start time; and an acquisition device that performs image data acquisition in the heart rate waveform in a cross-cardiac cycle based on the acquisition start time and duration.

Description

A device for image data acquisition across cardiac cycles

technical field

The present invention relates to the technical field of image data acquisition, and more particularly, to an image data acquisition device across cardiac cycles.

Background technique

Neonatal cardiomyopathy mainly includes inflammatory cardiomyopathy and cardiomyopathy (eg, hypertrophic cardiomyopathy). A clinical study found that among neonates with non-structural heart disease, after active treatment, 53.1% of neonates had cardiac Troponin I (cTnI) higher than normal at discharge, and 36.7% of neonates The cTnI level of the children increased progressively, and no obvious abnormality was found in the echocardiogram and electrocardiogram. In addition, previous studies have found that in families with hypertrophic cardiomyopathy (HCM) with mutations in the sarcomere gene, myocardial thickening can be detected within 2 weeks of birth in 11.5% of neonates. According to relevant research reports, most HCMs in the neonatal period die within 1 year of age. Therefore, it is one of the urgent clinical problems to evaluate the cardiomyopathy of children more accurately, so as to make better treatment decisions.

The role of Cardiac Magnetic Resonance imaging (CMR) in the assessment of cardiomyopathy is beyond doubt. At present, CMR technology has been more and more widely used in the assessment and diagnosis of various myocardial diseases. Quantitative and qualitative evaluation of myocardial lesions from the histological level can be carried out through various sequence combinations, and changes such as myocardial edema and myocardial fibrosis can be visually observed. CMR technology is the "gold standard" for the diagnosis of myocardial disease, especially cardiomyopathy, and it is currently difficult to replace by any other non-invasive examination.

During the scanning process of conventional CMR examination, the patient is required to cooperate with breath-holding, limit thoracic movement, and require the patient to be at a low heart rate (for example, below 90 beats/min) to achieve a better signal-to-noise ratio, thereby reducing artifacts and preventing Get clear images. However, these requirements are difficult for infants (eg, infants under 3 years of age) or newborns. Infants or newborns cannot hold their breath, especially the heart rate of newborns can be as high as 120-160 beats/min, almost twice the heart rate required for conventional detection, so it is difficult to meet the detection or scanning requirements of conventional CMR technology.

Currently, in adults and children with a rapid heart rate, cardiac MRI is mainly performed with drugs (eg, metoprolol) or deep anesthesia to lower the heart rate to around 90 beats per minute, so that the scan can be performed. Usually, the normal heart rate of newborns is between 120-160 beats/min. If the heart rate drops to 90 beats/min, it will affect the blood perfusion of various organs in the body and cause organ damage. Therefore, newborns cannot be scanned by reducing their heart rate.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention breaks through the inherent thinking mode that data collection can only be performed in a single cardiac cycle considered in the prior art. The existing technology cannot complete the neonatal or infant cardiac magnetic resonance scan, and cannot acquire effective images, but the multi-cardiac cycle or cross-cardiac cycle image data acquisition method of the present invention can complete the neonatal cardiac magnetic resonance scan, and can obtain High quality images.

According to one aspect of the present invention, there is provided a method for acquiring image data across cardiac cycles, the method comprising:

Obtaining the actual heart rate determined by the heart rate detection instrument, determining the comparison result between the actual heart rate and the heart rate threshold, and determining the period coefficient during image data acquisition based on the comparison result;

Determine the number of cardiac cycles included in each acquisition cycle when image data acquisition is performed based on the period coefficient, and determine the time length of each cardiac cycle when image data acquisition is performed based on the actual heart rate;

obtaining a predetermined reversal time, determining the pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time, and determining the trigger delay time based on the reversal time and the pulse preparation time;

determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time; and

The duration of image data acquisition is determined, and the image data acquisition is performed on the heart rate waveform map in a cross-cardiac cycle based on the acquisition start time and duration.

The heart rate detection instrument is used to detect the heart rate value of the target object.

The heart rate detection instrument performs multiple detections on the target object to obtain multiple heart rate values;

Determining any one heart rate value among the plurality of heart rate values as the actual heart rate of the target object; or,

The average value of the plurality of heart rate values is determined as the actual heart rate of the target subject.

Wherein, determining the period coefficient during image data acquisition based on the comparison result includes:

When the comparison result is that the actual heart rate is greater than the heart rate threshold, the period coefficient during image data acquisition is set to 2.

Determining, based on the period coefficient, the number of cardiac cycles included in each acquisition period during image data acquisition includes:

The number of cardiac cycles included in each acquisition cycle when image data acquisition is performed is set equal to the period coefficient.

Determining, based on the actual heart rate, the time length of each cardiac cycle during image data acquisition includes:

The ratio of the unit time to the actual heart rate was taken as the time length of each cardiac cycle during image data acquisition.

The determining of the pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time includes:

Determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the actual heart rate, α is the adjustment factor, and TI is the reversal time.

The determining of the trigger delay time based on the reversal time and the pulse preparation time includes:

The sum of the inversion time and the pulse preparation time is taken as the trigger delay time.

The determining of the acquisition start time for image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes:

In the heart rate waveform, taking the cycle start time of the first cardiac cycle of the acquisition cycle as the first time, the second time in the second cardiac cycle after the trigger delay time starts from the first time As the acquisition start time of image data acquisition;

The cycle start time of the acquisition cycle is the same as the cycle start time of the first cardiac cycle.

The image data acquisition in the heart rate waveform in a cross-cardiac cycle based on the acquisition start time and duration includes:

Image data for a duration of time is acquired in the heart rate waveform in a cross-cardiac cycle, starting from an acquisition start time located in a second cardiac cycle of the acquisition period rather than the first cardiac cycle.

According to one aspect of the present invention, there is provided a device for acquiring image data across cardiac cycles, the device comprising:

a comparison device, which obtains the actual heart rate determined by the heart rate detection instrument, determines the comparison result between the actual heart rate and the heart rate threshold, and determines the period coefficient when image data collection is performed based on the comparison result;

a cycle determination device, which determines, based on the cycle coefficient, the number of cardiac cycles included in each acquisition cycle during image data acquisition, and determines the time length of each cardiac cycle during image data acquisition based on the actual heart rate;

a delay determination device that acquires a predetermined reversal time, determines the pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time, and determines the trigger delay time based on the reversal time and the pulse preparation time;

a time determination device, which determines the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time; and

The acquisition device determines the duration of image data acquisition, and based on the acquisition start time and duration, performs image data acquisition in the heart rate waveform in a cross-cardiac cycle manner.

The heart rate detection instrument is used to detect the heart rate value of the target object.

The heart rate detection instrument performs multiple detections on the target object to obtain multiple heart rate values;

Determining any one of the multiple heart rate values as the actual heart rate of the target object;

or,

The average value of the plurality of heart rate values is determined as the actual heart rate of the target subject.

Wherein the comparison device determines, based on the comparison result, the period coefficient during image data acquisition including:

When the comparison result determined by the comparison device is that the actual heart rate is greater than the heart rate threshold, the comparison device sets the period coefficient for image data acquisition to 2.

Wherein, the number of cardiac cycles included in each acquisition cycle when the image data acquisition is performed by the period determining device based on the period coefficient includes:

The period determination means sets the number of cardiac cycles included in each acquisition period when image data acquisition is performed to be equal to the period coefficient.

The period determining device determines, based on the actual heart rate, the time length of each cardiac cycle during image data acquisition, including:

The cycle determination means takes the ratio of the unit time to the actual heart rate as the time length of each cardiac cycle during image data acquisition.

The delay determination device determining the pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time includes:

The delay determination device determines the unit time T, and calculates the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the actual heart rate, α is the adjustment factor, and TI is the reversal time.

The delay determination means determining the trigger delay time based on the reversal time and the pulse preparation time includes:

The delay determination means uses the sum of the inversion time and the pulse preparation time as a trigger delay time.

The time determining device determines, according to the cycle start time of the capture cycle and the trigger delay time, the capture start time for image data capture in the capture cycle, including:

In the heart rate waveform, the time determining means takes the cycle start time of the first cardiac cycle of the acquisition cycle as the first time, and starts from the first time and passes the trigger delay time at the second cardiac cycle. The second time in the image data collection is taken as the start time of image data collection;

The cycle start time of the acquisition cycle is the same as the cycle start time of the first cardiac cycle.

The acquisition device performs image data acquisition in the heart rate waveform in a cross-cardiac cycle based on the acquisition start time and duration, including:

The acquisition device, in the heart rate waveform, in a cross-cardiac cycle, starts from the acquisition start time in the second cardiac cycle of the acquisition period, rather than the first cardiac cycle, on the image data for the duration of the time length. collection.

According to one aspect of the present invention, there is provided a method for image data acquisition in a cross-cycle manner, the method comprising:

Obtaining the dynamic frequency determined by the detection instrument, determining the comparison result between the dynamic frequency and the frequency threshold, and determining the period coefficient during image data acquisition based on the comparison result;

Determine the number of waveform periods included in each acquisition period when image data acquisition is performed based on the period coefficient, and determine the time length of each waveform period when image data acquisition is performed based on the dynamic frequency;

Obtaining a predetermined inversion time, determining the pulse preparation time according to the dynamic frequency, the adjustment factor and the inversion time, and determining the trigger delay time based on the inversion time and the pulse preparation time;

determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time; and

The duration of image data acquisition is determined, and image data acquisition is performed in the target waveform in a cross-cycle manner based on the acquisition start time and duration.

The detection instrument is used to detect the frequency value of the target waveform.

The detection instrument performs multiple detections on the target waveform to obtain multiple frequency values;

Determine any one of the multiple frequency values as the dynamic frequency of the target waveform; or,

The average value of multiple frequency values is determined as the dynamic frequency of the target waveform.

Wherein, determining the period coefficient during image data acquisition based on the comparison result includes:

When the comparison result is that the dynamic frequency is greater than the frequency threshold, the period coefficient during image data acquisition is set to 2.

Determining the number of waveform periods included in each acquisition period during image data acquisition based on the period coefficient includes:

The number of waveform periods included in each acquisition period when image data acquisition is performed is set equal to the period coefficient.

Determining the time length of each waveform cycle during image data acquisition based on the dynamic frequency includes:

The ratio of unit time to dynamic frequency is taken as the time length of each waveform cycle during image data acquisition.

The determining of the pulse preparation time according to the dynamic frequency, the adjustment factor and the reversal time includes:

Determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the dynamic frequency, α is the adjustment factor, and TI is the inversion time.

The determining of the trigger delay time based on the reversal time and the pulse preparation time includes:

The sum of the inversion time and the pulse preparation time is taken as the trigger delay time.

The determining of the acquisition start time for image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes:

In the target waveform, taking the cycle start time of the first waveform cycle of the acquisition cycle as the first time, the second time in the second waveform cycle after the trigger delay time starts from the first time As the acquisition start time of image data acquisition;

The cycle start time of the acquisition cycle is the same as the cycle start time of the first waveform cycle.

The image data acquisition in the target waveform in the manner of spanning waveform cycles based on the acquisition start time and duration includes:

In the target waveform, the image data within the time length of the duration is acquired in a manner of spanning waveform periods, starting from the acquisition start time located in the second waveform period of the acquisition period rather than the first waveform period.

According to one aspect of the present invention, there is provided a device for acquiring image data in a cross-cycle manner, the device comprising:

a comparison device, which acquires the dynamic frequency determined by the detection instrument, determines the comparison result between the dynamic frequency and the frequency threshold, and determines the period coefficient during image data acquisition based on the comparison result;

a period determination device, which determines, based on the period coefficient, the number of waveform periods included in each acquisition period during image data acquisition, and determines the time length of each waveform period when image data acquisition is performed based on the dynamic frequency;

a delay determination device that acquires a predetermined reversal time, determines the pulse preparation time according to the dynamic frequency, the adjustment factor and the inversion time, and determines the trigger delay time based on the inversion time and the pulse preparation time;

a time determination device, which determines the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time; and

The acquisition device determines the duration of image data acquisition, and performs image data acquisition in the target waveform in a cross-cycle manner based on the acquisition start time and duration.

The detection instrument is used to detect the frequency value of the target waveform.

The detection instrument performs multiple detections on the target waveform to obtain multiple frequency values;

Determine any one of the multiple frequency values as the dynamic frequency of the target waveform;

or,

The average value of multiple frequency values is determined as the dynamic frequency of the target waveform.

Wherein the comparison device determines, based on the comparison result, the period coefficient during image data acquisition including:

When the comparison result of the comparison device is that the dynamic frequency is greater than the frequency threshold, the period coefficient during image data acquisition is set to 2.

Wherein the period determining means determines, based on the period coefficient, the number of waveform periods included in each acquisition period during image data acquisition, including:

The period determination means sets the number of waveform periods included in each acquisition period when image data acquisition is performed to be equal to the period coefficient.

Wherein, the period determining means determines, based on the dynamic frequency, the time length of each waveform period during image data acquisition, including:

The period determining means takes the ratio of the unit time to the dynamic frequency as the time length of each waveform period during image data acquisition.

The delay determination device determining the pulse preparation time according to the dynamic frequency, the adjustment factor and the reversal time includes:

Determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the dynamic frequency, α is the adjustment factor, and TI is the inversion time.

The delay determination means determining the trigger delay time based on the reversal time and the pulse preparation time includes:

The delay determination means uses the sum of the inversion time and the pulse preparation time as a trigger delay time.

The time determining device determines, according to the cycle start time of the capture cycle and the trigger delay time, the capture start time for image data capture in the capture cycle, including:

In the target waveform, the time determining device takes the cycle start time of the first waveform cycle of the acquisition cycle as the first time, and starts from the first time and after the trigger delay time elapses in the second waveform cycle The second time in the image data collection is taken as the start time of image data collection;

The cycle start time of the acquisition cycle is the same as the cycle start time of the first waveform cycle.

The acquisition device performs image data acquisition in the target waveform in a manner of spanning waveform cycles based on the acquisition start time and duration, including:

The acquisition device, in the target waveform, starts from the acquisition start time located in the second waveform period of the acquisition period rather than the first waveform period in a manner of crossing the waveform period, and performs the image data within the time length of the duration. collection.

The multi-cardiac cycle data acquisition technology proposed by the present invention does not need to reduce the heart rate of the newborn or infant, and performs inspection under the normal heart rate of the newborn or infant, avoiding the risk of damage to other organs due to low heart rate. In addition, the multi-cardiac cycle data acquisition technology proposed in the present invention does not need to perform deep anesthesia on the newborn or infant when scanning the newborn or infant, which greatly reduces the risk and adverse consequences of the infant's deep anesthesia.

Description of drawings

Exemplary embodiments of the present invention may be more fully understood by reference to the following drawings:

1 is a schematic diagram of image data acquisition according to a single cardiac cycle;

2 is a flow chart of a method for acquiring image data across cardiac cycles according to the present invention;

3 is a schematic diagram of image data acquisition across cardiac cycles according to the present invention;

4 is a schematic structural diagram of an image data acquisition device across cardiac cycles according to the present invention;

5 is a flowchart of a method for image data acquisition in a cross-cycle manner according to the present invention; and

FIG. 6 is a schematic structural diagram of a device for acquiring image data in a cross-cycle manner according to the present invention.

Detailed ways

Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for the purpose of this thorough and complete disclosure invention, and fully convey the scope of the invention to those skilled in the art. The terms used in the exemplary embodiments shown in the drawings are not intended to limit the invention. In the drawings, the same elements/elements are given the same reference numerals.

Unless otherwise defined, terms (including scientific and technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is to be understood that terms defined in commonly used dictionaries should be construed as having meanings consistent with the context in the related art, and should not be construed as idealized or overly formal meanings.

FIG. 1 is a schematic diagram of image data acquisition according to a single cardiac cycle. Usually, CMR detection or scanning adopts a single cardiac cycle acquisition method, that is, through prospective ECG gating, triggered by the upward R wave in the QRS (full process of ventricular depolarization) complex of each cardiac cycle Pulse and acquire images in subsequent graphs. Due to technical limitations, there is a length of time for pulse preparation between the moment the R-wave triggers the pulse and the moment the scan begins. In addition, in order to detect the corresponding data or content, the CMR detection or scanning needs to keep the inversion time TI (Inversion Time). During the length of the inversion time TI, the CMR may, for example, perform other conventional detections or scans. Typically, the acquired image data provides the best contrast between diseased myocardium and non-diseased myocardium when the TI value is in the interval of 250-300ms. The time between the R-wave trigger pulse and the moment when the image starts to be acquired is the trigger delay, that is, the trigger delay time length is equal to the sum of the pulse preparation time length (eg greater than or equal to 15ms) and the inversion time TI. For adults or adolescents with a heart rate between 60-90 beats/min, since the R-R interval is long enough, clear images can basically be collected with good coordination (as shown in Figure 1). In Figure 1, for example, the target subject's heart rate is 90 beats/min, and the R-R period is 666 ms. Image acquisition durations in the interval 300-400ms are usually optimal. In addition, the trigger delay was 285ms, the pulse preparation was 15ms, the TI was 270ms and the acquisition time or duration was 100ms.

FIG. 2 is a flow chart of a method 200 of image data acquisition across cardiac cycles in accordance with the present invention. The method 200 adopts the data acquisition technology of multiple cardiac cycles, without reducing the actual heart rate greater than the heart rate threshold, the image data acquisition can be performed in the natural or normal or normal heartbeat state of the target object, avoiding the need for artificially reducing the heart rate. Risk of damage to other organs.

Method 200 begins at step 201 . In step 201, the actual heart rate determined by the heart rate detection instrument is acquired, the comparison result between the actual heart rate and the heart rate threshold is determined, and the period coefficient for image data acquisition is determined based on the comparison result.

Among them, the heart rate detection instrument is used to detect the heart rate value of the target object in a way that does not involve in the human body or cause no trauma. The heart rate value refers to the number of heartbeats per minute in a normal person's resting state. The heart rate detection instrument can be any instrument capable of detecting the heart rate or heart rate value of the target subject in a manner that does not involve human body or cause trauma. The unit of heart rate or heart rate value is beats/minute.

The heart rate detection instrument performs multiple detections on the target object to obtain multiple heart rate values. For example, a heart rate detection instrument detects a target object multiple times at fixed intervals (eg, 2 minutes, 3 minutes, or 5 minutes). The time for each detection is any reasonable value such as 2 minutes, 1 minute, 30 seconds or 20 seconds. In this way, the heart rate detection instrument can obtain multiple heart rate values through detection.

In the present application, the heart rate detection instrument may determine any one heart rate value among the plurality of heart rate values as the actual heart rate of the target object. For example, the heart rate detection apparatus may determine the maximum or minimum value among the plurality of heart rate values as the actual heart rate of the target subject. Alternatively, the heart rate detection apparatus may determine the heart rate value closest to the median value among the plurality of heart rate values as the actual heart rate of the target subject. Alternatively, the heart rate detection apparatus may determine a heart rate value randomly selected from a plurality of heart rate values as the actual heart rate of the target subject.

In addition, the heart rate detection apparatus determines the average value of the plurality of heart rate values as the actual heart rate of the target subject. Preferably, an integer value obtained by rounding up or down the average value may be determined as the actual heart rate of the target subject. Alternatively, for example, the heart rate detection instrument obtains a plurality of heart rate values H ₁ , H ₂ , H ₃ , . . . , H _n through detection, then the actual heart rate H _act can be determined in the following manner:

Among them, t is the interval time between each detection when the heart rate detection instrument performs multiple detections on the target object, and t is a natural number greater than 2, in minutes;

H _max is the maximum heart rate value among the multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

H _min is the minimum heart rate value among the multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

μ is the adjusted heart rate value

H _i is the i-th heart rate value among the plurality of heart rate values H ₁ , H ₂ , H ₃ , ..., H _n

n is the number of multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

为多个心率值H₁、H₂、H₃、……、H_n的平均值。

is the average value of a plurality of heart rate values H ₁ , H ₂ , H ₃ , ..., H _n .

Heart rate thresholds can be preset and dynamically adjusted based on actual operation or actual detection. For example, the heart rate threshold is 105/min, 110/min, 115/min, 120/min, 125/min, 130/min or 135/min.

Wherein, determining the period coefficient for image data acquisition based on the comparison result includes: when the comparison result is that the actual heart rate is greater than the heart rate threshold, setting the period coefficient for image data acquisition to 2. That is, when performing actual detection, two cardiac cycles constitute one acquisition cycle, so that better image data can be acquired under the condition of delayed triggering. It should be understood that the period factor can be any reasonable value, such as 3, 4, 5, etc.

In addition, when the comparison result is that the actual heart rate is less than or equal to the heart rate threshold, the period coefficient when image data acquisition is performed is set to 1. That is, during actual detection, one cardiac cycle constitutes one acquisition cycle, as shown in FIG. 1 .

In step 202 , the number of cardiac cycles included in each acquisition cycle during image data acquisition is determined based on the period coefficient, and the time length of each cardiac cycle during image data acquisition is determined based on the actual heart rate. Determining the number of cardiac cycles included in each acquisition period when image data acquisition is performed based on the period coefficient includes setting the number of cardiac cycles included in each acquisition period when image data acquisition is performed to be equal to the period coefficient. For example, when the period coefficient is 2, the number of cardiac cycles included in each acquisition period during image data acquisition is set to 2. That is, each acquisition cycle includes two cardiac cycles.

Determining the time length of each cardiac cycle during image data acquisition based on the actual heart rate includes: taking the ratio of the unit time to the actual heart rate as the time length of each cardiac cycle during image data acquisition. In this application, the unit time may be set to 1 minute, or it may be equal to 60000 milliseconds (ms), ie 6×10 ⁴ ms. It should be understood that the unit time can be any reasonable value, for example, 2 minutes, 30 seconds, or 20 seconds, and the like. For example, when the actual heart rate of the target subject is 150 beats/min, the time length of each cardiac cycle is 6×10 ⁴ ms/150=400 ms. Then, since each acquisition cycle includes two cardiac cycles, each acquisition cycle is 400ms×2=800ms.

In step 203, a predetermined inversion time is obtained, the pulse preparation time is determined according to the actual heart rate, the adjustment factor and the inversion time, and the trigger delay time is determined based on the inversion time and the pulse preparation time. Generally, the inversion time of the inversion recovery sequence of cardiac magnetic resonance imaging can be preset. Cardiac magnetic resonance imaging is a multimodal imaging technique that assesses various parameters including cardiovascular anatomy and function. During scanning or imaging, choosing an appropriate TI time can improve the signal-to-noise ratio of the image and reduce breathing artifacts. In fact, during the TI time, the cardiac magnetic resonance imaging device needs to perform other scanning or imaging actions for the heart rate waveform. For this reason, the TI time may preferably be set to 250 to 300 ms. It should be understood that in the present application, the initial TI time can be dynamically modified according to the actual operation situation, for example, according to whether the imaging or scanning under the initial TI time meets the requirements, so as to achieve a better signal-to-noise ratio.

Determining the pulse preparation time according to the actual heart rate, adjustment factor and reversal time includes: calculating the pulse preparation time by using T as the unit time, R as the actual heart rate, α as the adjustment factor and TI as the reversal time. For the specific address, determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the actual heart rate, α is the adjustment factor, and TI is the reversal time. The unit time is, for example, 1 minute, 2 minutes, 30 seconds, or 20 seconds. The actual heart rate is in beats/minute. α is an adjustment factor and the value of α is preferably 0.375 to 0.5. The inversion time TI is preferably 250ms to 300ms.

Wherein, determining the trigger delay time based on the inversion time and the pulse preparation time includes: taking the sum of the inversion time and the pulse preparation time as the trigger delay time. As above, the trigger delay time may be P+TI. Preferably, the trigger delay time can also be linearly proportional to the sum of the inversion time and the pulse preparation time. For example, the trigger delay time may be (P+TI)×β.

In step 204, the acquisition start time of image data acquisition in the acquisition period is determined according to the period start time of the acquisition period and the trigger delay time. Wherein, determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes: in the heart rate waveform, taking the cycle start time of the first cardiac cycle of the acquisition cycle as the first At the time, the second time in the second cardiac cycle after the trigger delay time has elapsed from the first time as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the same as the cycle start time of the first cardiac cycle.

It should be appreciated that in the heart rate waveform, there are multiple QRS complexes. In the present application, the trigger pulse of the upward wave R wave in the current QRS complex is used as the starting point, and the trigger pulse of the upward wave R wave in the next QRS complex is used as the end point to determine a cardiac cycle. As shown in Figure 3, between two R waves is a cardiac cycle, a waveform associated with one complete beat of the heart. As above, according to the technical solution of the present application, in the heart rate waveform of the target to be measured, the moment at which the R wave peak point of the first cardiac cycle of the current acquisition cycle is located is taken as the first moment, which will start from the first moment and go through a trigger delay. The second time in the second cardiac cycle after time (P+TI) (the second time is between the time at which the peak point of the R wave of the second cardiac cycle is located and the time when the peak point of the R wave in the third cardiac cycle is located) ) as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the time at which the peak point of the R wave of the first cardiac cycle is located.

At step 205, a duration of image data acquisition is determined, and image data acquisition is performed in a heart rate waveform diagram in a cross-cardiac cycle based on the acquisition start time and duration. Wherein, performing image data acquisition in the heart rate waveform diagram in a cross-cardiac cycle based on the acquisition start time and duration includes: in the heart rate waveform in a cross-cardiac cycle, from the second cardiac cycle in the acquisition period rather than the first cardiac cycle The acquisition start time of the cardiac cycle (the acquisition start time is between the time when the peak point of the R wave in the second cardiac cycle is located and the time when the peak point of the R wave in the third cardiac cycle is located) begins, within the time length of the duration. image data is collected. Because according to the technical solution of the present application, the acquisition cycle starts from the first cardiac cycle, but the image data is acquired during the second cardiac cycle (or the cardiac cycle after the first cardiac cycle, in a specific case, the third cardiac cycle). Therefore, the present application provides a technical solution for image data acquisition in a cross-cardiac cycle.

3 is a schematic diagram of image data acquisition across cardiac cycles according to the present invention. The single cardiac cycle acquisition method of conventional magnetic resonance imaging or scanning takes too short an image acquisition time or cannot acquire an effective image, so the present application provides a multi-cardiac cycle or cross-cardiac cycle acquisition method.

As shown in Figure 3, the multi-cardiac cycle or cross-cardiac cycle acquisition method is based on the R-R interval adjusted according to the actual heart rate setting (for example, if the actual heart rate of the object to be measured is 150 beats/min, the instrument sets the heart rate to be equal to the actual heart rate half, i.e. 75 times/min, thus making up an acquisition cycle from two R-R intervals). For this reason, the R-wave trigger is determined by the set heart rate of the instrument, that is, after adjusting the set heart rate, a scan is triggered every 2 cardiac cycles. By setting the pulse preparation time, image data in the second cardiac cycle is acquired after R-wave triggering, and thus clear images are obtained with sufficient data acquisition time.

Among them, the setting of the main parameters in the multi-cardiac cycle or cross-cardiac cycle data acquisition includes: setting the heart rate of the instrument to be 1/2 of the actual heart rate, and thus determining the pulse delay time setting formula as: (6×10 ⁴ ms/ Actual heart rate)+(6×10 ⁴ ms/actual heart rate×α)-TI value. where the TI value is any value between 250 and 300ms. Preferably, the TI value can take any reasonable value. α is an adjustment factor and the value range of α is preferably 0.375 to 0.5. It should be understood that the value range of α can be any reasonable range.

Figure 3 illustrates with an actual heart rate of 150 beats/min. When the actual heart rate is 150 beats/min, the instrument sets the heart rate to 75 beats, and a single actual R-R interval (ie, cardiac cycle) is 400 ms. Since the instrument sets the heart rate to 75 beats, the R-R interval (ie, 2 cardiac cycles) calculated by the instrument is 800 ms. The best acquisition phase is 150-300ms after R1 and R2. Since the optimal acquisition phase time after R1 is too short or cannot be obtained, the pulse preparation time (time length) is set to 285ms, and the TI time (time length) is set to 270ms. After the pulse is triggered by R1, the image data in the best acquisition phase after R2 is acquired, and the acquisition time or duration is 70-80ms. The acquisition time or duration is indicated by the downward-directed arrow in FIG. 3 .

Therefore, based on the concept of multi-cardiac or trans-cardiac data acquisition, a multi-cardiac or trans-cardiac acquisition sequence for infants or neonates is determined. The application can automatically adjust under the condition of monitoring heart rate and changing TI time, so as to achieve an ideal balance in data acquisition time, acceleration technology, and breath holding time, and adjust settings for different heart rates to extend the R-R interval in disguised form. To collect data of the second or third cardiac cycle after R-wave triggering. This application compares the traditional single cardiac cycle acquisition technology and the rapid scanning technology, compares the success rate and image quality of the images acquired by each technology, and provides a new method for infant or neonatal myocardial scanning.

FIG. 4 is a schematic structural diagram of an image data acquisition device 400 across cardiac cycles according to the present invention. The device 400 includes: a comparison device 401 , a period determination device 402 , a delay determination device 403 , a delay determination device 404 , and a collection device 405 . The device 400 adopts the multi-cardiac cycle data acquisition technology, without reducing the actual heart rate greater than the heart rate threshold, it can collect image data in the natural or normal or normal heartbeat state of the target object, avoiding the need for artificially lowering the heart rate. Risk of damage to other organs.

The actual heart rate determined by the heart rate detection instrument is acquired, the comparison device 401 determines the comparison result between the actual heart rate and the heart rate threshold, and based on the comparison result, determines the period coefficient for image data acquisition.

Among them, the heart rate detection instrument is used to detect the heart rate value of the target object in a way that does not involve in the human body or cause no trauma. The heart rate value refers to the number of heartbeats per minute in a normal person's resting state. The heart rate detection instrument can be any instrument capable of detecting the heart rate or heart rate value of the target subject in a manner that does not involve human body or cause trauma. The unit of heart rate or heart rate value is beats/minute.

The heart rate detection instrument performs multiple detections on the target object to obtain multiple heart rate values. For example, a heart rate detection instrument detects a target object multiple times at fixed intervals (eg, 2 minutes, 3 minutes, or 5 minutes). The time for each detection is any reasonable value such as 2 minutes, 1 minute, 30 seconds or 20 seconds. In this way, the heart rate detection instrument can obtain multiple heart rate values through detection.

In the present application, the heart rate detection instrument may determine any one heart rate value among the plurality of heart rate values as the actual heart rate of the target object. For example, the heart rate detection apparatus may determine the maximum or minimum value among the plurality of heart rate values as the actual heart rate of the target subject. Alternatively, the heart rate detection apparatus may determine the heart rate value closest to the median value among the plurality of heart rate values as the actual heart rate of the target subject. Alternatively, the heart rate detection apparatus may determine a heart rate value randomly selected from a plurality of heart rate values as the actual heart rate of the target subject.

In addition, the heart rate detection apparatus determines the average value of the plurality of heart rate values as the actual heart rate of the target subject. Preferably, an integer value obtained by rounding up or down the average value may be determined as the actual heart rate of the target subject. Alternatively, for example, the heart rate detection instrument obtains a plurality of heart rate values H ₁ , H ₂ , H ₃ , . . . , H _n through detection, then the actual heart rate H _act can be determined in the following manner:

Among them, t is the interval time between each detection when the heart rate detection instrument performs multiple detections on the target object, and t is a natural number greater than 2, in minutes;

H _max is the maximum heart rate value among the multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

H _min is the minimum heart rate value among the multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

μ is the adjusted heart rate value

H _i is the i-th heart rate value among the plurality of heart rate values H ₁ , H ₂ , H ₃ , ..., H _n

n is the number of multiple heart rate values H ₁ , H ₂ , H ₃ , ..., H _n ;

为多个心率值H₁、H₂、H₃、……、H_n的平均值。

is the average value of a plurality of heart rate values H ₁ , H ₂ , H ₃ , ..., H _n .

Heart rate thresholds can be preset and dynamically adjusted based on actual operation or actual detection. For example, the heart rate threshold is 105/min, 110/min, 115/min, 120/min, 125/min, 130/min or 135/min.

Wherein, determining the period coefficient for image data acquisition based on the comparison result includes: when the comparison result is that the actual heart rate is greater than the heart rate threshold, setting the period coefficient for image data acquisition to 2. That is, when performing actual detection, two cardiac cycles constitute one acquisition cycle, so that better image data can be acquired under the condition of delayed triggering. It should be understood that the period factor can be any reasonable value, such as 3, 4, 5, etc.

In addition, when the comparison result is that the actual heart rate is less than or equal to the heart rate threshold, the period coefficient when image data acquisition is performed is set to 1. That is, during actual detection, one cardiac cycle constitutes one acquisition cycle, as shown in FIG. 1 .

The cycle determination device 402 determines, based on the cycle coefficient, the number of cardiac cycles included in each acquisition cycle during image data acquisition, and determines the time length of each cardiac cycle during image data acquisition based on the actual heart rate. Determining the number of cardiac cycles included in each acquisition period when image data acquisition is performed based on the period coefficient includes setting the number of cardiac cycles included in each acquisition period when image data acquisition is performed to be equal to the period coefficient. For example, when the period coefficient is 2, the number of cardiac cycles included in each acquisition period during image data acquisition is set to 2. That is, each acquisition cycle includes two cardiac cycles.

Determining the time length of each cardiac cycle during image data acquisition based on the actual heart rate includes: taking the ratio of the unit time to the actual heart rate as the time length of each cardiac cycle during image data acquisition. In this application, the unit time may be set to 1 minute, or it may be equal to 60000 milliseconds (ms), ie 6×10 ⁴ ms. It should be understood that the unit time can be any reasonable value, for example, 2 minutes, 30 seconds, or 20 seconds, and the like. For example, when the actual heart rate of the target subject is 150 beats/min, the time length of each cardiac cycle is 6×10 ⁴ ms/150=400 ms. Then, since each acquisition cycle includes two cardiac cycles, each acquisition cycle is 400ms×2=800ms.

The delay determination device 403 obtains a predetermined inversion time, determines the pulse preparation time according to the actual heart rate, the adjustment factor and the inversion time, and determines the trigger delay time based on the inversion time and the pulse preparation time. Generally, the inversion time of the inversion recovery sequence of cardiac magnetic resonance imaging can be preset. Cardiac magnetic resonance imaging is a multimodal imaging technique that assesses various parameters including cardiovascular anatomy and function. During scanning or imaging, choosing an appropriate TI time can improve the signal-to-noise ratio of the image and reduce breathing artifacts. In fact, during the TI time, the cardiac magnetic resonance imaging device needs to perform other scanning or imaging actions for the heart rate waveform. For this reason, the TI time may preferably be set to 250 to 300 ms. It should be understood that in the present application, the initial TI time can be dynamically modified according to the actual operation situation, for example, according to whether the imaging or scanning under the initial TI time meets the requirements, so as to achieve a better signal-to-noise ratio.

Determining the pulse preparation time according to the actual heart rate, adjustment factor and reversal time includes: calculating the pulse preparation time by using T as the unit time, R as the actual heart rate, α as the adjustment factor and TI as the reversal time. For the specific address, determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the actual heart rate, α is the adjustment factor, and TI is the reversal time. The unit time is, for example, 1 minute, 2 minutes, 30 seconds, or 20 seconds. The actual heart rate is in beats/minute. α is an adjustment factor and the value of α is preferably 0.375 to 0.5. The inversion time TI is preferably 250ms to 300ms.

Wherein, determining the trigger delay time based on the inversion time and the pulse preparation time includes: taking the sum of the inversion time and the pulse preparation time as the trigger delay time. As above, the trigger delay time can be P+TI. Preferably, the trigger delay time can also be linearly proportional to the sum of the inversion time and the pulse preparation time. For example, the trigger delay time may be (P+TI)×β.

The time determining device 404 determines, according to the cycle start time of the capture cycle and the trigger delay time, the capture start time of image data capture in the capture cycle. Wherein, determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes: in the heart rate waveform, taking the cycle start time of the first cardiac cycle of the acquisition cycle as the first At the time, the second time in the second cardiac cycle after the trigger delay time has elapsed from the first time as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the same as the cycle start time of the first cardiac cycle.

It should be appreciated that in the heart rate waveform, there are multiple QRS complexes. In the present application, the trigger pulse of the upward wave R wave in the current QRS complex is used as the starting point, and the trigger pulse of the upward wave R wave in the next QRS complex is used as the end point to determine a cardiac cycle. As shown in Figure 3, between two R waves is a cardiac cycle, a waveform associated with one complete beat of the heart. As above, according to the technical solution of the present application, in the heart rate waveform of the target to be measured, the moment at which the R wave peak point of the first cardiac cycle of the current acquisition cycle is located is taken as the first moment, which will start from the first moment and go through a trigger delay. The second time in the second cardiac cycle after time (P+TI) (the second time is between the time at which the peak point of the R wave of the second cardiac cycle is located and the time when the peak point of the R wave in the third cardiac cycle is located) ) as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the time at which the peak point of the R wave of the first cardiac cycle is located.

The acquisition device 405 determines the duration of image data acquisition, and based on the acquisition start time and duration, performs image data acquisition in the heart rate waveform diagram in a manner across cardiac cycles. Wherein, performing image data acquisition in the heart rate waveform diagram in a cross-cardiac cycle based on the acquisition start time and duration includes: in the heart rate waveform in a cross-cardiac cycle, from the second cardiac cycle in the acquisition period rather than the first cardiac cycle The acquisition start time of the cardiac cycle (the acquisition start time is between the time when the peak point of the R wave in the second cardiac cycle is located and the time when the peak point of the R wave in the third cardiac cycle is located) begins, within the time length of the duration. image data is collected. Because according to the technical solution of the present application, the acquisition cycle starts from the first cardiac cycle, but the image data is acquired during the second cardiac cycle (or the cardiac cycle after the first cardiac cycle, in a specific case, the third cardiac cycle). Therefore, the present application provides a technical solution for image data acquisition in a cross-cardiac cycle.

It should be understood that the technical solution of the present invention is not limited to image data acquisition for the heart rate waveform, but can be image data acquisition for other waveforms. Other waveforms are, for example, various types of suitable waveforms such as vibration waveforms, detection waveforms, voltage waveforms, current waveforms, and pulse waveforms.

FIG. 5 is a flowchart of a method for image data acquisition in a cross-cycle manner according to the present invention. The method 500 adopts a multi-cycle or cross-cycle data collection technology, and can collect image data when the frequency of the waveform to be measured or the target waveform is relatively high or the waveform period is relatively short. Method 500 begins at step 501 . In step 501, the dynamic frequency determined by the detection instrument is acquired, the comparison result between the dynamic frequency and the frequency threshold is determined, and the period coefficient during image data acquisition is determined based on the comparison result.

Among them, the detection instrument is used to detect the frequency value of the target waveform or the waveform to be measured. The frequency value is the number of repetitions of each waveform unit of the waveform to be measured or the target waveform per unit time. The detection instrument can be any instrument capable of detecting the frequency or frequency value of the waveform to be measured or the target waveform. The unit of frequency or frequency value is counts/minute, counts/second, counts/millisecond, etc.

The detection instrument performs multiple detections on the waveform to be tested or the target waveform to obtain multiple frequency values. For example, the detection instrument performs multiple detections of the waveform to be measured or the target waveform at a fixed interval (eg, 2 minutes, 3 minutes, or 5 minutes). The time for each detection is any reasonable value such as 2 minutes, 1 minute, 30 seconds or 20 seconds. In this way, the detection instrument can obtain multiple frequency values through detection.

In the present application, the detection instrument may determine any one of the multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. For example, the detection instrument can determine the maximum value or the minimum value among the plurality of frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, the detection instrument may determine the frequency value closest to the median value among the multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, the detection instrument may determine a frequency value randomly selected from a plurality of frequency values as the dynamic frequency of the waveform to be measured or the target waveform.

In addition, the testing instrument determines the average value of multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Preferably, the integer value obtained by rounding up or down the average value may be determined as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, for example, the detection instrument obtains a plurality of frequency values H ₁ , H ₂ , H ₃ , . . . , H _n through detection, then the dynamic frequency H _act can be determined in the following manner:

Among them, t is the interval time between each detection when the detection instrument performs multiple detections of the waveform to be measured or the target waveform, and t is a natural number greater than 2, in minutes;

H _max is the maximum frequency value among the multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

H _min is the minimum frequency value among the multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

μ is the adjusted frequency value

H _i is the ith frequency value among the plurality of frequency values H ₁ , H ₂ , H ₃ , ..., H _n

n is the number of multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

为多个频率值H₁、H₂、H₃、……、H_n的平均值。

It is the average value of a plurality of frequency values H ₁ , H ₂ , H ₃ , ..., H _n .

The frequency threshold can be preset and can be dynamically adjusted according to actual operation or actual detection conditions. For example, the frequency threshold is 105 times/minute, 110 times/minute, 115 times/minute, 120 times/minute, 125 times/minute, 130 times/minute, or 135 times/minute.

Wherein, determining the period coefficient when performing image data acquisition based on the comparison result includes: when the comparison result is that the dynamic frequency is greater than the frequency threshold, setting the period coefficient when performing image data acquisition to 2. That is, when performing actual detection, two cardiac cycles constitute one acquisition cycle, so that better image data can be acquired under the condition of delayed triggering. It should be understood that the period factor can be any reasonable value, such as 3, 4, 5, etc.

In addition, when the comparison result is that the dynamic frequency is less than or equal to the frequency threshold, the period coefficient during image data acquisition is set to 1. That is, during actual detection, one cardiac cycle constitutes one acquisition cycle, as shown in FIG. 1 .

In step 502, the number of waveform periods included in each acquisition period during image data acquisition is determined based on the period coefficient, and the time length of each waveform period during image data acquisition is determined based on the dynamic frequency. Determining the number of waveform periods included in each acquisition period during image data acquisition based on the period coefficient includes: setting the number of waveform periods included in each acquisition period during image data acquisition equal to the period coefficient. For example, when the period coefficient is 2, the number of waveform periods included in each acquisition period during image data acquisition is set to 2. That is, each acquisition cycle includes two waveform cycles.

Determining the time length of each waveform period during image data acquisition based on the dynamic frequency includes: taking the ratio of the unit time to the dynamic frequency as the time length of each waveform period during image data acquisition. In this application, the unit time may be set to 1 minute, or it may be equal to 60000 milliseconds (ms), ie 6×10 ⁴ ms. It should be understood that the unit time can be any reasonable value, for example, 2 minutes, 30 seconds, or 20 seconds, and the like. For example, when the dynamic frequency of the target waveform is 150 times/min, the time length of each waveform cycle is 6×10 ⁴ ms/150=400 ms. Then, since each acquisition period includes two waveform periods, each acquisition period is 400ms×2=800ms.

In step 503, a predetermined inversion time is obtained, the pulse preparation time is determined according to the dynamic frequency, the adjustment factor and the inversion time, and the trigger delay time is determined based on the inversion time and the pulse preparation time. Generally, the inversion time TI can be set in advance. In fact, during the TI time, the imaging device needs to perform other scanning or imaging actions for the frequency waveform. For this reason, the TI time may preferably be set to 250 to 300 ms. It should be understood that in the present application, the initial TI time can be dynamically modified according to the actual operation situation, for example, according to whether the imaging or scanning under the initial TI time meets the requirements, so as to achieve a better signal-to-noise ratio.

The determination of the pulse preparation time according to the dynamic frequency, the adjustment factor and the inversion time includes: calculating the pulse preparation time by using T as the unit time, R as the dynamic frequency, α as the adjustment factor and TI as the inversion time. For the specific address, determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the dynamic frequency, α is the adjustment factor, and TI is the inversion time. The unit time is, for example, 1 minute, 2 minutes, 30 seconds, or 20 seconds. The unit of dynamic frequency is times/minute. α is an adjustment factor and the value of α is preferably 0.375 to 0.5. The inversion time TI is preferably 250ms to 300ms.

Wherein, determining the trigger delay time based on the inversion time and the pulse preparation time includes: taking the sum of the inversion time and the pulse preparation time as the trigger delay time. As above, the trigger delay time can be P+TI. Preferably, the trigger delay time can also be linearly proportional to the sum of the inversion time and the pulse preparation time. For example, the trigger delay time may be (P+TI)×β.

In step 504, the acquisition start time of image data acquisition in the acquisition period is determined according to the period start time of the acquisition period and the trigger delay time. Wherein, determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes: in the target waveform, taking the cycle start time of the first waveform cycle of the acquisition cycle as the first time, starting from the first time and after the trigger delay time has elapsed, the second time in the second waveform cycle is taken as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the same as the cycle start time of the first waveform cycle.

It should be appreciated that in a frequency waveform, there may be peaks and valleys. In the present application, a waveform cycle is determined by taking the peak or trough in the current waveform cycle as the starting point, and the peak or trough in the next waveform cycle as the ending point. As shown in Figure 3, there is one waveform cycle between two peaks or troughs. As above, according to the technical solution of the present application, in the waveform to be measured or the target waveform, the moment at which the peak or trough of the first waveform cycle of the current acquisition cycle is located is taken as the first moment, and the trigger delay time will start from the first moment and pass the trigger delay time. The second time in the second waveform period after (P+TI) (the second time is between the time when the peak or trough of the second waveform cycle is located and the time when the peak or trough of the third waveform cycle is located) is used as the The acquisition start time of image data acquisition. The cycle start time of the acquisition cycle is the time when the peak or trough of the first waveform cycle is located.

At step 505, a duration of image data acquisition is determined, and image data acquisition is performed in a frequency waveform graph or a target waveform in a manner across waveform cycles based on the acquisition start time and duration. The acquisition of image data in the frequency waveform graph or the target waveform in a way of crossing the waveform cycle based on the acquisition start time and duration includes: in the frequency waveform graph or the target waveform in the way of crossing the waveform cycle, from the first in the acquisition cycle. The acquisition start time of the second waveform cycle instead of the first waveform cycle (the acquisition start time is between the time when the peak or trough of the second waveform cycle is located and the time when the peak or trough of the third waveform cycle is located) starts, and the Image data is acquired over a length of time. Because according to the technical solution of the present application, the acquisition period starts from the first waveform period, but the acquisition of image data is performed within the second waveform period (or the waveform period after the first waveform period, in a specific case, the third waveform period) , so the present application provides a technical solution for image data acquisition in a manner of spanning waveform cycles.

FIG. 6 is a schematic structural diagram of a device 600 for collecting image data in a cross-cycle manner according to the present invention. The device 600 includes: a comparison device 601 , a period determination device 602 , a delay determination device 603 , a delay determination device 604 , and a collection device 605 . The device 600 adopts a multi-cycle or cross-cycle data collection technology, and can collect image data when the frequency of the waveform to be measured or the target waveform is relatively high or the waveform period is relatively short.

The dynamic frequency determined by the detection instrument is acquired, and the comparison device 601 determines the comparison result between the dynamic frequency and the frequency threshold, and determines the period coefficient during image data acquisition based on the comparison result.

Among them, the detection instrument is used to detect the frequency value of the target waveform or the waveform to be measured. The frequency value is the number of repetitions of each waveform unit of the waveform to be measured or the target waveform per unit time. The detection instrument can be any instrument capable of detecting the frequency or frequency value of the waveform to be measured or the target waveform. The unit of frequency or frequency value is counts/minute, counts/second, counts/millisecond, etc.

The detection instrument performs multiple detections on the waveform to be tested or the target waveform to obtain multiple frequency values. For example, the detection instrument performs multiple detections of the waveform to be measured or the target waveform at a fixed interval (eg, 2 minutes, 3 minutes, or 5 minutes). The time for each detection is any reasonable value such as 2 minutes, 1 minute, 30 seconds or 20 seconds. In this way, the detection instrument can obtain multiple frequency values through detection.

In the present application, the detection instrument may determine any one of the multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. For example, the detection instrument can determine the maximum value or the minimum value among the plurality of frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, the detection instrument may determine the frequency value closest to the median value among the multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, the detection instrument may determine a frequency value randomly selected from a plurality of frequency values as the dynamic frequency of the waveform to be measured or the target waveform.

In addition, the testing instrument determines the average value of multiple frequency values as the dynamic frequency of the waveform to be measured or the target waveform. Preferably, the integer value obtained by rounding up or down the average value may be determined as the dynamic frequency of the waveform to be measured or the target waveform. Alternatively, for example, the detection instrument obtains a plurality of frequency values H ₁ , H ₂ , H ₃ , . . . , H _n through detection, then the dynamic frequency H _act can be determined in the following manner:

Among them, t is the interval time between each detection when the detection instrument performs multiple detections of the waveform to be measured or the target waveform, and t is a natural number greater than 2, in minutes;

H _max is the maximum frequency value among the multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

H _min is the minimum frequency value among the multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

μ is the adjusted frequency value

H _i is the ith frequency value among the plurality of frequency values H ₁ , H ₂ , H ₃ , ..., H _n

n is the number of multiple frequency values H ₁ , H ₂ , H ₃ , ..., H _n ;

为多个频率值H₁、H₂、H₃、……、H_n的平均值。

It is the average value of a plurality of frequency values H ₁ , H ₂ , H ₃ , ..., H _n .

The frequency threshold can be preset and can be dynamically adjusted according to actual operation or actual detection conditions. For example, the frequency threshold is 105 times/minute, 110 times/minute, 115 times/minute, 120 times/minute, 125 times/minute, 130 times/minute, or 135 times/minute.

Wherein, determining the period coefficient when performing image data acquisition based on the comparison result includes: when the comparison result is that the dynamic frequency is greater than the frequency threshold, setting the period coefficient when performing image data acquisition to 2. That is, when performing actual detection, two cardiac cycles constitute one acquisition cycle, so that better image data can be acquired under the condition of delayed triggering. It should be understood that the period factor can be any reasonable value, such as 3, 4, 5, etc.

In addition, when the comparison result is that the dynamic frequency is less than or equal to the frequency threshold, the period coefficient during image data acquisition is set to 1. That is, during actual detection, one cardiac cycle constitutes one acquisition cycle, as shown in FIG. 1 .

The period determination device 602 determines the number of waveform periods included in each acquisition period during image data acquisition based on the period coefficient, and determines the time length of each waveform period during image data acquisition based on the dynamic frequency. Determining the number of waveform periods included in each acquisition period during image data acquisition based on the period coefficient includes: setting the number of waveform periods included in each acquisition period during image data acquisition equal to the period coefficient. For example, when the period coefficient is 2, the number of waveform periods included in each acquisition period during image data acquisition is set to 2. That is, each acquisition cycle includes two waveform cycles.

Determining the time length of each waveform period during image data acquisition based on the dynamic frequency includes: taking the ratio of the unit time to the dynamic frequency as the time length of each waveform period during image data acquisition. In this application, the unit time may be set to 1 minute, or it may be equal to 60000 milliseconds (ms), ie 6×10 ⁴ ms. It should be understood that the unit time can be any reasonable value, for example, 2 minutes, 30 seconds, or 20 seconds, and the like. For example, when the dynamic frequency of the target waveform is 150 times/min, the time length of each waveform cycle is 6×10 ⁴ ms/150=400 ms. Then, since each acquisition period includes two waveform periods, each acquisition period is 400ms×2=800ms.

The delay determination device 603 obtains a predetermined inversion time, determines the pulse preparation time according to the dynamic frequency, the adjustment factor and the inversion time, and determines the trigger delay time based on the inversion time and the pulse preparation time. Generally, the inversion time TI can be set in advance. In fact, during the TI time, the imaging device needs to perform other scanning or imaging actions for the frequency waveform. For this reason, the TI time may preferably be set to 250 to 300 ms. It should be understood that in the present application, the initial TI time can be dynamically modified according to the actual operation situation, for example, according to whether the imaging or scanning under the initial TI time meets the requirements, so as to achieve a better signal-to-noise ratio.

The determination of the pulse preparation time according to the dynamic frequency, the adjustment factor and the inversion time includes: calculating the pulse preparation time by using T as the unit time, R as the dynamic frequency, α as the adjustment factor and TI as the inversion time. For the specific address, determine the unit time T, and calculate the pulse preparation time P according to the following formula:

Among them, T is the unit time, R is the dynamic frequency, α is the adjustment factor, and TI is the inversion time. The unit time is, for example, 1 minute, 2 minutes, 30 seconds, or 20 seconds. The unit of dynamic frequency is times/minute. α is an adjustment factor and the value of α is preferably 0.375 to 0.5. The inversion time TI is preferably 250ms to 300ms.

Wherein, determining the trigger delay time based on the inversion time and the pulse preparation time includes: taking the sum of the inversion time and the pulse preparation time as the trigger delay time. As above, the trigger delay time can be P+TI. Preferably, the trigger delay time can also be linearly proportional to the sum of the inversion time and the pulse preparation time. For example, the trigger delay time may be (P+TI)×β.

The delay determination device 604 determines the acquisition start time of image data acquisition in the acquisition period according to the period start time of the acquisition period and the trigger delay time. Wherein, determining the acquisition start time of image data acquisition in the acquisition cycle according to the cycle start time of the acquisition cycle and the trigger delay time includes: in the target waveform, taking the cycle start time of the first waveform cycle of the acquisition cycle as the first time, starting from the first time and after the trigger delay time has elapsed, the second time in the second waveform cycle is taken as the acquisition start time for image data acquisition. The cycle start time of the acquisition cycle is the same as the cycle start time of the first waveform cycle.

It should be appreciated that in a frequency waveform, there may be peaks and valleys. In the present application, a waveform cycle is determined by taking the peak or trough in the current waveform cycle as the starting point, and the peak or trough in the next waveform cycle as the ending point. As shown in Figure 3, there is one waveform cycle between two peaks or troughs. As above, according to the technical solution of the present application, in the waveform to be measured or the target waveform, the moment at which the peak or trough of the first waveform cycle of the current acquisition cycle is located is taken as the first moment, and the trigger delay time will start from the first moment and pass the trigger delay time. The second time in the second waveform period after (P+TI) (the second time is between the time when the peak or trough of the second waveform cycle is located and the time when the peak or trough of the third waveform cycle is located) is used as the The acquisition start time of image data acquisition. The cycle start time of the acquisition cycle is the time when the peak or trough of the first waveform cycle is located.

The acquisition device 605 determines the duration of image data acquisition, and based on the acquisition start time and duration, performs image data acquisition in the frequency waveform diagram or the target waveform in a manner of spanning waveform cycles. The acquisition of image data in the frequency waveform diagram or the target waveform in a manner of crossing the waveform cycle based on the acquisition start time and duration includes: in the frequency waveform diagram or the target waveform in the manner of crossing the waveform period, from the acquisition cycle The second waveform cycle of the second waveform cycle is not the acquisition start time of the first waveform cycle (the acquisition start time is between the time when the peak or trough of the second waveform cycle is located and the time when the peak or trough of the third waveform cycle is located), Image data is acquired for a duration of time. Because according to the technical solution of the present application, the acquisition period starts from the first waveform period, but the acquisition of image data is performed within the second waveform period (or the waveform period after the first waveform period, in a specific case, the third waveform period) , so the present application provides a technical solution for image data acquisition in a manner of spanning waveform cycles.

The present invention has been described with reference to a few embodiments. However, as is known to those skilled in the art, other embodiments than the above disclosed invention are equally within the scope of the invention, as defined by the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a//the [means, component, etc.]" are open to interpretation as at least one instance of a means, component, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Claims (10)

1. A method of image data acquisition across a cardiac cycle, the method comprising:

acquiring an actual heart rate determined by a heart rate detection instrument, determining a comparison result of the actual heart rate and a heart rate threshold value, and determining a cycle coefficient when image data is acquired based on the comparison result;

determining the number of cardiac cycles included in each acquisition cycle when image data acquisition is performed based on the cycle coefficient, and determining the time length of each cardiac cycle when image data acquisition is performed based on the actual heart rate;

acquiring predetermined reversal time, determining pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time, and determining trigger delay time based on the reversal time and the pulse preparation time;

determining the acquisition starting time for acquiring the image data in the acquisition period according to the period starting time of the acquisition period and the trigger delay time; and

the duration of time for which image data acquisition is performed is determined, and image data acquisition is performed in a heart rate waveform map across a cardiac cycle based on the acquisition start time and duration.

2. The method of claim 1, the heart rate detection instrument to detect a heart rate value of a target subject.

3. The method of claim 2, the heart rate detection instrument performing a plurality of detections on a target subject to obtain a plurality of heart rate values;

determining any one of a plurality of heart rate values as an actual heart rate of the target subject;

or,

an average of the plurality of heart rate values is determined as the actual heart rate of the target subject.

4. The method of claim 1, wherein determining a periodicity coefficient at which to perform image data acquisition based on the comparison comprises:

and when the comparison result shows that the actual heart rate is greater than the heart rate threshold value, setting the cycle coefficient when image data acquisition is carried out to be 2.

5. The method of claim 1 or 4, determining the number of cardiac cycles included per acquisition cycle at which image data acquisition is performed based on the cycle coefficient comprises:

the number of cardiac cycles included in each acquisition cycle when image data acquisition is performed is set equal to the cycle coefficient.

6. An image data acquisition device spanning a cardiac cycle, the device comprising:

the comparison device is used for acquiring the actual heart rate determined by the heart rate detection instrument, determining the comparison result of the actual heart rate and the heart rate threshold value, and determining the cycle coefficient during image data acquisition based on the comparison result;

a cycle determination device that determines the number of cardiac cycles included in each acquisition cycle when image data acquisition is performed based on the cycle coefficient, and determines the time length of each cardiac cycle when image data acquisition is performed based on the actual heart rate;

the delay determining device is used for acquiring the predetermined reversal time, determining the pulse preparation time according to the actual heart rate, the adjustment factor and the reversal time, and determining the trigger delay time based on the reversal time and the pulse preparation time;

the time determining device is used for determining the acquisition starting time for acquiring the image data in the acquisition cycle according to the cycle starting time of the acquisition cycle and the trigger delay time; and

an acquisition device determines a duration of time for performing image data acquisition and performs image data acquisition in a heart rate waveform across a cardiac cycle based on an acquisition start time and duration.

7. The apparatus of claim 6, the heart rate detection instrument to detect a heart rate value of a target subject.

8. The apparatus of claim 7, the heart rate detection instrument to perform a plurality of detections on a target subject to obtain a plurality of heart rate values;

determining any one of a plurality of heart rate values as an actual heart rate of the target subject;

or,

an average of the plurality of heart rate values is determined as the actual heart rate of the target subject.

9. The apparatus of claim 6, wherein the comparing means determining the periodicity coefficient at the time of image data acquisition based on the comparison result comprises:

and when the comparison result determined by the comparison device is that the actual heart rate is greater than the heart rate threshold value, the comparison device sets the cycle coefficient during image data acquisition to be 2.

10. The apparatus according to claim 6 or 9, wherein the cycle determining means determines the number of cardiac cycles included per acquisition cycle when image data acquisition is performed based on the cycle coefficient includes:

the cycle determining means sets the number of cardiac cycles included in each acquisition cycle at the time of image data acquisition equal to the cycle coefficient.

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