BOLD-MRI system, blood blocking device thereof, control method of BOLD-MRI system and blood blocking device, and storage medium

Abstract

The invention relates to the technical field of magnetic resonance, in particular to a BOLD-MRI system, a blood blocking device thereof, a control method of the BOLD-MRI system and a control method of the BOLD-MRI system The blood blocking device comprises an inflation bandage which is used for being wound on a first body part of a subject and applying extrusion force towards the inner circumferential side to the first body part, and the extrusion force is increased in response to the increase of air pressure in the inflation bandage and is reduced in response to the reduction of the air pressure in the inflation bandage; the first inflating pump is used for inflating the inflating bandage; the second inflation pump is used for inflating the inflation bandage, and the rated power of the second inflation pump is smaller than that of the first inflation pump; the air extracting pump is used for extracting air from the inflatable bandage; the pressure sensor is used for measuring the air pressure value in the inflatable bandage; and the controller is connected to the first inflator pump, the second inflator pump, the sucking pump and the pressure sensor.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance imaging technology, and in particular to a BOLD-MRI system and its blood blocking device, as well as the control method and storage medium for both. Background Technology

[0002] When performing perfusion-weighted magnetic resonance imaging (MR-PWI) or blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) on body parts such as the lower leg or forearm, an inflatable bandage of the blood-blocking device is attached to another body part upstream of the aforementioned body part, such as the patient's thigh or upper arm. The bandage is inflated to apply sufficient binding pressure to the other body part, thus blocking blood from entering the aforementioned body part and placing it in an ischemic phase. Then, by deflating the bandage, the binding pressure is released, allowing the body part to transition to a reactive hyperemia phase.

[0003] The blood-blocking devices proposed in related technologies for magnetic resonance imaging (MRI) involve manually pressurizing and depressurizing the pneumatic band, resulting in low detection efficiency and poor accuracy. Furthermore, when performing MR-PWI or BOLD-MRI studies on subjects, it would be significant to consider the subject's heart rate data during this period, a function that traditional blood-blocking devices and corresponding MR-PWI or BOLD-MRI systems lack. Summary of the Invention

[0004] In order to solve at least one of the above-mentioned technical problems, this application provides a BOLD-MRI system and its blood blocking device, as well as a control method and storage medium for both.

[0005] Firstly, a BOLD-MRI system is proposed, including a blood-blocking device and an MRI device; The blood-blocking device includes: An inflatable strap is used to wrap around a first body part of a subject and apply a compressive force toward the inner periphery of the first body part, the compressive force increasing in response to an increase in air pressure within the inflatable strap and decreasing in response to a decrease in air pressure within the inflatable strap. A first air pump is used to inflate the inflatable straps; A second air pump is used to inflate the air straps, and the rated power of the second air pump is less than the rated power of the first air pump. An air pump is used to extract air from the inflatable straps; A pressure sensor is used to measure the air pressure inside the inflatable straps; The controller, connected to the first air pump, the second air pump, the vacuum pump, and the pressure sensor, is configured to: The pressure sensor acquires the air pressure measurement value inside the inflatable strap in real time. Determine the start time; In response to the interval between the current time (i.e., the first intermediate time) and the starting time reaching a first target time, both the first air pump and the second air pump are controlled to inflate the inflatable strap, wherein the inflation rate of the second air pump is less than the inflation rate of the first air pump. When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap so that the air pressure measurement value is maintained near the target air pressure value. In response to the second target duration being reached between the current time (i.e., the second intermediate time) and the first intermediate time, the air pump is controlled to draw air from the inflatable straps. The MRI device includes a surface receiving coil covering a second body part of the subject, the second body part being downstream of the blood flow of the first body part.

[0006] In some possible implementations, the MRI device is configured as follows: The magnetic resonance signal of the second body part is acquired via the surface receiving coil, and the BOLD signal of the second body part is determined based on the magnetic resonance signal. The BOLD signal includes a BOLD signal during the resting period, a BOLD signal during the ischemic period, and a BOLD signal during the reactive hyperemia period. The resting period corresponds to the period from the start time to the first intermediate time, the hypoxia period corresponds to the period from the first intermediate time to the second intermediate time, and the reactive hyperemia period corresponds to the period after the second intermediate time.

[0007] In some possible implementations, the step of controlling both the first and second air pumps to inflate the inflatable strap in response to the interval between the current time (i.e., the first intermediate time) and the starting time reaching a first target duration includes: In response to the interval between the current time, i.e. the first intermediate time, and the starting time reaching the first target time, the first air pump is controlled to inflate the inflatable strap at a first inflation rate, and the first air pump is controlled to inflate the inflatable strap at a second inflation rate that is smaller than the first inflation rate and constant. The step of continuing to control the second air pump to inflate the air strap includes: Continue to control the second air pump to inflate the inflatable strap at a constant second air inflation rate.

[0008] In some possible implementations, the controller is configured to: In response to the interval between the current time (i.e., the termination time) and the second intermediate time reaching the third target time, the acquisition of the air pressure measurement value from the pressure sensor is stopped.

[0009] In some possible implementations, when the measured air pressure value reaches the target air pressure value, controlling the first air pump to stop inflating and continuing to control the second air pump to inflate the inflatable strap to maintain the measured air pressure value near the target air pressure value includes: When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap at a constant second air inflation rate, so that the air pressure measurement value is maintained within the threshold range, wherein the target air pressure value is a value within the threshold range.

[0010] In some possible implementations, while continuing to control the second air pump to inflate the inflatable straps at a constant second air rate, the controller is configured to: If the measured air pressure value is less than the lower limit of the threshold range, the first air pump is controlled to inflate the inflatable strap until the measured air pressure value reaches the target air pressure value; and thereafter, the second air pump is controlled to inflate the inflatable strap at a constant inflation rate greater than the second inflation rate. If the measured air pressure value is greater than the upper limit of the threshold range, the second air pump is controlled to stop inflating the inflatable strap until the measured air pressure value reaches the target air pressure value; and thereafter, the second air pump is controlled to inflate the inflatable strap at a constant inflation rate that is lower than the second inflation rate.

[0011] In some possible implementations, the reactive hyperemia period corresponds to the period from the second intermediate time to the termination time.

[0012] Secondly, a control method for the BOLD-MRI system as described in the first aspect is proposed, including: The pressure sensor obtains the air pressure measurement value inside the inflatable strap in real time, and the surface receiving coil obtains the magnetic resonance signal of the second body part in real time. Determine the start time; In response to the interval between the current time, i.e. the first intermediate time, and the starting time reaching the first target time, the first air pump is controlled to inflate the inflatable strap at a first inflation rate, and the first air pump is controlled to inflate the inflatable strap at a second inflation rate that is smaller than the first inflation rate and constant. When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap at a constant second air inflation rate, so that the air pressure measurement value is maintained near the target air pressure value. In response to the second target duration being reached between the current time and the first intermediate time, the air pump is controlled to draw air from the inflatable straps. In response to the interval between the current moment (i.e., the termination moment) and the second intermediate moment reaching the third target duration, the acquisition of the air pressure measurement value from the pressure sensor is stopped, and the acquisition of the magnetic resonance signal of the second body part is also stopped.

[0013] Thirdly, a computer-readable storage medium is proposed, on which computer program instructions are stored, which, when executed by a computer device, cause the computer device to implement the control method described in the second aspect.

[0014] The BOLD-MRI system provided in this application can automatically and rapidly pressurize and depressurize the inflatable bandage, and can control the binding force of the inflatable bandage on the obstructed blood flow site of the subject to maintain stability during the ischemic period, which helps to improve the research quality of BOLD-MRI and MR-PWI. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application, and are not intended to limit this application.

[0016] Figure 1 This is a structural block diagram of the blood-blocking device provided in the embodiments of this application.

[0017] Figure 2 This is a schematic diagram illustrating the application of the BOLD-MRI system provided in the embodiments of this application.

[0018] Figure 3 This is a schematic diagram of the BOLD-MRI system control method provided in the embodiments of this application.

[0019] Figure 4 This is a flowchart illustrating the BOLD-MRI system control method provided in the embodiments of this application.

[0020] Figure 5 This is a flowchart illustrating the BOLD-MRI system control method provided in the embodiments of this application.

[0021] Figure 6 This is a flowchart illustrating the BOLD-MRI system control method provided in the embodiments of this application.

[0022] Figure 7 This is a flowchart illustrating the BOLD-MRI system control method provided in the embodiments of this application.

[0023] Explanation of reference numerals in the attached figures: P1 - First body part, P2 - Second body part; t0 - start time, t1 - first intermediate time, t2 - second intermediate time, t3 - end time; T1 - Duration of the first objective, T2 - Duration of the second objective, T3 - Duration of the third objective; 1-Inflatable straps; 2-Inflation equipment, 3-First inflation pump, 4-Second inflation pump; 5-Evacuation equipment, 6-Evacuation pump; 7-Pressure sensor; 8-Controller; 9-Five-way valve; 10 - Surface receiving coil; 11-Support airbag. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the described embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0025] In the description of this application, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects, and, for example, the term "first element" itself does not imply the existence of a "second element," nor does the term "second element" itself imply the existence of a "first element." Furthermore, words such as "a" or "one" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates not less than two.

[0026] Figure 1 The present application illustrates a blood-blocking device according to an embodiment of the present application, which can be used to assist in magnetic resonance imaging (e.g., BOLD-MRI or MR-PWI), and Figure 2 It shows including Figure 1 This is an example of an application of the BOLD-MRI system with the blood-blocking device shown. In this example, Figure 1 The blood-blocking device shown includes an inflatable strap 1, an inflation device 2, an air suction device 5, a pressure sensor 7, and a controller 8. Figure 2 The BOLD-MRI system shown includes an MRI unit and Figure 1 The blood-blocking device, the MRI device includes a surface receiving coil 10. Figure 2 The image shows only a portion of the MRI device and the hemostatic device, including the surface receiving coil 10 of the MRI device and the inflatable bandage 1 of the hemostatic device, as well as the trachea connected to the inflatable bandage 1.

[0027] The inflatable strap 1 can be inflated and deflated. It is used to wrap around a first body part P1 of the subject and apply a compressive force toward the inner periphery of the first body part P1. The compressive force increases in response to an increase in the air pressure inside the inflatable strap 1 and decreases in response to a decrease in the air pressure inside the inflatable strap 1.

[0028] The aforementioned first body part P1 can be a body part containing arteries, such as one of the limbs. Based on this, during a BOLD-MRI examination of a subject using the BOLD-MRI system, the subject's heartbeat signal can also be monitored via a blood flow blocking device, allowing for joint analysis of the subject's BOLD data and heartbeat data. It is understood that arteries connect to the subject's heart and beat in response to the heartbeat. The beating of the arteries physically acts on the inflatable bandage 1 wrapped around them. By monitoring this physical action, the subject's heartbeat signal can be indirectly obtained.

[0029] Furthermore, the surface receiving coil 10 of the MRI device is used to cover a second body part P2 of the subject, which is located downstream of the blood flow to the first body part P1. Thus, by binding and pressing the upstream first body part P1 with the inflatable strap 1, an ischemic response can be achieved in the downstream second body part P2, thereby enabling BOLD-MRI examination of the second body part P2. For example, in Figure 2 In the application example shown, the first body part P1 is the subject's thigh, and the second body part P2 is the subject's lower leg. As is known, in the direction of blood flow, the lower leg is downstream of the thigh, or in other words, the thigh is upstream of the lower leg. Furthermore... Figure 2 In the middle, two support airbags 11 are placed under the knees and feet of the examinee respectively to reduce the external load on the second body part P2, namely the lower leg.

[0030] The inflation device 2 is connected to the inflation strap 1 via an airflow conduit and is configured to inflate the inflation strap 1. In this embodiment, as... Figure 1 As shown, the inflation device 2 includes a first inflation pump 3 and a second inflation pump 4, wherein the rated power of the first inflation pump 3 is significantly greater than that of the second inflation pump 4. Thus, the first inflation pump 3 is primarily used for rapidly inflating the inflatable strap 1, allowing it to quickly increase pressure and reliably seal the blood flow to the first body part P1 within a very short time, enabling the second body part P2 to rapidly transition from the resting phase to the ischemic phase. The second inflation pump 4 can be used for slowly inflating (replenishing air) the inflatable strap 1 to compensate for pressure loss caused by unavoidable gas leakage. Furthermore, the second inflation pump 4 is a high-precision air pump, while the first inflation pump 3 uses a non-high-precision, ordinary air pump.

[0031] The suction device 5 is also connected to the inflatable bandage 1 via an airflow conduit. It is configured to draw air from the inflatable bandage 1 to rapidly reduce the air pressure within it, thereby releasing the compressive force exerted by the inflatable bandage 1 on the first body part P1 and allowing the subject's second body part P2 to quickly transition from the ischemic phase to the reactive hyperemia phase. The suction power and resulting suction rate of the suction device 5 can be designed to be appropriately high so that the aforementioned compressive force applied to the first body part P1 can be instantly released to zero, thereby allowing the subject's second body part P2 to rapidly and completely transition from the ischemic phase to the reactive hyperemia phase. In this embodiment, the suction device 5 is a suction pump 6 that draws the gas from the inflatable bandage 1 into the atmosphere.

[0032] Pressure sensor 7 is also connected to inflatable strap 1 via an airflow line and is configured to measure the air pressure value inside inflatable strap 1.

[0033] The aforementioned airflow pipeline includes a five-way valve 9, whose five ports are respectively connected to an inflation strap 1, a first inflation pump 3, a second inflation pump 4, a vacuum pump 6, and a pressure sensor 7.

[0034] The controller 8 is connected to the aforementioned inflation device 2, vacuum device 5, and pressure sensor 7, and is capable of controlling the operation of the inflation device 2 and vacuum device 5, and of obtaining the air pressure information of the inflation strap 1 from the pressure sensor 7. In some embodiments, the controller 8 may be a microcontroller.

[0035] Next, please see Figure 4 and combined Figure 3 The embodiments of this application also provide Figure 2 A control method for the BOLD-MRI system shown, comprising the following steps S401 to S407: S401, the air pressure measurement value inside the inflatable strap 1 is obtained in real time from the pressure sensor 7, and the magnetic resonance signal of the second body part P2 is obtained in real time via the surface receiving coil 10.

[0036] In implementation, the controller 8 of the hemostatic device can acquire the air pressure measurement value inside the inflatable strap 1 in real time from the pressure sensor 7, and the MRI device can acquire the magnetic resonance signal of the second body part P2 in real time via the surface receiving coil 10. Furthermore, the controller 8 of the hemostatic device can communicate with the control center of the MRI device. Alternatively, the aforementioned controller 8 of the hemostatic device can also be provided by the MRI device itself; for example, the controller 8 can be the control center of the MRI device. This application embodiment does not limit this. It should be understood that the control center of the MRI device can be a PC (Personal Computer), for example, a PC installed in a control room adjacent to the MRI examination room and operated by a radiologist.

[0037] S402, determine the start time t0. The time period after this start time t0 corresponds to the resting period of the subject's second body part P2.

[0038] The start time t0 can be determined in response to the operator's instructions or automatically by the system. Automatic system determination can include setting the current time as the start time t0 after obtaining multiple stable air pressure measurements consecutively. Furthermore, the real-time acquisition of the magnetic resonance signal of the second body part P2 via the surface receiving coil 10, as described in S401, can begin before the start time t0 or after the start time t0 is reached; this embodiment does not limit this process.

[0039] In some embodiments, the radio frequency (RF) signal generated by the magnetic resonance transmitter is supplied to the RF transmitting coil via an RF transmitting circuit, causing the RF transmitting coil to transmit an RF signal of a predetermined frequency toward the second body part P2 to generate a B1 field. This predetermined frequency corresponds to the Larmor frequency of the hydrogen nucleus, thereby exciting the hydrogen nuclei within the second body part P2 to generate magnetic resonance signals. The magnetic resonance signals of the hydrogen nuclei are received by a surface receiving coil 10, and these magnetic resonance signals are transmitted to the magnetic resonance receiver via an RF receiving circuit to obtain a magnetic resonance image of the second body part P2 of the subject based on the magnetic resonance effect of the hydrogen nuclei. The MRI transmitter, RF transmitting coil, and magnetic resonance receiver can be components of a BOLD-MRI system.

[0040] Blood oxygen level dependent (BOLD) magnetic resonance imaging (BOLD-MRI) is a non-invasive magnetic resonance imaging method that utilizes the different magnetic properties of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) to detect blood oxygenation in a second body part P2. Changes in blood oxygenation indirectly reflect local neuronal activity. Specifically, HbO2 (oxyhemoglobin) is diamagnetic and has little impact on magnetic field homogeneity, while Hb (deoxyhemoglobin) is paramagnetic and produces local magnetic field inhomogeneity. The content of oxyhemoglobin and deoxyhemoglobin in the second body part P2 varies depending on the blood state during the resting phase, the ischemic phase (described later), the reactive hyperemia phase, and different time periods within the reactive hyperemia phase. Therefore, the magnetic resonance signal received by the surface receiving coil 10 varies, and this variation can be interpreted as a BOLD signal (blood oxygen level dependent signal). The BOLD signal is a signal used in functional magnetic resonance imaging that reflects changes in blood oxygenation levels in local areas of the human body. S403, in response to the time interval from the start time t0 reaching the first target duration T1 (this indicates that the current time has reached the end of the expected rest period; for ease of description, this time is denoted as the first intermediate time t1, as follows...), Figure 3 If the first air pump 3 and the second air pump 4 are operated simultaneously, the first air pump 3 inflates the inflatable strap 1 at a first inflation rate, and the second air pump 4 inflates the inflatable strap 1 at a second inflation rate lower than the first inflation rate, until the air pressure measurement value reaches the target air pressure value. This causes the second body part P2 to enter the ischemic phase.

[0041] Here, "until the air pressure measurement value reaches the target air pressure value" means that when the air pressure measurement value reaches the target air pressure value, the operation of controlling the first air pump 3 to inflate the air strap 1 at the first air inflation rate and controlling the second air pump 4 to inflate the air strap 1 at the second air inflation rate will no longer be executed. This obviously includes the following situation: controlling the first air pump 3 to stop inflating, but continuing to control the second air pump 4 to perform the inflating action, as detailed in the following description.

[0042] The first target duration T1 corresponds to the resting period, i.e., the duration during which the second body part P2 is in a free state. During the period from the initial time t0 to the first intermediate time t1, the magnetic resonance signal acquired by the MRI device via the surface receiving coil 10 corresponds to the magnetic resonance signal during the resting period. The BOLD (blood oxygen level-dependent) signal determined based on the magnetic resonance signal during this period corresponds to the BOLD signal of the second body part P2 during the resting period. For example, the first target duration T1 can be 152 seconds.

[0043] In some embodiments, the first inflation rate can be the inflation rate corresponding to the first air pump 3 operating at its rated power (maximum output power), and the second inflation rate can be the inflation rate corresponding to the second air pump 4 operating at its rated power. Thus, in S403, the inflation device 2 inflates the inflatable strap 1 at its maximum inflation rate. In some embodiments, the inflation device 2 can inflate the inflatable strap 1 to 200 kPa within 1-2 seconds.

[0044] In other embodiments, the output power of the second air pump 4 and the resulting inflation rate can be precisely adjusted and controlled, and the aforementioned second inflation rate can be the inflation rate corresponding to the second air pump 4 operating at a non-maximum output power (e.g., half the rated power of the second air pump 4). With this design, the inflation rate of the second air pump 4 can be adjusted in S404, S601, and S602 described later to better adapt to the leakage rate of the inflation strap 1.

[0045] It can be understood that in this S403, the inflation device 2 inflates the inflation strap 1 at an inflation rate equal to the sum of the first inflation rate and the second inflation rate, i.e., the third inflation rate.

[0046] In some other embodiments, in S403, only the first air pump 3 is controlled to inflate the air strap 1 at its rated power, while the second air pump 4 is not operated.

[0047] S404, control the second air pump 4 to inflate the air strap 1 at an inflation rate lower than the first inflation rate, so that the air pressure measurement value is maintained near the aforementioned target air pressure value.

[0048] In some embodiments, S403, when the first air pump 3 inflates the inflatable strap 1 at a first inflation rate, thereby causing the air pressure measurement value to reach the target air pressure value, the first air pump 3 and the second air pump 4 can be controlled to stop inflating. However, the inflatable strap 1 cannot achieve absolute airtightness. Therefore, after the first air pump 3 and the second air pump 4 stop inflating, if the inflatable strap 1 is not replenished with air, the high-pressure gas inside the inflatable strap 1 will slowly leak outward, causing the binding pressure of the inflatable strap 1 on the first body part P1 to gradually decrease. Therefore, the second air pump 4 can be controlled to slowly replenish air to the inflatable strap 1 at an inflation rate lower than the first inflation rate, so that the air pressure value inside the air pressure strap can be maintained near the target air pressure value, thereby enabling the inflatable strap 1 to reliably inhibit blood flow to the first body part P1 of the examinee, and reliably keep the second body part P2 of the examinee in the ischemic period.

[0049] like Figure 5 As shown, in some embodiments, S404 may specifically include the following S501.

[0050] S501, control the second air pump 4 to continue inflating the air strap 1 at a second inflation rate so that the air pressure measurement value is maintained within a threshold range (for example, so that the air pressure measurement value is maintained within the threshold range for at least 60 consecutive seconds), wherein the second inflation rate is a constant value, the target air pressure value is a value within the threshold range, and the second inflation rate is less than the aforementioned first inflation rate.

[0051] That is, in S403, the second inflation rate provided by the second air pump 4 is a nearly constant value (the second air pump 4 is a high-precision air pump). When the air pressure measurement value reaches the target air pressure value, only the first air pump 3 is controlled to stop inflation, while the second air pump 4 continues to maintain a constant second inflation rate to inflate the inflation strap 1, so that the air pressure measurement value is maintained near the target air pressure value for at least a certain period of time. In addition, the aforementioned first inflation rate provided by the first air pump 3 can be a fluctuating rate.

[0052] For example, the lower limit and upper limit of the threshold range can be 99.9% and 100.1% of the target air pressure value, respectively.

[0053] Understandably, the pressure measurement would only remain within the threshold range indefinitely if the second inflation rate were exactly equal to the leakage rate of the inflation band 1; however, this is highly unlikely. Therefore, the previously determined second inflation rate may be too small or too large compared to the leakage rate of the inflation band 1, potentially causing the pressure measurement to fall below the lower limit of the threshold range or exceed the upper limit before the expected end of the ischemic period. Conversely, an appropriate second inflation rate can maintain the pressure measurement within the threshold range for a longer period (e.g., the expected duration of the ischemic period or half of the expected duration). The magnitude of the second inflation rate is typically determined based on prior experiments.

[0054] In view of this, such as Figure 6 As shown, for Figure 5 In corresponding embodiments of this type, the control method may further include the following S601 and S602.

[0055] S601, if the air pressure measurement value is less than the lower limit of the threshold range, the first air pump 3 is controlled to inflate the air strap 1 at the first inflation rate until the air pressure measurement value reaches the target air pressure value; and thereafter, the second air pump 4 is controlled to inflate the air strap 1 at a constant inflation rate greater than the second inflation rate.

[0056] S602, if the air pressure measurement value is greater than the upper limit of the threshold range, the second air pump 4 is controlled to stop inflating the air strap 1 until the air pressure measurement value drops to the target air pressure value; and thereafter, the second air pump 4 is controlled to inflate the air strap 1 at a constant inflation rate that is smaller than the second inflation rate.

[0057] In addition, Figure 5 and Figure 6 In the illustrated embodiment, S601 and S602 can be repeatedly executed, and each time S601 is repeated, the inflation rate of the second air pump 4 is determined to be greater than the inflation rate of the previous execution of S601. Similarly, each time S602 is repeated, the inflation rate of the second air pump 4 is determined to be smaller than the inflation rate of the previous execution of S602. With this design, the inflation rate of the second air pump 4 on the inflation strap 1 can be adjusted to gradually approach the leakage rate of the inflation strap 1.

[0058] S405: During the execution of S404, the pulse and heartbeat signals of the subject are acquired.

[0059] In this embodiment, S405 specifically includes: during the execution of S404, monitoring the fluctuation of the air pressure measurement value, and acquiring the subject's pulse signal and heartbeat signal based on the fluctuation of the air pressure measurement value. Since the inflatable bandage 1 is wrapped around the first body part with arteries, the pulsation of the arteries will affect the inflatable bandage 1. Therefore, when the air pressure measurement value is maintained near the aforementioned target air pressure value, that is, when there is a stable air pressure environment within the inflatable bandage 1, the pulsation of the heart and arteries will cause a small fluctuation in the air pressure measurement value—a short-term increase followed by an instantaneous decrease. Therefore, the small fluctuation of the monitored air pressure measurement value can be interpreted as the subject's pulse and heartbeat, thereby obtaining the subject's pulse signal and heartbeat signal.

[0060] like Figure 7 As shown, in Figure 5 and Figure 6 In the embodiments shown, the corresponding S405 can be further designed to specifically include S701 to S703: During any one of the following periods: a, b, c, and d, S701 periodically monitors the instantaneous value of the air pressure measurement; S702, if the difference between the maximum and minimum instantaneous values ​​among ten instantaneous values ​​monitored in ten consecutive monitoring cycles (or other preset number) reaches a set difference, it is determined that the subject experienced one pulse and heartbeat during that period, and the subject's pulse amplitude can be determined based on the difference between the maximum and minimum instantaneous values. Furthermore, the time point of the next pulse and heartbeat signal can be determined as a time point at least 0.2 seconds away from the monitoring time point of the previous maximum instantaneous value.

[0061] a: During the period when the controlled inflation device 2 inflates the air strap at a constant second inflation rate (corresponding to the aforementioned S501). b period: During the period when the control of the second air pump 4 stops inflating the air strap 1 (corresponding to S602). c: During the period when the second air pump 4 is inflating the air strap 1 at a constant inflation rate greater than the second inflation rate (corresponding to S601). During period d: During the period when the second air pump 4 is inflating the air strap 1 at a constant inflation rate that is smaller than the second inflation rate (corresponding to S602).

[0062] For example, if the pressure measurement value of pressure sensor 7 is 200 kPa at the first monitoring time point, 201 kPa at the second monitoring time point immediately following the first monitoring time point (monitoring cycle), 202 kPa at the third monitoring time point immediately following the second monitoring time point, 201 kPa at the fourth monitoring time point immediately following the third monitoring time point, 200 kPa at the fifth monitoring time point immediately following the fourth monitoring time point, and 200 kPa at the sixth to thirteenth monitoring time points thereafter, then the difference between the maximum instantaneous value of 202 kPa and the minimum instantaneous value of 200 kPa is 2 kPa, which reaches the set difference of 0.5 kPa. Therefore, it can be determined that the subject's pulse amplitude indicates that the subject had a pulse and heartbeat during that period, especially at the third monitoring time point. Among them, any two adjacent monitoring time points from the first monitoring time point to the thirteenth monitoring time point can be 10 milliseconds apart.

[0063] It should be understood that requiring a predetermined difference between the maximum and minimum instantaneous values ​​before determining that the subject experienced a pulse and heartbeat during that time period is necessary to reduce error. This predetermined difference can be determined experimentally based on the effect of the pulse on the air pressure within the strap, such as the aforementioned 0.5 kPa.

[0064] And see again Figure 7 The control methods may also include: S703, if the difference between the aforementioned maximum instantaneous value and the aforementioned minimum instantaneous value exceeds a set threshold, then control the air pump 6 to extract air from the inflation strap 1.

[0065] It is understandable that the difference between the maximum instantaneous value and the minimum instantaneous value is positively correlated with the amplitude of the arterial pulsation, i.e., the pulse amplitude. If the difference between the maximum instantaneous value and the aforementioned minimum instantaneous value exceeds the set threshold (upper limit), it indicates that the pulse amplitude of the examinee during this period is too large. This is likely due to an adverse reaction caused by the excessive binding and squeezing force of the inflatable strap 1 on the first body part P1. Therefore, the air pump 6 can be immediately controlled to extract air from the inflatable strap 1 to release the binding and squeezing force that the examinee cannot adapt to.

[0066] In other embodiments, the blood-blocking device further includes a photoelectric sensor mounted on the inflatable strap to acquire the pulse wave signal of the superficial artery at its location using the photoelectric sensor (rather than using air pressure fluctuations). Since there is a natural correspondence between the pulse and the heartbeat, the heartbeat signal, especially the heart rate, can be determined based on the arterial pulse signal. In other words, S405 may also specifically include: during the execution of S404, acquiring the pulse wave signal of the first body part P1 using the photoelectric sensor, and determining the subject's heartbeat signal based on the pulse wave signal. It should be understood that when the subject's pulse and heartbeat signals are acquired using the photoelectric sensor, the pulse amplitude, i.e., the amplitude of the arterial pulsation, can also be determined. If, in each measurement interval of multiple consecutive measurement cycles, the subject's pulse amplitude is measured to be consistently too large, the air pump 6 is controlled to extract air from the inflatable strap 1 to release the binding pressure that the subject cannot tolerate.

[0067] In some embodiments, the control method may further include: Based on the acquired heartbeat signals, the subject's heart rate is determined; If the heart rate is greater than the preset rate, control the air extraction device 5 to extract air from the air inflating strap 1.

[0068] Understandably, this control method can determine the timing of each heartbeat of the subject, and therefore, based on the relationship between these heartbeat timings, the subject's heart rate can be determined. If the determined heart rate is greater than a preset rate, for example, a preset rate of 200 BPM (Beats Per Minute), it indicates that the subject is likely experiencing an adverse reaction of excessively fast heart rate due to excessive binding pressure from the inflatable strap 1 on the first body part P1. Therefore, the air pump 6 can be immediately controlled to extract air from the inflatable strap 1 to release the binding pressure that the subject cannot tolerate.

[0069] S406, in response to the current time being equal to the second target duration T2 after the interval between the current time and the aforementioned first intermediate time t1 (this indicates that the current time has reached the expected end of the ischemic period; for ease of description, this time is denoted as the second intermediate time t2, as follows...), Figure 3 If the air pump 6 is activated, it will draw air from the inflatable strap 1. This causes the second body part P2 to enter the reactive hyperemia phase.

[0070] The second target duration T2 corresponds to the duration of the ischemic phase of the second body part P2. During the period from the first intermediate time t1 to the second intermediate time t2, the magnetic resonance signals acquired by the MRI device via the surface receiving coil 10 correspond to the magnetic resonance signals during the ischemic phase. The BOLD (blood oxygen level-dependent) signal determined based on the magnetic resonance signals during this period is the BOLD signal of the second body part P2 during the ischemic phase. For example, the second target duration T2 can be 352 seconds.

[0071] In this S405, the vacuum pump 6 can be controlled to extract air from the inflatable strap 1 at its rated power, so that the inflatable strap 1 is rapidly depressurized, thereby completely releasing the binding and compressive force on the first body part P1 in a very short time, allowing the second body part P2 to quickly transition from the ischemic phase to the reactive hyperemia phase. The vacuum pump 6's vacuuming rate is significantly greater than the inflation rate of the second inflation pump 4. When the pressure measurement value reflecting the internal air pressure of the inflatable strap 1 drops to the set pressure value due to vacuuming, the vacuum pump 6 is controlled to stop vacuuming.

[0072] S407, in response to the time interval between the current time and the second intermediate time t2 reaching the third target time T3 (this indicates that the current time has reached the expected end of the congestion period, which is also the end of the entire BOLD-MRI measurement; for ease of description, this time is referred to as the termination time t3, as follows...) Figure 3 If so, the acquisition of air pressure measurement values ​​from pressure sensor 7 can be stopped immediately or after a certain period of time, and the acquisition of magnetic resonance signals from the second body part P2 can also be stopped.

[0073] In some embodiments, the blood-blocking device is also equipped with a display screen connected to the controller 8, which can display the cumulative duration from the start time t0 and the remaining duration from the end time t3 in real time during the measurement process.

[0074] Based on the above description, it can be understood that some or all of the aforementioned control methods can be executed by the controller 8 of the blood-blocking device. The controller 8 may include a memory storing computer program instructions and a processor connected to the memory. When the computer program instructions are executed by the processor, the controller 8 implements the aforementioned control methods.

[0075] It is understandable that the aforementioned blood-blocking device can also be applied to other MRI systems (such as MR-PWI systems) to assist the relevant systems in completing magnetic resonance imaging examinations.

[0076] In addition, this application embodiment also provides a computer-readable storage medium storing computer program instructions thereon, which, when executed by a computer device, causes the computer device to implement the above-described control method.

Claims

1. A BOLD-MRI system, characterized in that, Including blood flow blocking devices and MRI equipment; The blood-blocking device includes: An inflatable strap is used to wrap around a first body part of a subject and apply a compressive force toward the inner periphery of the first body part, the compressive force increasing in response to an increase in air pressure within the inflatable strap and decreasing in response to a decrease in air pressure within the inflatable strap. A first air pump is used to inflate the inflatable straps; A second air pump is used to inflate the air straps, and the rated power of the second air pump is less than the rated power of the first air pump. An air pump is used to extract air from the inflatable straps; A pressure sensor is used to measure the air pressure inside the inflatable straps; The controller, connected to the first air pump, the second air pump, the vacuum pump, and the pressure sensor, is configured to: The pressure sensor acquires the air pressure measurement value inside the inflatable strap in real time. Determine the start time; In response to the interval between the current time (i.e., the first intermediate time) and the starting time reaching a first target time, both the first air pump and the second air pump are controlled to inflate the inflatable strap, wherein the inflation rate of the second air pump is less than the inflation rate of the first air pump. When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap so that the air pressure measurement value is maintained near the target air pressure value. In response to the second target duration being reached between the current time (i.e., the second intermediate time) and the first intermediate time, the air pump is controlled to draw air from the inflatable straps. The MRI device includes a surface receiving coil covering a second body part of the subject, the second body part being downstream of the blood flow of the first body part.

2. The BOLD-MRI system according to claim 1, characterized in that, The MRI device is configured to: The magnetic resonance signal of the second body part is acquired via the surface receiving coil, and the BOLD signal of the second body part is determined based on the magnetic resonance signal. The BOLD signal includes a BOLD signal during the resting period, a BOLD signal during the ischemic period, and a BOLD signal during the reactive hyperemia period. The resting period corresponds to the period from the start time to the first intermediate time, the hypoxia period corresponds to the period from the first intermediate time to the second intermediate time, and the reactive hyperemia period corresponds to the period after the second intermediate time.

3. The blood-blocking device according to claim 2, characterized in that, The response that the interval between the current time (i.e., the first intermediate time) and the starting time reaches a first target duration, controlling both the first and second air pumps to inflate the inflatable straps includes: In response to the interval between the current time, i.e. the first intermediate time, and the starting time reaching the first target time, the first air pump is controlled to inflate the inflatable strap at a first inflation rate, and the first air pump is controlled to inflate the inflatable strap at a second inflation rate that is smaller than the first inflation rate and constant. The step of continuing to control the second inflation pump to inflate the inflatable strap includes: Continue to control the second air pump to inflate the inflatable strap at a constant second air inflation rate.

4. The blood-blocking device according to claim 3, characterized in that, The controller is configured to: In response to the interval between the current time (i.e., the termination time) and the second intermediate time reaching the third target time, the acquisition of the air pressure measurement value from the pressure sensor is stopped.

5. The blood-blocking device according to claim 3, characterized in that, When the measured air pressure value reaches the target air pressure value, the first air pump is controlled to stop inflating, while the second air pump continues to inflate the inflatable straps to maintain the measured air pressure value near the target air pressure value, including: When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap at a constant second air inflation rate, so that the air pressure measurement value is maintained within the threshold range, wherein the target air pressure value is a value within the threshold range.

6. The blood-blocking device according to claim 5, characterized in that, While continuing to control the second air pump to inflate the inflatable straps at a constant second air inflation rate, the controller is configured to: If the measured air pressure value is less than the lower limit of the threshold range, the first air pump is controlled to inflate the inflatable strap until the measured air pressure value reaches the target air pressure value; and thereafter, the second air pump is controlled to inflate the inflatable strap at a constant inflation rate greater than the second inflation rate. If the measured air pressure value is greater than the upper limit of the threshold range, the second air pump is controlled to stop inflating the inflatable strap until the measured air pressure value reaches the target air pressure value; and thereafter, the second air pump is controlled to inflate the inflatable strap at a constant inflation rate that is lower than the second inflation rate.

7. The BOLD-MRI system according to claim 3, characterized in that, The reactive hyperemia period corresponds to the period from the second intermediate time to the termination time.

8. A control method for the BOLD-MRI system as described in any one of claims 1 to 7, characterized in that, include: The pressure sensor obtains the air pressure measurement value inside the inflatable strap in real time, and the surface receiving coil obtains the magnetic resonance signal of the second body part in real time. Determine the start time; In response to the interval between the current time, i.e. the first intermediate time, and the starting time reaching the first target time, the first air pump is controlled to inflate the inflatable strap at a first inflation rate, and the first air pump is controlled to inflate the inflatable strap at a second inflation rate that is smaller than the first inflation rate and constant. When the air pressure measurement value reaches the target air pressure value, the first air pump is controlled to stop inflating, and the second air pump is controlled to continue inflating the air strap at a constant second air inflation rate, so that the air pressure measurement value is maintained near the target air pressure value. In response to the second target duration being reached between the current time and the first intermediate time, the air pump is controlled to draw air from the inflatable straps. In response to the interval between the current moment (i.e., the termination moment) and the second intermediate moment reaching the third target duration, the acquisition of the air pressure measurement value from the pressure sensor is stopped, and the acquisition of the magnetic resonance signal of the second body part is also stopped.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the computer device, the computer device implements the control method as described in claim 8.

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