Modularized CT perfusion phantom for simulating brain tissue and collateral circulation and application

Abstract

The invention discloses a modularized CT perfusion phantom simulating brain tissue and collateral circulation and application, and the phantom is provided with a brain tissue state simulation module which is used for simulating healthy brain tissue, ischemic penumbra and infarction core and is provided with a plurality of independent cavities; the artery input simulation module is used for simulating artery input blood flow, is arranged on the input side of the brain tissue state simulation module in a sealed mode and further communicates with all the cavities; the vein output simulation module is used for simulating vein output blood flow, is arranged on the output side of the brain tissue state simulation module in a sealed mode and further communicates with all the cavities; the collateral circulation module is used for simulating brain collateral circulation. The device is simple in structure and convenient to assemble, cavity filling can be adjusted, and the device can be used for time-density curves and hemodynamic parameters under different injection parameters and flow conditions so as to support CTP protocol optimization, cross-equipment standardization and new algorithm verification.

Description

Technical Field

[0001] This invention relates to the fields of medical imaging and biomedical engineering, and in particular to a modular CT perfusion phantom that simultaneously simulates healthy brain parenchyma, local ischemic penumbra, infarct core and collateral circulation, and its applications. Background Technology

[0002] Computed Tomography Perfusion (CTP) is a functional imaging method that can be used to assess the level of microcirculation. It has become a core tool for the diagnosis and treatment of cerebrovascular diseases, such as the comprehensive assessment of acute stroke. CTP involves multiple CT scans after the injection of contrast agent, and then reconstructing two-dimensional or three-dimensional time series images containing the time evolution of contrast agent concentration. Time density curves (TDC) are generated by tracking the input data of contrast agent in selected arteries and veins. After deconvolution calculation, hemodynamic parameter maps (HPMs) containing cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP) are generated [2], which can be widely used in the diagnosis and treatment of diseases. These parametric maps typically show the amount of blood absorbed in certain tissue areas, identifying salvageable brain tissue regions and precisely locating the core infarction zone and ischemic penumbra, providing crucial guidance and clinical decision-making for thrombolysis or thrombectomy in acute stroke patients. However, under current conditions, due to radiation dose and medical ethics issues, it is difficult to conduct repeated experimental scans on human subjects to obtain real perfusion values ​​under different perfusion conditions for verification and evaluation. Perfusion models, by physically simulating blood flow in tissues to simulate perfusion-related physical processes, have advantages such as good repeatability and high stability, making them important test objects for the verification and evaluation of perfusion imaging and providing a standard for evaluating imaging systems.

[0003] Internationally, patents such as US8563919B2 and US9198633B2, and international patent WO2010089699A3 have proposed dynamic flow phantom schemes. These phantoms simulate the perfusion process through compartmentalized chambers and controllable flow resistance design, generating repeatable time-density curves (TDC) to achieve cross-device parameter calibration. However, most of these phantoms only reflect the overall fluid dynamics process and lack detailed simulation of pathological states in brain tissue (such as the ischemic penumbra and infarct core). Commercial products such as the SunNuclearCTPerfusionPhantom are also mainly used to repeatedly generate standardized perfusion curves for quality control between devices, but they also fail to reflect multiple pathological states and collateral circulation characteristics.

[0004] The technical solutions disclosed in Chinese patent publications CN104287764B and CN107491636B mainly focus on CT perfusion algorithms or numerical simulation systems, rather than physical phantoms. While Chinese patent publication CN110840475A involves the design of an imaging reference body, it does not optimize for perfusion dynamics. Overall, a physical CT perfusion phantom capable of simultaneously simulating normal brain tissue, the ischemic penumbra, the infarct core, and collateral circulation remains a gap in the field.

[0005] In recent years, some studies have attempted to reproduce some cerebral hemodynamic features using experimental phantoms, but their structures remain relatively simplified and fail to fully integrate lesion heterogeneity and compensatory blood flow characteristics. Therefore, how to construct a modular, scalable CT perfusion phantom that can realistically simulate various pathological states of cerebral blood flow has become an urgent technical problem to be solved in this field.

[0006] In existing technologies, most perfusion CT phantoms employ a single cavity or simplified fluid pathway design, capable of simulating only the overall time-density curve, and failing to simultaneously represent the hemodynamic characteristics of different pathological regions such as normal tissue, the ischemic penumbra, and the infarct core. Furthermore, existing commercial phantoms are primarily used for cross-device quality control, lacking a realistic representation of key physiological compensatory mechanisms such as collateral circulation. These shortcomings result in a lack of effective experimental platforms for perfusion CT in protocol optimization, cross-platform standardization, and new algorithm validation, thus limiting its clinical application and promotion.

[0007] Therefore, in order to address the shortcomings of existing technologies, it is essential to provide a modular CT perfusion phantom and imaging method that simulates brain tissue and collateral circulation. Summary of the Invention

[0008] The primary objective of this invention is to overcome the shortcomings of existing technologies by providing a modular CT perfusion phantom that simulates brain tissue and collateral circulation. This modular CT perfusion phantom, simulating brain tissue and collateral circulation, has a simple structure, is easy to assemble, and allows for adjustable chamber filling. It can be used for time-density curves (TDC) and hemodynamic parameters (CBF, CBV, MTT, TTP) under different injection parameters and flow rates, supporting CTP protocol optimization, cross-device standardization, and validation of new algorithms.

[0009] The above-mentioned objectives of the present invention are achieved through the following technical measures: A modular CT perfusion phantom simulating brain tissue and collateral circulation is provided, comprising: Brain tissue state simulation module – used to simulate healthy brain tissue, local ischemic penumbra and infarct core, with multiple independent chambers; Arterial input simulation module – used to simulate arterial blood flow, sealed on the input side of the brain tissue state simulation module, and also connected to all the chambers respectively; The venous output simulation module—used to simulate venous output blood flow—is sealed on the output side of the brain tissue state simulation module and is also connected to all of the chambers. Collateral circulation module – a collateral circulation module used to simulate brain collateral circulation, which is connected to the brain tissue state simulation module.

[0010] Preferably, the brain tissue state simulation module has three independent chambers, which are defined as the healthy brain tissue microcirculation chamber, the local ischemic penumbra chamber, and the infarct core chamber, respectively.

[0011] Preferably, the microcirculation chamber of the healthy brain tissue can be replaced with microspheres to simulate the microcirculation of the brain parenchyma.

[0012] Preferably, the aforementioned ischemic penumbra chamber can be replaced with microspheres for simulating microcirculation in the brain parenchyma and soft wax for simulating partial contrast agent residue in the ischemic penumbra.

[0013] Preferably, the aforementioned infarct core chamber can be replaced with microspheres and rigid plastic parts used to simulate the microcirculation of brain parenchyma.

[0014] Preferably, the aforementioned collateral circulation module is connected to the infarcted core chamber.

[0015] Preferably, the above-mentioned arterial input simulation module is provided with three independent arterial channels, which are defined as the first arterial channel, the second arterial channel and the third arterial channel, respectively. The first arterial channel is connected to the microcirculation chamber of the healthy brain tissue, the second arterial channel is connected to the local ischemic penumbra chamber, and the third arterial channel is connected to the infarct core chamber.

[0016] Preferably, the above-mentioned venous output simulation module is provided with three independent venous channels, which are defined as the first venous channel, the second venous channel and the third venous channel, respectively. The first venous channel is connected to the microcirculation chamber of the healthy brain tissue, the second venous channel is connected to the local ischemic penumbra chamber, and the third venous channel is connected to the infarct core chamber.

[0017] Preferably, the third arterial channel and the third venous channel are respectively connected to the collateral circulation module.

[0018] When simulating the blood-brain barrier restricting the diffusion and flow of contrast agents, the microspheres are polyoxymethylene microspheres.

[0019] When simulating different X-ray attenuation states, the microspheres are sodium alginate microspheres.

[0020] Arranged from highest to lowest obstruction ratio, the order is: the infarct core chamber, the locally ischemic penumbra chamber, and the healthy brain tissue microcirculation chamber.

[0021] Preferably, the brain tissue state simulation module is further provided with three pairs of sieve plates, each pair of sieve plates being sealed and disposed in two opposite openings of the same chamber.

[0022] Within the same chamber, the sieve plate near the arterial input simulation module is defined as the arterial sieve plate, and the sieve plate near the venous output simulation module is defined as the venous sieve plate.

[0023] Preferably, the sieve plate is provided with multiple through holes.

[0024] Preferably, the brain tissue state simulation module is further provided with two barrier plates that set the chamber blockage ratio by blocking the area of ​​the through hole. One barrier plate is located inside the local ischemic penumbra chamber and is stacked with the corresponding venous cribriform plate, and the other barrier plate is located inside the infarct core chamber and is stacked with the corresponding venous cribriform plate.

[0025] The barrier plate located in the partially ischemic penumbra chamber is defined as the first barrier plate, and the barrier plate located in the infarct core chamber is defined as the second barrier plate; arranged from largest to smallest, the diameters of the sieve plate, the second barrier plate, and the first barrier plate are as follows.

[0026] Preferably, the above-mentioned collateral circulation module is provided with two three-way valves and pipes, one three-way valve is provided in the third arterial channel, and the two ends of the pipe are respectively connected to the two three-way valves.

[0027] Preferably, the diameter of the microspheres is 1.5 mm to 2.5 mm; Preferably, the diameter of the through hole is 1.0 mm to 2.0 mm.

[0028] In the partially ischemic penumbra chamber, the volume ratio of the soft wax to the microspheres is 1:(1.56-1.80).

[0029] In the infarct core chamber, the volume ratio of the rigid plastic component to the microspheres is 1:(1.82~2.02).

[0030] Preferably, the perfusion fluid of the above-mentioned modular CT perfusion phantom is water, and the contrast agent is iodine.

[0031] Preferably, the rigid plastic part is ABS.

[0032] A second objective of this invention is to provide a use that overcomes the shortcomings of the prior art. This use involves time-density curves (TDC) and hemodynamic parameters (CBF, CBV, MTT, TTP) under different injection parameters and flow rates to support CTP protocol optimization, cross-device standardization, and validation of new algorithms.

[0033] The above-mentioned objectives of the present invention are achieved through the following technical measures: This invention provides a modular CT perfusion phantom that simulates brain tissue and collateral circulation as described above, the purpose of which is to standardize, evaluate, and optimize CTP imaging protocols on different CT scanning devices.

[0034] This invention discloses a modular CT perfusion phantom simulating brain tissue and collateral circulation, and its applications. The modular CT perfusion phantom includes: a brain tissue state simulation module for simulating healthy brain tissue, a regional ischemic penumbra, and an infarct core, comprising multiple independent chambers; an arterial input simulation module for simulating arterial blood flow, sealed on the input side of the brain tissue state simulation module and connected to all the chambers; a venous output simulation module for simulating venous blood flow, sealed on the output side of the brain tissue state simulation module and connected to all the chambers; and a collateral circulation module for simulating collateral circulation in the brain, connected to the brain tissue state simulation module. This modular CT perfusion phantom has a simple structure, is easy to assemble, and allows for adjustable chamber filling. It can be used to obtain time-density curves (TDC) and hemodynamic parameters (CBF, CBV, MTT, TTP) under different injection parameters and flow rates, supporting CTP protocol optimization, cross-device standardization, and new algorithm verification. Attached Figure Description

[0035] The invention will be further described with reference to the accompanying drawings, but the contents of the drawings do not constitute any limitation on the invention.

[0036] Figure 1 This is a schematic diagram of a modular CT perfusion phantom.

[0037] Figure 2 A schematic diagram of the modular CT perfusion phantom with the collateral circulation module concealed.

[0038] Figure 3 for Figure 2 Perspective view.

[0039] Figure 4 for Figure 2 Another perspective illustrating the intended meaning.

[0040] Figure 5 for Figure 4 A schematic diagram of the cross-section along the "AA" direction.

[0041] Figure 6 This is a schematic diagram of the brain tissue state simulation module.

[0042] Figure 7 for Figure 6 Another perspective diagram.

[0043] Figure 8 for Figure 7 A schematic diagram of the cross-section along the "AA" direction.

[0044] Figure 9 This is a schematic diagram of the structure of an arterial input simulation module or a venous output simulation module.

[0045] Figure 10 This is a schematic diagram of the microcirculation chamber of healthy brain tissue after microspheres have been filled.

[0046] Figure 11 A schematic diagram of a partially ischemic, semi-dark chamber after filling with microspheres and soft wax.

[0047] Figure 12 A schematic diagram of the infarcted core chamber after filling with microspheres and rigid plastic parts.

[0048] Figure 13 A schematic diagram of a modular CT perfusion phantom after being equipped with the supporting devices.

[0049] Figure 14 This is a schematic diagram of a modular CT perfusion phantom during imaging.

[0050] Figure 15 Time-density curves (TDC plots) of the arterial input function AIF for different contrast agent injection volumes.

[0051] Figure 16 Time-density curves (TDC) of venous output function (VOF) for different contrast agent injection volumes.

[0052] Figure 17 Time-density curves (TDC plots) of the arterial input function AIF at different contrast agent injection rates.

[0053] Figure 18 Time-density curves (TDC plots) of the venous output function (VOF) at different contrast agent injection rates.

[0054] Figure 19 Hemodynamic parameters for different contrast agent doses and the same contrast agent injection rate.

[0055] Figure 20 Hemodynamic parameters for different contrast agent injection rates and the same contrast agent dose.

[0056] exist Figures 1 to 20 This includes: Modular CT perfusion phantom 10, CT scanning system 20, scanning bed 30 Arterial input simulation module 100, arterial channel 110, Brain tissue state simulation module 200 Chamber 210, healthy brain tissue microcirculation chamber 211, ischemic penumbra chamber 212, infarct core chamber 213 Microspheres 220, soft wax 230, rigid plastic parts 240 Crizonal sieve plate 250, arterial siezonal sieve plate 251, venous siezonal sieve plate 252 Through hole 260, barrier plate 270 300 venous output simulation module, 310 venous access channel Side circulation module 400, three-way valve 410, pipe 420, 500 water buckets, 600 external peristaltic pumps, 700 high-pressure injectors, and 800 recovery containers. Detailed Implementation

[0057] The technical solution of the present invention will be further described in conjunction with the following embodiments.

[0058] Example 1 A modular CT perfusion phantom that simulates brain tissue and collateral circulation, such as Figures 1 to 5 As shown, the following settings are included: Brain tissue state simulation module 200 - used to simulate healthy brain tissue, local ischemic penumbra and infarct core, and has multiple independent chambers 210; Arterial input simulation module 100—used to simulate arterial blood flow, is sealed on the input side of brain tissue state simulation module 200 and is also connected to all chambers 210, such as... Figure 9 ; The venous output simulation module 300—used to simulate venous blood flow—is sealed on the output side of the brain tissue state simulation module 200 and is also connected to all chambers 210, such as... Figure 9 ; Collateral circulation module 400 – The collateral circulation module 400, used to simulate brain collateral circulation, is connected to the brain tissue state simulation module 200.

[0059] It should be noted that the brain tissue state simulation module 200 of the present invention can have multiple chambers 210, such as 2, 4, 5 or more chambers 210; the filling material in different chambers 210 can also be replaced with other equivalent materials (such as silicone, ceramic particles, etc.) to adapt to the experimental requirements of simulating brain tissue in different states. Figures 6 to 8 As shown, this embodiment takes three independent chambers 210 as an example. The brain tissue state simulation module 200 in this embodiment simulates the microcirculation of healthy brain tissue, the local ischemic penumbra, and the infarct core.

[0060] The three chambers 210 are defined as the healthy brain tissue microcirculation chamber 211, the ischemic penumbra chamber 212, and the infarct core chamber 213, respectively.

[0061] like Figure 10 The healthy brain tissue microcirculation chamber 211 can be replaced with microspheres 220 for simulating the microcirculation of the brain parenchyma.

[0062] like Figure 11 The ischemic penumbra chamber 212 can be replaced with microspheres 220 for simulating microcirculation in the brain parenchyma and soft wax 230 for simulating partial contrast agent residue in the ischemic penumbra. like Figure 12 The infarct core chamber 213 is replaceably filled with microspheres 220 and rigid plastic parts 240 for simulating microcirculation in the brain parenchyma.

[0063] Arranged from highest to lowest obstruction ratio, the order is: infarct core chamber 213, ischemic penumbra chamber 212, and healthy brain tissue microcirculation chamber 211; the diameter of microspheres 220 is 1.5 mm to 2.5 mm; in the ischemic penumbra chamber 212, the volume ratio of soft wax 230 to microspheres 220 is 1:(1.56 to 1.80); in the infarct core chamber 213, the volume ratio of rigid plastic parts 240 to microspheres 220 is 1:(1.82 to 2.02).

[0064] The collateral circulation module 400 is connected to the infarcted core chamber 213.

[0065] The modular CT perfusion phantom 10 has an effective volume of approximately 70ml to 80ml for each chamber 210, with a diameter of approximately 32mm to 35mm and a length of approximately 40mm. The brain tissue state simulation module 200, arterial input simulation module 100, and venous output simulation module 300 of the modular CT perfusion phantom 10 are manufactured using 3D printing technology. The printing material can be polymethyl methacrylate (PMMA) or equivalent engineering plastics, and the preferred manufacturing method is fused deposition modeling (FDM). The assembly points between the brain tissue state simulation module 200, arterial input simulation module 100, and venous output simulation module 300 are sealed and fixed using nitrile rubber gaskets and plastic screws.

[0066] The perfusion fluid of the modular CT perfusion phantom 10 of this invention is water, and the contrast agent is iodine.

[0067] The arterial input simulation module 100 has three independent arterial channels 110, defined as the first arterial channel 110, the second arterial channel 110, and the third arterial channel 110. The first arterial channel 110 is connected to the microcirculation chamber 211 of healthy brain tissue, the second arterial channel 110 is connected to the ischemic penumbra chamber 212, and the third arterial channel 110 is connected to the infarct core chamber 213. The venous output simulation module 300 has three independent venous channels 310, defined as the first venous channel 310, the second venous channel 310, and the third venous channel 310. The first venous channel 310 is connected to the microcirculation chamber 211 of healthy brain tissue, the second venous channel 310 is connected to the ischemic penumbra chamber 212, and the third venous channel 310 is connected to the infarct core chamber 213. The third arterial channel 110 and the third venous channel 310 are connected to the collateral circulation module 400.

[0068] It should be noted that the arterial channel 110 and the venous channel 310 of the present invention are funnel-shaped on the side near the chamber 210, so that the liquid can enter and exit the chamber 210 evenly.

[0069] When simulating the blood-brain barrier restricting the diffusion and flow of contrast agents, microspheres 220 are polyoxymethylene microspheres 220; when simulating different X-ray attenuation states, microspheres 220 are sodium alginate microspheres 220.

[0070] It should be noted that because polyoxymethylene microspheres 220 are insoluble in water and do not react with water, they can be used to simulate the blood-brain barrier restricting the diffusion and flow of contrast agents. Sodium alginate microspheres 220, on the other hand, can adjust their density automatically, thus simulating different X-ray attenuation states.

[0071] The brain tissue state simulation module 200 is also provided with three pairs of sieve plates 250, each pair of sieve plates 250 being sealed and disposed in two opposite openings of the same chamber 210. The sieve plates 250 are provided with multiple through holes 260, the diameter of which is 1.0 mm to 2.0 mm.

[0072] Within the same chamber 210, the sieve plate 250 near the arterial input simulation module 100 is defined as the arterial sieve plate 251, and the sieve plate 250 near the venous output simulation module 300 is defined as the venous sieve plate 252. The thickness of the venous sieve plate 252 is 1 mm to 10 mm, and the thickness of the arterial sieve plate 251 is 0.5 mm to 1 mm, with the thickness of the venous sieve plate 252 being greater than that of the arterial sieve plate 251.

[0073] It should be noted that the thickness of the sieve plate 250, the diameter of the through hole 260, the blocking ratio of the chamber 210, the diameter of the microsphere 220, and the size of the soft wax 230 of the present invention can all be repeatedly adjusted by replacing components. The purpose of the venous sieve plate 252 being thicker than the arterial sieve plate 251 is to facilitate the assembly of the modular CT perfusion phantom 10. In actual operation, the venous sieve plate 252 is first snapped into the opening of the chamber 210, and then the filling material is filled before sealing and assembling the arterial sieve plate 251 and the arterial input simulation module 100 with the brain tissue state simulation module 200.

[0074] The brain tissue state simulation module 200 also includes two barrier plates 270 that set the obstruction ratio of the chambers 210 by blocking the area of ​​the through-holes 260. One barrier plate 270 is located inside the ischemic penumbra chamber 212 and is stacked with the corresponding venous cribriform plate 252. The other barrier plate 270 is located inside the infarct core chamber 213 and is stacked with the corresponding venous cribriform plate 252. The barrier plate 270 located in the ischemic penumbra chamber 212 is defined as the first barrier plate 270, and the barrier plate 270 located in the infarct core chamber 213 is defined as the second barrier plate 270. Arranged from largest to smallest, the diameters of the cribriform plate 250, the second barrier plate 270, and the first barrier plate 270 are considered. The obstruction ratio of the ischemic penumbra chamber 212 is 30%–70%; the obstruction ratio of the infarct core chamber 213 is greater than 70%.

[0075] It should be noted that the function of stacking the barrier plate 270 and the venous cribriform plate 252 in this invention is to facilitate the entry of liquid from the arterial infusion simulation module 100 into the interior of the chamber 210, reducing excessive internal pressure and preventing the modular CT perfusion phantom 10 from bursting at the connection due to excessive pressure. The barrier plate 270 is provided at the outflow end of the chamber 210 of the modular CT perfusion phantom 10 of this invention to achieve occlusion ratio control within the range of 0% to 100%, thereby precisely setting the degree of occlusion in the infarct core and the degree of partial occlusion in the penumbra. The function of the barrier plate 270 in this invention is to partially block the through-hole 260 of the cribriform plate 250, thus partially sealing it off. For the locally ischemic penumbra chamber 212, a smaller diameter first barrier plate 270 is used, and it is filled with a mixture of soft wax 230 with viscous and residual properties and microspheres 220, which can effectively simulate the partial retention and delayed clearance of contrast agent in the locally ischemic penumbra. For the infarcted core chamber 213, a second barrier plate 270 with a larger diameter is used, and it is filled with microspheres 220 using rigid plastic parts 240, thus simulating a severely restricted or nearly occluded perfusion state. For the microcirculation chamber 211 of healthy brain tissue, no barrier plate 270 is used.

[0076] The side circulation module 400 is equipped with two three-way valves 410 and a pipe 420 for regulating flow. One three-way valve 410 is located in the third arterial channel 110, and the two ends of the pipe 420 are connected to the two three-way valves 410 respectively.

[0077] It should be noted that the collateral circulation module 400 connects the infarcted core chamber 213 to the third arterial channel 110 and the third venous channel 310 via conduits. The bypass flow is regulated by a three-way valve 410, thereby simulating the blood flow compensation process of collateral circulation. This invention establishes a bypass channel between the infarcted core chamber 213 and the adjacent normal chamber 210 or upstream and downstream conduits by setting the opening and closing of the three-way valve 410. The collateral module is in two states, open and closed, to simulate the conditions of having / not having collateral circulation, respectively. The three-way valve 410 can be a ball valve or a needle valve for precise regulation of the bypass flow.

[0078] The modular CT perfusion phantom 10 of this invention is also equipped with corresponding supporting devices, such as a washing / recovery container 800, a syringe, a pressurizer, an air bubble removal device, a stirring device, as well as connectors and fixing brackets, to facilitate the operation of the entire system during assembly, venting, injection, and repeated measurements. Specifically, the distribution tubing, external peristaltic pump 600, high-pressure syringe 700, water tank 500, and recovery container 800 are as follows: Figure 13 As shown in the diagram, the arrows indicate the direction of liquid flow.

[0079] The modular CT perfusion phantom 10, simulating brain tissue and collateral circulation, is simple in structure, easy to assemble, and allows for adjustment of the filling of chambers 210. Using this modular CT perfusion phantom 10, time-density curves (TDC) and hemodynamic parameters (CBF, CBV, MTT, TTP) can be generated under different injection parameters and flow rates, supporting CTP protocol optimization, cross-device standardization, and new algorithm validation. The beneficial effects of this modular CT perfusion phantom 10 are: 1. By combining three chambers 210 with heterogeneous filling materials, the differential perfusion characteristics of normal cerebral microcirculation, ischemic penumbra, and infarct core can be simultaneously reproduced on the same physical platform, improving simulation realism and facilitating experimental reproducibility; 2. The detachable / controllable design of the collateral circulation module 400 can simulate compensatory blood flow effects with and without collaterals, supporting systematic research on the influence of collaterals on perfusion parameters; 3. The use of the barrier plate 270 technology allows for fine adjustment of the flow resistance and residual effects of chamber 210, thereby enhancing CT... The parameter sensitivity analysis of the P protocol optimization and image reconstruction algorithm provides a quantitative benchmark; 4. The modular CT perfusion phantom 10 is manufactured by 3D printing, which not only reduces manufacturing costs but also improves customizability. This allows the phantom to be quickly designed and produced according to different needs, thus facilitating rapid iteration and sharing of control prototypes among different institutions; 5. This invention is compatible with conventional CT scanning and injection equipment (such as peristaltic pumps and high-pressure injectors 700), making it easy to deploy in clinical or research scenarios for cross-vendor / cross-equipment imaging standardization verification and new algorithm evaluation under low-dose conditions.

[0080] Example 2 The use of a modular CT perfusion phantom, as described above, simulating brain tissue and collateral circulation, is to standardize, evaluate, and optimize CTP imaging protocols on different CT scanning devices.

[0081] This embodiment uses a modular CT perfusion phantom simulating brain tissue and collateral circulation, as described in Example 1, for imaging. The effective volume of each chamber 210 in this modular CT perfusion phantom 10 is calculated to be 70.774 ml. Microspheres 220 are polyoxymethylene microspheres with a diameter of 2.0 mm. In the ischemic penumbra chamber 212, the volume ratio of soft wax 230 to microspheres 220 is 1:1.70; in the infarct core chamber 213, the volume ratio of rigid plastic component 240 to microspheres 220 is 1:1.90. The aperture of the through-hole 260 is 1.5 mm. The thickness of the venous cribriform plate 252 is 4 mm, and the thickness of the arterial cribriform plate 251 is 1 mm. The occlusion rate of the ischemic penumbra chamber 212 is 50%; the occlusion rate of the infarct core chamber 213 is 90%.

[0082] In the imaging method of the present invention, the modular CT perfusion phantom 10 is placed on the scanning bed 30 of the CT scanning system 20 to complete dynamic scanning, such as... Figure 14 .

[0083] Before the experiment, the modular CT perfusion phantom 10 is preferably flushed with a water pump for 10 minutes and shaken to remove air bubbles. At least 3 hours are maintained between each two contrast experiments to reduce the influence of residual contrast agent.

[0084] The modular CT perfusion phantom 10 can be used with a conventional CT scanning system 20 for dynamic scanning. Specific scanning parameters include tube voltage of 80kVp, tube current of 300mA, time resolution of 0.85s / frame, total scan time of approximately 51s, slice thickness / slice spacing of 2.5mm, and a matrix of 512×512. The image reconstruction algorithm can be ClearInfinity or other commercial reconstruction algorithms. This embodiment uses a 50% weight as an example.

[0085] Regarding the contrast agent injection strategy, an iodine contrast agent with an iodine concentration of 350 mgI / ml is used for injection, such as iohexol or iodofol. The injection protocol can be implemented according to two types of experimental protocols: 1. Fix the injection rate and change the injection volume (e.g., volume 2ml, 3ml, 4ml, 5ml, injection rate for example 0.5ml / s, corresponding duration 4s, 6s, 8s, 10s). 2. Fix the injection volume and change the injection rate (e.g., volume 3ml, rate 0.3, 0.5, 0.6, 0.8ml / s, corresponding duration 10, 6, 5, 3.75s).

[0086] After injection, it is preferable to rinse with 20 ml of normal saline at a rate of 2 ml / s.

[0087] Regarding the parameterization of contrast agent kinetics, the injection conditions are first set using the following relationship, and then the required injection rate and injection volume are estimated accordingly. Under ideal and stable conditions, the following must be satisfied:

[0088] in, Iodine flow rate; Iodine concentration; f The fluid velocity. This refers to the iodine concentration at the arterial inlet. Blood flow velocity; Contrast agent concentration; The contrast agent injection rate; The required CT value for contrast enhancement This refers to the volume of the contrast agent. The effective volume of a single chamber 210;D This is the total iodine dose. Contrast volume This represents the volume of the contrast agent.

[0089] Therefore, the required injection rate and volume can be calculated by using the target arterial enhancement peak value, such as the clinically commonly used peak value of approximately 400 HU. Under the calculation conditions of this embodiment, when the target peak value is set to 400 HU and the contrast agent concentration is 350 mgI / ml, the obtained injection rate is approximately 0.23 ml / s, and the minimum required injection volume is approximately 2.0 ml.

[0090] However, it should be understood that the above values ​​are merely illustrative examples, and the specific parameters can be adjusted according to experimental conditions, equipment characteristics, or different contrast agent concentrations. The above formulas and their equivalent substitutions are also within the protection scope of this invention.

[0091] The measurement and data processing methods for the phantom include: acquiring time density curves (TDC) of arterial input function (AIF) and venous output function (VOF) during CT scanning, and using a matching workstation or algorithm to calculate perfusion parameter maps such as CBF, CBV, MTT, and TTP to evaluate the perfusion response under different chamber 210 (normal, penumbra, infarct) and different injection / flow conditions.

[0092] The imaging method of this invention, through the switching control of the collateral circulation module 400, can achieve two experimental conditions: with and without collateral circulation. During the experiment, the injection protocol includes the following methods: First, fix the injection rate, such as 0.5 ml / s, and change the injection volume, such as 2 ml, 3 ml, 4 ml, and 5 ml, to form contrast agent curves for different durations; Second, with a fixed injection volume, such as 3 ml, the injection rate is varied to 0.3, 0.5, 0.6, and 0.8 ml / s to create contrast agent curves with different peak values.

[0093] Each injection was followed by rinsing with 20 ml of physiological saline at a rate of 2 ml / s, and the experimental intervals should be ≥3 hours to avoid interference from residual contrast agent.

[0094] The CT scan parameters were: tube voltage 80kVp, tube current 300mA, temporal resolution 0.85s / frame, total duration 51s, slice thickness / slice spacing 2.5mm, and matrix 512×512. The preferred reconstruction algorithm was ClearInfinity or an equivalent iterative reconstruction method.

[0095] After imaging, the acquired time-density curves were analyzed using a workstation to obtain the CBF, CBV, MTT, and TTP values ​​for each chamber 210, which were then used to compare the effects of different injection conditions, collateral circulation status, and degree of obstruction on the perfusion parameters. Figures 15 to 18 As shown, this invention's modular CT perfusion phantom 10 demonstrates that, at the application level, it can simulate time-density curves (TDC) perfusion curves under different contrast agent injection protocols, such as TDC curves under arterial input function (AIF) and venous output function (VOF). Figure 19 and Figure 20 As shown, hemodynamic parameters such as CBF, CBV, MTT, and TTP were calculated from the time-density curves (TDC) of each chamber 210.

[0096] This imaging method, using the aforementioned modular CT perfusion phantom 10, can be used for hemodynamic parameters (CBF, CBV, MTT, TTP) under different injection parameters and flow conditions to support CTP protocol optimization, cross-device standardization, and new algorithm validation.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A modular CT perfusion phantom simulating brain tissue and collateral circulation, characterized in that, The settings are as follows: Brain tissue state simulation module – used to simulate healthy brain tissue, local ischemic penumbra and infarct core, with multiple independent chambers; Arterial input simulation module – used to simulate arterial blood flow, sealed on the input side of the brain tissue state simulation module, and also connected to all the chambers respectively; The venous output simulation module—used to simulate venous output blood flow—is sealed on the output side of the brain tissue state simulation module and is also connected to all of the chambers. Collateral circulation module – a collateral circulation module used to simulate brain collateral circulation, which is connected to the brain tissue state simulation module.

2. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 1, characterized in that: The brain tissue state simulation module has three independent chambers, which are defined as the healthy brain tissue microcirculation chamber, the local ischemic penumbra chamber, and the infarct core chamber, respectively. The healthy brain tissue microcirculation chamber can be replaced with microspheres to simulate the microcirculation of brain parenchyma. The local ischemic penumbra chamber can be replaced with microspheres to simulate brain parenchymal microcirculation and soft wax to simulate partial contrast agent residue in the local ischemic penumbra. The infarct core chamber can be replaced with microspheres and rigid plastic parts to simulate the microcirculation of brain parenchyma; The collateral circulation module is connected to the infarcted core chamber; Arranged from highest to lowest obstruction ratio, the order is: the infarct core chamber, the locally ischemic penumbra chamber, and the healthy brain tissue microcirculation chamber.

3. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 2, characterized in that: The arterial input simulation module is equipped with three independent arterial channels, which are defined as the first arterial channel, the second arterial channel and the third arterial channel respectively. The first arterial channel is connected to the microcirculation chamber of the healthy brain tissue, the second arterial channel is connected to the chamber of the local ischemic penumbra, and the third arterial channel is connected to the infarct core chamber. The venous output simulation module is equipped with three independent venous channels, which are defined as the first venous channel, the second venous channel and the third venous channel respectively. The first venous channel is connected to the microcirculation chamber of the healthy brain tissue, the second venous channel is connected to the chamber of the local ischemic penumbra, and the third venous channel is connected to the infarct core chamber. The third arterial channel and the third venous channel are respectively connected to the collateral circulation module.

4. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 3, characterized in that: When simulating the blood-brain barrier restricting the diffusion and flow of contrast agents, the microspheres are polyoxymethylene microspheres; When simulating different X-ray attenuation states, the microspheres are sodium alginate microspheres.

5. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 4, characterized in that: The brain tissue state simulation module is also equipped with three pairs of sieve plates, each pair of sieve plates being sealed and installed in two opposite openings of the same chamber; the sieve plates are provided with multiple through holes; Within the same chamber, the sieve plate near the arterial input simulation module is defined as the arterial sieve plate, and the sieve plate near the venous output simulation module is defined as the venous sieve plate. The brain tissue state simulation module is also equipped with two barrier plates that set the chamber blockage ratio by blocking the area of ​​the through hole. One barrier plate is located inside the local ischemic penumbra chamber and is stacked with the corresponding venous cribriform plate, while the other barrier plate is located inside the infarct core chamber and is stacked with the corresponding venous cribriform plate.

6. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 5, characterized in that: The barrier plate located in the partially ischemic penumbra chamber is defined as the first barrier plate, and the barrier plate located in the infarct core chamber is defined as the second barrier plate. Arranged from largest to smallest, the diameter of the sieve plate, the diameter of the second barrier plate, and the diameter of the first barrier plate are as follows: The obstruction rate of the local ischemic penumbra chamber is 30% to 70%; The obstruction rate of the infarcted core chamber is greater than 70%.

7. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 6, characterized in that: The side circulation module is equipped with two three-way valves and pipes for regulating flow. One three-way valve is located in the third arterial channel, and the two ends of the pipe are connected to the two three-way valves respectively.

8. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to claim 7, characterized in that: The diameter of the microspheres is 1.5 mm to 2.5 mm; The diameter of the through hole is 1.0 mm to 2.0 mm.

9. The modular CT perfusion phantom simulating brain tissue and collateral circulation according to any one of claims 2 to 8, characterized in that: In the partially ischemic penumbra chamber, the volume ratio of the soft wax to the microspheres is 1:(1.56~1.80). In the infarct core chamber, the volume ratio of the rigid plastic component to the microspheres is 1:(1.82~2.02). The perfusion fluid for the modular CT perfusion phantom is water, and the contrast agent is iodine. The rigid plastic part is ABS.

10. The use of a modular CT perfusion phantom simulating brain tissue and collateral circulation as described in any one of claims 1 to 9, characterized in that: The purpose is to standardize, evaluate, and optimize the CTP imaging protocol on different CT scanning devices.

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