Method and system for operating x-ray device for creating reconstructed image of body region

Abstract

The invention relates to a method and a system for operating an X-ray device for creating a reconstructed image of a body region, comprising the following steps: triggering an administration of a first contrast agent to pre-saturate the body region with the contrast agent, in particular until a desired equilibrium concentration is reached, the administration contrast agent implementation of a second contrast agent implementation in the form of a larger mass than in the first contrast agent implementation is triggered, spectral image data (D) is recorded in at least two different beam energies, an image (Z, E) is reconstructed from the spectral image data (D), and the reconstructed image (Z, E) is output.

Description

Technical Field

[0001] The invention comprises a method and a system for operating an X-ray device for creating reconstructed images of body regions, in particular for CT angiography, as well as a control device and a computed tomography system. The invention relates in particular to selective imaging of blood vessels and thin-walled tissues by means of control of a contrast agent based on a concentration threshold. Background Art

[0002] Angiography is a method established in medicine for the radiological visualization of vessels, usually blood vessels, by means of diagnostic imaging methods. For this purpose, a contrast agent is usually injected into a vessel, usually an artery, for the evaluation of the vessels and thin-walled tissue, and a recording is simultaneously performed, so that the vessel becomes visible in the X-ray image. The recording can be an X-ray recording, a CT recording (CT: “Computed Tomography”) or an MRI recording, wherein the present invention primarily relates to X-ray recordings, in particular CT recordings.

[0003] Usually, the contrast medium is injected after the (previous) original recording. Depending on the region, organ, pathology and / or question, a temporally coordinated recording is created and repeated if necessary.

[0004] In the specific example of aortic dissection, the arterial phase is recorded. In the case of a ruptured endoprosthesis, leakage or a larger thrombus or an erroneous lumen, a supplementary record must be performed. Here, the illustration of the input and output ends of the erroneous vascular lumen is just very important for treatment. However, the erroneous vascular lumen is often not detected or only insufficiently detected in the initial record. Here, the contrast amount implemented is optimized according to the illustration of the lumen that is usually perfused, not only in terms of timing (scan start and scan duration) but also in terms of quantity (e.g., according to patient weight, -BMI, -BSA, -LBW being scaled). Thus, the following problem may occur in emergency situations, i.e., it is difficult to distinguish acute bleeding entering the existing bleeding cavity. Even in the best time of the clump of contrast agent administration, it may also cause a huge change in the circulation time in the vascular segment of interest due to pathology, which can lead to worse or even missing angiography. Ultimately, in the above-mentioned case, the operator's misunderstanding of the examination results and the omission of further scanning may also cause problems.

[0005] These problems can occur in a range of other areas and problems, for example due to arteriovenous malformations of the brain, lungs or liver, in highly vascularized tumors, such as hepatocellular carcinoma or in neuroendocrine tumors, and can also occur in a temporally limited manner in low-vascularized tumors, such as pituitary adenomas.

[0006] Hitherto, these problems have been counteracted by carrying out further scans or examinations (directly in succession or separated in time), which, however, leads to an increase in the radiation exposure of the patient. In addition, each additional examination disables the imaging system used, which can otherwise be used for other examinations. If an indication has been given or an erroneous execution has been quickly identified, an additional contrast medium dose is sometimes also provided. In the case of iodinated contrast media, this can lead to an increased risk of acute kidney injury or contrast-induced nephropathy. Summary of the invention

[0007] The object of the present invention is to specify an alternative, more comfortable method for producing recordings or images, in particular CT angiography, and a corresponding system, in particular for controlling a CT system, with which the above-mentioned disadvantages are avoided.

[0008] This object is achieved by a method according to claim 1 , a system according to claim 11 , a control device according to claim 13 and an x-ray device according to claim 14 .

[0009] According to the invention, a method for operating an X-ray device (for example a CT scanner) for creating a reconstructed image of a body region is proposed, comprising the following steps:

[0010] - triggering the administration of a first contrast agent to presaturate the body region with the contrast agent, in particular until a desired equilibrium concentration is reached,

[0011] - triggering a contrast medium administration that administers a second contrast medium administration in the form of a larger bolus than in the first contrast medium administration,

[0012] - recording spectral image data (D) at at least two different beam energies,

[0013] - reconstructing images (Z, E) from the spectral image data (D),

[0014] - Output the reconstructed image (Z, E).

[0015] The invention is based on the combination of a new contrast agent protocol with the recording of spectral (or spectrally resolved) image data and in particular additionally also on the possibility of contrast agent concentration-dependent image reconstruction, as described in more detail below. A particularly preferred contrast agent is iodine.

[0016] In angiographic recordings, in particular CT angiography, images of body regions are recorded, showing blood vessels and in particular also surrounding tissue. The blood vessels are provided with a contrast agent by means of a contrast agent so that the blood vessels can be better distinguished from the surrounding tissue and recorded using a CT system.

[0017] In general, according to the present invention, two contrast agents are implemented. The first contrast agent is implemented for presaturating a body region. Here, in the first contrast agent implementation, a relatively low contrast dose or a contrast agent with a relatively low contrast agent concentration is implemented. In the second contrast agent implementation, a relatively high contrast dose or a contrast agent with a relatively high contrast agent concentration is implemented. For this reason, within the scope of the first contrast agent implementation, a lot of contrast agents are administered, for example, until the desired equilibrium concentration is reached in particular. The equilibrium concentration corresponds to a uniform distribution of contrast agents (for example iodine content) to the entire blood volume of the patient or at least in the body region to be recorded. The equilibrium concentration is known in the prior art. For example, if the contrast agent that forms a mass in the tissue is distributed, the distribution is uniform. Basically, it can be said that when the concentration of the contrast agent in a region reaches its maximum value or decreases again, a uniform distribution is produced in the region. For example, the same contrast agent concentration should be prevalent in the organ. However, it is now possible that the contrast agent accumulates in certain places in the organ due to pathology or due to biological / geometric reasons. However, it is still clearly visible when a uniform distribution is achieved. It should be noted that this does not have to be constantly re-acquired. There are already tests that show after which time period after the contrast agent administration an equilibrium concentration is reached for a given contrast agent concentration or contrast agent amount in a body region.

[0018] Thus, by the first contrast agent administration, a presaturation of the tissue of interest is achieved until a desired concentration, in particular a (for example patient weight-specific) equilibrium concentration, is reached. Preferably, significantly less contrast is indicated for the first contrast agent administration, in contrast to conventional imaging with a contrast agent having a desired concentration for the contrast agent administration. This is based in particular on the contrast / noise ratio (CNR), which is important for diagnosis in the low keV value range.

[0019] The contrast agent administration is preferably performed by an administration unit (eg a controlled injector) which is suitable for diluting the contrast agent concentration for administration.

[0020] The equilibrium concentration depends on the examined body region and, if necessary, also on the type of examination. In this respect, it can be assumed that, for the examination of a body region, less than 90%, in particular less than 50%, but preferably more than 10%, in particular more than 30%, is administered within the scope of the first contrast agent administration compared to conventional contrast agent administration.

[0021] The phase of the first contrast agent implementation can also be used to obtain the best time point for the second contrast agent implementation. This can be done, for example, similarly to the test bolus method. The test bolus method is described exemplarily in DE 10 2006 055167A1. It should be noted that it may be advantageous to perform a (pre) CT recording between the first contrast agent implementation and the second contrast agent implementation, for example in order to record the vascular or arterial phase in a state of equilibrium concentration.

[0022] In the context of the second contrast agent administration, a highly concentrated, as well-defined bolus as possible (ie a short injection time with a high flow rate) is now provided, which is optionally adapted to the cardiac output per minute and the anatomical structure or pathology to be analyzed. The examination type and body region must also be taken into account.

[0023] However, in the second contrast medium administration, the bolus is always larger than in the first contrast medium administration, in particular the contrast amount or the contrast medium concentration in the bolus of the second contrast medium administration is higher than in the first contrast medium administration.

[0024] In the bolus implementation of the second contrast agent, the contrast agent is preferably administered at more than 4 ml / s, preferably more than 6 ml / s or even more than 7 ml / s, for example at 8 ml / s.

[0025] Compared with the first contrast agent implementation, the second contrast agent implementation should especially have a higher flow rate, especially more than 2 times higher, preferably more than 4 times higher. However, this may be related to the anatomical structure. The second contrast agent implementation should have a shorter injection time than the first contrast agent implementation, and especially in less than half the time, preferably in less than 25% of the time. However, people are often limited by the limits of the drug administration method or the maximum flow rate. It should be noted here that the injection time should not be shorter than the limit of the implementation unit, and the contrast agent injected per unit time should not exceed a medically significant amount, because the risk of extravasation or paraosmosis will increase in high flow rates. The minimum injection duration can be determined by the required volume, which is mostly related to the patient's weight.

[0026] Typically, contrast medium administration is achieved through the right brachial vein in the anterior fossa region, and less often into the left brachial vein. Other veins in the arm or leg are used less frequently, and contrast medium is also administered less frequently into the jugular vein via a peripheral central catheter.

[0027] After two contrast agent applications, spectral image data, such as CT data, are now recorded in at least two different beam energies or in at least two different radiation spectra. This preferably occurs by using an X-ray beam with at least two different spectra (e.g. dual source imaging, kV switching, double spiral CT) or by resolving the spectrum (e.g. energy-resolving double-layer detector, energy-resolving photon counting detector, separation filter arrangement). The recording time points and the number of recordings are generated by the technology used. For example, in a double-layer detector, a photon counting detector or a separation filter arrangement, a single recording is sufficient.

[0028] Depending on the examination type, for example early arterial phase, arterial phase, venous phase, portal venous phase, late phase, recordings, for example CT scans, can be performed with a delay. Especially in the arterial phase, the ideal time point for the scan is related to patient-specific parameters, such as cardiac performance.

[0029] After recording, an image is reconstructed from the recorded image data, wherein in particular two or more images of the same area are generated in which different image parts are highlighted differently. These images are then preferably settled with one another by means of special calculation methods, so that some areas are thereby highlighted and other areas are weakened. Such calculation methods are known, act on the values ​​of the image points, and for example comprise one of the basic calculation types, in particular addition or subtraction, or comprise one of the known image processing techniques for settling two image planes. Particularly preferably, an arterial image is calculated, a so-called "delayed" image is calculated, or a quantification of the contrast agent is performed. For example, an arterial image can be simulated on the original image. It is also possible to calculate a predetermined contrast agent concentration, for example a concentration below a threshold value or outside a predetermined value range, from the image. The reconstructed image is then output.

[0030] Using the peculiarities in spectral image data, for example in spectral CT, there is the possibility (due to the different image information of the same region of the recorded spectrum) of generating concentration-dependent masks for the aforementioned further image processing. In this case, it is particularly preferred to calculate a predetermined contrast agent concentration, in particular an equilibrium concentration, from the image.

[0031] The system according to the invention for carrying out the method for operating an X-ray device for creating a reconstructed image of a body region is preferably designed to carry out the method according to the invention and comprises the following components:

[0032] an administration unit (14) designed to trigger administration of a first contrast agent administration to presaturate the body region with contrast agent, in particular until a desired equilibrium concentration is reached, and to trigger administration of a second contrast agent administration in the form of a larger bolus than in the first contrast agent administration, wherein in the bolus the contrast agent is administered at a rate of more than 4 ml / s,

[0033] a number of X-ray device components (2), such as CT scanners, which are designed to record spectral image data (D) at at least two different beam energies,

[0034] a reconstruction unit (13) designed to reconstruct an image (Z, E) from the image data (D), preferably wherein during the reconstruction of the image (Z, E) concentration-relevant parts of the image (Z, E) are selectively enhanced, weakened or concealed,

[0035] - an output unit (12) designed to output the reconstructed image (Z, E).

[0036] X-ray devices are particularly CT scanners.

[0037] The functions of the components of the X-ray device have been described as examples in the context of the method. The implementation unit is preferably designed to automatically dilute the contrast agent to a first determined value or the vicinity of the first determined value and to dilute it for the first contrast agent, and to dilute it to a second determined value or the vicinity of the second determined value and to dilute it for the second contrast agent, and particularly preferably to dilute it undiluted for the second contrast agent. Therefore, only a storage container for the contrast agent and a storage container for a solvent, such as a saline solution, are required. It can also be preferred that the contrast agent is diluted for both contrast agents, but that the contrast agent is diluted less for the second contrast agent than for the first contrast agent.

[0038] A control device according to the invention for controlling an x-ray device, in particular a computed tomography system, is designed to carry out a method according to the invention and / or comprises a system according to the invention.

[0039] An X-ray device according to the invention, in particular a computed tomography system, comprises a system according to the invention and / or a control device according to the invention.

[0040] Most of the above-mentioned components of the system can be implemented completely or partially in the form of software modules in a processor of a corresponding computing system, for example by a control device of a computed tomography system. An implementation scheme based largely on software has the advantage that computing systems that have been used so far can also be transformed in a simple manner by software updates so as to work in the manner according to the invention. In this regard, the object is also solved by a corresponding computer program product with a computer program, which can be directly loaded into a computing system and has program segments so that when the program is executed in the computing system, the steps of the method according to the invention are implemented, at least the steps that can be implemented by a computer. It should be said that in this implementation scheme, the recording of spectral image data corresponds to the reception of image data, for example, via a data bus or by reading a memory unit. In addition to the computer program, such a computer program product may also include additional components, such as documents and / or additional components, such as hardware components, such as hardware keys (dongles, etc.) for using the software.

[0041] Computer-readable media, such as memory sticks, hard disks or other removable or fixedly mounted data carriers, can be used for transport to a computing system or a control device and / or for storage at or in a computing system or a control device, in which program segments of a computer program that are readable and executable by a computing system are stored. For this purpose, a computing system can have, for example, one or more cooperating microprocessors or the like.

[0042] It is pointed out that method steps, such as triggering the administration of contrast agent and recording image data, correspond to the output of corresponding control commands.

[0043] Further particularly advantageous designs and improvements of the invention result from the dependent claims and the following description, wherein the claims of one claim category may also be partially improved similarly to the claims and the description of another claim category, and individual features of different embodiments or variants may in particular also be combined to form new embodiments or variants.

[0044] According to a preferred method, a segmentation of different base materials is implemented in the image reconstruction. In this case, segments in the image are selectively highlighted, weakened or hidden depending on the concentration. This can be done depending on the problem and the anatomical structure. In a simple case, the segmentation can be carried out by assigning all image points within a certain value range to the base material. However, it is advantageous to logically link the images of different recording energies, for example, the image values ​​in one image must be within a first value range and the image values ​​in the second image must be within another value range.

[0045] In the example of an aortic dissection into the wrong lumen and a small overlying hemorrhage, the following workup steps may be used:

[0046] For example, in the case of a problem with a covering rupture and continued bleeding, similar to the existing problem in the brain, it is simple to identify contrast agent (especially iodine) in the bleeding area to visualize the potential jet. Here, it is possible to consider selectively enhancing the areas with higher contrast agent concentrations. In this case, unlike conventional CT, the concentration-dependent diagram shows the extent and location of local contrast agent escape.

[0047] In the illustration of the arterial lumen of the aorta, a high contrast agent concentration (e.g., iodine concentration) is visualized on a virtual original image in order to show the real lumen of the aorta. In this case, the density increase is eliminated by the contrast agent in, for example, the venous vascular system. The method can also be used similarly to the above, in order to visualize, for example, a jet of a higher contrast agent concentration entering an erroneous lumen.

[0048] When visualizing the wrong lumen and distinguishing thrombi, in order to show the degree of perfusion of the wrong lumen, the contrast of low concentrations is selectively enhanced. In addition, other information from spectral image data can be included. It can therefore be, for example, a proof of fresh thrombi versus organized thrombi. In this example, the parts with high concentrations can be hidden according to the best visualization and are not further amplified or linearly co-amplified. Similarly, it is conceivable to separate the arterial phase from the venous phase in the brain or bronchus, or to distinguish the arterial phase from the portal venous phase of contrast agent accumulation in the liver.

[0049] Preferably, the parts with higher contrast agent concentration are selectively enhanced. The enhancement is preferably stage, anatomical structure or physiologically related. In the early stage of contrast agent implementation, the concentration in the artery will increase. In the later stage, the area of ​​thin-walled tissue. Especially in the liver, the enhancement is significantly improved in the later stage, because the liver is supplied in the portal vein close to 2 / 3, that is, after a longer transmission time.

[0050] Preferably, a contrast agent concentration, in particular an iodine concentration, in particular a contrast agent concentration which lies outside a predefined value range and in particular is particularly high, is visualized on the virtual raw image.

[0051] The value range preferably depends on whether the contrast agent concentration in the blood vessels or in the parenchyma is considered. For example, a high contrast agent concentration in the blood vessels can correspond to about 10 mgI / ml, and a low contrast agent concentration can correspond to 0.2 mgI / ml. The value of the kidney (medullary) can be scaled, for example, by about 1 / 3, and the value in the liver parenchyma and pancreas can be scaled by about 1 / 10. Preferably, the contrast agent concentration is visualized if it is greater than 5 mgI / ml, in particular greater than 8 mgI / ml or even greater than 9 mgI / ml.

[0052] Preferably, for contrast agent concentrations below a preset threshold, a selective enhancement of the contrast is performed. Preferably, for this purpose, further information from the spectral image data is included, in particular the identification of fresh thrombi versus organized thrombi. The determination of the contrast agent concentration is preferably determined by means of a spectral image data record. Preferably, the thrombus density (ρ / z) is measured and analyzed or a spectral thrombus type is acquired.

[0053] Preferably, areas with a contrast agent concentration above a preset threshold value (in particular corresponding to an optimal visualization) are hidden and not further amplified or linearly co-amplified. Preferably, the threshold value for the contrast agent concentration in the artery is preset by the concentration in the aorta. With regard to the later stage, the threshold value can be related to the original value. Here, an optimal visualization with a small signal-to-noise ratio is sought.

[0054] Preferably, the arterial phase and the venous phase in the brain or the bronchi are separated. The separation is preferably performed based on the proportion of contrast in the arterial part of the body region compared to the proportion of contrast in the venous part.

[0055] Preferably, the arterial phase and the portal venous phase of the accumulation of contrast agent in the liver are distinguished. Preferably, the beginning of the portal venous phase of the liver is indicated by the time point of the peak enhancement in the spleen. As mentioned above, since the liver is mainly supplied by the portal vein, the enhancement rate at this time point is higher than the enhancement rate in the arterial phase.

[0056] According to a preferred method, a VNC image (VNC: "virtual plain scan") and a material image are reconstructed. In this case, the VNC image simulates a CT recording without contrast agent and thus imitates a so-called "real plain scan" image. The material image represents information about the local concentration of the contrast agent, i.e. allows the contrast agent concentration to be inferred, in particular in mgI / ml. Depending on the phase, the concentration in the artery / organ / vein is high or low. A result image is then created from these images by means of image superposition, in particular by means of subtraction and / or by means of hiding image information that lies outside a preset value range. Thus, areas in which more (high vascularization) or less (low vascularization) contrast agent is recorded can be identified. This enables information that can be used for differential diagnosis. The weakening or hiding can be adjusted by means of threshold values. These thresholds can be set, for example, manually (for example, hiding the concentration to below 1 mgI / ml) or automatically (by means of a clustering algorithm, for example k-means).

[0057] According to a preferred method, at least the first contrast agent administration is performed using an administration unit, which in particular comprises an automatically controlled injector. Preferably, a contrast agent concentration is selected for the second contrast agent administration and the contrast agent concentration for the administration is diluted for the first contrast agent administration. Basically, the contrast agent concentration can be diluted as desired with saline solution. It is particularly advantageous if both contrast agent administrations are performed by the same administration unit, in particular the same injector, and the first contrast agent administration is performed diluted and the second contrast agent administration is performed undiluted.

[0058] According to a preferred method, the first contrast agent application is used to determine the time point of the second contrast agent application. This can be achieved in particular with the aid of a test bolus. After the test bolus application, for example, a series of low-dose CT scans can be recorded, and the local "flooding" of the contrast agent can be determined (retrospectively) from these low-dose CT scans. From this, the so-called "time to peak" (ttp), i.e. the time at which the maximum value of the contrast agent concentration is reached, can be determined.

[0059] According to a preferred method, in the second contrast agent implementation, the contrast agent is administered at a rate greater than 4 ml / s, preferably greater than 5 ml / s, and in particular greater than 6 ml / s (i.e., 100 ml in 16.6 s). A higher rate greater than 7 ml / s or even greater than 8 ml / s (i.e., 100 ml in 12.5 s) is also preferred. Preferably, the second contrast agent implementation is adapted to the cardiac output per minute and / or the anatomical structure and / or pathology to be analyzed. Information about cardiac performance, i.e., cardiac output, can be derived from the above-mentioned measurements of the test mass. For example, in people with reduced cardiac performance, the time point of optimal enhancement will be delayed. In the case of the test mass, the timing is determined as described above. However, there are also some pathologies that may affect vitality. This is, for example, various heart diseases (such as shunts or defective heart valves), dissections or aneurysms. Preferably, the time point of the scan and / or the volume of the contrast agent are adjusted. Preferably, the injection point is not adjusted.

[0060] Preferably, the bolus in the second contrast agent implementation provides behavior equivalent to conventional contrast agent implementation. In the first contrast agent implementation for reaching the equilibrium phase, the injection rate is essentially unimportant, at least as long as timing should not be performed. In the second contrast agent implementation, high flow is important.

[0061] Preferably, the method is combined with information from the spectral topography for planning CT examinations, in particular by automatically detecting pathological aortas using report suggestions and placement of ROIs, determining cardiac output per minute, determining the second mass stage or estimating the soft tissue compartment, including determining the ratio of fat tissue to thin-walled tissue, and determining necessary presaturation based thereon. When detecting metallic stents or internal stents, preferably the reconstruction parameters are adjusted.

[0062] According to the preferred method, the parameters of the method are selected according to the expected pathology, especially tumor biology and / or the selected inspection type and / or the body area to be inspected. These parameters are preferably the boundaries and / or threshold values ​​of the value range and / or the contrast dose and / or contrast agent concentration implemented and / or the reconstruction of the image, especially the kernel for reconstruction. As mentioned above, for example, the contrast agent implementation is very relevant to the body area. However, different types of inspections may also require different contrast agents to be implemented. When inspecting pathology, different tumor biology, for example, may also require different contrast agents to be implemented. This applies equally to the reconstruction and post-processing of the image.

[0063] For example, in oncological problems for showing different aspects of a tumor, the possibility for manually or automatically adjusting the threshold value more finely may be advantageous. It is also advantageous to adapt to the tumor biology in terms of the duration and height of the presaturation. In addition, in particular for tumor vascularization, a particularly high resolution for showing the microstructure of the blood vessels is advantageous. It is preferred here to also generate specially adapted kernels and visualization possibilities on data based on pure contrast agents, but here it is also advantageous to use concentration-dependent threshold values. Images representing high concentrations show, for example, the microstructure of malignant tissue, images representing normal concentrations show normal parenchyma, and images representing very low concentrations show, for example, the diffusion of contrast agent into necrotic areas.

[0064] Kernels are used in the reconstruction algorithm of CT image data. The kernel determines the sharpness, granularity, contrast resolution and edge information of the reconstructed image. The choice of kernel depends on the diagnostic problem. People mention "sharp" kernels (for example for fine structures of bones and blood vessels) and "soft" kernels (for organ imaging). Preferably, a list of kernels can be used for different reconstructions, for example for quantitative, high-resolution reconstruction of images of areas: body, blood vessels, head, etc. Different kernels can also have different sharpness levels in particular. For example, high resolution of blood vessels can be achieved by a recording mode with low collimation (for example the so-called ultra-high resolution mode) and a reconstruction with thin layers, low increments and sharp kernels.

[0065] According to a preferred method, an additional recording of the image data is performed at different recording time points between the first contrast medium application and the second contrast medium application and / or after the second contrast medium application. In particular, the recording of the spectral image data is performed in at least two different beam energies or two different radiation spectra. Preferably, a result image is created from the respectively recorded images for the different recording time points by means of image superposition, in particular by means of subtraction and / or by means of concealing image information that lies outside a predefined value range. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The invention will be described in more detail again with reference to the drawings, using embodiments and explained by way of example. In this case, identical components are provided with the same reference numerals in the various drawings. These drawings are generally not to scale.

[0067] In particular, the features and advantages described in conjunction with the method according to the invention can also be designed as corresponding subunits of the system according to the invention or the control device according to the invention, the X-ray device according to the invention and the computer program product according to the invention.

[0068] On the contrary, the features and advantages described in conjunction with the system according to the invention or the control device according to the invention, the X-ray device according to the invention and the computer program product according to the invention can also be configured as corresponding method steps of the method according to the invention. In this case:

[0069] Figure 1 Detailed description of an exemplary embodiment of an X-ray device and a control device as well as a system for carrying out the method according to the invention is shown.

[0070] Figure 2 A sketch of the method flow is shown. DETAILED DESCRIPTION

[0071] Figure 1 An embodiment of an X-ray device, here in the form of a computed tomography system (CT system) 1, is shown, which has a radiation detector 4 and a radiation source 5. The radiation source 5 is designed to irradiate the radiation detector 4 with radiation. The CT system 1 shown comprises a gantry 2 having a rotor 3. The rotor 3 comprises an X-ray source as a radiation source 5 and a radiation detector 4 designed to detect X-ray radiation.

[0072] The radiation detector 4 and / or the radiation source 5 are designed for spectral CT recording. Thus, the radiation source 5 can be broadband, for example, and the radiation detector 4 can detect two or more energies in an analytical manner. However, the radiation source 5 can also emit two or more different spectra in sequence, which are then detected by the radiation detector 4. It is also possible that the gantry 2 has two or more systems consisting of a radiation source 5 and a radiation detector 4, which perform measurements in different energy spectra.

[0073] The rotor 3 can rotate about an axis of rotation 8, which can be considered as the patient longitudinal axis 8. The patient 6 is placed on a patient couch 7 and can be moved through the gantry 2 along the axis of rotation 8. The computer unit 9 is configured to control the imaging system 1 and / or to generate image data sets based on the signals detected by the radiation detector 4.

[0074] Typically, (raw) X-ray image data sets of the object 6 are recorded from a plurality of angular directions in the corresponding beam energies by means of the radiation detector 4, i.e. two or more raw data sets. Subsequently, the final image data set can be reconstructed based on the (raw) X-ray image data set by means of mathematical methods (e.g. including filtered back projection or iterative reconstruction methods). In this case, the image data set comprises images Z, E that have been reconstructed using the method according to the invention.

[0075] The computing unit 9 may include or be a control device 9 for controlling the CT system 1 and a generation unit for generating an X-ray image data set. In the case shown here, the computing unit 9 is a control device 9 .

[0076] Furthermore, an input device 10 and an output device 11 are connected to the computing unit 9. The input device 10 and the output device 11 enable, for example, an interaction by a user or a display of generated image data sets or an output of a determined solution to a problem.

[0077] According to the invention, the computer unit 9 as control device 9 comprises a data interface 12 for receiving the acquired CT data D and a reconstruction unit 13 for reconstructing the images Z, E (see, for example, Figure 2 ). The computing unit is also designed to control the implementation unit 14 according to the method according to the invention.

[0078] The data interface 12 is designed to receive spectral CT data D at at least two different average beam energies and to output a reconstructed image E. The data interface also serves as an output unit 12 in this case.

[0079] The reconstruction unit 13 is designed to reconstruct at least an intermediate image Z or a result image E from the CT data D. The reconstruction unit can be designed such that it reconstructs intermediate images Z from the CT data D and subsequently calculates a number of result images E from these intermediate images Z, but it can also reconstruct a number of result images based on a specific consideration of the CT data D.

[0080] The execution unit 14, the reconstruction unit 13 and the CT components required for recording images, such as the gantry 2, form an example of a system according to the invention. Basically, the CT system 1 can also be regarded as a system according to the invention here, since all components are already integrated there.

[0081] The CT system shown here may be, for example, a CT system 1 with a photon counting detector, a dual-source CT system 1 , a CT system 1 with a dual-slice detector, a CT system with a kV switch or a CT system 1 with a separate prefilter.

[0082] Figure 2 A block diagram of a preferred exemplary embodiment of the method according to the invention for producing a CT angiography E of a body region is shown.

[0083] In step I, the body region is presaturated with a first contrast agent until a desired equilibrium concentration is reached. This equilibrium concentration exists, for example, if the contrast agent K is distributed uniformly in the blood vessels in the body region.

[0084] In step II, a second contrast medium administration is performed in the form of a larger bolus than in the first contrast medium administration. In this bolus, contrast medium K is administered, for example, at more than 4 ml / s and is intended to lead to a strong and rapid increase in contrast medium concentration KK in the blood vessels.

[0085] Normally, this is undesirable, since it may lead to errors in the recording. However, by the first contrast agent implementation an equilibrium concentration is already established, whereby these errors are avoided.

[0086] In step III, spectral CT data D are recorded at at least two different beam energies. This can be done, for example, using Figure 1 The CT system 1 is implemented by a gantry 2.

[0087] In step IV, images Z, E are reconstructed from the CT data D. In this example, when reconstructing the images Z, E, a segmentation of the different base materials should be performed and segments in the images Z, E should be selectively highlighted depending on the concentration. For example, a VNC image is reconstructed as an intermediate image Z and a material image as a further intermediate image Z. The VNC image simulates a CT recording without contrast agent, and the material image represents information about the local concentration of contrast agent. A result image E is then created from these intermediate images Z by means of image superposition, for example by means of subtraction.

[0088] Subsequently, the reconstructed images Z, E are output. In this case, only the result image E or also the intermediate image Z can be output.

[0089] Finally, it is pointed out again that the drawings described in detail above are only embodiments, and those skilled in the art may modify the embodiments in different ways without departing from the scope of the present invention. In addition, the use of the indefinite article "a" or "an" does not exclude that the relevant features may appear multiple times. The terms "unit" and "device" also do not exclude that the relevant components may be composed of multiple interacting subcomponents, which may also be distributed in space if necessary. The expression "a certain number" should be understood as "at least one". Regardless of the grammatical gender of a particular term, individuals with male or female gender identities are also included in the term.

Claims

1. A method for operating an X-ray device for creating a reconstructed image of a body region, the method comprising the following steps: - triggering the administration of a first contrast agent to presaturate the body region with the contrast agent, in particular until a desired equilibrium concentration is reached, - triggering a contrast medium administration that administers a second contrast medium administration in the form of a larger bolus than in the first contrast medium administration, - recording spectral image data (D) at at least two different beam energies, - reconstructing images (Z, E) from said spectral image data (D), - Outputting said reconstructed image (Z, E).

2. The method according to claim 1, wherein: In the bolus implementation of the second contrast agent, the contrast agent is administered at more than 4 ml / s.

3. The method according to claim 1 or 2, wherein: In the reconstruction of the image (Z, E), a segmentation of different base materials is performed and, depending on the concentration, segments in the image (Z, E) are selectively highlighted, weakened or hidden, preferably wherein: - selective enhancement of areas with higher contrast agent concentration (KK), and / or - visualizing the contrast medium concentration (KK), in particular a contrast medium concentration (KK) which lies outside a predefined value range, on a virtual original image, and / or - selectively enhancing the contrast of concentrations below a preset threshold, wherein preferably further information from the spectral image data is included for this, in particular the identification of fresh thrombus versus organized thrombus, and / or - sites with concentrations above a preset threshold are hidden and not further amplified or linearly co-amplified, and / or - separation of the arterial and venous phases in the brain or bronchi, and / or -Distinguish between the arterial and portal venous phases of contrast medium accumulation in the liver.

4. A method according to any one of the preceding claims, wherein: A VNC image (Z) and a material image (Z) are reconstructed, wherein the VNC image simulates an image recording without a contrast agent and the material image represents information about the local concentration of the contrast agent, and a result image (E) is created from these images (Z) by means of image superposition, in particular by means of subtraction and / or by means of concealment of image information lying outside a preset value range.

5. A method according to any one of the preceding claims, wherein: At least the first contrast agent administration is performed by means of an automatically controlled administration unit (14), preferably wherein: A contrast agent concentration (KK) is selected for the second contrast agent implementation and said contrast agent concentration (KK) for said implementation is diluted for the first contrast agent implementation.

6. A method according to any one of the preceding claims, wherein: The first contrast agent administration is used to determine a time point for the second contrast agent administration.

7. A method according to any one of the preceding claims, wherein: In the second contrast agent implementation, the contrast agent (K) is administered at a rate of more than 5 ml / s, in particular more than 6 ml / s, preferably wherein: The second contrast medium administration is adapted to the cardiac output per minute and / or the anatomical structure and / or pathology to be analyzed, preferably wherein the bolus in the second contrast medium administration provides a behavior that is equivalent to a conventional contrast medium administration.

8. A method according to any one of the preceding claims, wherein: The X-ray device is a computed tomography device and the method is combined with information from the spectral topography for planning the CT recording, in particular by automatically detecting the pathological aorta using report suggestions and placement of the ROI, thereby determining the cardiac output per minute, determining the second mass phase and / or estimating the soft tissue compartment, including determining the ratio of fat tissue to parenchyma tissue and determining the necessary presaturation based thereon.

9. A method according to any one of the preceding claims, wherein: The limits of the value range and / or the threshold values ​​and / or the contrast amount and / or the contrast agent concentration (KK) carried out and / or the reconstruction of the image (Z, E), in particular the kernel used for the reconstruction, are selected as a function of: - the expected pathology, especially the tumor biology and / or - The selected examination type and / or body area to be examined.

10. A method according to any one of the preceding claims, wherein: Additional recording of the image data (D) is performed at different recording time points between the first contrast agent application and the second contrast agent application and / or after the second contrast agent application, in particular spectral image data are recorded at at least two different beam energies, preferably wherein a result image (E) is created from the respectively recorded images (Z) for the different recording time points by means of image superposition, in particular by means of subtraction, and / or by means of concealing image information lying outside a preset value range.

11. A system for performing a method for operating an X-ray device for creating a reconstructed image of a body region, the system comprising: - an administration unit (14) designed to trigger administration of a first contrast agent administration in order to presaturate the body region with contrast agent, in particular until a desired equilibrium concentration is reached, and to trigger administration of a second contrast agent administration in the form of a larger bolus than in the first contrast agent administration, wherein in the bolus the contrast agent is administered at a rate of more than 4 ml / s, - a number of X-ray device components (2) designed to record spectral image data (D) at at least two different beam energies, a reconstruction unit (13) designed to reconstruct an image (Z, E) based on the image data (D), preferably wherein, when reconstructing the image (Z, E), concentration-relevant parts of the image (Z, E) are selectively enhanced, weakened or concealed, - an output unit (12) designed to output said reconstructed images (Z, E).

12. The system according to claim 11, wherein: The execution unit (14) is designed to automatically dilute the contrast agent (K) to a first determined value or near the first determined value and to perform the dilution for a first contrast agent, and to dilute the contrast agent to a second determined value or near the second determined value and to perform the dilution for a second contrast agent, and particularly preferably to perform the dilution for the second contrast agent without dilution.

13. A control device (9) designed to control an X-ray device (1), in particular a computed tomography system, designed to carry out a method according to any one of claims 1 to 10, and preferably comprising a system according to claim 11 or 12.

14. An X-ray device (1), in particular a computed tomography system, comprising a system according to claim 11 or 12 and / or a control device (9) according to claim 13.

15. A computer program product comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 10, wherein: Method steps, such as triggering the administration of contrast agent (K) and recording image data (D), correspond to outputting corresponding control commands.

16. A computer-readable storage medium comprising instructions, which, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 10, wherein: Method steps, such as administration of contrast agent (K) and acquisition of CT data (D), correspond to the output of corresponding control commands.

Images