Energy spectrum image performance evaluation method for CT dual-energy imaging

Abstract

The invention discloses a CT dual-energy imaging energy spectrum image performance evaluation method, which comprises a motif main body, the motif main body comprises a motif and a plug-in, and the motif and the plug-in are subjected to CT dual-energy imaging and energy spectrum application processing to obtain a substance separation image. Evaluating the performance of the substance separation image through the CT value representation of the to-be-separated substance plug-in and the base substance plug-in in the image; after the motif and the plug-in are subjected to CT dual-energy imaging, a CT energy spectrum image with quantitative information is obtained based on image reconstruction, and the substance quantitative performance of the corresponding CT energy spectrum image is evaluated by comparing a pixel value of the substance quantitative image with a theoretical value or a calibration value of a to-be-measured physical quantity of the corresponding plug-in. The invention provides an energy spectrum image performance evaluation method for CT dual-energy imaging, which can promote establishment of a dual-energy imaging performance evaluation system for CT products or related post-processing software products.

Description

Technical Field

[0001] The invention relates to the technical field of medical equipment, and in particular to a method for evaluating the performance of energy spectrum images of CT dual-energy imaging. Background Art

[0002] Compared with conventional CT imaging methods, CT dual-energy imaging and energy spectrum applications can provide more clinical diagnostic information and can further optimize image quality in specific scenarios. In recent years, after sufficient clinical scientific research and practical accumulation, the clinical value of CT dual-energy imaging and energy spectrum applications has been widely recognized by the radiology community, and has gradually entered the standard process of clinical application and the clinical diagnosis and treatment guidelines for specific diseases. On the other hand, with the development of CT imaging technology, diversified CT dual-energy imaging modes and energy spectrum applications have also been adopted by more and more CT products. However, due to the diversity of related technical implementation methods, there is currently no unified performance evaluation method and standard. Based on the above situation, the present invention provides an evaluation method for dual-energy CT and related energy spectrum imaging performance. Summary of the invention

[0003] In order to solve the above technical problems, the invention provides a method for evaluating the performance of energy spectrum images of CT dual-energy imaging and a method for detecting the same.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the invention is as follows:

[0005] A method for evaluating the performance of spectral images of CT dual-energy imaging comprises a phantom body, wherein the phantom body comprises a phantom and a plug-in, wherein the phantom and the plug-in are subjected to CT dual-energy imaging and spectral application processing to obtain a material separation image, and then the performance of the material separation image is evaluated by the CT value performance of the plug-in for the material to be separated and the plug-in for the base material in the image;

[0006] After CT dual-energy imaging of the phantom and the plug-in, a CT energy spectrum image with quantitative information is obtained based on image reconstruction, and the material quantitative performance of the corresponding CT energy spectrum image is evaluated by comparing the pixel value of the material quantitative image with the theoretical value or calibration value of the physical quantity to be measured of the corresponding plug-in.

[0007] Preferably, the CT value of the phantom body is the same as or close to that of water, the plug-in contains a mixture of a substance to be separated and a base substance at a certain concentration, and the concentration covers a concentration range commonly used in clinical practice, the axis of the plug-in is parallel to the axis of the phantom, the substance to be separated is a substance selected to be removed in the substance separation image, and the base substance is a substance selected to be displayed in the image in the substance separation image after removing the substance to be separated.

[0008] The performance evaluation of the above-mentioned material separation image includes the following steps:

[0009] Image acquisition: dual-energy imaging is performed on the main body of the phantom to obtain the corresponding material separation image;

[0010] Image evaluation: select a region of interest at the center of the corresponding plug-in on the material separation image, and calculate the average CT value of the pixels in the region of interest, wherein the size of the region of interest is selected according to the principle that the diameter of the region of interest is approximately or equal to 80% of the diameter of the plug-in, and the measurement of the CT value includes the plug-in CT value of the mixture of the to-be-separated material and the base material with different concentrations, and the plug-in CT value of the pure base material;

[0011] Expression of results: The information of the phantom and plug-in used combined with the type of material separation image clearly defines the material to be separated and the base material, and the material separation performance is evaluated by measuring the average CT value of the region of interest corresponding to different plug-ins.

[0012] The quantitative performance evaluation of the material of the above corresponding CT energy spectrum image includes the following steps:

[0013] Image acquisition, adopting specific reconstruction or image processing methods to obtain corresponding quantitative images of substances;

[0014] Image evaluation: select a region of interest at the center of the corresponding plug-in on a specific material separation image and calculate the average CT value of the pixels in the region of interest, wherein the size of the region of interest follows the following selection criteria: the diameter of the region of interest should be approximately equal to 80% of the diameter of the plug-in;

[0015] The result expression includes the information of the phantom and plug-in used for the quantitative image of a specific substance, as well as the average value of the region of interest corresponding to different plug-ins, and gives a reference theoretical value or calibration value based on the corresponding standard substance database information.

[0016] Compared with the prior art, the invention has the following beneficial effects:

[0017] The present invention provides an energy spectrum image performance evaluation method for CT dual-energy imaging, which can promote the establishment of a dual-energy imaging performance evaluation system for CT products or related post-processing software products. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of an existing dual-energy test phantom.

[0019] Figure symbols: 1. model, 2. plug-in. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the invention more clearly understood, the invention is further described in detail below in conjunction with embodiments and drawings. The illustrative implementation modes of the invention and their descriptions are only used to explain the invention and are not intended to limit the invention.

[0021] Example 1

[0022] A method for evaluating the performance of spectral images of CT dual-energy imaging includes a phantom body, such as Figure 1 As shown, the phantom body includes a phantom 1 and a plug-in 2. The phantom 1 and the plug-in 2 are subjected to CT dual-energy imaging and energy spectrum application processing to obtain a material separation image, and then the performance of the material separation image is evaluated by the CT value performance of the to-be-separated material plug-in and the base material plug-in in the image; the phantom 1 and the plug-in 2 are subjected to CT dual-energy imaging to obtain a CT energy spectrum image with quantitative information based on image reconstruction, and the material quantitative performance of the corresponding CT energy spectrum image is evaluated by comparing the pixel value of the material quantitative image with the theoretical value or calibration value of the physical quantity to be measured of the corresponding plug-in.

[0023] The CT value of the above-mentioned phantom body is the same as or close to that of water. The plug-in 2 contains a mixture of a substance to be separated and a base substance at a certain concentration, and the concentration covers the concentration range commonly used in clinical practice. The axis of the plug-in 2 is parallel to the axis of the phantom 1. The substance to be separated is the substance selected to be removed in the substance separation image, and the base substance is the substance selected to be displayed in the image in the substance separation image after removing the substance to be separated.

[0024] The performance evaluation of material separation images includes the following steps:

[0025] Image acquisition: dual-energy imaging is performed on the main body of the phantom to obtain the corresponding material separation image;

[0026] Image evaluation: select a region of interest at the center of the corresponding plug-in on the material separation image, and calculate the average CT value of the pixels in the region of interest, wherein the size of the region of interest is selected according to the principle that the diameter of the region of interest is approximately or equal to 80% of the diameter of the plug-in, and the measurement of the CT value includes the plug-in CT value of the mixture of the to-be-separated material and the base material with different concentrations, and the plug-in CT value of the pure base material;

[0027] Expression of results: The information of the phantom and plug-in used combined with the type of material separation image clearly defines the material to be separated and the base material, and the material separation performance is evaluated by measuring the average CT value of the region of interest corresponding to different plug-ins.

[0028] The phantom information should be combined with the material separation image type to clearly identify the material to be separated and the base material. If the corresponding image processing settings are different from the typical imaging conditions of the specified CT dual-energy imaging, additional instructions should be given. The result expression and other information that should be included are shown in Table 1:

[0029] Table 1 Evaluation of spectral image performance of CT dual-energy imaging: Material separation performance

[0030]

[0031] The quantitative performance evaluation of materials corresponding to CT energy spectrum images includes the following steps:

[0032] Image acquisition: adopt specific reconstruction or image processing methods to obtain the corresponding quantitative images of substances;

[0033] Image evaluation: Select a region of interest at the center of the corresponding plug-in on a specific material separation image and calculate the average CT value of the pixels within the region of interest. The size of the region of interest follows the following selection criteria: the diameter of the region of interest should be approximately equal to 80% of the diameter of the plug-in;

[0034] Result expression: includes information about the phantom and plug-in used for quantitative images of specific substances, as well as the average values ​​of the regions of interest corresponding to different plug-ins, and gives reference theoretical values ​​or calibration values ​​based on the corresponding standard substance database information.

[0035] If the corresponding material quantification image processing settings are different from the typical imaging conditions specified for CT dual-energy imaging, additional instructions should be given. The result expression and other information that should be included are shown in Table 2 Table 2 Spectral image performance evaluation of CT dual-energy imaging: material quantification performance

[0036]

[0037] The typical imaging conditions of the above-mentioned CT dual-energy imaging include the CT operating conditions when the CT scanning device performs CT dual-energy imaging, and the operating conditions include: the peak X-ray tube voltage of the scan or a combination of different peak X-ray tube voltages; the energy spectrum filter required to achieve data acquisition under different energy spectra; the X-ray tube current and loading time corresponding to the peak X-ray tube voltage, or the current-time product; the collimation width, pitch coefficient, rotation time and other optional settings related to CT dual-energy imaging.

[0038] The technical implementation methods corresponding to the typical imaging conditions of CT dual-energy imaging are shown in Table 3. The focus of CT dual-energy imaging is to collect the absorption values ​​of the scanned object under two X-ray energies. Its implementation methods can be diverse. Each CT manufacturer has designed different CT dual-energy imaging modes according to the technical characteristics of its products. Some commercial CT dual-energy imaging technology implementation methods are shown in Table 3.

[0039] Table 3 List of implementation methods of CT dual energy imaging technology

[0040] Technology Category – Implementation Method Based on detector-side technology - double-layer detector Based on detector-side technology – photon counting detector Based on the radiation source technology – spectrum separation filter plate Based on the X-ray source technology – two scans with different tube voltages Based on the X-ray source technology – dual source scanning with different tube voltages Helical / axial scanning based on the X-ray source technology – periodic tube voltage switching Based on the technology of the source end of the ray - fast tube voltage switching

[0041] Typical imaging conditions of CT dual-energy imaging also include reconstruction parameters and image processing settings corresponding to generating quasi-mono-energy CT images, high-energy images / low-energy images or corresponding CT energy spectrum images based on data obtained from CT dual-energy imaging, including:

[0042] Image reconstruction algorithms, such as filtered back projection, iterative reconstruction, etc.;

[0043] Convolution kernel, reconstruction slice thickness, and other settings related to image reconstruction.

[0044] For CT scanning devices, if dual-energy imaging functions are provided for different body types (adults or children) and different parts (head or body), corresponding typical imaging conditions should be given, and corresponding imaging performance evaluations should be carried out for different typical imaging conditions.

[0045] For energy spectrum applications or post-processing software, when evaluating the performance of CT energy spectrum images, the typical imaging conditions corresponding to the supported CT scanning device should be given to correspond to the energy spectrum image performance under the corresponding imaging conditions.

[0046] Examples of typical imaging conditions and other relevant information that need to be given are shown in Table 4:

[0047] Table 4 Typical imaging conditions and other relevant information for CT dual-energy imaging

[0048]

[0049]

[0050] The conventional diagnosis in Table 4 refers to the traditional CT reading and diagnosis report using the corresponding image types.

[0051] Of course, the invention may have many other implementation modes. Without departing from the spirit and essence of the invention, technicians familiar with the field may make various corresponding changes and deformations based on the invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the invention.

Claims

1. A method for evaluating the performance of spectral images of CT dual-energy imaging, comprising a phantom body, the phantom body comprising a phantom (1) and a plug-in (2), characterized in that: The phantom (1) and the plug-in (2) are subjected to CT dual-energy imaging and spectrum application processing to obtain a material separation image, and the performance of the material separation image is evaluated by the CT value performance of the plug-in for the material to be separated and the base material plug-in in the image; The phantom (1) and the plug-in (2) are subjected to CT dual-energy imaging to obtain a CT energy spectrum image with quantitative information based on image reconstruction, and the material quantitative performance of the corresponding CT energy spectrum image is evaluated by comparing the pixel value of the material quantitative image with the theoretical value or calibration value of the physical quantity to be measured of the corresponding plug-in.

2. The method for evaluating the performance of spectral images of CT dual-energy imaging according to claim 1, characterized in that: The CT value of the phantom body is the same as or close to that of water. The plug-in (2) contains a mixture of a substance to be separated and a base substance at a certain concentration, and the concentration covers a common clinical concentration range. The axis of the plug-in (2) is parallel to the axis of the phantom (1).

3. The method for evaluating the performance of spectral images of CT dual-energy imaging according to claim 2, characterized in that: The substance to be separated is the substance selected to be removed in the substance separation image, and the base substance is the substance selected to be displayed in the substance separation image after removing the substance to be separated.

4. The method for evaluating the performance of spectral images of CT dual-energy imaging according to claim 3, characterized in that: The performance evaluation of material separation images includes the following steps: Image acquisition: dual-energy imaging is performed on the main body of the phantom to obtain the corresponding material separation image; Image evaluation: select a region of interest at the center of the corresponding plug-in on the material separation image, and calculate the average CT value of the pixels in the region of interest, wherein the size of the region of interest is selected according to the principle that the diameter of the region of interest is approximately or equal to 80% of the diameter of the plug-in, and the measurement of the CT value includes the plug-in CT value of the mixture of the to-be-separated material and the base material with different concentrations, and the plug-in CT value of the pure base material; Expression of results: The information of the phantom and plug-in used combined with the type of material separation image clearly defines the material to be separated and the base material, and the material separation performance is evaluated by measuring the average CT value of the region of interest corresponding to different plug-ins.

5. The method for evaluating the performance of spectral images of CT dual-energy imaging according to claim 3, characterized in that: The quantitative performance evaluation of materials corresponding to CT energy spectrum images includes the following steps: Image acquisition, adopting specific reconstruction or image processing methods to obtain corresponding quantitative images of substances; Image evaluation: select a region of interest at the center of the corresponding plug-in on a specific material separation image and calculate the average CT value of the pixels in the region of interest, wherein the size of the region of interest follows the following selection criteria: the diameter of the region of interest should be approximately equal to 80% of the diameter of the plug-in; The result expression includes the information of the phantom and plug-in used for the quantitative image of a specific substance, as well as the average value of the region of interest corresponding to different plug-ins, and gives a reference theoretical value or calibration value based on the corresponding standard substance database information.

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