CN112581556B - Multi-energy CT image hardening correction method and device, computer equipment and storage medium - Google Patents
Multi-energy CT image hardening correction method and device, computer equipment and storage medium Download PDFInfo
- Publication number
- CN112581556B CN112581556B CN202011564828.1A CN202011564828A CN112581556B CN 112581556 B CN112581556 B CN 112581556B CN 202011564828 A CN202011564828 A CN 202011564828A CN 112581556 B CN112581556 B CN 112581556B
- Authority
- CN
- China
- Prior art keywords
- image
- hardening
- energy spectrum
- energy
- correction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000012937 correction Methods 0.000 title claims abstract description 124
- 238000000034 method Methods 0.000 title claims abstract description 53
- 238000001228 spectrum Methods 0.000 claims abstract description 173
- 239000000463 material Substances 0.000 claims abstract description 67
- 239000000126 substance Substances 0.000 claims abstract description 58
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 41
- 230000003595 spectral effect Effects 0.000 claims description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 230000006870 function Effects 0.000 claims description 24
- 210000000988 bone and bone Anatomy 0.000 claims description 23
- 238000009499 grossing Methods 0.000 claims description 16
- 238000004364 calculation method Methods 0.000 claims description 14
- 238000004590 computer program Methods 0.000 claims description 12
- 238000004445 quantitative analysis Methods 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 5
- 238000012545 processing Methods 0.000 description 11
- 238000004891 communication Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 6
- 229910052740 iodine Inorganic materials 0.000 description 6
- 239000011630 iodine Substances 0.000 description 6
- 230000009467 reduction Effects 0.000 description 5
- 230000005855 radiation Effects 0.000 description 4
- 230000009977 dual effect Effects 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 3
- 210000001519 tissue Anatomy 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 206010028980 Neoplasm Diseases 0.000 description 2
- 102000019307 Sclerostin Human genes 0.000 description 2
- 108050006698 Sclerostin Proteins 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000003745 diagnosis Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000003902 lesion Effects 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 201000011510 cancer Diseases 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011982 device technology Methods 0.000 description 1
- 238000003748 differential diagnosis Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001575 pathological effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T11/00—2D [Two Dimensional] image generation
- G06T11/003—Reconstruction from projections, e.g. tomography
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T5/00—Image enhancement or restoration
- G06T5/70—Denoising; Smoothing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10072—Tomographic images
- G06T2207/10081—Computed x-ray tomography [CT]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/30—Subject of image; Context of image processing
- G06T2207/30004—Biomedical image processing
- G06T2207/30008—Bone
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Apparatus For Radiation Diagnosis (AREA)
Abstract
The application relates to a multi-energy CT image hardening correction method, a device, a computer device and a storage medium, wherein the multi-energy CT image hardening correction method comprises the following steps: performing base material decomposition on the first energy spectrum image and the second energy spectrum image; projecting the first base substance image and the second base substance image under a first energy spectrum and a second energy spectrum to obtain a first projection value and a second projection value; reconstructing based on the first projection values and the second projection values; obtaining a first hardening item image based on the first reconstruction image and the first energy spectrum image, and obtaining a second hardening item image based on the second reconstruction image and the second energy spectrum image; and carrying out hardening correction on the first energy spectrum image and the second energy spectrum image. The multi-energy CT image hardening correction method, the multi-energy CT image hardening correction device, the computer equipment and the storage medium ensure that the CT value after high-energy and low-energy image hardening correction is unchanged, subsequent quantitative analysis results are not influenced, the correction effect is better, and the efficiency is higher.
Description
Technical Field
The present application relates to the field of medical device technology, and in particular, to a method and an apparatus for correcting hardening of a multi-energy CT image, a computer device, and a storage medium.
Background
With the development of X-ray detectors and imaging systems, dual energy CT has been widely used. Compared with the traditional single-energy CT, the double-energy CT can accurately quantify iodine or calcium in tissues by utilizing substance separation imaging, and low-keV and high-keV single-energy spectrum images can respectively improve the contrast of the images, effectively reduce metal and hardening artifacts and increase the lesion display rate. Therefore, dual energy CT is of great significance in the field of clinical medical diagnosis. The substance separation imaging can effectively extract iodine components in tissues and obtain an iodine map by matching pseudo-color, and can visually reflect the iodine concentration value in the pathological tissues so as to evaluate the vascularization degree of tumors. Therefore, dual energy CT, a high-level form of CT, not only provides morphological information of tumors, but also allows diagnosis and differential diagnosis of some lesions based on their iodine content after enhancement of benign and malignant tumors.
Since the energy of the radiation emitted from the bulb shows a spectral distribution, and the radiation is not a monoenergetic radiation, a beam hardening phenomenon occurs when the radiation passes through an irradiated object, and thus, hardening correction processing needs to be performed on the image. The conventional hardening correction comprises water hardening correction and bone hardening correction, but the result of the bone hardening correction usually causes a certain deviation of the CT value in the bone region, and for the dual-energy image, if the high-energy image and the low-energy image are respectively hardened and corrected, the CT value of the original image is changed, so that the subsequent quantitative analysis of the dual-energy image cannot be performed.
Disclosure of Invention
The embodiment of the application provides a hardening correction method and device for a multi-energy CT image, computer equipment and a storage medium, and aims to at least solve the problem that in the related technology, the hardening correction of dual-energy images respectively changes the CT value of the original image, so that the subsequent quantitative analysis of the dual-energy images cannot be carried out.
In a first aspect, an embodiment of the present application provides a hardening correction method for a multi-energy CT image, which is used for correcting a hardening term of a high-low energy spectrum image scanned by a multi-energy CT system, where the high-low energy spectrum image includes a first energy spectrum image and a second energy spectrum image, and the method includes:
performing base material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first base material image and a second base material image;
projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value;
reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image;
obtaining a first hardening item image based on the first reconstructed image and the first energy spectrum image, and obtaining a second hardening item image based on the second reconstructed image and the second energy spectrum image;
and carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first correction image and a second correction image.
In some embodiments, the performing hardening correction on the first spectral image and the second spectral image based on the first hardening correction term and the second hardening correction term to obtain a first corrected image and a second corrected image further includes:
and repeating the steps by taking the first correction image and the second correction image as initial images, and iterating for a preset number of times to obtain a first target image and a second target image.
In some embodiments, the projecting the first and second basic substance images under the first energy spectrum to obtain the first projection value, and projecting the first and second basic substance images under the second energy spectrum to obtain the second projection value includes:
forward projecting the first base material image to obtain a first forward projection value, and forward projecting the second base material image to obtain a second forward projection value;
carrying out linear weighting on the first positive projection value and the second positive projection value to obtain a linear weighted value;
and performing projection calculation on the linear weighted value under a first energy spectrum to obtain a first projection value, and performing projection calculation on the linear weighted value under a second energy spectrum to obtain a second projection value.
In some embodiments, the performing the basis substance decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first basis substance image and a second basis substance image includes:
and performing water/bone decomposition on the first energy spectrum image and the second energy spectrum image to obtain a water decomposition image and a bone decomposition image.
In some embodiments, the reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image further includes:
and performing HU correction on the first reconstructed image and the second reconstructed image to obtain a corrected first reconstructed image and a corrected second reconstructed image.
In some embodiments, the deriving the first sclerostin image based on the first reconstructed image and the first spectral image, and the deriving the second sclerostin image based on the second reconstructed image and the second spectral image further comprises:
smoothing the first energy spectrum image and the second energy spectrum image based on a Gaussian function to obtain a first adjustment image and a second adjustment image;
adjusting the first reconstruction image based on the first adjustment image to obtain the first hardening item image; and adjusting the second reconstructed image based on a second adjusting image to obtain a second hardening item image.
In some embodiments, the smoothing the first energy spectrum image and the second energy spectrum image based on the gaussian function to obtain a first adjusted image and a second adjusted image further includes:
and adjusting parameters of the Gaussian function, and smoothing the first energy spectrum image and the second energy spectrum image based on the Gaussian function with different parameters until the first hardening item image and the second hardening item image reach the minimum value.
In a second aspect, an embodiment of the present application provides a multi-energy CT image hardening correction apparatus, including:
the base material decomposition module is used for carrying out base material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first base material image and a second base material image;
the projection module is used for projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value;
the reconstruction module is used for reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image;
a hardening item acquisition module, configured to obtain a first hardening item image based on the first reconstructed image and the first spectral image, and obtain a second hardening item image based on the second reconstructed image and the second spectral image;
and the correction module is used for carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first correction image and a second correction image.
In a third aspect, an embodiment of the present application provides a computer device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor, when executing the computer program, implements the multi-energy CT image hardening correction method according to the first aspect.
In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the multi-energy CT image hardening correction method according to the first aspect.
Compared with the related art, the method, the device, the computer equipment and the storage medium for correcting the hardening of the multi-energy CT image provided by the embodiment of the application obtain a first base material image and a second base material image by performing base material decomposition on the first energy spectrum image and the second energy spectrum image; projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value; reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image; obtaining a first hardening item image based on the first reconstruction image and the first energy spectrum image, and obtaining a second hardening item image based on the second reconstruction image and the second energy spectrum image; hardening correction is carried out on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image, and a first correction image and a second correction image are obtained, so that the CT value of the high-low energy image after hardening correction is unchanged, the subsequent quantitative analysis result is not influenced, the correction effect is better, and the efficiency is higher.
The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the application.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a schematic flow chart illustrating a multi-energy CT image hardening correction method according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a multi-energy CT image hardening correction method according to another embodiment of the present invention;
FIG. 3 is a block diagram of a multi-energy CT image hardening calibration device according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a hardware structure of a computer device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided in the present application without any inventive step are within the scope of protection of the present application.
It is obvious that the drawings in the following description are only examples or embodiments of the present application, and that it is also possible for a person skilled in the art to apply the present application to other similar contexts on the basis of these drawings without inventive effort. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of ordinary skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms referred to herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs. Reference to "a," "an," "the," and similar words throughout this application are not to be construed as limiting in number, and may refer to the singular or the plural. The present application is directed to the use of the terms "including," "comprising," "having," and any variations thereof, which are intended to cover non-exclusive inclusions; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to the listed steps or elements, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. Reference to "connected," "coupled," and the like in this application is not intended to be limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" as referred to herein means two or more. "and/or" describes the association relationship of the associated object, indicating that there may be three relationships, for example, "a and/or B" may indicate: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. Reference herein to the terms "first," "second," "third," and the like, are merely to distinguish similar objects and do not denote a particular ordering for the objects.
Currently, the commonly used hardening correction is performed on a single image, the water hardening correction generally needs to scan air and an eccentric water model, and water hardening correction parameters can be obtained by fitting projection data and ideal data, so that the water hardening correction is performed on the image. Performing threshold segmentation on each image, performing forward projection on the segmented water image and bone image to obtain projection data, performing polynomial calculation on the projection data to obtain bone hardening artifact projection data, reconstructing the projection data to obtain a hardening artifact image, and performing difference between the hardening artifact image and an original image to obtain a corrected image; or directly carrying out polynomial calculation on the original projection data to obtain error projection data of the bone, and then subtracting the error projection data from the original raw data domain to obtain corrected raw data for reconstruction. However, the hardening correction of the dual-energy images respectively usually causes a certain deviation of the CT value in the bone region, and for the dual-energy images, the CT value cannot be applied to the high-energy and low-energy images separately, and the change of the original image CT value makes the dual-energy subsequent quantitative analysis impossible.
Referring to fig. 1, fig. 1 is a schematic flowchart illustrating a multi-energy CT image hardening correction method according to an embodiment of the invention.
In this embodiment, the method for correcting the hardening term of the multi-energy CT image is used for correcting the hardening term of the high-low energy spectrum image obtained by scanning the multi-energy CT system, where the high-low energy spectrum image includes a first energy spectrum image and a second energy spectrum image, and includes:
s101, performing base material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first base material image and a second base material image.
In the present embodiment, the multi-energy CT image hardening correction method is applied to the dual-energy CT system as an example, and it is understood that in other embodiments, the multi-energy CT image hardening correction method may also be applied to other multi-energy CT systems. Illustratively, the basis material decomposition is to say, if the scanned object is composed of two basis materials, the first energy spectrum image and the second energy spectrum image are decomposed by using the mass attenuation coefficient of the basis materials, and the density maps of the two materials are obtained
At this time, for the image of the same layer, each pixel point is composed of two substances. In a dual-energy CT system, the first spectral image may be a high-energy image or a low-energy image and the second spectral image may be a low-energy image or a high-energy image. Illustratively, the substrateThe decomposition method may be water/bone decomposition, water/calcium decomposition, or water/iodine decomposition, and is not particularly limited herein.
S102, projecting the first base substance image and the second base substance image under the first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under the second energy spectrum to obtain a second projection value.
Illustratively, a first base material image and a second base material image are projected under a first energy spectrum, and the attenuation result of the combination of the two materials under different ray energies is calculated as data of a subsequent reconstruction image.
S103, reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image.
It can be understood that the reconstructed image reconstructed based on the first projection value and the second projection value can reflect that the scanned object is not hardened in the scanning process, and after the processing, a correction term can be generated to correct the first energy spectrum image and the second energy spectrum image.
And S104, obtaining a first hardening term image based on the first reconstructed image and the first energy spectrum image, and obtaining a second hardening term image based on the second reconstructed image and the second energy spectrum image.
For example, the spatial resolution of the obtained reconstructed image may be reduced by the foregoing projection and reconstruction process, and in order to obtain the hardening correction term that can be adjusted for the first spectral image and the second spectral image, it is necessary to perform resolution reduction processing on the first spectral image and the second spectral image, and adjust the reconstructed image based on the first spectral image and the second spectral image after resolution reduction to obtain the first hardening term image and the second hardening term image.
And S105, carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first corrected image and a second corrected image.
It can be understood that the first and second hardening term images are the images which are restored by the above-mentioned processing and reflect the hardening conditions of the first and second energy spectrum images, so that the first and second energy spectrum images can be corrected based on the first and second hardening term images.
According to the multi-energy CT image hardening correction method, the first base material image and the second base material image are obtained by performing base material decomposition on the first energy spectrum image and the second energy spectrum image; projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value; reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image; obtaining a first hardening item image based on the first reconstruction image and the first energy spectrum image, and obtaining a second hardening item image based on the second reconstruction image and the second energy spectrum image; the mode of carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first correction image and a second correction image ensures that the CT value of the high-low energy image after hardening correction is unchanged, subsequent quantitative analysis results are not influenced, the correction effect is better, and the efficiency is higher.
In another embodiment, the hardening correction of the first spectral image and the second spectral image based on the first hardening correction term and the second hardening correction term to obtain the first corrected image and the second corrected image further includes the following steps: and taking the first correction image and the second correction image as initial images, repeating the steps, and iterating for a preset number of times to obtain a first target image and a second target image.
For example, the first corrected image and the second corrected image obtained after the primary correction are used as initial images, that is, the first spectral image and the second spectral image, the steps S101, S102, S103, S104, and S105 are repeated, the correction is continued, and the hardening correction is performed for a plurality of times through a preset number of iterations, so that the hardening correction effect can be better. It is understood that the number of iterations may be set by the user based on the actual situation. Preferably, the first spectral image and the second spectral image are corrected for an even number of iterations.
In another embodiment, the performing the basis material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first basis material image and a second basis material image further includes the following steps: and performing water/bone decomposition on the first energy spectrum image and the second energy spectrum image to obtain a water decomposition image and a bone decomposition image.
Illustratively, the process of base material decomposition needs to be calculated through two measurements, which is equivalent to assuming that the scanned object consists of water and bone, but the contents of the two materials are unknown, so that the two energy spectrum images are used for decomposition, two unknowns are solved through two equations to obtain the contents of the two materials, the contents of the two materials do not change along with energy, and finally, a water decomposition image and a bone decomposition image are obtained. It will be appreciated that in other embodiments, other base materials may be selected for base material decomposition in the same manner.
In the embodiment, the first energy spectrum image and the second energy spectrum image are preprocessed by adopting a basic substance decomposition method, so that the method is more accurate than the traditional threshold segmentation method.
In another embodiment, the step of projecting the first base material image and the second base material image under the first energy spectrum to obtain the first projection value and the step of projecting the first base material image and the second base material image under the second energy spectrum to obtain the second projection value further includes the following steps:
step 1, carrying out forward projection on a first base material image to obtain a first forward projection value, and carrying out forward projection on a second base material image to obtain a second forward projection value;
step 2, carrying out linear weighting on the first positive projection value and the second positive projection value to obtain a linear weighted value;
and 3, performing projection calculation on the linear weighted value under the first energy spectrum to obtain a first projection value, and performing projection calculation on the linear weighted value under the second energy spectrum to obtain a second projection value.
Illustratively, the forward projection calculation is performed on the density images of two basic substances respectively, wherein the forward projection value represents the path integral value, which is related to the dimension material of the scanned object, and is equivalent to separately considering the attenuation capacity of the two basic substances to the ray, which is independent of energy, and is an intermediate result. And then, carrying out linear weighting on the first positive projection value and the second positive projection value to obtain a linear weighted value, namely combining the two base substances, respectively carrying out projection calculation on the linear weighted value under the first energy spectrum and the second energy spectrum, and calculating the attenuation result of the combination of the two substances under the two ray energies.
Specifically, the density maps of two base substances are orthographically projected to obtain the projection value p of the density maps on the detector water (L),p bone (L). The first energy spectrum emitted by the bulb is denoted S L (E) The second energy spectrum is represented as S H (E) The detector response is denoted D (E) and the mass attenuation coefficient of the base material is denoted μ m (E) Where E is the energy of X-photons, the projection values of the illuminated object in the first and second energy spectrums can be expressed as:
p L,H (L)＝-ln∫ω L.H (E)·exp[-(p water (L)μ m,water (E)+p bone (L)μ m,bone (E))]dE
wherein the content of the first and second substances,
in the embodiment, the attenuation capacity of the two base substances to the ray is separately considered, then linear weighting is carried out, the two base substances are combined, the attenuation result of the combination of the two substances under the two ray energies is calculated, and the obtained projection value is more accurate.
In another embodiment, the reconstructing based on the first projection value and the second projection value further includes the following steps after obtaining the first reconstructed image and the second reconstructed image: and performing HU correction on the first reconstructed image and the second reconstructed image to obtain a corrected first reconstructed image and a corrected second reconstructed image.
Illustratively, based on the first projection value and the second projection valueReconstructing projection value to obtain linear attenuation coefficient graph under two energies
If the first spectral image and the second spectral image are displayed by the CT value, before the linear attenuation coefficient map is compared with the first spectral image and the second spectral image for hardening correction, HU correction needs to be performed on the reconstructed linear attenuation coefficient map, and the linear attenuation coefficient of water is expressed as μ l,water Then, the calculation formula is:
wherein
For corrected reconstructed images, E L,H Selecting specific energy corresponding to linear attenuation coefficient under the first energy spectrum and the second energy spectrum, generally average energy of each energy spectrum, reasonable mu l,water The selection may reduce the number of iterative corrections.
The embodiment performs HU correction on the reconstructed image obtained by reconstruction so as to adapt to the first energy spectrum image and the second energy spectrum image displayed by the CT value, so that the correction is more accurate.
In another embodiment, obtaining the first hardening term image based on the first reconstructed image and the first spectral image, and obtaining the second hardening term image based on the second reconstructed image and the second spectral image further comprises the steps of:
step 1, smoothing the first energy spectrum image and the second energy spectrum image based on a Gaussian function to obtain a first adjustment image and a second adjustment image.
Step 2, adjusting the first reconstructed image based on the first adjusting image to obtain a first hardening item image; and adjusting the second reconstructed image based on the second adjusting image to obtain a second hardening item image.
For example, the spatial resolution of the obtained reconstructed image may be reduced by the aforementioned projection and reconstruction process, and in order to obtain the hardening correction term that can be adjusted for the first spectral image and the second spectral image, it is necessary to perform resolution reduction processing on the first spectral image and the second spectral image, and adjust the reconstructed image based on the first spectral image and the second spectral image after resolution reduction. The first energy spectrum image and the second energy spectrum image are smoothed by using a smoothing function, specifically, the first energy spectrum image and the second energy spectrum image may be smoothed by using a gaussian function with a center value of 0 and a spread of σ. It is understood that, in other embodiments, other smoothing functions may be used to smooth the first spectral image and the second spectral image, and other methods of reducing the resolution may also be used, which are not limited in this respect.
In this embodiment, the formula for smoothing the first energy spectrum image and the second energy spectrum image by using the gaussian function with the center value of 0 and the broadening of σ is as follows:
wherein the content of the first and second substances,
gauss (0, sigma) is a Gaussian function for the first hardening term image or the second hardening term image,
the first spectral image or the second spectral image.
The embodiment performs smoothing processing on the first energy spectrum image and the second energy spectrum image, overcomes the problem of reduction of spatial resolution of a reconstructed image caused by projection and reconstruction processes, and enables hardening correction to be more accurate.
In another embodiment, the step of smoothing the first spectral image and the second spectral image based on the gaussian function to obtain the first adjustment image and the second adjustment image further comprises the steps of: and adjusting parameters of the Gaussian function, and smoothing the first energy spectrum image and the second energy spectrum image based on the Gaussian function with different parameters until the first hardening item image and the second hardening item image reach the minimum value.
Illustratively, the sigma value of the Gaussian function is respectively adjusted for the first energy spectrum image and the second energy spectrum image, smoothing processing is sequentially carried out, and corresponding hardening term images are found
Is used as the hardening term image calculated this time. It can be understood that when the first energy spectrum image and the second energy spectrum image are blurred by applying other functions, the hardening term image can also be obtained by adjusting the parameters of the functions
Is measured.
In the embodiment, the minimum value of the hardening term image is obtained by adjusting the parameters of the gaussian function, and the minimum value is used as the hardening term image to correct the first energy spectrum image and the second energy spectrum image, so that the correction result is more accurate.
Illustratively, the formula for performing hardening correction on the first spectral image and the second spectral image based on the first hardening term image and the second hardening term image is as follows:
wherein the content of the first and second substances,
either the first corrected image or the second corrected image,
either the first spectral image or the second spectral image,
is the first hardening item image or the second hardening itemAnd (4) an image.
Please refer to fig. 2, fig. 2 is a schematic flowchart illustrating a hardening correction method for a multi-energy CT image according to another embodiment of the present invention. In this embodiment, the multi-energy CT image hardening correction method is applied to a dual-energy CT system, and the dual-energy CT system scans to obtain a high-energy image and a low-energy image. Illustratively, the high-energy image and the low-energy image are subjected to base material decomposition to obtain a water image and a bone image, the water image and the bone image are subjected to forward projection and energy spectrum weighting calculation to obtain a high-energy projection value and a low-energy projection value, reconstruction is carried out on the basis of the high-energy projection value and the low-energy projection value to obtain a high-energy linear attenuation coefficient image and a low-energy linear attenuation coefficient image, HU correction and spatial resolution matching are respectively carried out on the high-energy linear attenuation coefficient image and the low-energy linear attenuation coefficient image to obtain a high-energy hardening correction image and a low-energy hardening correction image, the high-energy image and the low-energy image are corrected on the basis of the high-energy hardening correction image and the low-energy hardening correction image, and iterative correction is carried out according to the steps until preset times or preset image quality is reached.
It should be noted that the steps illustrated in the above-described flow diagrams or in the flow diagrams of the figures may be performed in a computer system, such as a set of computer-executable instructions, and that, although a logical order is illustrated in the flow diagrams, in some cases, the steps illustrated or described may be performed in an order different than here.
The present embodiment further provides a multi-energy CT image hardening correction device, which is used to implement the foregoing embodiments and preferred embodiments, and the description of the device is omitted here. As used hereinafter, the terms "module," "unit," "subunit," and the like may implement a combination of software and/or hardware for a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.
Fig. 3 is a block diagram of a multi-energy CT image hardening correction apparatus according to an embodiment of the present application, and as shown in fig. 3, the apparatus includes:
and a basis material decomposition module 10, configured to perform basis material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first basis material image and a second basis material image.
The base material decomposition module 10 is further configured to perform water/bone decomposition on the first energy spectrum image and the second energy spectrum image to obtain a water decomposition image and a bone decomposition image.
The projection module 20 is configured to project the first base substance image and the second base substance image under the first energy spectrum to obtain a first projection value, and project the first base substance image and the second base substance image under the second energy spectrum to obtain a second projection value.
The projection module 20, further configured to:
carrying out positive projection on the first base material image to obtain a first positive projection value, and carrying out positive projection on the second base material image to obtain a second positive projection value;
carrying out linear weighting on the first positive projection value and the second positive projection value to obtain a linear weighted value;
and performing projection calculation on the linear weighted value under the first energy spectrum to obtain a first projection value, and performing projection calculation on the linear weighted value under the second energy spectrum to obtain a second projection value.
And a reconstruction module 30, configured to perform reconstruction based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image.
And a hardening term obtaining module 40, configured to obtain a first hardening term image based on the first reconstructed image and the first spectral image, and obtain a second hardening term image based on the second reconstructed image and the second spectral image.
A hardening item acquisition module 40, further configured to:
smoothing the first energy spectrum image and the second energy spectrum image based on a Gaussian function to obtain a first adjustment image and a second adjustment image;
adjusting the first reconstructed image based on the first adjusting image to obtain a first hardening item image; and adjusting the second reconstructed image based on the second adjusting image to obtain a second hardening item image.
The hardening term obtaining module 40 is further configured to adjust parameters of the gaussian function, and perform smoothing processing on the first energy spectrum image and the second energy spectrum image based on the gaussian functions of different parameters until the first hardening term image and the second hardening term image reach a minimum value.
And the correcting module 50 is configured to perform hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first corrected image and a second corrected image.
The multi-energy CT image hardening correction device further comprises: and (5) an iteration module.
And the iteration module is used for taking the first correction image and the second correction image as initial images, repeating the steps, and iterating for a preset number of times to obtain a first target image and a second target image.
The multi-energy CT image hardening correction device further comprises: HU correction module.
And the HU correction module is used for carrying out HU correction on the first reconstructed image and the second reconstructed image to obtain a corrected first reconstructed image and a corrected second reconstructed image.
The above modules may be functional modules or program modules, and may be implemented by software or hardware. For a module implemented by hardware, the modules may be located in the same processor; or the modules can be respectively positioned in different processors in any combination.
In addition, the multi-energy CT image hardening correction method described in conjunction with fig. 1 in the embodiment of the present application may be implemented by a computer device. Fig. 4 is a hardware structure diagram of a computer device according to an embodiment of the present application.
The computer device may comprise a processor 61 and a memory 62 in which computer program instructions are stored.
Specifically, the processor 61 may include a Central Processing Unit (CPU), or A Specific Integrated Circuit (ASIC), or may be configured to implement one or more Integrated circuits of the embodiments of the present Application.
The memory 62 may be used to store or cache various data files that need to be processed and/or used for communication, as well as possible computer program instructions executed by the processor 61.
The processor 61 may implement any one of the multi-energy CT image hardening correction methods in the above embodiments by reading and executing computer program instructions stored in the memory 62.
In some of these embodiments, the computer device may also include a communication interface 63 and a bus 60. As shown in fig. 4, the processor 61, the memory 62, and the communication interface 63 are connected via a bus 60 to complete communication therebetween.
The communication interface 63 is used for implementing communication between modules, devices, units and/or apparatuses in the embodiments of the present application. The communication interface 63 may also enable communication with other components such as: the data communication is carried out among external equipment, image/data acquisition equipment, a database, external storage, an image/data processing workstation and the like.
The computer device may execute the multi-energy CT image hardening correction method in the embodiment of the present application based on the acquired computer program instructions, thereby implementing the multi-energy CT image hardening correction method described in conjunction with fig. 1.
In addition, in combination with the multi-energy CT image hardening correction method in the foregoing embodiments, the embodiments of the present application may be implemented by providing a computer-readable storage medium. The computer readable storage medium having stored thereon computer program instructions; the computer program instructions, when executed by a processor, implement any one of the multi-energy CT image hardening correction methods in the above embodiments.
According to the multi-energy CT image hardening correction method, the multi-energy CT image hardening correction device, the computer equipment and the storage medium, the first base material image and the second base material image are obtained by performing base material decomposition on the first energy spectrum image and the second energy spectrum image; projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value; reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image; obtaining a first hardening item image based on the first reconstruction image and the first energy spectrum image, and obtaining a second hardening item image based on the second reconstruction image and the second energy spectrum image; the mode of carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first correction image and a second correction image ensures that the CT value of the high-low energy image after hardening correction is unchanged, subsequent quantitative analysis results are not influenced, the correction effect is better, and the efficiency is higher.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent application shall be subject to the appended claims.
Claims (10)
1. A hardening correction method for a multi-energy CT image is characterized in that the hardening correction method is used for correcting hardening terms of high-low energy spectrum images obtained by scanning of a multi-energy CT system, wherein the high-low energy spectrum images comprise a first energy spectrum image and a second energy spectrum image, and the hardening correction method comprises the following steps:
performing base material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first base material image and a second base material image;
projecting the first base substance image and the second base substance image under a first energy spectrum to obtain a first projection value, and projecting the first base substance image and the second base substance image under a second energy spectrum to obtain a second projection value;
reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image;
obtaining a first hardening term image based on the first reconstructed image and the first energy spectrum image, and obtaining a second hardening term image based on the second reconstructed image and the second energy spectrum image, wherein the first hardening term image and the second hardening term image are images reflecting hardening conditions of the first energy spectrum image and the second energy spectrum image;
and carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first corrected image and a second corrected image.
2. The method for hardening correction of multi-energy CT images as claimed in claim 1, wherein the hardening correction of the first and second spectral images based on the first and second hardening correction terms further comprises:
and repeating the steps by taking the first correction image and the second correction image as initial images, and iterating for a preset number of times to obtain a first target image and a second target image.
3. The method for correcting hardening in multi-energy CT images according to claim 1, wherein the projecting the first and second basic material images under the first spectrum to obtain a first projection value, and projecting the first and second basic material images under the second spectrum to obtain a second projection value comprises:
carrying out positive projection on the first base material image to obtain a first positive projection value, and carrying out positive projection on the second base material image to obtain a second positive projection value;
carrying out linear weighting on the first positive projection value and the second positive projection value to obtain a linear weighted value;
and performing projection calculation on the linear weighted value under a first energy spectrum to obtain a first projection value, and performing projection calculation on the linear weighted value under a second energy spectrum to obtain a second projection value.
4. The method of claim 1, wherein the performing a basis material decomposition on the first and second spectral images to obtain first and second basis material images comprises:
and performing water/bone decomposition on the first energy spectrum image and the second energy spectrum image to obtain a water decomposition image and a bone decomposition image.
5. The method for correcting hardening of multi-energy CT images according to claim 1, wherein the reconstructing based on the first projection value and the second projection value to obtain the first reconstructed image and the second reconstructed image further comprises:
and performing HU correction on the first reconstructed image and the second reconstructed image to obtain a corrected first reconstructed image and a corrected second reconstructed image.
6. The method of claim 1, wherein obtaining a first hardening term image based on the first reconstructed image and a first spectral image, and obtaining the second hardening term image based on the second reconstructed image and a second spectral image further comprises:
smoothing the first energy spectrum image and the second energy spectrum image based on a Gaussian function to obtain a first adjustment image and a second adjustment image;
adjusting the first reconstruction image based on the first adjustment image to obtain the first hardening item image; and adjusting the second reconstruction image based on a second adjustment image to obtain the second hardening item image.
7. The method of claim 6, wherein the smoothing the first and second energy spectrum images based on the Gaussian function to obtain first and second adjusted images further comprises:
and adjusting parameters of the Gaussian function, and smoothing the first energy spectrum image and the second energy spectrum image based on the Gaussian function with different parameters until the first hardening item image and the second hardening item image reach the minimum value.
8. A multi-energy CT image hardening correction apparatus, comprising:
the base material decomposition module is used for carrying out base material decomposition on the first energy spectrum image and the second energy spectrum image to obtain a first base material image and a second base material image;
the projection module is used for projecting the first basic substance image and the second basic substance image under a first energy spectrum to obtain a first projection value, and projecting the first basic substance image and the second basic substance image under a second energy spectrum to obtain a second projection value;
the reconstruction module is used for reconstructing based on the first projection value and the second projection value to obtain a first reconstructed image and a second reconstructed image;
a hardening term obtaining module, configured to obtain a first hardening term image based on the first reconstructed image and the first spectrum image, and obtain a second hardening term image based on the second reconstructed image and the second spectrum image, where the first hardening term image and the second hardening term image are images that reflect hardening conditions of the first spectrum image and the second spectrum image;
and the correction module is used for carrying out hardening correction on the first energy spectrum image and the second energy spectrum image based on the first hardening item image and the second hardening item image to obtain a first correction image and a second correction image.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the multi-energy CT image hardening correction method according to any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, implements the multi-energy CT image hardening correction method according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011564828.1A CN112581556B (en) | 2020-12-25 | 2020-12-25 | Multi-energy CT image hardening correction method and device, computer equipment and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011564828.1A CN112581556B (en) | 2020-12-25 | 2020-12-25 | Multi-energy CT image hardening correction method and device, computer equipment and storage medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112581556A CN112581556A (en) | 2021-03-30 |
| CN112581556B true CN112581556B (en) | 2023-01-03 |
Family
ID=75140609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011564828.1A Active CN112581556B (en) | 2020-12-25 | 2020-12-25 | Multi-energy CT image hardening correction method and device, computer equipment and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112581556B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116458906B (en) * | 2023-06-19 | 2023-09-22 | 有方（合肥）医疗科技有限公司 | Side bitmap generation method and device, electronic equipment and storage medium |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002067201A1 (en) * | 2001-02-15 | 2002-08-29 | The Regents Of The University Of Michigan | Statistically reconstructing an x-ray computed tomography image with beam hardening corrector |
| US8194961B2 (en) * | 2008-04-21 | 2012-06-05 | Kabushiki Kaisha Toshiba | Method, apparatus, and computer-readable medium for pre-reconstruction decomposition and calibration in dual energy computed tomography |
| CN104346820B (en) * | 2013-07-26 | 2017-05-17 | 清华大学 | X-ray dual-energy CT reconstruction method |
| US10111638B2 (en) * | 2016-05-24 | 2018-10-30 | Toshiba Medical Systems Corporation | Apparatus and method for registration and reprojection-based material decomposition for spectrally resolved computed tomography |
| CN108051458B (en) * | 2017-11-27 | 2020-08-11 | 首都师范大学 | X-ray energy spectrum estimation method based on rational fraction fitting multi-energy projection curve |
| CN108010099B (en) * | 2017-12-04 | 2020-12-25 | 首都师范大学 | X-ray multi-energy spectrum CT finite angle scanning and image iterative reconstruction method |
| US10945695B2 (en) * | 2018-12-21 | 2021-03-16 | Canon Medical Systems Corporation | Apparatus and method for dual-energy computed tomography (CT) image reconstruction using sparse kVp-switching and deep learning |
| US20200342640A1 (en) * | 2019-04-24 | 2020-10-29 | University Of Central Florida Research Foundation, Inc. | System and method for beam hardening correction (bhc) in computed tomography (ct) image reconstruction |
| CN111062882B (en) * | 2019-11-27 | 2023-10-03 | 上海联影医疗科技股份有限公司 | Energy spectrum projection data processing method and device, electronic equipment and storage medium |
| CN111476856B (en) * | 2020-04-08 | 2023-06-06 | 中北大学 | Multispectral CT imaging method |
-
2020
- 2020-12-25 CN CN202011564828.1A patent/CN112581556B/en active Active
Non-Patent Citations (2)
| Title |
|---|
| 基于投影空间的CT射束硬化校正方法;张小可等;《河北大学学报(自然科学版)》;20181125(第06期);全文 * |
| 基于重投影的CT图像硬化伪影校正;吴志宏等;《原子能科学技术》;20150520(第05期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112581556A (en) | 2021-03-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10147168B2 (en) | Spectral CT | |
| US11328391B2 (en) | System and method for controlling noise in multi-energy computed tomography images based on spatio-spectral information | |
| Meignan et al. | Metabolic tumour volumes measured at staging in lymphoma: methodological evaluation on phantom experiments and patients | |
| Arabi et al. | Deep learning–based metal artefact reduction in PET/CT imaging | |
| US7362845B2 (en) | Method and apparatus of global de-noising for cone beam and fan beam CT imaging | |
| US10111638B2 (en) | Apparatus and method for registration and reprojection-based material decomposition for spectrally resolved computed tomography | |
| CN111627083B (en) | Bone hardening artifact correction method, device, computer equipment and readable storage medium | |
| CN110636796B (en) | Beam hardening correction in X-ray dark field imaging | |
| CN112581556B (en) | Multi-energy CT image hardening correction method and device, computer equipment and storage medium | |
| Grimmer et al. | Empirical cupping correction for CT scanners with primary modulation (ECCP) | |
| Dalehaug et al. | ADMIRE vs. SAFIRE: Objective comparison of CT reconstruction algorithms and their noise properties | |
| JP7370989B2 (en) | a non-spectral computed tomography (CT) scanner configured to generate spectral volumetric image data; | |
| Koike et al. | Pseudo low-energy monochromatic imaging of head and neck cancers: Deep learning image reconstruction with dual-energy CT | |
| CN111754436B (en) | Acceleration method for medical image artifact correction, computer device and storage medium | |
| CN112634250A (en) | Image registration method and device for multi-energy CT system, computer equipment and storage medium | |
| CN112790780A (en) | Parameter adjusting method and device of multi-energy CT system and computer equipment | |
| Anam et al. | Impact of ROI size on the accuracy of noise measurement in CT on computational and ACR phantoms | |
| Guleng | Radiation dose and image quality in CT-evaluation of how slice thickness, tube current modulation and reconstruction algorithms affect radiation dose and image noise | |
| Koike et al. | Synthetic Low-Energy Monochromatic Image Generation in Single-Energy Computed Tomography System Using a Transformer-Based Deep Learning Model | |
| CN117830456B (en) | Method and device for correcting image metal artifact and electronic equipment | |
| Setiawan et al. | Comparison of noise-power spectrum and modulation-transfer function for CT images reconstructed with iterative and deep learning image reconstructions: An initial experience study | |
| CN115810414A (en) | Method and device for generating correction file of detector and computer equipment | |
| US20230419455A1 (en) | System and method for image correction | |
| CN117830456A (en) | Method and device for correcting image metal artifact and electronic equipment | |
| CN114549360A (en) | Multi-energy CT de-scattering noise-reducing substance decomposition method, device, equipment and medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |