JP5422171B2 - X-ray diagnostic imaging equipment - Google Patents

Description

  The present invention relates to an X-ray image diagnostic apparatus used in the medical field, particularly in the field of X-ray image diagnosis and treatment using X-ray images.

  Conventionally, in order to display a region such as a blood vessel that has very little X-ray absorption on its own on an X-ray diagnostic image, a method of contrasting the region of interest and displaying it is used. In such an imaging method, in order to clearly separate the contrast region from the non-contrast region that is the non-interest region, first, an image (: Mask image) before the contrast agent of the region of interest is collected is collected. In addition, an image (: Contrast image) after the contrast agent is administered to the region of interest is collected, and a DSA (Distal Subtraction Angiography) image in which the contrast region is clearly separated is obtained by subtracting the Mask image from this Contrast image DSA technique is used (for example, refer to Patent Document 1).

  Since the DSA image acquired by such a DSA technique is intended to display only the contrast region that is the region of interest, it is normal that other portions are not displayed on the acquired image.

However, when such DSA images are used for examinations and treatments, it has been confirmed that the contrast region, which is the region of interest, has been confirmed to overlap with surrounding organs and bones that were not originally the region of interest. There is also. Thus, conventionally, as one of the functions of the DSA technique, there has been considered one that can display a Mask image on a DSA image with an arbitrary degree of overlap.
JP 2007-195633 A

  However, in the conventional method, background parts such as peripheral organs and skeletons displayed on the Mask image collected with the same X-ray energy as the Contrast image are directly displayed on the Contrast image. For this reason, for example, when only the bone part is overlaid and displayed on the contrast part as the background part and it is desired to check the overlapping state, or only the soft part part (organ etc.) is overlaid and displayed on the contrast part. If so, these could not be realized.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an X-ray diagnostic imaging apparatus that can reliably add and display a desired background region with respect to a contrast region that is a region of interest.

The X-ray diagnostic imaging apparatus according to the present invention is
A first mask image before contrast agent injection collected by a predetermined X-ray energy, a second mask image before contrast agent injection collected by an X-ray energy lower than the first mask image, and the first X-ray image acquisition means for acquiring each contrast image after contrast agent injection collected by the same X-ray energy as the Mask image;
([Contrast image]-[First Mask image])
+ A (b [first mask image] -c [second mask image]) (where a, b, and c are coefficients)
From the above formula, the DSA image obtained by [Contrast image]-[first mask image] is replaced with the bone portion obtained by the above-mentioned a (b [first mask image] -c [second mask image]). or image processing means for crowded adding background portion showing the soft tissue to produce an image, Ru varied based on the operation by each operator the coefficient b and the coefficients c,
Display means for displaying an image generated by the image processing means, and displaying in real time an image changed based on the operation ,
The X-ray energy condition used for the second mask image can capture the bone and the soft tissue more clearly than the first mask image based on the information for collecting the first mask image. there it is selected from the X-ray energy conditions of the first Mask image as a small X-ray energy,
The information is the thickness of the subject with respect to the first Mask image, the second Mask image, and the Contrast image,
The coefficient b and the coefficient c are determined based on the background part and the correction coefficient for each X-ray energy condition when collecting the first mask image and the second mask image. In order to selectively display as the bone part or the soft tissue, the density level of the pixel value related to the part to be erased in the difference between the first mask image and the second mask image is the same as 1 It is determined as a combination of pairs .

The X-ray diagnostic imaging apparatus according to the present invention is
A first mask image before injection of contrast medium collected by a predetermined X-ray energy, a second mask image before injection of contrast medium collected by X-ray energy lower than the first mask image, X-rays for acquiring a third mask image before contrast agent injection acquired with higher X-ray energy than the mask image and a contrast image after contrast agent injection acquired with the same X-ray energy as the first mask image, respectively. Image acquisition means;
([Contrast image]-[First Mask image])
+ A (b [third mask image] -c [second mask image]) (where a, b, and c are coefficients)
From the above formula, the DSA image obtained by [Contrast image]-[first mask image] is replaced with the bone part obtained by the above a (b [third mask image] -c [second mask image]). or image processing means for crowded adding background portion showing the soft tissue to produce an image, Ru varied based on the operation by each operator the coefficient b and the coefficients c,
Display means for displaying an image generated by the image processing means, and displaying in real time an image changed based on the operation ,
The X-ray energy condition used for the second mask image can capture the bone and the soft tissue more clearly than the first mask image based on the information for collecting the first mask image. there is selected from the X-ray energy conditions of the first Mask image as a small X-ray energy, the third Mask X-ray energy conditions used in the image, the information for the collection of the first Mask image Based on the above, a bone part larger than the X-ray energy condition of the first Mask image is selected as resorbable X-ray energy ,
The information is the thickness of the subject with respect to the first Mask image, the second Mask image, the third Mask image, and the Contrast image,
The coefficient b and the coefficient c are calculated based on the background part and the correction coefficient for each X-ray energy condition when collecting the second mask image and the third mask image. In order to selectively display as the bone part or the soft tissue, the density level of the pixel value relating to the part to be erased in the difference between the second mask image and the third mask image is set to be the same. To be determined as a pair combination,
X-ray image diagnostic apparatus characterized by the above .

  ADVANTAGE OF THE INVENTION According to this invention, the X-ray image diagnostic apparatus which can add and display the desired background site | part reliably with respect to the contrast region which is a region of interest can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the basic principle of the X-ray diagnostic imaging apparatus of the present invention will be described with reference to FIGS. In FIG. 1, 100 is a first mask image [Mask Ne] collected before injection of a contrast medium collected in normal DSA imaging, and 200 is injected with a contrast medium collected in normal DSA imaging. The Contrast image [Contrast Ne] collected under the same X-ray energy conditions as the first mask image [Mask Ne] 100 for the collection for an arbitrary period after the operation is shown. Reference numeral 300 denotes a second mask image [Mask Le] that is collected before the contrast agent injection following the first mask image [Mask Ne] 100, and is lower than the first mask image [Mask Ne] 100. It is collected with line energy, and a soft X-ray absorption site such as a bone part and a soft X-ray absorption site such as an organ with low X-ray absorption are shown more clearly.

  In FIG. 1, the first term represented by ([Contrast Ne] − [Mask Ne]) indicates a DSA image of a normal region of interest, and a (b [Mask Ne] −c [Mask Le]) The expressed second term indicates the degree of the background part (peripheral part) added to the DSA image. Here, a, b, and c are coefficients. Of these, the coefficient a sets how much background part is added to the normal DSA image indicated by the first term, and is set in the range of 1 to 0. be able to. For example, if a = 0 is selected, the entire second term becomes zero, so that a normal DSA image that does not add any background part can be displayed. The coefficients b and c are determined according to which part is selectively displayed when the second Mask image [Mask Le] 300 is subtracted from the first Mask image [Mask Ne] 100. It is a coefficient. That is, as described above, the first mask image [Mask Ne] 100 and the second mask image [Mask Le] 300 are displayed in each mask image because the X-ray energy at the time of image collection is different. Concentrations of bone and soft parts (organs, etc.) are also different. Therefore, in order to leave only the intended part and erase the other parts by subtraction processing, the density level of the part to be erased is set to the first Mask image [Mask Ne] 100 and the second Mask image [Mask Le]. It is necessary to make the same between 300, and therefore, different coefficients b and c can be set. Here, the relationship between the coefficients b and c is important in the ratio between the two. For example, when b = 2 and c = 4 are set, and when b = 1 and c = 2 are set, the same meaning is obtained. have. If c = 0 in the selection of the coefficient c, an image in which only the first mask image [Mask Ne] 100 is added to the background of the DSA image can be displayed.

  On the other hand, there is a case where it is desired to add a soft part such as an organ more strictly as a background part to be added to a normal DSA image. In this case, when it is estimated that the X-ray energy used for obtaining the first Mask image [Mask Ne] 100 is not the intended high X-ray energy, the method shown in FIG. 2 is used. In FIG. 2, in addition to the first mask image [Mask Ne] 100 and the second mask image [Mask Le] 300 described in FIG. 1, higher X-ray energy is obtained from the first mask image [Mask Ne] 100. Thus, the third Mask image [Mask He] 400 collected is used. In this case, the high X-ray energy includes a high X-ray absorption site such as a bone portion and a low soft X-ray absorption site such as an organ having low X-ray absorption.

  Also in this case, in FIG. 2, the first term represented by ([Contrast Ne] − [Mask Ne]) indicates a DSA image of a normal region of interest, and a (b [Mask He] −c [Mask Le ]) Represents the degree of the background part (peripheral part) added to the DSA image. Here, a, b, and c are coefficients and are set in the same manner as described above.

  According to the idea shown in FIG. 2, since the third Mask image [Mask He] 400 is collected by high X-ray energy, reflection of a soft part such as an organ other than a bone part is reduced. Therefore, it is possible to obtain a large density difference from the second Mask image [Mask Le] 300 even in a soft part (organ etc.) where a difference due to X-ray energy is difficult to occur. ) Can be added to DSA images more strictly.

  Also in this case, if the coefficient c = 0, it is possible to display an image obtained by adding only the bone portion of the third mask image [Mask He] 400 to the background of the normal DSA image.

  The subtraction process executed based on FIG. 1 and FIG. 1 preferably uses a log process for avoiding the brightness of the region of interest being affected by the background non-interest region.

  Next, an X-ray diagnostic imaging apparatus based on such a basic principle will be described. FIG. 3 shows a schematic configuration of an X-ray image diagnostic apparatus according to an embodiment of the present invention. In the figure, 1 is a subject, and this subject 1 is placed on a bed (top plate) 2. The bed 2 is rotated in a state where a predetermined positional relationship is maintained with an X-ray tube 3 and an X-ray detector 7 described later in a state where the subject 1 is placed.

  An X-ray tube 3 is disposed so as to face the subject 1. The X-ray tube 3 emits X-rays to the subject 1. An X-ray generator 4 is connected to the X-ray tube 3, and an X-ray diaphragm 5 is disposed in the X-ray irradiation path between the X-ray tube 3 and the subject 1. The X-ray generator 4 controls the tube voltage, tube current, X-ray pulse width, etc. of the X-ray tube 3 based on the X-ray irradiation conditions given from the X-ray generator control means 81 described later. The X-ray diaphragm 5 sets an irradiation region of X-rays radiated from the X-ray tube 3 to the subject 1. The X-ray diaphragm 5 is provided with a radiation quality adjustment filter 6. The radiation quality adjusting filter 6 is made of, for example, a metal plate, and varies the X-ray exposure dose to the subject 1 by selecting the thickness and material of the metal plate.

  An X-ray detector 7 is disposed on the back surface of the bed 2. The X-ray detector 7 detects X-rays that have passed through the irradiation area of the subject 1 by X-ray irradiation from the X-ray tube 3. For example, the X-ray detector 7 converts the detected X-rays into electric charges and temporarily accumulates them. Then, image data is generated based on the accumulated charges.

  A controller 8 is connected to the X-ray generator 4 and the X-ray detector 7. The control unit 8 controls the entire apparatus, and is connected to a TV monitor 9 as display means and an operation panel 10 as operation means. The operation on the operation panel 10 will be described later.

  The control unit 8 includes an X-ray generator control unit 81, an X-ray detector control unit 82, an image storage unit 83, an image processing unit 84, and a table storage unit 85. The X-ray generator control means 81 sets X-ray irradiation conditions such as the tube voltage, tube current, and X-ray pulse width of the X-ray tube 3 and outputs them to the X-ray generator 4. Details of the X-ray irradiation condition setting here will be described later. The X-ray detector control means 82 controls the above-described series of operations from detection of X-rays by the X-ray detector 7 to generation of image data. The image storage unit 83 stores Mask image data, which is image data before contrast medium injection, output from the X-ray detector 7 and Contrast image data, which is image data after contrast medium injection. The image processing unit 84 generates a DSA image and a background image to be added to the DSA image based on the Mask image data and the Contrast image data stored in the image storage unit 83. The table storage unit 85 stores various tables used for setting the X-ray irradiation conditions. Here, as shown in FIG. 4, the X-ray condition table (L) 851, the X-ray condition table (H) 852, A coefficient combination table 853, a correction coefficient table 854, and an X-ray energy table 855 are provided.

  The X-ray condition table (L) 851 stores mAs (tube current / X-ray pulse width) conditions that affect the image density for each X-ray energy and estimated subject thickness. That is, the X-ray energy is determined by selecting the speed of photons by the tube voltage of the X-ray tube 3 generated by the X-ray generator 4, but if the X-ray energy is constant, the subject The density of the collected image changes depending on the one physique condition, that is, the thickness of the subject. Therefore, as shown in FIG. 5, the X-ray condition table (L) 851 takes X-ray energies X1, X2,... X8 on the vertical axis and estimated subject thicknesses D1, D2,. A mAs condition is set for each estimated subject thickness D1, D2,... D6 corresponding to the energy X1, X2,... X8, and the collected image density is made constant by changing the amount of photons according to the mAs condition. I have to. In this case, mAs 11 to 86 (see FIG. 5) are written as mAs conditions for each estimated subject thickness D1, D2,... D6 corresponding to each X-ray energy X1, X2,. The X-ray energy here decreases as it goes from X1 to X8, and the estimated subject thickness increases as it goes from D1 to D6.

  The X-ray condition table (H) 852 stores, for each estimated subject thickness, the maximum X-ray energy condition necessary for clearly displaying the bone portion of the third Mask image [Mask He] 400 described above. In this X-ray condition table (H) 852, X-ray energies X6, X5,... X1 are written in correspondence with the estimated subject thicknesses D1, D2,. Thereby, when acquiring the second Mask image [Mask Le] 300, for example, if D1 is obtained as the estimated subject thickness, the X-ray energy X6 is automatically selected based on the estimated subject thickness D1. .

  The coefficient combination table 853 uses a combination of coefficients b and c necessary for clearly displaying the selected part when a background part to be added to the DSA screen is selected (a certain reference X-ray energy pair is used). The combination of coefficients required by the dual energy subtraction technology). Further, the correction coefficient table 854 includes X-ray energy conditions for collecting the first Mask image [Mask Ne] 100, the second Mask image [Mask Le] 300, and the third Mask image [Mask He] 400, respectively. A necessary correction coefficient (coefficient for correcting the influence of the difference between the X-ray energy pair value described above and the actually used X-ray energy) is stored. The X-ray energy table 855 stores combinations of quality control filters 6 prepared corresponding to the tube voltage of the X-ray tube 3 generated by the X-ray generator 4 that determines the X-ray energy.

  In FIG. 3, reference numeral 11 denotes an X-ray exposure switch, and X-rays are radiated from the X-ray tube 3 when turned on. Reference numeral 12 denotes a contrast medium injector, which injects a contrast medium into a region of interest such as a blood vessel of the subject 1.

  FIG. 7 shows an example of an operation menu on the operation panel 10. In this case, a selection switch 102 for selecting background part addition processing ON and a selection switch 103 for selecting background part addition processing OFF (normal DSA image) are arranged on the operation screen 101, and a DSA image collection sequence is selected. The selection switch 105 for selecting the DSA image acquisition according to FIG. 1 and the selection switch 106 for selecting the DSA image acquisition according to FIG. Further, a background addition site selection unit 107 and an addition degree setting unit 108 are arranged on the operation screen 101. The background addition region selection unit 107 displays a plurality of background addition conditions as shown in the figure, and these background addition conditions can be selected by radio buttons. In addition, slide bars 109, 110, and 111 for setting the values of coefficients a, b, and c are arranged in the addition degree setting unit 108, and the slide bars 109, 110, and 111 are operated to slide. Thus, the values of the coefficients a, b, and c can be varied. In this case, the slide bar 109 changes the coefficient a and selects the background portion addition degree in the range of 0 to 1. The slide bar 109 selects the addition portion selected by the radio button of the background addition portion selection unit 107. Used in common. The slide bars 110 and 111 are used to change the coefficients b and c, respectively. The first mask image [Mask Ne] 100 and the second mask collected to obtain the added portion selected by the radio button. Used for each Mask image [Mask Le] 300 and third Mask image [Mask He] 400.

  Next, the operation of the embodiment configured as described above will be described.

  First, the operation menu shown in FIG. Then, on this operation menu, for example, the selection switch 102 is turned on, and then, for example, “addition only of the soft part A” is selected by the radio button of the background addition part selection unit 107, and further, the DSA image collection sequence When the selection switch 105 is turned on as 104 and “DSA image acquisition according to FIG. 1” is selected, the sequence of “DSA image acquisition according to FIG. 1” is executed.

  In this case, first, the first Mask image [Mask Ne] 100 is collected. The first mask image [Mask Ne] 100 is an image used for normal DSA imaging, and therefore X-ray irradiation conditions are determined by controlling normal X-ray energy conditions. In this case, it is desirable to collect on the high X-ray energy side as much as possible in order to keep the patient exposure dose low within the range in which the S / N ratio of the target contrast region can be obtained.

  In this state, a mAs (tube current, X-ray pulse width) condition is set together with an optimum tube voltage as an X-ray irradiation condition that has been used for acquiring the first Mask image [Mask Ne] 100. It is output to the X-ray generator 4 from the line generator control means 81. In this case, the X-ray energy table 855 also sets the quality control filter 6 corresponding to the tube voltage.

  Next, when the X-ray exposure switch 11 is turned on, X-rays with the above-mentioned X-ray irradiation conditions are emitted from the X-ray tube 3. X-rays radiated from the X-ray tube 3 reach the subject 1 through the X-ray diaphragm 5 and the quality control filter 6, pass through the subject 1, and are detected by the X-ray detector 7. The X-ray detector 7 converts the detected X-rays into charges and accumulates them, and generates image data based on the accumulated charges. The image data is stored in the image storage unit 83 as the first mask image [Mask Ne] 100 before the contrast agent injection.

  Next, the second mask image [Mask Le] 300 is acquired based on the sequence of “DSA image acquisition according to FIG. 1”.

  Here, the second Mask image [Mask Le] 300 has a large X-ray energy difference from the first Mask image [Mask Ne] 100 as much as possible, as is clear from the description of the second term in FIG. Therefore, it is necessary that the X-ray energy is as low as possible. In this case, referring to the X-ray condition table (L) 851 shown in FIG. 5, the physique condition of the subject 1 obtained at the time of acquiring the first Mask image [Mask Ne] 100, that is, the estimated subject thickness is obtained. Based on this, the lowest allowable X-ray energy is determined from the mAs spec range determined from the performance of the apparatus itself. For example, in FIG. 5, when the estimated subject thickness of the subject 1 obtained when collecting the first Mask image [Mask Ne] 100 is D2, the lowest X-ray in the mAs spec range determined by the device performance If the mAs condition allowed for obtaining energy is mAs52, the X-ray energy X5 is determined. In this way, the low X-ray energy having a large X-ray energy difference from the first Mask image [Mask Ne] 100 is determined based on the information when the first Mask image [Mask Ne] 100 is acquired.

  In this state, as the X-ray irradiation condition of the second Mask image [Mask Le] 300, the X-ray tube voltage corresponding to the low X-ray energy obtained from the X-ray condition table (L) 851 shown in FIG. (Tube current, X-ray pulse width) conditions are set and output from the X-ray generator control means 81 to the X-ray generator 4. Also in this case, the X-ray energy table 855 sets the quality control filter 6 corresponding to the tube voltage.

  Next, when the X-ray exposure switch 11 is turned on, X-rays radiated from the X-ray tube 3 under the above-described X-ray irradiation conditions are transmitted through the subject 1 and detected by the X-ray detector 7, and the contrast is increased. A second Mask image [Mask Le] 300 is stored in the image storage unit 83 as image data before the agent administration.

  In this case, the first mask image [Mask Ne] 100 and the second mask image [Mask Le] 300 are collected at least one, and after collecting a plurality of images, the image adding unit 84 adds the images. Random noise components can also be reduced by averaging.

  Next, a Contrast image [Contrast Ne] 200 is collected based on the sequence of “DSA image collection according to FIG. 1”.

  In this case, the X-ray tube voltage and mAs (tube current, X-ray pulse width) used when acquiring the first Mask image [Mask Ne] 100 are set as X-ray irradiation conditions as they are, and the X-ray generator It is output from the control means 81 to the X-ray generator 4. Then, when the contrast agent is injected into the region of interest such as the blood vessel of the subject 1 by the contrast agent injector 12, X-rays are emitted from the X-ray tube 3 in the above-described X-ray irradiation conditions in synchronization with this, A contrast image [Contrast Ne] 200 after contrast medium administration is stored in the image storage unit 83 as image data before contrast medium administration through the subject 1 and detected by the X-ray detector 7. In this case, several to several tens of Contrast images [Contrast Ne] 200 are collected per second and stored as moving images.

  Thereafter, each image data of the first Mask image [Mask Ne] 100, the second Mask image [Mask Le] 300, and the Contrast image [Contrast Ne] 200 stored in the image storage unit 83 is sent to the image processing unit 84. Sent to perform DSA processing. In this case, the DSA process in the image processing unit 84 is a coefficient read from the coefficient combination table 853 corresponding to “addition of only the soft part A” selected by the background addition part selection unit 107 on the operation menu. b, c, and correction coefficients necessary for each X-ray energy condition used when collecting the first Mask image [Mask Ne] 100 and the second Mask image [Mask Le] 300 read from the correction coefficient table 854 The optimum coefficients b and c are set based on the above, and a background part is generated from the second term shown in FIG. 1 using these coefficients b and c and added to the DSA image.

  Then, the calculation result of “DSA processing shown in FIG. 1” in the image processing unit 84 is displayed on the TV monitor 9. In this case, on the screen of the TV monitor 9, a (b [Mask Ne] -c [Mask Le] is added to the normal DSA image represented by ([Contrast Ne]-[Mask Ne]) described in FIG. ) Is added, and the slide bars 110 and 111 corresponding to the coefficients b and c of the operation menu shown in FIG. 7 are displayed in the coefficients set during the DSA process. The values of b and c are shown.

  Here, in the image displayed on the TV monitor 9, when the user determines that the background part added on the DSA image is different from the intended one, the slide b bar 110, 111 is operated to slide the coefficient b, By changing c manually, the effect can be confirmed in real time from the image of the TV monitor 9. In addition, the coefficient a can be selected in a range of 0 to 1 by adding the background portion by the slide operation of the slide bar 109, and is arbitrarily observed while observing the image displayed on the TV monitor 9 in real time. Can be set to

  Next, the selection switch 102 is turned on on the operation menu of the operation panel 10 shown in FIG. 7, and subsequently, for example, “addition of only the soft part B” is selected by using the radio button of the background addition part selection unit 107, Further, when the selection switch 105 is turned on as the DSA image acquisition sequence 104 and “DSA image acquisition according to FIG. 2” is selected, the sequence of “DSA image acquisition according to FIG. 2” is executed.

  In this case, in addition to the image collection of the first Mask image [Mask Ne] 100, the second Mask image [Mask Le] 300, and the Contrast image [Contrast Ne] 200, the third Mask image [Mask He] is further collected. ] 400 is collected. The X-ray energy condition in the third Mask image [Mask He] 400 is an X-ray condition table (H) 852 in which the maximum X-ray energy condition that can clearly display the bone is stored for each estimated subject thickness. Determined by. In this case, since the estimated subject thickness is obtained when the second Mask image [Mask Le] 300 is acquired, the optimum X-ray energy is automatically selected based on the estimated subject thickness at this time. In this case, in the X-ray condition table (H) 852 shown in FIG. 6, since the estimated subject thickness is D2 as described above, the X-ray energy X2 is automatically selected. The mAs condition is also determined from the relationship between the X-ray energy condition and the estimated subject thickness in the X-ray condition table (L) 851 shown in FIG.

  In this state, the X-ray tube voltage and the mAs (tube current, X-ray pulse width) condition obtained from the X-ray condition table (L) 851 are set by the X-ray energy obtained from the X-ray condition table (H) 852. The X-ray generator control means 81 outputs the result to the X-ray generator 4. Also in this case, the X-ray energy table 855 sets the quality control filter 6 corresponding to the tube voltage.

  Next, when the X-ray exposure switch 11 is turned on, X-rays radiated from the X-ray tube 3 under the above-described X-ray irradiation conditions are transmitted through the subject 1 and detected by the X-ray detector 7, and the contrast is increased. A third mask image [Mask He] 400 is stored in the image storage unit 83 as image data before the agent injection.

  Also in this case, the number of third Mask images [Mask He] 400 to be collected is one or more. After collecting a plurality of the third Mask images [Mask He] 400, the random noise component can be reduced by the image addition averaging process of the image processing unit 84. it can.

  Thereafter, the first Mask image [Mask Ne] 100, the second Mask image [Mask Le] 300, the third Mask image [Mask He] 400, and the Contrast image [Contrast Ne] 200 stored in the image storage unit 83 are stored. Each of the image data is sent to the image processing unit 84, and DSA processing is executed. In this case, the DSA process in the image processing unit 84 is a coefficient read from the coefficient combination table 853 corresponding to “addition of only the soft part B” selected by the background addition part selection unit 107 on the operation menu. b, c, and the first mask image [Mask Ne] 100, the second mask image [Mask Le] 300, and the third mask image [Mask He] 400 read out from the correction coefficient table 854 are used. The optimum coefficients b and c are set based on the correction coefficients necessary for each X-ray energy condition, and the background part is generated from the second term shown in FIG. 2 using these coefficients b and c, and is added to the DSA image. Is included.

  Then, the calculation result of “DSA processing shown in FIG. 2” in the image processing unit 84 is displayed on the TV monitor 9. In this case, on the screen of the TV monitor 9, a (b [Mask He] -c [Mask Le] is added to a normal DSA image represented by ([Contrast Ne]-[Mask Ne]) described in FIG. ) Is added, and the slide bars 110 and 111 corresponding to the coefficients b and c of the operation menu shown in FIG. 7 are displayed in the coefficients set during the DSA process. The values of b and c are shown.

  Here again, in the image displayed on the TV monitor 9, when the user determines that the background part added to the DSA image is different from the intended one, the slide bars 110 and 111 are slid to operate the coefficients b and c. Can be changed manually, and the effect can be confirmed in real time on the image of the TV monitor 9. In addition, the coefficient a can be selected in a range of 0 to 1 by adding the background portion by the slide operation of the slide bar 109, and is arbitrarily observed while observing the image displayed on the TV monitor 9 in real time. Can be set to

  Therefore, in this way, the DSA image of the region of interest generated by the first Mask image [Mask Ne] 100 and the Contrast image [Contrast Ne] 200 is lower than the first Mask image [Mask Ne] 100. The second mask image [Mask Le] 300 is collected by X-ray energy, and the first mask image [Mask Ne] 100 and the second mask image [Mask Le] 300 are subtracted to generate an image of the background part. And this background part was added to the DSA image. As a result, the desired background part such as bone part and soft part part (organ etc.) can be surely added to the DSA image (contrast part) and displayed, so the background part overlaps the DSA image accurately. The accuracy of examinations and treatments using DSA images can be further improved.

  Further, the DSA image of the region of interest generated by the first Mask image [Mask Ne] 100 and the Contrast image [Contrast Ne] 200 is collected with lower X-ray energy than the first Mask image [Mask Ne] 100. In addition to the second mask image [Mask Le] 300, the third mask image [Mask He] 400 with less reflection of the soft part due to the higher X-ray energy than the first mask image [Mask Ne] 100. The third mask image [Mask He] 400 and the second mask image [Mask Le] 300 are subtracted to generate a background part image, and this background part is added to the DSA image. As a result, the bone part can be removed as the background part, and the background part of only the desired soft part part (such as an organ) can be surely added to the DSA image to be displayed. It can be confirmed with high accuracy.

  Further, the first Mask image [Mask Ne] 100, the second Mask image [Mask Le] 300, and the third Mask image [Mask He] 400 used for generating the image of the background part are different in coefficients b and c, respectively. Can be multiplied, and by changing the combination of these coefficients b and c, it is possible to select an arbitrary background part so as to leave the intended part and erase the others.

  Furthermore, since several to several tens of Contrast images [Contrast Ne] 200 are collected per second, a moving image in which a background part is added to a DSA image that changes every moment from the injection of a contrast agent is obtained. It can also be displayed.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

The figure for demonstrating the basic principle of the X-ray image diagnostic apparatus of this invention. The figure for demonstrating the basic principle of the X-ray image diagnostic apparatus of this invention. 1 is a diagram showing a schematic configuration of an X-ray image diagnostic apparatus according to an embodiment of the present invention. The figure which shows schematic structure of the table memory | storage part used for one embodiment. The figure which shows schematic structure of the X-ray condition table (L) used for one embodiment. The figure which shows schematic structure of the X-ray condition table (H) used for one Embodiment. The figure which shows an example of the operation menu in the operation panel used for one embodiment.

Explanation of symbols

100 ... 1st Mask image [Mask Ne]
200 ... Contrast image [Contrast Ne]
300 ... Second Mask image [Mask Le]
400 ... Third Mask image [Mask He]
DESCRIPTION OF SYMBOLS 1 ... Test subject, 2 ... Bed, 3 ... X-ray tube 4 ... X-ray generator, 5 ... X-ray aperture, 6 ... Radiation adjustment filter 7 ... X-ray detector, 8 ... Control part, 81 ... X-ray Generator control means 82 ... X-ray detector control means, 83 ... Image storage section 84 ... Image processing section, 85 ... Table storage section 851 ... X-ray condition table (L), 852 ... X-ray condition table (H)
853 ... Coefficient combination table, 854 ... Correction coefficient table 855 ... X-ray energy table, 9 ... TV monitor 10 ... Operation panel, 101 ... Operation screen, 102, 103 ... Selection switch 104 ... Image acquisition sequence, 105, 106 ... Selection Switch 107 ... Background addition part selection part, 108 ... Addition degree setting part 109-111 ... Slide bar, 11 ... X-ray exposure switch 12 ... Contrast agent injector

Claims (2)

A first mask image before contrast agent injection collected by a predetermined X-ray energy, a second mask image before contrast agent injection collected by an X-ray energy lower than the first mask image, and the first X-ray image acquisition means for acquiring each contrast image after contrast agent injection collected by the same X-ray energy as the Mask image;
([Contrast image]-[First Mask image])
+ A (b [first mask image] -c [second mask image]) (where a, b, and c are coefficients)
From the above formula, the DSA image obtained by [Contrast image]-[first mask image] is replaced with the bone portion obtained by the above-mentioned a (b [first mask image] -c [second mask image]). or image processing means for crowded adding background portion showing the soft tissue to produce an image, Ru varied based on the operation by each operator the coefficient b and the coefficients c,
Display means for displaying an image generated by the image processing means, and displaying in real time an image changed based on the operation ,
The X-ray energy condition used for the second mask image can capture the bone and the soft tissue more clearly than the first mask image based on the information for collecting the first mask image. there it is selected from the X-ray energy conditions of the first Mask image as a small X-ray energy,
The information is the thickness of the subject with respect to the first Mask image, the second Mask image, and the Contrast image,
The coefficient b and the coefficient c are determined based on the background part and the correction coefficient for each X-ray energy condition when collecting the first mask image and the second mask image. In order to selectively display as the bone part or the soft tissue, the density level of the pixel value related to the part to be erased in the difference between the first mask image and the second mask image is the same as 1 An X-ray diagnostic imaging apparatus determined as a pair combination . A first mask image before injection of contrast medium collected by a predetermined X-ray energy, a second mask image before injection of contrast medium collected by X-ray energy lower than the first mask image, X-rays for acquiring a third mask image before contrast agent injection acquired with higher X-ray energy than the mask image and a contrast image after contrast agent injection acquired with the same X-ray energy as the first mask image, respectively. Image acquisition means;
([Contrast image]-[First Mask image])
+ A (b [third mask image] -c [second mask image]) (where a, b, and c are coefficients)
From the above formula, the DSA image obtained by [Contrast image]-[first mask image] is replaced with the bone part obtained by the above a (b [third mask image] -c [second mask image]). or image processing means for crowded adding background portion showing the soft tissue to produce an image, Ru varied based on the operation by each operator the coefficient b and the coefficients c,
Display means for displaying an image generated by the image processing means, and displaying in real time an image changed based on the operation ,
The X-ray energy condition used for the second mask image can capture the bone and the soft tissue more clearly than the first mask image based on the information for collecting the first mask image. there is selected from the X-ray energy conditions of the first Mask image as a small X-ray energy, the third Mask X-ray energy conditions used in the image, the information for the collection of the first Mask image Based on the above, a bone part larger than the X-ray energy condition of the first Mask image is selected as resorbable X-ray energy ,
The information is the thickness of the subject with respect to the first Mask image, the second Mask image, the third Mask image, and the Contrast image,
The coefficient b and the coefficient c are calculated based on the background part and the correction coefficient for each X-ray energy condition when collecting the second mask image and the third mask image. In order to selectively display as the bone part or the soft tissue, the density level of the pixel value relating to the part to be erased in the difference between the second mask image and the third mask image is set to be the same. An X-ray diagnostic imaging apparatus determined as a pair combination .

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