JP6877881B2 - Medical image processing device, X-ray CT device and image processing method - Google Patents

Description

Embodiments of the present invention relate to medical image processing devices, X-ray CT devices, and image processing methods.

The bronchus of the subject is diagnosed using the three-dimensional image data obtained from a medical image diagnostic device such as an X-ray CT device by photographing the chest of the subject. Bronchial diagnosis requires observing temporal changes in the bronchi in relation to the respiratory cycle. The respiratory cycle can be found by extracting the lung field region from the three-dimensional image data and obtaining the volume.

Japanese Unexamined Patent Publication No. 2014-210171

However, in order to obtain the volume of the lung field related to the time change of the bronchus, it is necessary to extract the lung field region from the three-dimensional image data of multiple time phases in one cycle of respiration, so that the processing of the image data takes time. There is a problem that it takes.

The embodiment has been made to solve the above problems, and an object of the present invention is to provide a medical image processing apparatus, an X-ray CT apparatus, and an image processing method capable of shortening the time required for processing image data. To do.

In order to achieve the above object, the medical image processing apparatus of the embodiment includes a storage unit, an image data processing unit, and an association unit. The storage unit stores image data of a plurality of time phases regarding the subject obtained from the medical image diagnostic apparatus. The image data processing unit obtains an index value comparing the pixel value of the image data of the reference time phase among the image data of the plurality of time phases with the pixel value of each of the image data of the plurality of time phases. The association unit selects at least one of the image data of the plurality of time phases based on the index value obtained for each of the plurality of time phases, and sets the respiratory time phase in at least one of the inspiration and exhalation of the subject. Associate.

FIG. 1 is a block diagram showing a configuration of a medical image processing device according to the first embodiment. FIG. 2 is a flowchart showing the operation of the medical image processing apparatus according to the first embodiment. FIG. 3 shows the three-dimensional image data and the two-dimensional image data of each time phase in the respiratory cycle according to the first embodiment, and the difference between the two-dimensional image data of each time phase and the two-dimensional image data of the first time phase. The figure which shows an example of the difference image data of each time phase generated by a process. FIG. 4 shows the average value of the pixel values of the difference image data of each time phase generated by the difference processing between the two-dimensional image data of each time phase and the two-dimensional image data of the first time phase according to the first embodiment. A graph showing the relationship between and the volume of the lung field. FIG. 5 is a diagram showing an example of the difference image data of each time phase generated by the difference processing of the two-dimensional image data of two time phases adjacent to each other in the respiratory cycle according to the first embodiment. FIG. 6 shows the average value of the pixel values of the difference image data of each time phase generated by the difference processing of the two-dimensional image data of two adjacent time phases according to the first embodiment and the lung field of each time phase. A graph showing the relationship with the volume of. FIG. 7 is a block diagram showing a configuration of an X-ray CT apparatus according to a second embodiment. FIG. 8 is a diagram for explaining a second embodiment. FIG. 9A is a diagram (1) for explaining the timing of the respiratory synchronization scan according to the second embodiment. FIG. 9B is a diagram (2) for explaining the timing of the respiratory synchronization scan according to the second embodiment. FIG. 10 is a diagram for explaining a third embodiment. FIG. 11 is a diagram (1) for explaining other embodiments. FIG. 12 is a diagram (2) for explaining other embodiments. FIG. 13 is a diagram (3) for explaining other embodiments. FIG. 14 is a diagram (4) for explaining other embodiments.

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

(First Embodiment)
FIG. 1 is a block diagram showing a configuration of a medical image processing apparatus according to the first embodiment. The medical image processing device 100 is a communication interface 10 that receives three-dimensional image data of a plurality of time phases in at least one cycle of respiration transmitted from a medical image diagnostic device 110 such as an X-ray CT device by photographing the chest of a subject. It has. Further, the image data acquisition circuit 20 for acquiring the three-dimensional image data of each time phase received by the communication interface 10 is provided.

Further, the medical image processing apparatus 100 is an image data generation circuit that generates two-dimensional image data indicating a cross section of a designated position in the body axis direction of the subject from the three-dimensional image data of each time phase acquired by the image data acquisition circuit 20. It has 30. Further, the image data processing circuit 40 for processing the two-dimensional image data of each time phase generated by the image data generation circuit 30 is provided. Further, it includes a measurement circuit 50 that measures the pixel value of the image data processed by the image data processing circuit 40, measures the area, and the like. The image data processing circuit 40 and the measurement circuit 50 are integrated and also referred to as an image data processing unit.

A storage unit is provided inside or outside the medical image processing device 100, the three-dimensional image data acquired by the image data acquisition circuit 20 is stored in the internal or external storage unit, and the three-dimensional image data stored in the storage unit is stored. The image data generation circuit 30 may read the data to generate two-dimensional image data. That is, the storage unit stores image data of a plurality of time phases regarding the subject obtained from the medical image diagnostic apparatus 110.

Further, the medical image processing device 100 includes a selection circuit 60 that selects a predetermined time phase in inspiration and exhalation from a plurality of time phases in the respiratory cycle based on the measured values measured by the measurement circuit 50. The selection circuit 60 is also referred to as an association unit. Further, the display 70 is provided for displaying the three-dimensional image data acquired by the image data acquisition circuit 20, the two-dimensional image data generated by the image data generation circuit 30, the image data processed by the image data processing circuit 40, and the like. ..

Further, the medical image processing apparatus 100 performs generation of two-dimensional image data in the image data generation circuit 30, processing of two-dimensional image data in the image data processing circuit 40, input for executing measurement in the measurement circuit 50, and the like. It has an input interface 80. Further, it includes a communication interface 10, an image data acquisition circuit 20, an image data generation circuit 30, an image data processing circuit 40, a measurement circuit 50, a selection circuit 60, a display 70, and a control circuit 90 that controls the input interface 80 in an integrated manner. ing.

Hereinafter, an example of the operation of the medical image processing apparatus 100 will be described with reference to FIGS. 1 to 4.

FIG. 2 is a flowchart showing the operation of the medical image processing device 100.

When the communication interface 10 receives the three-dimensional image data of a plurality of time phases in the respiratory cycle transmitted from the medical image diagnostic device 110 by chest imaging including the lungs and bronchi of the subject, the medical image processing device 100 starts operation ( Step S1).

As shown in FIG. 3, the image data acquisition circuit 20 divides one respiratory cycle into M (M is a positive integer) as a plurality of time phases in the respiratory cycle obtained from the medical diagnostic imaging apparatus 110 by receiving the communication interface 10. ) First to M time phases Ph1 to PhM, for example, three-dimensional image data which is volume data is acquired (step S2).

The image data processing circuit 40 reads out the three-dimensional image data of the time phase in response to an input for designating any time phase from the input interface 80 for observing the bronchi of the subject, and sets a preset range. Pixels in the bronchial region are extracted based on the pixel values in. Next, for example, three-dimensional image data showing the bronchi of the subject is generated by a volume rendering method and displayed on the display 70.

When the input interface 80 inputs the three-dimensional image data displayed on the display 70 to specify a desired position in the airway direction of the bronchi, the image data generation circuit 30 displays the image data as shown in FIG. Generates, for example, two-dimensional image data indicating a cross section at the center position corresponding to a designated input in the body axis direction indicated by an arrow in the three-dimensional image data of each of the first to M time phases Ph1 to PhM acquired by the acquisition circuit 20. (Step S3).

When a plurality of two-dimensional image data of the first to M time phases Ph1 to PhM in the respiratory cycle can be obtained from the medical image diagnostic apparatus 110, the image data generation circuit 30 has the first to M time phases Ph1 to Ph1 to each. By reconstructing a plurality of two-dimensional image data of PhM, three-dimensional image data of each of the first to M time phases Ph1 to PhM is generated. Further, the two-dimensional image data at the position corresponding to the designated input in the body axis direction is selected from the plurality of two-dimensional image data of each of the first to M time phases Ph1 to PhM.

The image data processing circuit 40 is a reference time phase set in advance from the two-dimensional image data of the first to M time phases Ph1 to PhM generated by the image data generation circuit 30, for example, the first time phase Ph1. Based on the two-dimensional image data of the above, the two-dimensional image data of each of the first to M time phases Ph1 to PhM is processed. Then, as shown in FIG. 3, by the difference processing between the two-dimensional image data of the first to M time phases Ph1 to PhM and the two-dimensional image data of the first time phase Ph1, the first to M time phases Ph1 -PhM difference image data is generated (step S4).

When the two-dimensional image data of each of the first to M phase phases Ph1 to PhM includes a region other than the lung field region and the bronchial region, the entire region including the other regions is subjected to the difference processing.

Here, the difference image data of the first time phase Ph1 is generated by differentiating the two-dimensional image data of the first time phase Ph1 from the two-dimensional image data of the first time phase Ph1. Further, the two-dimensional image data of the first phase Ph1 is differentiated from the two-dimensional image data of the second phase Ph2 to generate the difference image data of the second phase Ph2, and the two-dimensional image data of the third phase Ph3 is generated. The two-dimensional image data of the first phase Ph1 is differentiated from the above to generate the difference image data of the third phase Ph3. Further, the second (M-1) time phase Ph (M-1) is obtained by differentiating the two-dimensional image data of the first time phase Ph1 from the two-dimensional image data of the first (M-1) time phase Ph (M-1). The difference image data of the first phase Ph1 is generated, and the two-dimensional image data of the first phase Ph1 is subjected to the difference processing from the two-dimensional image data of the third phase PhM to generate the difference image data of the third phase PhM.

The measurement circuit 50 obtains an index value comparing the pixel value of the image data of the reference time phase and the pixel value of each of the image data of the plurality of time phases among the image data of the plurality of time phases. For example, the measurement circuit 50 obtains the average value of the pixel values of the entire difference image data of each of the first to M time phases Ph1 to PhM generated by the processing in the image data processing circuit 40 (step S5).

FIG. 4 is a graph showing the relationship between the average value of the pixel values of the difference image data of each time phase and the volume of the lung field. The graphs 120 and 121 show a cross section of the three-dimensional image data of the first to eleventh phase when one cycle of respiration obtained from the medical image diagnostic apparatus 110 is divided into 11 by taking a chest image of the subject at a predetermined position. It was created based on the two-dimensional image data shown.

Graph 120 shows the volume of the lung field in the first to eleventh phases. The volume of the lung field is maximum in the second phase and minimum in the seventh phase. Further, in the graph 121, when the pixel values of the two-dimensional image data of the first to eleventh time phases are converted into CT values expressed in units of "HU" (Hounsfield Unit) and the eleventh time phase is used as the reference time phase. The average value of the CT values of the difference image data of each of the first to eleventh phase is shown. Then, the average value of the CT values becomes the maximum in the second time phase and the minimum in the seventh time phase.

As described above, the inventors have found that the CT value of the difference image data, that is, the average value of the pixel values is maximized in the time phase of the maximum inspiration when the volume of the lung field is maximized. It was also found that the average value of the pixel values of the difference image data is the minimum in the time phase of the maximum exhalation where the volume of the lung field is the minimum.

The selection circuit 60 is selected from among the first to M time phases Ph1 to PhM in the respiratory cycle based on the pixel values of the entire difference image data of the first to M time phases Ph1 to PhM shown in FIG. Select a given time phase for at least one of inspiration and expiration. Here, the time phase of the difference image data that maximizes the average value of the pixel values is selected as the time phase of the maximum inspiration of the subject, and the time phase of the difference image data that minimizes the average value of the pixel values is the maximum time phase of the subject. It is selected as the time phase of exhalation (step S6).

In this way, the time phase of maximum inspiration and the time phase of maximum expiration can be easily determined without extracting the lung field region from the three-dimensional image data, so that the time required for processing the image data can be shortened. This makes it possible to improve the throughput.

Further, the image data processing circuit 40 extracts pixels in the bronchial region included in the two-dimensional image data of the time phases of the maximum inspiration and the maximum expiration selected by the selection circuit 60. The measurement circuit 50 obtains the cross-sectional area of the bronchial region extracted by the image data processing circuit 40 and displays it on the display 70.

The display 70 shows three-dimensional image data showing the bronchus of the subject, a marker showing a designated position of the bronchus in the airway direction, two-dimensional image data of the first to M phase phases Ph1 to PhM, and the first to M o'clock. Identification information that identifies the time phase of the maximum inspiration and the maximum expiration of the phases Ph1 to PhM, the cross-sectional area of the bronchus in the maximum inspiration and the maximum expiration, and the like are displayed.

(Modified example of the first embodiment)
The present invention is not limited to the first embodiment, and may be carried out in the form described below. First, as shown in FIG. 5, in the first to M time phases Ph1 to PhM, the reference time phase is set as one of the two time phases adjacent to each other, and each of the first to third phases is the other time phase. (M-1) The difference processing is performed between the two-dimensional image data of the time phases Ph1 to Ph (M-1) and the two-dimensional image data of one of the time phases. Here, the difference image data of the first phase Ph1 is generated by differentiating the two-dimensional image data of the second phase Ph2 from the two-dimensional image data of the first phase Ph1. Further, the difference image data of the second phase Ph2 is generated by differentiating the two-dimensional image data of the third phase Ph3 from the two-dimensional image data of the second phase Ph2. Further, the difference image data of the (M-1) time phase is generated by differentiating the two-dimensional image data of the M time phase PhM from the two-dimensional image data of the third (M-1) time phase Ph (M-1). To do. Then, the difference image data of the first to first (M-1) time phases Ph1 to Ph (M-1) is generated.

FIG. 6 shows the relationship between the average value of the pixel values of the difference image data of each time phase generated by the difference processing of the two-dimensional image data of two adjacent time phases and the volume of the lung field of each time phase. It is a graph. The graphs 122 and 123 show a cross section at a predetermined position of the three-dimensional image data of the first to tenth phases obtained by dividing one cycle of respiration obtained from the medical image diagnostic apparatus 110 by taking a chest image of the subject into ten parts. It was created based on the three-dimensional image data.

Graph 122 shows the volume of the lung field in the 1st to 10th phase in the respiratory cycle. The volume of the lung field is maximum in the 4th phase and minimum in the 8th phase. Further, in the graph 123, in the first to tenth time phases, the reference time phase is set to the later time phase of the two adjacent time phases, and each of the first to tenth time phases which is the earlier time phase. The average value of CT values of the difference image data of the 1st to 9th phase obtained by differentiating the 2D image data of the slower time phase from the 2D image data is shown. Then, the average value of the CT values becomes the maximum in the 4th phase and the minimum in the 8th phase.

In this way, the inventors have found that the average value of the pixel values of the difference image data decreases to a value near 0 or 0 during the time phase of maximum inspiration when the volume of the lung field is maximum. .. It was also found that the average value of the pixel values of the difference image data increases to 0 or a value near 0 in the time phase of the maximum exhalation in which the volume of the lung field is the minimum.

From this, the average value of the pixel values of the difference image data generated by the difference processing between the two-dimensional image data of the two earlier phase and the two-dimensional image data of the later phase adjacent to each other. The time phase in which is reduced to a value near 0 or 0 is selected as the maximum inspiratory time phase, and the time phase in which the average value is increased to a value near 0 or 0 is selected as the maximum expiratory time phase. You may.

In this way, the time phase of maximum inspiration and the time phase of maximum expiration can be easily determined without extracting the lung field region from the three-dimensional image data, so that the time required for processing the image data can be shortened. This makes it possible to improve the throughput.

According to the above-described embodiment, the first to M time phases Ph1 to PhM are obtained from the three-dimensional image data of the first to M time phases Ph1 to PhM in the respiratory cycle of the subject obtained from the medical diagnostic imaging apparatus 110. 2D image data is generated, and a reference set from the 2D image data of the 1st to Mth time phases Ph1 to PhM and the 2D image data of the 1st to Mth phase Ph1 to PhM respectively. Difference image data of the first to M time phases Ph1 to PhM can be generated by the difference processing with the two-dimensional image data of the time phase. Then, the average value of the pixel values of the difference image data of each of the first to M time phases Ph1 to PhM is obtained, and the time phase of the difference image data at which the average value of the pixel values is maximum is the time phase of the maximum intake of the subject. The time phase of the difference image data that minimizes the average value of the pixel values can be selected as the time phase of the maximum exhalation of the subject.

As a result, a predetermined time phase in inspiration and exhalation can be easily determined without extracting the lung field region from the three-dimensional image data, so that the time required for processing the image data can be shortened. Throughput can be improved.

(Second Embodiment)
In the first embodiment and the modified examples of the first embodiment, the case where the image processing method is realized by the medical image processing apparatus has been described, but the embodiment is not limited to this. For example, the image processing method described in the first embodiment and the modification of the first embodiment may be realized by the medical image diagnostic apparatus 110.

Therefore, in the second embodiment, the case where the image processing method is realized by the medical image diagnostic apparatus 110 will be described. In the second embodiment, the case where the medical image diagnostic apparatus 110 is an X-ray CT apparatus will be described. FIG. 7 is a block diagram showing a configuration example of the X-ray CT apparatus according to the second embodiment.

FIG. 7 is a diagram showing an example of the configuration of the X-ray CT apparatus 200 according to the second embodiment. As shown in FIG. 7, the X-ray CT apparatus 200 according to the second embodiment has a pedestal 210, a sleeper 220, and a console 230.

The gantry 210 is a device that irradiates the subject P (patient) with X-rays, detects the X-rays transmitted through the subject P, and outputs the X-rays to the console 230. The X-ray irradiation control circuit 211 and the X-ray generator are generated. It has a device 212, a detector 213, a data acquisition circuit (DAS: Data Acquisition System) 214, a rotating frame 215, and a gantry drive circuit 216. Further, in the gantry 210, as shown in FIG. 7, a Cartesian coordinate system including an X-axis, a Y-axis, and a Z-axis is defined. That is, the X-axis indicates the horizontal direction, the Y-axis indicates the vertical direction, and the Z-axis indicates the body axis direction of the subject P.

The rotating frame 215 supports the X-ray generator 212 and the detector 213 so as to face each other with the subject P in between, and rotates at high speed in a circular orbit centered on the subject P by a gantry drive circuit 216 described later. It is a circular frame.

The X-ray irradiation control circuit 211 is a device that supplies a high voltage to the X-ray tube 212a as a high voltage generating unit, and the X-ray tube 212a uses the high voltage supplied from the X-ray irradiation control circuit 211 to X-ray. Generate a line. The X-ray irradiation control circuit 211 adjusts the X-ray dose to be irradiated to the subject P by adjusting the tube voltage and the tube current supplied to the X-ray tube 212a under the control of the scan control circuit 233 described later. ..

Further, the X-ray irradiation control circuit 211 switches the wedge 212b. Further, the X-ray irradiation control circuit 211 adjusts the X-ray irradiation range (fan angle and cone angle) by adjusting the opening degree of the collimator 212c. In this embodiment, the operator may manually switch between a plurality of types of wedges.

The X-ray generator 212 is a device that generates X-rays and irradiates the subject P with the generated X-rays, and has an X-ray tube 212a, a wedge 212b, and a collimator 212c.

The X-ray tube 212a is a vacuum tube that irradiates the subject P with an X-ray beam by a high voltage supplied by a high voltage generator (not shown), and the X-ray beam is sent to the subject P as the rotating frame 215 rotates. Irradiate against. The X-ray tube 212a generates an X-ray beam that spreads with a fan angle and a cone angle. For example, under the control of the X-ray irradiation control circuit 211, the X-ray tube 212a is continuously exposed to X-rays all around the subject P for full reconstruction, or half-reconstructable for half-reconstruction. It is possible to continuously expose X-rays within the range (180 degrees + fan angle). Further, by controlling the X-ray irradiation control circuit 211, the X-ray tube 212a can intermittently emit X-rays (pulse X-rays) at a preset position (tube position). The X-ray irradiation control circuit 211 can also modulate the intensity of X-rays exposed from the X-ray tube 212a. For example, the X-ray irradiation control circuit 211 increases the intensity of X-rays emitted from the X-ray tube 212a at a specific tube position, and exposes the X-ray tube 212a to a range other than the specific tube position. Decreases the intensity of the emitted X-rays.

The wedge 212b is an X-ray filter for adjusting the X-ray dose of X-rays exposed from the X-ray tube 212a. Specifically, the wedge 212b transmits the X-rays exposed from the X-ray tube 212a so that the X-rays radiated from the X-ray tube 212a to the subject P have a predetermined distribution. It is a filter that attenuates. For example, the wedge 212b is a filter made of aluminum so as to have a predetermined target angle and a predetermined thickness. The wedge is also called a wedge filter or a bow-tie filter.

The collimator 212c is a slit for narrowing down the X-ray irradiation range in which the X-ray dose is adjusted by the wedge 212b under the control of the X-ray irradiation control circuit 211.

The gantry drive circuit 216 rotates the rotating frame 215 to rotate the X-ray generator 212 and the detector 213 on a circular orbit centered on the subject P.

The detector 213 is a two-dimensional array type detector (surface detector) that detects X-rays that have passed through the subject P, and the detection element sequence formed by arranging X-ray detection elements for a plurality of channels is the subject P. A plurality of rows are arranged along the body axis direction (Z-axis direction shown in FIG. 7). Specifically, the detector 213 in the second embodiment has X-ray detection elements arranged in multiple rows such as 320 rows along the body axis direction of the subject P, for example, the lungs of the subject P. It is possible to detect X-rays that have passed through the subject P over a wide range, such as in the range including the heart and the heart.

The data collection circuit 214 is a DAS and collects projection data from the X-ray detection data detected by the detector 213. For example, the data acquisition circuit 214 generates projection data by performing amplification processing, A / D conversion processing, sensitivity correction processing between channels, and the like on the X-ray intensity distribution data detected by the detector 213. The projected projection data is transmitted to the console 230, which will be described later. For example, when X-rays are continuously exposed from the X-ray tube 212a during the rotation of the rotation frame 215, the data acquisition circuit 214 collects the projection data group for the entire circumference (360 degrees). Further, the data collection circuit 214 associates the tube position with each of the collected projection data and transmits the data to the console 230, which will be described later. The tube position is information indicating the projection direction of the projection data. The sensitivity correction processing between channels may be performed by the preprocessing circuit 234, which will be described later.

The sleeper 220 is a device on which the subject P is placed, and has a sleeper drive device 221 and a top plate 222 as shown in FIG. 7. The sleeper drive device 221 moves the top plate 222 in the Z-axis direction to move the subject P into the rotating frame 215. The top plate 222 is a plate on which the subject P is placed.

The gantry 210 executes, for example, a helical scan in which the rotating frame 215 is rotated while the top plate 222 is moved to spirally scan the subject P. Alternatively, the gantry 210 executes a conventional scan in which the rotating frame 215 is rotated while the position of the subject P is fixed after the top plate 222 is moved to scan the subject P in a circular orbit. Alternatively, the gantry 210 executes a step-and-shoot method in which the position of the top plate 222 is moved at regular intervals to perform a conventional scan in a plurality of scan areas.

The console 230 is a device that accepts the operation of the X-ray CT device 200 by the operator and reconstructs the X-ray CT image data using the projection data collected by the gantry 210. As shown in FIG. 7, the console 230 has an input circuit 231, a display 232, a scan control circuit 233, a preprocessing circuit 234, a storage circuit 235, an image reconstruction circuit 236, and a processing circuit 237. ..

The input circuit 231 has a mouse, keyboard, trackball, switch, button, joystick, etc. used by the operator of the X-ray CT device 200 to input various instructions and various settings, and information on the instructions and settings received from the operator. Is transferred to the processing circuit 237. For example, the input circuit 231 receives from the operator the imaging conditions for the X-ray CT image data, the reconstruction conditions for reconstructing the X-ray CT image data, the image processing conditions for the X-ray CT image data, and the like. Further, the input circuit 231 accepts an operation for selecting a test for the subject P. Further, the input circuit 231 accepts a designation operation for designating a portion on the image.

The display 232 is a monitor referred to by the operator, and under the control of the processing circuit 237, the display 232 displays the image data generated from the X-ray CT image data to the operator, or the operator via the input circuit 231. Displays a GUI (Graphical User Interface) for receiving various instructions and settings from. In addition, the display 232 displays a plan screen for a scan plan, a screen during scanning, and the like.

The scan control circuit 233 controls the operations of the X-ray irradiation control circuit 211, the gantry drive circuit 216, the data acquisition circuit 214, and the sleeper drive device 221 under the control of the processing circuit 237 to control the operation of the projection data on the gantry 210. Control the collection process. Specifically, the scan control circuit 233 controls the collection process of projection data in the imaging in which the positioning image (scano image) is collected and the main imaging (scan) in which the image used for diagnosis is collected. For example, the scan control circuit 233 collects three-dimensional image data of a plurality of time phases in at least one cycle of respiration by chest imaging including the lungs and bronchi of the subject P. That is, the scan control circuit 233 collects image data of a plurality of time phases relating to the subject P. The scan control circuit 233 is also referred to as a collecting unit.

The preprocessing circuit 234 performs logarithmic transformation processing and correction processing such as offset correction, sensitivity correction, and beam hardening correction on the projection data generated by the data acquisition circuit 214, and obtains the corrected projection data. Generate. Specifically, the preprocessing circuit 234 generates corrected projection data for each of the projection data of the positioning image generated by the data acquisition circuit 214 and the projection data collected by the main shooting, and the storage circuit 235. Store in.

The storage circuit 235 stores the projection data generated by the preprocessing circuit 234. Specifically, the storage circuit 235 stores the projection data of the positioning image generated by the preprocessing circuit 234 and the projection data for diagnosis collected by the main imaging. Further, the storage circuit 235 stores the image data generated by the image reconstruction circuit 236, which will be described later. Further, the storage circuit 235 appropriately stores the processing result by the processing circuit 237 described later.

The image reconstruction circuit 236 reconstructs the X-ray CT image data using the projection data stored in the storage circuit 235. Specifically, the image reconstruction circuit 236 reconstructs the X-ray CT image data from the projection data of the positioning image and the projection data of the image used for diagnosis. Here, as the reconstruction method, there are various methods, and examples thereof include a back projection process. Further, as the back projection process, for example, a back projection process by the FBP (Filtered Back Projection) method can be mentioned. Alternatively, the image reconstruction circuit 236 can reconstruct the X-ray CT image data by using the successive approximation method.

Further, the image reconstruction circuit 236 generates image data by performing various image processing on the X-ray CT image data. Then, the image reconstruction circuit 236 stores the reconstructed X-ray CT image data and the image data generated by various image processes in the storage circuit 235. For example, the image reconstruction circuit 236 generates two-dimensional image data indicating a cross section of, for example, a central position corresponding to a designated input in the body axis direction of the three-dimensional image data of each of the first to M time phases Ph1 to PhM. ..

The processing circuit 237 controls the entire operation of the X-ray CT apparatus 200 by controlling the operations of the gantry 210, the sleeper 220, and the console 230. Specifically, the processing circuit 237 controls the CT scan performed on the gantry 210 by controlling the scan control circuit 233. Further, the processing circuit 237 controls the image reconstruction processing and the image generation processing in the console 230 by controlling the image reconstruction circuit 236. Further, the processing circuit 237 controls the display 232 to display various image data stored in the storage circuit 235.

Further, as shown in FIG. 7, the processing circuit 237 executes the image data processing function 237a, the selection function 237b, and the synchronous scan control function 237c. Here, for example, each processing function executed by the image data processing function 237a, the selection function 237b, and the synchronous scan control function 237c, which are the components of the processing circuit 237 shown in FIG. 7, is stored in the form of a program that can be executed by a computer. Recorded in circuit 235. The processing circuit 237 is a processor that realizes a function corresponding to each program by reading each program from the storage circuit 235 and executing the program. In other words, the processing circuit 237 in the state where each program is read has each function shown in the processing circuit 237 of FIG. 7. The image data processing function 237a is also referred to as an image data processing unit, the selection function 237b is also referred to as an association unit, and the synchronous scan control function 237c is also referred to as a synchronous scan control unit.

The image data processing function 237a executes the same functions as the image data processing circuit 40 and the measurement circuit 50 according to the first embodiment. That is, the image data processing function 237a obtains an index value comparing the pixel value of the image data of the reference time phase among the image data of the plurality of time phases with the pixel value of each of the image data of the plurality of time phases.

The selection function 237b executes the same function as the selection circuit 60 according to the first embodiment. That is, the selection function 237b selects at least one of the image data of the plurality of time phases based on the index value obtained for each of the plurality of time phases, and sets the respiratory time phase in at least one of the inspiration and the exhalation of the subject P. Associate.

For example, the image data processing function 237a obtains an index value by performing difference processing between the image data of each of the plurality of time phases and the image data of the reference time phase. Then, the selection function 237b selects the time phase in which the index value obtained by the image data processing function 237a becomes the maximum value as the time phase in the maximum inspiration of the subject P. Further, the selection function 237b selects the time phase in which the index value obtained by the image data processing function 237a is the minimum value as the time phase in the maximum exhalation of the subject P.

The reference time phase can be one of two adjacent time phases among the plurality of time phases. In such a case, for example, the image data processing function 237a performs differential processing between the image data of the other time phase of the adjacent time phase and the image data of one time phase to obtain an index value. Then, the selection function 237b selects a time phase in which the index value obtained by the image data processing function 237a decreases to 0 or near 0 as the time phase in the maximum inspiration of the subject P. Further, the selection function 237b selects a time phase in which the index value obtained by the image data processing function 237a increases to 0 or near 0 as the time phase in the maximum exhalation of the subject P.

Further, the image data processing function 237a extracts pixels in the bronchial region included in the two-dimensional image data of the time phases of the maximum inspiration and the maximum expiration selected by the selection function 237b. Then, the image data processing function 237a obtains the cross-sectional area of the extracted bronchial region and displays it on the display 232. In such a case, the display 232 shows three-dimensional image data indicating the bronchus of the subject P, a marker indicating a designated position of the bronchus in the airway direction, two-dimensional image data of the first to M time phases Ph1 to PhM, and the first. ~ M time phase Identification information for identifying the time phase of maximum inspiration and maximum expiration among Ph1 to PhM, the cross-sectional area of the bronchus in maximum inspiration and maximum expiration, and the like are displayed.

The configuration of the X-ray CT apparatus 200 according to the second embodiment has been described above. Under such a configuration, the X-ray CT apparatus 200 according to the second embodiment collects three-dimensional image data of a plurality of time phases in at least one cycle of respiration by chest imaging including the lungs and bronchi of the subject P. In addition, the X-ray CT apparatus 200 may be used for a respiratory synchronous scan when performing a chest image including the lungs and bronchi of the subject P.

In general, respiratory-gated scans are performed during periods of maximum inspiration and maximum expiration. For example, the X-ray CT apparatus 200 acquires the respiratory waveform of the subject P from the respiratory detection apparatus in the respiratory synchronous scan, and scans at the time phase of the maximum inspiration and the maximum expiration. However, the respiratory waveform obtained from the respiratory detector may not be accurate. In such a case, even if the X-ray CT apparatus 200 performs a scan based on the respiratory waveform acquired from the respiratory detection apparatus, the X-ray CT apparatus 200 may not be able to perform the scan at the time phase of the maximum inspiration or the maximum expiration of the subject P. Therefore, in the second embodiment, the X-ray CT apparatus 200 uses the image data processing function 237a, the selection function 237b, and the synchronous scan control function 237c to perform the time phase of the maximum inspiration and the maximum expiration of the subject P. Control to scan. FIG. 8 is a diagram for explaining the second embodiment.

When performing a respiratory synchronous scan in the X-ray CT apparatus 200 according to the second embodiment, the scan control circuit 233 sequentially collects image data of a plurality of time phases relating to the subject P under the X-ray irradiation conditions in the preliminary imaging. .. For example, the scan control circuit 233 sequentially collects three-dimensional image data of the first to M phase phases Ph1 to PhM under low-dose X-ray irradiation conditions. Then, the image reconstruction circuit 236 generates the two-dimensional image data by using the three-dimensional image data collected by the scan control circuit 233. For example, the image reconstruction circuit 236 generates the 2D image data of Ph1 from the 3D image data of Ph1 and obtains the 2D image data of Ph2 from the 3D image data of Ph2 as shown in the upper figure of FIG. Generate and generate PhM 2D image data from PhM 3D image data.

Subsequently, the image data processing function 237a obtains an index value each time image data of a new time phase is collected. For example, the image data processing function 237a generates differential image data by difference processing of two-dimensional image data of two time phases adjacent to each other as shown in the middle figure of FIG. 8, and as shown in the lower figure of FIG. , Calculate the average CT value of the generated difference image data. As an example, the image data processing function 237a generates difference image data between the two-dimensional image data of Ph1 and the two-dimensional image data of Ph2 when the two-dimensional image data of Ph2 is generated, and the generated difference image. Calculate the average value of the pixel values of the data. Similarly, when the PhM two-dimensional image data is generated, the image data processing function 237a generates and generates the difference image data between the Ph (M-1) two-dimensional image data and the PhM two-dimensional image data. Calculate the average value of the pixel values of the difference image data.

Then, the selection function 237b determines whether or not the image data of the new time phase is the image data corresponding to the respiratory time phase in at least one of the maximum inspiration and the maximum expiration of the subject P each time the index value is obtained. judge. For example, the selection function 237b determines that the time phase in which the average CT value changes from plus to minus is the respiratory time phase of maximum inspiration, and the time phase in which the average CT value changes from minus to plus is the time of respiration of maximum exhalation. Determined to be a phase.

Then, the synchronous scan control function 237c displays the image data for the subject P under the X-ray irradiation conditions in the main imaging when the image data of the new time phase is the respiratory time phase in at least one of the maximum exhalation and the maximum inspiration. The scan control circuit 233 collects the data. 9A and 9B are diagrams for explaining the timing of the respiratory synchronous scan according to the second embodiment.

9A and 9B are graphs showing the average value of the pixel values of the difference image data of each time phase generated by the difference processing of the two-dimensional image data of two time phases adjacent to each other. The horizontal axis of FIGS. 9A and 9B indicates the time phase, and the vertical axis indicates the CT value expressed in "HU" units. In the example shown in FIG. 9A, the selection function 237b determines that the fourth phase is the maximum inspiration and the eighth phase is the maximum exhalation. In such a case, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging in the fourth phase, which is the maximum intake. Further, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging in the eighth phase, which is the maximum exhalation.

Similar to the example shown in FIG. 9A, the selection function 237b determines that the first time phase is the maximum inspiration and the seventh time phase is the maximum exhalation in the example shown in FIG. 9B. In such a case, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging in the first phase, which is the maximum intake. Further, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging in the 7th phase, which is the maximum exhalation.

As a result, the X-ray CT apparatus 200 can perform scanning under the X-ray irradiation conditions in the main imaging in the time phase of the maximum inspiration and the maximum expiration of the subject P. Further, in the second embodiment described above, the case where the difference processing is performed on the two-dimensional image data of two time phases adjacent to each other has been described, but the embodiment is not limited to this. For example, each of the first to first phases is based on the two-dimensional image data of the first time phase Ph1 which is a preset reference time phase from the two-dimensional image data of the first to M time phases Ph1 to PhM. The two-dimensional image data of the M time phase Ph1 to PhM may be processed. In such a case, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging, with the time phase in which the index value is maximized as the time phase for maximum inspiration. Further, the synchronous scan control function 237c causes the scan control circuit 233 to collect image data for the subject P under the X-ray irradiation conditions in the main imaging, with the time phase in which the index value becomes the minimum is set as the time phase in the maximum exhalation.

In the X-ray CT apparatus 200 according to the second embodiment, the processing circuit 237 may be configured not to execute the synchronous scan control function 237c. That is, in the X-ray CT apparatus 200 according to the second embodiment, the processing circuit 237 may be configured to execute the image data processing function 237a and the selection function 237b.

(Third Embodiment)
In the above-described embodiment, the case where at least one of the image data of the plurality of time phases is selected and associated with the respiratory phase in at least one of the inspiration and the exhalation of the subject P has been described. By the way, when the three-dimensional image data of a plurality of time phases in at least one cycle of respiration is collected by chest imaging including the lungs and bronchi of the subject P, the total capacity of the collected three-dimensional image data becomes large.

On the other hand, the images usually used for diagnosis are images of the time phase of maximum expiration and maximum inspiration. Therefore, only the three-dimensional image of the time phase of the maximum inspiration and the three-dimensional image of the time phase of the maximum expiration need to be saved. Therefore, in the third embodiment, the case where the medical image processing apparatus 100 stores the three-dimensional image data corresponding to the respiratory phase in at least one of the maximum inspiration and the maximum expiration of the subject P in a predetermined storage unit will be described. To do.

The configuration of the medical image processing apparatus 100 according to the third embodiment is the configuration of the medical image processing apparatus 100 according to the first embodiment shown in FIG. 1, except that the selection circuit 60 is provided with some additional functions. Similar to the configuration. Therefore, the additional functions provided in the selection circuit 60 will be described below. FIG. 10 is a diagram for explaining a third embodiment.

As shown in the upper part of FIG. 10, the image data acquisition circuit 20 acquires three-dimensional image data of a plurality of time phases in at least one cycle of respiration transmitted from a medical image diagnosis device 110 such as an X-ray CT device. Then, as shown in the middle figure of FIG. 10, the image data generation circuit 30 is, for example, from the three-dimensional image data of each time phase acquired by the image data acquisition circuit 20 in the same manner as in the first embodiment. Two-dimensional image data showing a cross section of a designated position in the body axis direction of the subject P is generated. Then, as shown in the lower figure of FIG. 10, the image data processing circuit 40 performs differential processing on the two-dimensional image data of each time phase generated by the image data generation circuit 30. Note that FIG. 10 shows a case where the two-dimensional image data of each of the first to M time phases Ph1 to PhM is subjected to the difference processing with Ph1 as the reference time phase. Further, the measurement circuit 50 obtains the average value of the pixel values of the entire difference image data of each of the first to M time phases Ph1 to PhM generated by the processing in the image data processing circuit 40.

Then, the selection circuit 60 according to the third embodiment has at least one of the maximum inspiration and the maximum exhalation of the subject P from the image data of the plurality of time phases based on the index values obtained for each of the plurality of time phases. Select the image data corresponding to the respiratory phase in. In the example shown in FIG. 10, the selection circuit 60 according to the third embodiment selects the time phase having the maximum average CT value as the maximum inspiratory time phase, and the time phase having the minimum average CT value as the maximum expiratory time phase. Select as. Then, the selection circuit 60 according to the third embodiment stores the three-dimensional image data corresponding to the time phase of the selected image data in a predetermined storage unit.

As described above, the medical image processing apparatus 100 according to the third embodiment reconstructs only the central slice of the three-dimensional image data, and based on the index value, from the image data of the plurality of time phases, for example, Image data corresponding to the respiratory phase in at least one of the maximum inspiration and the maximum expiration of the subject P is selected. Then, the medical image processing apparatus 100 according to the third embodiment stores the three-dimensional image data corresponding to the time phase of the selected image data in a predetermined storage unit. As a result, the medical image processing apparatus 100 according to the third embodiment can reduce the total capacity of the three-dimensional image data to be stored.

In the third embodiment described above, in the medical image processing apparatus 100, the selection circuit 60 stores three-dimensional image data corresponding to the respiratory phase in at least one of the maximum inspiration and the maximum expiration of the subject P. Although it has been described as being stored in the section, the embodiment is not limited to this. For example, the selection function 237b of the X-ray CT apparatus 200 may execute the same function as the selection circuit 60 according to the third embodiment.

(Other embodiments)
The embodiment is not limited to the above-described embodiment. In the following, the medical image processing apparatus 100 will be described as an example, but other embodiments described below can be similarly applied to the X-ray CT apparatus 200.

In the above-described embodiment, for example, the case of determining the time phase of maximum inspiration and the time phase of maximum expiration has been described, but the embodiment is not limited to this. For example, the selection circuit 60 of the medical image processing apparatus 100 displays information in which each time phase and an index value in each time phase are associated with each other when displaying an image of the time phase of maximum inspiration or an image of the time phase of maximum expiration. May be further generated and information may be output to a predetermined display unit. 11 and 12 are diagrams for explaining other embodiments.

FIG. 11 shows a case where the two-dimensional image data of each of the first to M time phases Ph1 to PhM is subjected to the difference processing with Ph1 as the reference time phase. The horizontal axis of FIG. 11 shows the time phase, and the vertical axis shows the CT value expressed in "HU" units. As shown in FIG. 11, the selection circuit 60 further displays a graph showing the average value of the pixel values of the difference image data of each time phase. Here, in the example shown in FIG. 11, the eighth phase with the maximum CT value is the maximum inspiration, and the fourth phase with the minimum CT value is the maximum exhalation. In such a case, the selection circuit 60 may display information indicating that it is the maximum inspiration and information indicating that it is the maximum exhalation. More specifically, the selection circuit 60 displays a broken line indicating that the eighth phase is the maximum inspiration and character information, and displays a broken line indicating that the fourth phase is the maximum exhalation and character information. indicate.

FIG. 12 shows a case where two-dimensional image data of two time phases adjacent to each other are subjected to difference processing. The horizontal axis of FIG. 12 shows the time phase, and the vertical axis shows the CT value expressed in "HU" units. As shown in FIG. 12, the selection circuit 60 further displays a graph showing the average value of the pixel values of the difference image data of each time phase. Here, in the example shown in FIG. 12, the third time phase in which the average CT value changes from plus to minus is the maximum inspiration, and the ninth time phase in which the average CT value changes from minus to plus is the maximum exhalation. Similarly, in such a case, the selection circuit 60 may display information indicating that it is the maximum inspiration and information indicating that it is the maximum exhalation. More specifically, the selection circuit 60 displays a broken line indicating that the third time phase is the maximum inspiration and character information, and displays a broken line indicating that the ninth phase is the maximum exhalation and character information. indicate. The selection circuit 60 may display only one of the broken line and the character information indicating the maximum inspiration, or may display only one of the broken line and the character information indicating the maximum exhalation. Further, the selection circuit 60 may display only one of the information indicating the maximum inspiration and the information indicating the maximum expiration.

In the above-described embodiment, the case where the time phase of the maximum inspiration and the time phase of the maximum expiration can be specified has been described, but the embodiment is not limited to this. For example, in the subject P having a disease in the lung, the time phase of the maximum inspiration and the time phase of the maximum exhalation may be different from those of the normal subject P. 13 and 14 are diagrams for explaining other embodiments.

FIG. 13 shows a case where the two-dimensional image data of each of the first to M time phases Ph1 to PhM is subjected to the difference processing with Ph1 as the reference time phase. The horizontal axis of FIG. 13 indicates the time phase, and the vertical axis indicates the CT value expressed in "HU" units. As shown in FIG. 13, the selection circuit 60 further displays a graph showing the average value of the pixel values of the difference image data of each time phase. Here, in the example shown in FIG. 13, the CT value becomes the maximum in the 6th time phase and the 8th time phase, and the CT value becomes the minimum in the 4th time phase and the 7th time phase. In this way, when a plurality of candidates for at least one of the time phase at the maximum inspiration and the time phase at the maximum expiration are detected, the selection circuit 60 can select the time phase at the maximum intake and the time phase at the maximum expiration. The information indicating that there is no such information is output to a predetermined output unit.

Further, FIG. 14 shows a case where two-dimensional image data of two time phases adjacent to each other are subjected to difference processing. The horizontal axis of FIG. 14 shows the time phase, and the vertical axis shows the CT value expressed in "HU" units. As shown in FIG. 14, the selection circuit 60 further displays a graph showing the average value of the pixel values of the difference image data of each time phase. Here, in the example shown in FIG. 14, the average CT value changes from plus to minus in the third phase and the sixth phase, and the average CT value changes from minus to plus in the fifth phase and the ninth phase. Changes to. In this way, when a plurality of candidates for at least one of the time phase at the maximum inspiration and the time phase at the maximum expiration are detected, the selection circuit 60 can select the time phase at the maximum intake and the time phase at the maximum expiration. The information indicating that there is no such information is output to a predetermined output unit.

Further, the image data generation circuit 30 has been described as generating two-dimensional image data showing a cross section (axial cross section) of the three-dimensional image data in the body axis direction, but the embodiment is not limited to this. For example, the image data generation circuit 30 is not a two-dimensional image data showing an axial cross section, but a two-dimensional image data showing a sagittal cross section (sagittal cross section) of the three-dimensional image data or a coronal cross section of the three-dimensional image data. Two-dimensional image data indicating (coronal cross section) may be generated. In such a case, the image data processing circuit 40 differs from the two-dimensional image data showing the sagittal cross section and the two-dimensional image data showing the coronal cross section in the same manner as the process of generating the difference image data from the two-dimensional image data showing the axial cross section. Generate image data. Then, the measurement circuit 50 uses the difference image data generated from the sagittal cross section and the coronal cross section as an index in each time phase in the same manner as the process of obtaining the index value using the difference image data generated from the axial cross section. Find the value. When the image data generation circuit 30 generates two-dimensional image data showing a sagittal cross section or two-dimensional image data showing a coronal cross section, the lung field is similar to the case of generating two-dimensional image data showing an axial cross section. It is desirable to generate a sagittal cross section or coronal cross section at the position estimated to be imaged. For example, the image data generation circuit 30 generates a sagittal cross section or a coronal cross section at the center position of the three-dimensional image data.

Further, in the above-described embodiment, the case where the image data generation circuit 30 generates one two-dimensional image data in each time phase has been described, but the embodiment is not limited to this. That is, the image data generation circuit 30 may generate two-dimensional image data showing a plurality of cross sections in each time phase.

For example, the image data generation circuit 30 may generate two-dimensional image data showing a plurality of cross sections in the body axis direction. More specifically, in the image data generation circuit 30, in addition to the two-dimensional image data showing the cross section of the central position in the body axis direction, the image data generation circuit 30 shows two 2 cross sections showing the cross sections of the front and rear positions of the center position in the body axis direction. Further generate dimensional image data. In such a case, the image data processing circuit 40 generates difference image data for each of a plurality of cross sections in each time phase. That is, the image data processing circuit 40 uses the three two-dimensional image data generated by the image data generation circuit 30 for each of the first to M time phases Ph1 to PhM to generate three difference image data of each time phase. Generate. More specifically, the image data processing circuit 40 includes the difference image data at the center position in the body axis direction, the difference image data at the position before the center position, and the difference image data at the position behind the center position. Is generated in each time phase. Then, in each time phase, the measurement circuit 50 obtains index values using the difference image data generated for each cross section of the plurality of cross sections, and obtains the average value of each index value obtained for each cross section. Find the index value for each time phase. More specifically, the measurement circuit 50 obtains the average value of the pixel values of the entire difference image data of each time phase generated by the processing in the image data processing circuit 40 as an index value, and averages the obtained index values. By finding the value, the index value of each time phase is found. The number of two-dimensional image data generated by the image data generation circuit 30 in each time phase can be arbitrarily changed.

Further, the image data generation circuit 30 may generate two-dimensional image data showing a sagittal cross section and two-dimensional image data showing a coronal cross section in addition to the two-dimensional image data showing the axial cross section. In such a case, the image data processing circuit 40 generates the difference image data from the two-dimensional image data showing the axial cross section, generates the difference image data from the two-dimensional image data showing the sagittal cross section, and the two-dimensional image data showing the coronal cross section. Generate difference image data from. Then, the measurement circuit 50 obtains the index value of the difference image data of the cross section in each direction in each time phase, and obtains the index value of each time phase by obtaining the average value of the obtained index values. Although the image data processing circuit 40 has shown an example of generating the difference image data using the axial cross section, the sagittal cross section, and the coronal cross section, the combination of the cross sections used for generating the difference image data in each direction can be arbitrarily changed. Is. Further, the image data processing circuit 40 can arbitrarily change the number of two-dimensional image data used for generating the difference image data in the axial cross section, the sagittal cross section, and the coronal cross section.

Further, in the above-described embodiment, the case where the entire pixel of the two-dimensional image data is used has been described, but the embodiment is not limited to this. For example, the measurement circuit 50 may use only the pixels existing within the range of the region of interest set by the operator. That is, the measurement circuit 50 sets the pixels in the region set in the image data of each of the plurality of time phases as the target pixels for the difference processing.

The two-dimensional image data of the first to M time phases Ph1 to PhM and the two-dimensional image data of the first time phase Ph1 may be added, multiplied, or divided.

Further, in the above-described embodiment, the case where the difference image data is generated and the index value is calculated has been described, but the embodiment is not limited to this. For example, the measurement circuit 50 obtains the difference between the sum of the pixel values of the image data of the reference time phase and the sum of the pixel values of the image data of the plurality of time phases as the difference processing, and uses the obtained difference as an index value. You may do so. That is, the measurement circuit 50 obtains the sum of the total pixel values in the difference image data of the first to M time phases Ph1 to PhM. Then, the selection circuit 60 selects the time phase of the difference image data having the maximum sum of the pixel values as the time phase of the maximum intake of the subject P, and receives the time phase of the difference image data having the minimum sum of the pixel values. It may be carried out so as to be selected as the time phase of the maximum exhalation of the sample P.

Further, in such a case, the measurement circuit 50 may set a pixel whose CT value is equal to or less than a predetermined threshold value in the image data of each of the plurality of time phases as the target pixel for the difference processing. More specifically, the measurement circuit 50 obtains the sum of the pixel values for the pixels having the CT value of minus 100 or less, and executes the difference processing.

Further, by the difference processing between the three-dimensional image data of each of the first to M time phases Ph1 to PhM and the three-dimensional image data of, for example, the first time phase Ph1 as the reference time phase, the first to M time phases Ph1 to The difference image data of PhM is generated, and the average value of the pixel values of the difference image data of each of the generated first to M time phases Ph1 to PhM is obtained. Then, the time phase of the difference image data that maximizes the average value of the pixel values is selected as the time phase of the maximum inspiration of the subject P, and the time phase of the difference image data that minimizes the average value of the pixel values is selected as the time phase of the subject P. It may be carried out so as to be selected as the time phase of maximum exhalation.

In the description of the above-described embodiment, each component of each of the illustrated devices is a functional concept, and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution / integration of each device is not limited to the one shown in the figure, and all or part of the device is functionally or physically distributed in arbitrary units according to various loads and usage conditions. Can be integrated and configured. Further, each processing function performed by each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

Further, the image processing method described in the above embodiment can be realized by executing an image processing program prepared in advance on a computer such as a personal computer or a workstation. This image processing program can be distributed via a network such as the Internet. Further, this image processing program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, flexible disk (FD), CD-ROM, MO, or DVD, and being read from the recording medium by the computer. ..

According to at least one embodiment described above, the time required for processing the image data can be shortened.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

30 Image data generation circuit 40 Image data processing circuit 50 Measurement circuit 60 Selection circuit 100 Medical image processing device 110 Medical image diagnostic device

Claims (20)

A storage unit for storing three-dimensional image data of a plurality of time phases in at least one cycle of respiration regarding the subject obtained from a medical diagnostic imaging apparatus.
An image data generation unit that generates two-dimensional image data of a plurality of time phases corresponding to at least two of an axial cross section, a sagittal cross section, and a coronal cross section from the three-dimensional image data.
An image data processing unit that obtains an index value by comparing the pixel value of the reference time phase two-dimensional image data of the plurality of time phase two-dimensional image data with the pixel value of each of the plurality of time phase two-dimensional image data. When,
An association that selects at least one of the two-dimensional image data of the plurality of time phases based on the index value obtained for each of the plurality of time phases and associates it with the respiratory time phase in at least one of the inspiration and exhalation of the subject. A medical image processing device equipped with a unit. The image data processing unit performs difference processing between the two-dimensional image data of each of the plurality of time phases and the two-dimensional image data of the reference time phase to obtain the index value.
Based on the index value obtained for each of the plurality of time phases, the association unit refers to the respiratory time phase in at least one of the maximum inspiration and the maximum expiration of the subject from the two-dimensional image data of the plurality of time phases. The medical image processing apparatus according to claim 1, wherein the two-dimensional image data corresponding to the above is selected. The reference time phase is any one of the plurality of time phases.
The image data processing unit performs difference processing between each of the two-dimensional image data of the plurality of time phases and the two-dimensional image data of the reference time phase to obtain the index value.
The association part
The time phase in which the index value obtained by the image data processing unit becomes the maximum value is selected as the time phase in the maximum intake of the subject.
The medical image processing apparatus according to claim 1 or 2, wherein the time phase in which the index value obtained by the image data processing unit is the minimum value is selected as the time phase in the maximum exhalation of the subject. The reference time phase is one of the two time phases adjacent to each other among the plurality of time phases.
The image data processing unit performs difference processing between the two-dimensional image data of the other time phase and the two-dimensional image data of the one time phase to obtain the index value.
The association part is
A time phase in which the index value obtained by the image data processing unit decreases and becomes 0 or near 0 is selected as the time phase in the maximum inspiration of the subject.
The medical image processing apparatus according to claim 1 or 2, wherein a time phase in which the index value obtained by the image data processing unit increases and becomes 0 or around 0 is selected as the time phase in the maximum exhalation of the subject. As the difference processing, the image data processing unit obtains a difference in pixel value in each pixel at a corresponding position for each of the two-dimensional image data of the reference time phase and the two-dimensional image data of the plurality of time phases. The medical image processing apparatus according to any one of claims 2 to 4, wherein image data is generated and the average value of the pixel values of the generated difference image data is used as the index value. As the difference processing, the image data processing unit obtains a difference in pixel value in each pixel at a corresponding position for each of the two-dimensional image data of the reference time phase and the two-dimensional image data of the plurality of time phases. The medical image processing apparatus according to any one of claims 2 to 4, wherein image data is generated and the sum of the pixel values of the generated difference image data is used as the index value. As the difference processing, the image data processing unit obtains and obtains the difference between the sum of the pixel values of the two-dimensional image data of the reference time phase and the sum of the pixel values of the two-dimensional image data of the plurality of time phases. The medical image processing apparatus according to any one of claims 2 to 4, wherein the difference is used as the index value. The medical image processing apparatus according to claim 7, wherein the image data processing unit sets pixels whose CT value is equal to or less than a predetermined threshold in the two-dimensional image data of each of the plurality of time phases as the target pixels for the difference processing. The image data processing unit according to any one of claims 2 to 7, wherein the pixel in the region set in the two-dimensional image data of each of the plurality of time phases is the target pixel of the difference processing. Medical image processing device. The image data processing unit obtains the index value by using the two-dimensional image data including the lung field of the subject obtained by photographing the chest of the subject as the two-dimensional image data. The medical image processing apparatus according to any one of claims 8. The medical image processing apparatus according to claim 10, wherein the image data processing unit obtains the index value using a plurality of the two-dimensional image data. The medical image processing apparatus according to claim 10 or 11, wherein the two-dimensional image data is at least one of an axial cross section, a sagittal cross section, and a coronal cross section of the subject. Any of claims 1 to 12, wherein the image data processing unit extracts a bronchial region in the two-dimensional image data with respect to the two-dimensional image data in a predetermined time phase associated with the associating unit. The medical image processing apparatus according to one. When a plurality of candidates for at least one of the time phase at the maximum inspiration and the time phase at the maximum exhalation of the subject are detected, the association unit determines the time phase at the maximum inspiration and the time phase at the maximum exhalation. The medical image processing apparatus according to any one of claims 2 to 13, which outputs information to the effect that it cannot be selected to a predetermined output unit. The association unit further generates information in which each time phase and the index value in each time phase are associated with each other, and outputs the information to a predetermined display unit, which is any one of claims 1 to 13. The medical image processing apparatus described in 1. Based on the index value obtained for each of the plurality of time phases, the association unit has a respiratory time phase in at least one of the maximum inspiration and the maximum expiration of the subject from the two-dimensional image data of the plurality of time phases. The method according to any one of claims 1 to 15, wherein the two-dimensional image data corresponding to the above is selected, and the three-dimensional image data corresponding to the time phase of the selected two-dimensional image data is stored in a predetermined storage unit. Medical image processing device. A collection unit that collects 3D image data of multiple time phases in at least one cycle of respiration for the subject,
An image data generation unit that generates two-dimensional image data of a plurality of time phases corresponding to at least two of an axial cross section, a sagittal cross section, and a coronal cross section from the three-dimensional image data.
An image data processing unit that obtains an index value by comparing the pixel value of the reference time phase two-dimensional image data of the plurality of time phase two-dimensional image data with the pixel value of each of the plurality of time phase two-dimensional image data. When,
An association that selects at least one of the two-dimensional image data of the plurality of time phases based on the index value obtained for each of the plurality of time phases and associates it with the respiratory time phase in at least one of the inspiration and exhalation of the subject. An X-ray CT apparatus including a unit. Further equipped with a synchronous scan control unit
The collecting unit sequentially collects three-dimensional image data of a plurality of time phases related to the subject under the X-ray irradiation conditions in the preliminary imaging.
The image data generation unit sequentially generates two-dimensional image data each time three-dimensional image data of a new time phase is collected.
The image data processing unit obtains the index value each time new two-dimensional image data of the time phase is generated.
The association unit is two-dimensional image data in which the new time phase two-dimensional image data corresponds to the respiratory time phase in at least one of the maximum inspiration and the maximum expiration of the subject each time the index value is obtained. Judge whether or not
When the two-dimensional image data of the new time phase is the respiratory time phase in at least one of the maximum exhalation and the maximum exhalation, the synchronous scan control unit performs an image on the subject under the X-ray irradiation conditions in the main imaging. The X-ray CT apparatus according to claim 17, wherein the data is collected by the collecting unit. Based on the index value obtained for each of the plurality of time phases, the association unit has a respiratory time phase in at least one of the maximum inspiration and the maximum expiration of the subject from the two-dimensional image data of the plurality of time phases. The X-ray CT apparatus according to claim 17, wherein the two-dimensional image data corresponding to the above is selected, and the three-dimensional image data corresponding to the time phase of the selected two-dimensional image data is stored in a predetermined storage unit. The three-dimensional image data of a plurality of time phases in at least one cycle of respiration regarding the subject obtained from the medical image diagnostic apparatus is stored in the storage unit.
From the three-dimensional image data, two-dimensional image data of a plurality of time phases corresponding to at least two of an axial cross section, a sagittal cross section, and a coronal cross section are generated.
An index value was obtained by comparing the pixel value of the reference time phase 2D image data of the plurality of time phase 2D image data with the pixel value of each of the plurality of time phase 2D image data.
A process of selecting at least one of the image data of the plurality of time phases based on the index value obtained for each of the plurality of time phases and associating with the respiratory time phase in at least one of the inspiration and exhalation of the subject is included. However, the image processing method.

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