JP6291809B2 - Medical image processing device - Google Patents

Description

  The present invention relates to a medical image processing apparatus.

Conventionally, a bone mineral density examination is performed for diagnosis of osteoporosis and determination of therapeutic effect. There are various bone mineral quantitative tests. Among them, the DIP (Digital Image Processing) method is widely used as a simple and highly accurate test.
In the DIP method, the aluminum slope of the standard substance and the left second metacarpal bone are X-rayed at the same time, and the shadow density between the aluminum slope and the left second metacarpal bone in the obtained X-ray image is compared. It is a method to measure.

  For example, Patent Document 1 discloses an X-ray image obtained by X-ray imaging of a subject (left hand second metacarpal bone) together with an aluminum slope in a medical image processing apparatus that performs a bone mineral quantitative examination using the DIP method. Image processing is performed on the data to create image data for interpretation, image data for bone mineral quantitative measurement is created from the image data for interpretation, the aluminum slope is detected by analyzing the image data for bone mineral quantitative measurement, and bone mineral It describes the measurement of quantitative amounts.

JP 2013-169 211 A

By the way, in X-ray imaging, in order to prevent harmful effects on the human body by irradiating a portion not necessary for observation of the subject and deterioration of image quality performance due to scattered light from the portion unnecessary for observation. In general, imaging is performed using an irradiation field stop that limits the irradiation area so that only necessary portions of the subject are irradiated with X-rays.
However, when imaging is performed using an irradiation field stop, as shown in FIG. 15A, a white image region W that is hardly irradiated with X-rays during imaging may be formed around the image. In this case, as shown in FIG. 15B, in the aluminum slope detection process, there is a problem that the white image region W is erroneously detected as an aluminum slope and the bone mineral content cannot be measured correctly.

  An object of the present invention is to eliminate erroneous detection of a standard substance and to perform accurate bone mineral content measurement.

To solve the above problem,
The invention described in claim 1
Image interpretation means for creating image data for image interpretation by performing image processing on medical image data obtained by X-raying the metacarpal bone as a subject together with a standard substance;
Creating bone mineral quantitative measurement image data based on image processing by the image interpretation image creating means, and measuring bone mineral quantitative measurement means based on the bone mineral quantitative measurement image data;
A medical image processing apparatus comprising:
The image interpretation image creating means includes:
Irradiation field recognition means for recognizing image data of an X-ray irradiation field region from the medical image data;
Blackening processing means for performing blackening processing on image data of an area outside the irradiation field area recognized by the irradiation field recognition means;
It is provided with.

According to a second aspect of the present invention, in the medical image processing apparatus according to the first aspect,
The blackening processing means, when the irradiation field area recognized by the irradiation field recognition means is within a preset reference area, an image of an area within the reference area and outside the irradiation field area It is characterized by performing blackening processing on the data.

According to a third aspect of the present invention, in the medical image processing apparatus according to the first or second aspect ,
The medical image data is captured using an irradiation field stop.

  According to the present invention, erroneous detection of an aluminum slope can be eliminated, and accurate bone mineral content measurement can be performed.

It is a figure which shows the whole structure of the system in a facility in embodiment of this invention. It is a block diagram which shows the functional structure of a medical image processing apparatus. It is a figure which shows the example of data storage of an image information table. It is a figure which shows the example of data storage of bone mineral quantitative determination DB. It is a figure for demonstrating the method of the X-ray imaging in a bone mineral quantitative examination. It is a flowchart which shows the diagnostic assistance process performed by the control part of a medical image processing apparatus. It is a figure which shows an example of a viewer screen. It is a figure which shows an example by which the irradiation field recognition process was performed with respect to the original image. It is a figure which shows an example by which the irradiation field recognition process was performed with respect to the original image. It is a figure which shows an example in which the irradiation field blackening process was performed with respect to the original image of FIG. 8B. It is a flowchart which shows the bone mineral quantitative measurement process performed in step S8 of FIG. It is a figure which shows an example of a bone mineral fixed quantity screen. It is a figure for demonstrating L value. It is a figure for demonstrating the bone width D and the bone marrow width d. It is a figure which shows an example of the bone mineral quantitative screen after a bone mineral quantitative measurement. It is a figure which shows an example of the viewer screen on which the graph which is a bone mineral quantitative measurement result was displayed. It is a figure for demonstrating the conventional problem. It is a figure for demonstrating the conventional problem.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Configuration of in-facility system 1]
FIG. 1 is a block diagram showing a system configuration of an in-facility system 1 according to the present embodiment.
The in-facility system 1 is a system that is applied to a relatively small-scale medical facility such as a practitioner or a clinic. As shown in FIG. 1, the modality 2, the medical image processing device 3, the reception device 4, A major 5, a general-purpose printer 6, and a client PC (Personal Computer) 7 are included.
Each device constituting the in-facility system 1 is connected to a communication network (hereinafter simply referred to as “network”) 8 such as a LAN (Local Area Network) via a switching hub (not shown), for example.
The medical image processing apparatus 3 is preferably a WS (workstation) provided in an examination room where a doctor is resident. Note that the WS that operates as the medical image processing apparatus 3 may control the activation of the modality 2, the processing conditions, and the like.

  In general, DICOM (Digital Image and Communication in Medicine) standard is used as a communication method in a hospital. In communication between devices connected to a LAN, DICOM MWM (Modality Worklist Management) and DICOM MPPS ( Modality Performed Procedure Step) is used. Note that the communication method applicable to this embodiment is not limited to this.

[Device configuration of each device of the in-facility system 1]
Hereinafter, each apparatus which comprises the in-facility system 1 is demonstrated.

The modality 2 is an image generation apparatus that performs imaging using a patient's diagnosis target region as a subject, and digitally converts the captured image to generate a medical image.
Examples of the modality 2 include a CR (Computed Radiography) apparatus, an ultrasonic diagnostic apparatus, an endoscope apparatus, a CT (Computed Tomography) imaging apparatus, and a magnetic resonance imaging apparatus (MRI). In the present embodiment, modality 2 will be described as a CR device, but other modality may be provided.

In the present embodiment, the modality 2 is a CR device that includes an X-ray imaging device, a CR cassette, and a reading device. The modality 2 arranges a subject between the X-ray imaging apparatus and the CR cassette to perform X-ray imaging, and reads a radiographic image recorded on the CR cassette with a reading apparatus to acquire digital image data.
Here, the CR cassette has a built-in radiation image conversion plate including a stimulable phosphor sheet that accumulates radiation energy, for example, and when irradiated with radiation, an amount of radiation according to the radiation transmittance distribution of the subject is emitted. The stimulable phosphor sheet is accumulated in the stimulable phosphor layer, and a radiographic image of the subject is recorded on the stimulable phosphor layer.
The reading device irradiates the stimulable phosphor sheet in the CR cassette with excitation light, photoelectrically converts the stimulated light emitted from the sheet, and A / D converts the obtained image signal to obtain image data. Is generated.

  In this embodiment, in order to prevent harmful effects on the human body by irradiating a portion that is not necessary for observation of the subject and deterioration of image quality performance due to scattered light from the portion unnecessary for observation, the subject It is also possible to perform X-ray imaging using an irradiation field stop that limits the irradiation area so that radiation is irradiated only on a necessary part of the subject according to the size and state of the subject.

  Further, in the present embodiment, the modality 2 has a function of assigning image attribute information such as UID, imaging date / time, examination ID, and imaging region to each medical image in a format conforming to the DICOM standard. The UID is a unique ID for specifying a medical image in the in-facility system 1.

The modality 2 includes an input unit (not shown) such as a keyboard having character input keys, numeric input keys, and the like, and inputs patient information for specifying a patient to be imaged from the input unit.
The patient information input here is, for example, patient ID, patient name (kanji), patient name (Kana), patient name (ASCII), gender, date of birth, and the like. Note that it is not necessary to input all of them in the modality 2, and no patient information can be input. When the modality 2 has a specification for inputting only a patient ID as patient information, the input unit of the modality 2 may be a numeric keypad, for example.

  The image attribute information and the patient information become supplementary information attached to the medical image generated by the modality 2. Modality 2 generates a medical image in a DICOM file format that conforms to the DICOM standard. The DICOM file is composed of an image part and a header part. In the image portion, image data of a medical image is written, and in the header portion, incidental information regarding the medical image is written.

The medical image processing apparatus 3 is installed, for example, in an examination room.
The medical image processing apparatus 3 stores the medical image generated by the modality 2 in the database in association with the patient information, or performs image processing on the medical image and displays it on the display unit for diagnosis by the doctor. It may be a device provided with a high-definition monitor than a monitor used for a general PC.
Further, the medical image processing apparatus 3 has a bone mineral density inspection function. The bone mineral density examination is an examination for measuring bone mineral density from a medical image in which a left hand and an aluminum slope (described later in detail) are taken.

FIG. 2 is a block diagram illustrating a functional configuration of the medical image processing apparatus.
As shown in FIG. 2, the medical image processing apparatus 3 includes a control unit 31, a RAM (Random Access Memory) 32, a storage unit 33, an operation unit 34, a display unit 35, a communication unit 36, a media drive 37, a time measuring unit 38, and the like. Each part is connected by a bus 39.

  The control unit 31 is configured by a CPU (Central Processing Unit) or the like, reads various programs such as system programs and processing programs stored in the storage unit 33, expands them in the RAM 32, and performs diagnosis support described later according to the expanded programs. By executing various processes including the processing and the bone mineral quantitative measurement process, it functions as an interpretation image creating means and a bone mineral quantitative measurement means.

  The RAM 32 temporarily stores a work area for temporarily storing various programs, input or output data, parameters, and the like that can be executed by the control unit 31 read from the storage unit 33 in various processes controlled by the control unit 31. Form. The RAM 32 stores the patient information list received from the receiving device 4.

  The storage unit 33 is configured by an HDD (Hard Disk Drive), a semiconductor nonvolatile memory, or the like. The storage unit 33 stores various programs as described above, and image processing parameters for adjusting a medical image to an image quality suitable for interpretation diagnosis (lookup defining a gradation curve used for gradation processing). Table (LUT) etc. are stored. In addition, fixed values (for example, LUT, G value, S value, etc. used for creating a bone mineral quantitative optimization image) stored in bone mineral quantitative measurement are stored.

In addition, the storage unit 33 includes an image DB (Data Base) 331 and a bone mineral content determination DB 332.
The image DB 331 is a database for storing a medical image and a bone mineral quantitative graph image. The image DB 331 has an image information table 331a for storing various information related to images stored in the image DB 331.
As shown in FIG. 3, the image information table 331 a includes “UID”, “imaging date / time”, “examination ID”, “imaging region”, “patient ID”, “patient name”, “age”, “sex”, It has items such as “image storage destination”, and stores examination information, patient information, image storage destination path, and the like related to each image stored in the image DB 331.
In addition, as an image storage destination, a medical image (referred to as an original image) transmitted from the modality 2, a processed image created from the original image, a thumbnail image created from the original image, and a graph image created by bone mineral quantitative examination , And a graph thumbnail image created from the graph image, each image storage destination path is stored. Based on the information stored in the image information table 331a, medical images and graph images are associated with patient information, examination information, and the like, and are stored so as to be searchable using patient information, imaging date and time as keys.

The bone mineral content determination DB 332 is a database for storing the results of bone mineral content inspection, parameters used for bone mineral content inspection, and the like.
As shown in FIG. 4, the bone mineral content determination DB 332 includes “examination ID”, “measurement date / time”, “patient ID”, “patient name”, “age”, “gender”, “result value”, “parameter”, etc. This information is stored for each bone mineral quantitative examination. The result value is, for example, an L value, a DIP value, an MCI, or the like. The parameters are, for example, the coordinates of two points designated at the time of inspection ((X1, Y1), (X2, Y2)), the coordinates of the measurement target area (upper left (X3, Y3), lower right (X4, Y4)), The coordinates of the aluminum slope (upper left (X5, Y5), lower right (X6, Y6)). Details of the result values and parameters will be described later.

  The operation unit 34 includes a keyboard having cursor keys, numeric input keys, various function keys, and the like, and a pointing device such as a mouse, and a key pressing signal pressed by the keyboard and an operation signal by the mouse. Is output to the control unit 31 as an input signal.

  The display unit 35 includes a monitor such as a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal Display), for example, and displays various screens according to instructions of a display signal input from the control unit 31.

  The communication unit 36 is configured by a network interface or the like, and transmits / receives data to / from an external device connected to the network 8 via a switching hub.

  The media drive 37 is a device that reads or writes data from / to a portable recording medium M such as a CD-R (Compact Disk Recordable), DVD-R (Digital Versatile Disk Recordable), or MO (Magnet Optical) disk. .

  Returning to FIG. 1, the reception device 4 is a computer device for performing reception registration, accounting calculation, insurance score calculation, etc. of a patient who visits, and includes a storage unit composed of a CPU, a ROM, a RAM, a keyboard, a mouse, and the like And a display unit configured by a CRT or LCD, a communication unit (none of which is shown) for controlling communication with each device connected to the network 8, and the like. When receiving a reception input screen is instructed from the input unit, the reception device 4 displays a reception input screen (not shown) on the display unit by software processing in cooperation with the CPU and a program stored in the storage unit. When reception information (reception number + patient name, etc.) is input by the input unit via this reception input screen, a patient information list of the received patients is created (updated), stored in the storage unit, and transmitted by the communication unit. The data is transmitted to the medical image processing apparatus 3 as appropriate.

  The imager 5 records a latent image by laser exposure on a transmissive recording medium (film) based on the medical image transmitted from the medical image processing apparatus 3, and visualizes the latent image by thermal phenomenon processing. It is a salt printer.

  The general-purpose printer 6 is a printer that records an image on a reflective recording medium (paper medium, sticker, etc.) by an ink jet method or a laser method.

  The client PC 7 is a computer device that displays a medical image or a graph image transmitted from the medical image processing device 3, for example.

[Flow of bone mineral quantity inspection]
Next, the flow (1) to (5) of the bone mineral density inspection in the medical facility where the in-facility system 1 is installed will be described.
(1) First, a patient is accepted at the reception. The received patient information of the patient is input by the receiving device 4, and a patient information list including this patient information is transmitted to the medical image processing device 3. In the medical image processing apparatus 3, the patient information list transmitted from the reception apparatus 4 is stored in the RAM 32.
(2) Next, in the examination room, examinations and necessary examination decisions are made. The examination is performed by an inquiry, a patient's past medical record, browsing of images and reports, and the like.
(3) When it is determined that a bone mineral density examination is necessary, X-ray imaging of the patient's left hand is performed by modality 2 in the imaging room.
In the present embodiment, it will be described as performing a bone mineral density examination by the DIP method.
In the DIP method, as shown in FIG. 5, the aluminum slope AL and the left hand second metacarpal bone B are arranged side by side and X-ray photographed at the same magnification, and the aluminum slope AL and the second metacarpal bone B in the obtained medical image are obtained. This is a comparative analysis of shadow density. The aluminum slope AL is a slope member made of aluminum having an inclination of 1 cm in thickness and 1 mm in the longitudinal direction. At the time of radiography, the aluminum slope AL is arranged right next to the patient's left hand so that the thicker side comes to the front, and X-ray imaging is performed by the modality 2.
As will be described later, the medical image processing apparatus 3 creates an image for interpretation that is suitable for interpretation regardless of individual differences in the body type of the patient that is the subject and changes in the irradiation X-ray dose due to changes in the apparatus characteristics of the modality 2. can do. Therefore, it is possible to perform shooting under fixed shooting conditions without performing individual adjustments during shooting.
(4) After the X-ray imaging of the left hand, the medical image obtained by the imaging is captured by the medical image processing apparatus 3 and bone mineral quantification is measured, and the measurement results (inspection results) such as result values and graphs are obtained. Is output.
(5) Diagnosis and treatment are performed based on the measurement result.

[Operation of Medical Image Processing Device 3]
Next, the operation of the medical image processing apparatus 3 will be described.
FIG. 6 shows a flowchart of a diagnosis support process executed by the control unit 31 of the medical image processing apparatus 3. The diagnosis support process is executed in cooperation with the control unit 31 and the program stored in the storage unit 33.

First, the control unit 31 causes the display unit 35 to display a viewer screen 351 for the diagnosis target patient (step S1).
The viewer screen 351 is a screen for taking a medical image from the modality 2 and displaying it for interpretation. The viewer screen 351 can instruct execution of bone mineral content measurement and display the measurement result. . The viewer screen 351 is displayed on the patient list screen of the patient to be diagnosed by the operation unit 34 from the patient list screen (screen on which the patient information list transmitted from the receiving device 4 is displayed) displayed on the display unit 35 by a predetermined operation of the operation unit 34. Displayed by selecting patient information.

FIG. 7 shows an example of the viewer screen 351.
As shown in FIG. 7, the viewer screen 351 has an image display field 351a for displaying an image, an image capture button 351b, a measurement button 351c, various tool buttons 351d, a print button 351e, a patient display field 351f, and a thumbnail display. A column 351g, a display image selection column 351h, an end button 351i, and the like are provided.

The image display column 351a is a column for displaying a medical image taken from the modality 2, a graph image of a test result, a past image of the same patient, and the like. FIG. 7 shows an example in which an image is displayed in the image display field 351a, but no image is displayed yet in step S1 (the image for interpretation in FIG. 7 is displayed in step S4).
The image capture button 351b is a button for instructing to capture a medical image transmitted from the modality 2 as an image of a patient (a patient displayed in the patient display field 351f) currently being diagnosed. When the image capture button 351b is pressed, the modality 2 until the image capture button 351b is pressed next to cancel the capture, or the viewer screen 351 is closed or transits to another screen. The medical image received from is captured as an image of the patient currently being diagnosed.
The measurement button 351c is a button for instructing display of a measurement menu. The measurement menu includes bone mineral quantitative measurement.

  The various tool buttons 351d are buttons for performing image processing such as density contrast adjustment processing and image quality adjustment processing on the displayed medical image, for example. When a button of a desired item of the tool button 351d is pressed, an input field, a button, a toolbar, or the like corresponding to the item is displayed. When an input to the displayed input field or an operation of a button or a toolbar is performed by the operation unit 34, processing corresponding to the operation is performed on the displayed image.

The print button 351e is a button for instructing to print the selected image from the general-purpose printer 6.
The patient display column 351f is a column for displaying patient information of a patient currently selected as a diagnosis target.
The thumbnail display column 351g is a column for displaying thumbnail images of medical images (including images taken in the past) of the same patient in order to select a medical image to be displayed in the image display column 351a.
The display image selection field 351h is a field for selecting the classification (CR, bone mineral content determination (graph)) of the images displayed in the thumbnail display field 351g.
The end button 351i is a button for instructing the end of the process.

When the image capture button 351b is pressed by the operation unit 34 and imaging is performed in the modality 2, the control unit 31 captures a medical image obtained by the imaging (step S2).
In step S2, when a medical image is received from modality 2 by the communication unit 36, the received medical image is associated with the patient information of the patient selected on the patient list screen, and stored in the image DB 331 as an original image. Is done. In the image information table 331a, the UID written in the header part of the received image, the photographing date and time, the examination site, the original image storage destination path, and the like are written. A thumbnail image is created from the original image and stored in the image DB 331. Further, the storage destination path of the created thumbnail image is written in the image information table 331a.

Next, the control unit 31 executes an image interpretation image creation process to create an image for image interpretation from the original image (step S3).
Here, in the modality 2, shooting is performed under fixed shooting conditions without performing individual adjustments at the time of each shooting. For this reason, the original image varies depending on the variation of the irradiation X-ray dose due to the patient's body shape (the thickness of the hand in the case of bone mineral quantitative examination), the change in apparatus characteristics of the modality 2, and the like. However, if there are variations in the images to be interpreted, stable interpretation diagnosis cannot be performed. Therefore, in the medical image processing apparatus 3, in order to stably output an image suitable for interpretation, the original image is subjected to the following various image processing, and the interpretation image satisfying a predetermined standard for interpretation is used. An image is created. The created image for interpretation is stored in the image DB 331 and the storage destination path is written in the image information table 331a.

Hereinafter, specific contents of the image interpretation image creation process will be described.
<Irradiation field recognition processing>
First, irradiation field recognition processing is executed on the input original image. The irradiation field refers to an area where X-rays have reached through the subject. In the irradiation field recognition processing, a determination is made between an irradiation field area and an irradiation field outside area (an area other than the irradiation field). This is because appropriate processing will not be performed if subsequent gradation conversion processing including an irradiation field region with a biased signal value (digital density signal value of a pixel) is performed. In this manner, the control unit 31 functions as an irradiation field recognition unit that recognizes image data of an X-ray irradiation field region from original image data.
In the present embodiment, a reference area M having a preset size is set for the original image. The reference area M defines the size of an image required in the subsequent bone mineral quantitative measurement process.

Any method of irradiation field recognition may be adopted.
For example, as disclosed in Japanese Patent Laid-Open No. 10-143634, a point that is considered to be a boundary of a circular irradiation field by a radial scan from a predetermined point of the irradiation field, that is, an edge candidate point is detected. For example, a method for obtaining a closed curve along edge candidate points by executing a dynamic contour extraction algorithm represented by, for example, a SNAKES model under the condition of emphasizing smoothness from the outside of the irradiation field toward the center of the irradiation field may be used. .
For example, as disclosed in Japanese Patent Laid-Open No. 5-7579, an original image is divided into a plurality of small areas, a dispersion value is obtained for each of the divided areas, and an irradiation field area is determined based on the obtained dispersion value. It is good as well. Usually, since the reaching X-ray dose is substantially uniform in the irradiation field region, the dispersion value of the small region becomes small. On the other hand, in a small region including the edge of the irradiation field region, a portion having a large arrival X-ray dose (outside the irradiation field region) and a portion (irradiation field region) in which the arrival X-ray dose is somewhat reduced by the subject are mixed, and thus the variance value is growing. Therefore, assuming that an edge is included in a small region having a variance value greater than a certain value, the region surrounded by such a small region is determined as an irradiation field region.

FIG. 8A and FIG. 8B illustrate the result of the irradiation field recognition process being executed. In FIG. 8A and FIG. 8B, the frame part K has shown the external shape of the area | region recognized as an irradiation field area | region.
FIG. 8A shows a case where an area (irradiation field) having a predetermined density of the original image substantially overlaps the reference area M. At this time, the frame portion K is positioned to overlap the outer shape of the reference area area M. That is, in such an original image, the irradiation field is not recognized in the reference area M.
On the other hand, FIG. 8B shows a case where an area (irradiation field) having a predetermined density of the original image is smaller than the reference area M. At this time, the frame portion K is located in the reference area M. The image in FIG. 8B is an image obtained when, for example, X-ray image capturing is performed using an irradiation field stop, and a region (white image region) W to which almost no radiation is irradiated at the time of imaging is around the irradiation field. It exists in the shape of a white frame.
Although illustration is omitted, when the region (irradiation field) having a predetermined density of the original image is larger than the reference region M, the frame K is located outside the reference region M.

  8A and 8B exemplify a case where the original image is upright with respect to the reference area M. However, when the original image is tilted, the reference area M is illustrated. The tilted irradiation field is recognized, and the frame K is positioned in a state tilted with respect to the reference region M. Further, the irradiation field is not limited to a rectangle, but may be a shape such as a circle or an ellipse.

<Irradiation field blackening treatment>
The irradiation field blackening process is a process of assigning a data value having a constant density to the image data of the white image area W around the irradiation field (filling the image data of the white image area W with a constant signal value). This is a process for preventing the white image region W from being erroneously detected as an aluminum slope in the subsequent bone mineral quantitative measurement process. Thus, the control unit 31 functions as a blackening processing unit that performs blackening processing on the image data of the white image region W outside the irradiation field region recognized by the irradiation field recognition unit.

Any method may be employed for the irradiation field blackening process, but for example, the method disclosed in Japanese Patent Laid-Open No. 10-275214 can be applied.
In this method, first, based on the image data (Sorg) of the radiation image, for example, a non-sharp mask composed of a pixel matrix of vertical 10 pixels × horizontal 10 pixels is set, and each pixel is set based on the set non-sharp mask. Each time, an unsharp mask signal (Sus) is obtained.
Next, with respect to the unsharp mask signal (Sus) for each pixel, a preset lookup table is referred to, and an addition component (f (Sus)) corresponding to the value of the unsharp mask signal (Sus) is output. . At this time, the addition component α is output to the non-sharp mask signal (Sus) corresponding to the irradiation field region (Pout), and the addition component 0 is output to the non-sharp mask signal (Sus) corresponding to the irradiation field region (Pin). Is done. That is, the addition component α is output for the pixel corresponding to the irradiation field region (Pout), and the addition component 0 is output for the pixel corresponding to the irradiation field region (Pin).
Then, the addition component (f (Sus)) for each pixel is added to the original image data (Sorg) of the pixel, and the result is output. At this time, the image data (Sproc) after the addition processing for the pixel corresponding to the irradiation field region (Pout) is the original image data (Sorg) substantially equal to 0 and the addition component (f (Sus)) of the highest density value. The sum is the highest concentration value. On the other hand, the image data (Sproc) after the addition processing for the pixel corresponding to the irradiation field region (Pin) is the sum of the original image data (Sorg) and the addition component (f (Sus)) substantially equal to 0, Substantially original image data (Sorg) is output as it is.
Accordingly, the irradiation field area is filled with the highest density, and the original image is output as it is in the irradiation field area.
In addition to this, as disclosed in, for example, Japanese Patent Laid-Open No. 9-97321, a method of displaying the image by inverting the luminance level based on the image signal level in the irradiation field region can be used.

FIG. 9 illustrates the result of the irradiation field blackening process performed on the original image shown in FIG. 8B.
As shown in FIG. 9, as a result of the irradiation field blackening process, the white image region W existing around the irradiation field is filled and similar to FIG. 8A (the white image region W does not exist in the reference region M). It becomes an image.
Here, the same irradiation field blackening process is also performed on the original image of FIG. 8A, but there is no white image area W in the reference area M. This is the same as when the blackening process is not executed.

Note that, as a result of the irradiation field recognition process, the irradiation field blackening process is performed only when the irradiation field area is inside the reference area M (that is, when the white image area W exists inside the reference area M). It is also possible to execute.
As a result of the irradiation field recognition process, when the irradiation field area is outside the reference area area M (that is, when the white image area W exists outside the reference area area M, or When the areas overlap), a known trimming process for cutting out the white image area W may be performed. As described above, the control unit 31 functions as a trimming unit that performs a trimming process for cutting out image data of the white image region W outside the irradiation field region when the irradiation field region is outside the range of the reference region M.

<Area of interest setting and reference signal value setting>
After the irradiation field blackening process is performed, a region of interest (hereinafter referred to as ROI: Region Of Interest) is set from the irradiation field region. At this time, the reference signal value is set together with the ROI setting.
For example, the ROI can be specified based on the signal value profile by sequentially scanning the horizontal direction and the vertical direction of the original image to create a signal value profile in each direction. Further, the ROI may be specified by pattern matching, and any method may be applied.

  Then, a histogram of the signal values of the specified ROI region is created, and the signal values having a predetermined frequency from the maximum value side and the minimum value side in the histogram are determined as the maximum reference value H and the minimum reference value L, respectively. To do. The maximum reference value H and the minimum reference value L are used as reference values when the signal value range of the original image is converted into the signal value range (maximum value SH, minimum value SL) in the image for interpretation.

<Tone conversion processing>
When the preprocessing is completed as described above, gradation conversion processing is performed.
The gradation conversion process is a process for adjusting the density and contrast of the original image. When a doctor diagnoses the presence or absence of a human body structure disease by interpretation of an X-ray image, the presence or absence of the disease is determined based on the density and contrast (gradation) of the structure on the X-ray image. Therefore, by adjusting the density and contrast suitable for interpretation, a doctor's disease detection operation can be supported.

  The gradation conversion processing is performed in two stages: (1) normalization processing and (2) conversion processing using a basic LUT (lookup table), and finally a signal value range predetermined as an image for interpretation. Gradation conversion is performed so as to obtain gradation characteristics.

  Conventionally, since a screen / film method has been adopted for photographing, input signal (reading signal) conversion processing is performed with a target of gradation characteristics (contrast) cultivated by the screen / film method. The gradation characteristic obtained by the screen / film system is an S-shaped curve. In the gradation conversion processing, an LUT indicating this gradation characteristic is prepared as a basic LUT for each part, and after performing individual signal adjustment on the original image by normalization processing, the signal value is calculated using this basic LUT. Perform conversion.

<Frequency enhancement processing>
As the frequency enhancement processing, for example, unsharp mask processing disclosed in Japanese Patent Publication No. 62-62373 or multi-resolution analysis disclosed in Japanese Patent Application Laid-Open No. 9-44645 can be applied. By this frequency enhancement processing, an image in which the edge of a structure such as a bone is enhanced can be obtained.

<Dynamic range compression processing>
As the dynamic range compression processing, for example, a technique disclosed in Japanese Patent No. 250950 can be applied.

  As described above, after performing irradiation field recognition processing and irradiation field blackening processing on the original image, the region of interest and reference signal value are set, and tone conversion processing, frequency enhancement processing, and dynamic range compression processing are performed. As a result, an image for image interpretation is created.

Returning to FIG. 6, the control unit 31 displays the created image for interpretation in the image display field 351a of the viewer screen 351 (see FIG. 7) (step S4).
The doctor can confirm whether the imaging has been successful (whether re-imaging is necessary) by observing the image for interpretation. Further, in the case of an examination that does not require measurement, it is possible to make a diagnosis by interpreting an image for interpretation. At this time, the tool button 351d can be operated to adjust to a desired image quality. Although details will be described later, in measurement of bone mineral quantity, an operator such as a doctor needs to designate two points on the second metacarpal bone of the left hand. In order to easily specify these two points, the density contrast button and the image quality adjustment button of the tool button 351d are operated in advance to adjust the image so that the operator can easily specify the two points and the edge is emphasized. It can also be left.

The control unit 31 determines whether or not to perform bone mineral content measurement (step S5). That is, the control unit 31 determines whether or not the measurement button 351c is pressed and the bone mineral quantitative measurement menu is selected.
When it is not determined that the bone mineral content measurement is to be performed, that is, when the operation unit 34 determines that an operation other than the pressing of the measurement button 351c and the selection of the bone mineral content measurement menu is performed by the operation unit 34 (step S5; NO), processing according to the operation is executed (step S6). Then, the control unit 31 determines whether or not the end button 351i is pressed by the operation unit 34 (step S7), and determines that the end button 351i is pressed by the operation unit 34 (step S7; YES), diagnosis support The process ends. If the control unit 31 does not determine that the end button 351i has been pressed by the operation unit 34 (step S7; NO), the control unit 31 proceeds to step S5.

  On the other hand, when the control unit 31 determines in step S5 that the measurement button 351c is pressed by the operation unit 34 and the bone mineral quantitative measurement menu is selected (step S5; YES), the bone mineral quantitative measurement process is executed (step S5). Step S8).

  In FIG. 10, the flowchart of the bone mineral quantity measurement process performed by the control part 31 is shown. The bone mineral density measurement process is executed in cooperation with the control unit 31 and a program stored in the storage unit 33.

  In the bone mineral content quantitative measurement process, first, the control unit 31 executes a bone mineral content quantitative optimization image creation process, and creates a bone mineral content quantitative optimization image (image for bone mineral content quantitative measurement) from the created image for interpretation. Then, it is temporarily stored in the RAM 32 (step S101).

  Specifically, for example, the gradation conversion curve (LUT) is BONE-02, the density correction value (S value) is 250, and the contrast value (G value) is 2.50. Apply tonal processing. In addition, when the image for interpretation is subjected to frequency enhancement processing and dynamic range compression processing, the parameters used when the frequency enhancement processing (dynamic range compression processing) are performed are used. The inverse conversion of the conversion performed by the compression processing) is performed. Note that an image for interpretation that has not been adjusted on the viewer screen 351 is used for the bone mineral quantitative optimization image creation processing.

Next, the control unit 31 displays the bone mineral content screen 352 on the display unit 35 (step S102).
FIG. 11 shows an example of the bone mineral content screen 352.
On the bone mineral content determination screen 352, patient information 352a, imaging region 352b, measurement date and time 352c, measurement value 352d, comment field 352e, confirmation button 352f, and the like of the patient to be diagnosed are displayed. In step S102, the final result value of the patient to be diagnosed (that is, the previous result value) stored in the bone mineral quantification DB 332 is read as the measurement value 352d and initially displayed.
In addition, the bone mineral amount determination screen 352 is provided with a two-point designation field 352g. In bone mineral quantitative measurement, it is necessary to designate two points, the most protruding part at the upper end of the second metacarpal bone of the left hand and the most depressed part at the lower end, and this two-point designation field 352g has two points. Displays an image for specifying.

  Here, it is preferable to display an image for interpretation (or an adjusted image for interpretation) as the image displayed in the two-point designation field 352g. The bone mineral quantification optimized image is generally darker than the image for interpretation (see FIG. 14), and processing for enhancing the edge of the bone portion such as frequency enhancement processing applied to the image for interpretation is performed. It has not been. Therefore, depending on the shape and arrangement of the bone of the patient's left hand, it may be very difficult to specify two points.

When two points of the left second second core bone are designated from the two-point designation field 352e by the operation unit 34 (for example, clicked with the mouse of the operation unit 34), the control unit 31 reads the coordinates of the designated two points. (X1, Y1) and (X2, Y2) are temporarily stored in the RAM 32 (step S103), and the coordinates (X1, Y1) and (X2, Y2) of these two points and the bone mineral quantity optimized image are used. Then, bone mineral content is measured (step S104).
In addition, designation of two points on the left second core core may be configured such that appropriate two points are automatically designated by the control unit 31 in addition to the operation by the operation unit 34 of the doctor.

  The measurement of the bone mineral amount in step S104 is performed by the DIP method. As described above, the DIP method is a known method for measuring the bone mineral density by comparing the shadow density of the aluminum slope in the image and the left second metacarpal bone.

Hereinafter, measurement of bone mineral content determination using the DIP method will be described with reference to FIGS. 12A to 12B.
First, as shown in FIG. 12A, a distance between coordinates of two designated points (X1, Y1) and (X2, Y2) is calculated as an L value (bone length).
Next, a range in which a portion of 10% of the bone length in the center portion between two points in the bone mineral quantitative optimization image has a vertical width and a horizontal width as a fixed value is determined as a measurement region.
Further, the position of the aluminum slope in the image is detected by pattern matching or the like. Here, in the present embodiment, as described above, the irradiation field blackening process is executed when the image for interpretation is created, so that the original image has the white image region W around the irradiation field (see FIG. 8B). Even in this case, the white image region W does not exist in the bone mineral quantitative optimization image, and the white image region W is prevented from being erroneously detected as an aluminum slope.
Then, based on the density of the aluminum slope image, the bone density GS is calculated based on which thickness part of the aluminum slope the bone density in the measurement region matches, and the integrated value of the calculated bone density A value obtained by dividing ΣGS by the bone width D (ΣGS / D (mmAl)) is calculated as the DIP value (bone mineral content).
Further, an average bone cortex width MCI (MCI = (D−d) / D) is calculated. D is the bone width and d is the bone marrow width d.
FIG. 12B is a diagram showing a tomographic plane and a concentration profile in the center portion of the second metacarpal bone B of the left hand.
The bone width D and the bone marrow width d can be calculated based on, for example, the concentration profile of the center portion of the left second metacarpal bone B as shown in FIG. 12B.
Calculated L value, DIP value, MCI, measurement area coordinates (upper left (X3, Y3), lower right (X4, Y4)), detected aluminum slope position coordinates upper left (upper left (X5, Y5), lower right (X6, Y6)) is temporarily stored in the RAM 32.

When the measurement of the bone mineral content is completed, the control unit 31 displays the result value on the bone mineral content screen 352 (step S105).
FIG. 13 shows a bone mineral content screen 352 after bone mineral content measurement.
As shown in FIG. 13, in step S105, the L value, ΣGS / D, and MCI, which are the results obtained by the measurement in step S104, are displayed on the measurement value 352d of the bone mineral quantitative screen 352. In addition, on the image displayed in the two-point designation field 352g, the coordinates P1, P2 of the designated two points, the measurement region R1, and the detected position R2 of the aluminum slope are displayed as annotations.

Next, the control unit 31 determines whether or not the operation unit 34 has instructed movement of the two coordinates P1 and P2 on the bone mineral amount determination screen 352 (step S106).
P1 and P2 can be moved by dragging and dropping the annotation using the operation unit 34.
When the control unit 31 determines that the movement of the two coordinate points P1 and P2 is instructed by the operation unit 34 (step S106; YES), the control unit 31 returns to step S104 and uses the newly designated two points (after the movement). Then perform the measurement again.
When the operation unit 34 does not instruct the movement of the two coordinates P1 and P2 (step S106; NO) and the confirm button 352f is pressed (step S107; YES), the control unit 31 confirms the measurement result. The bone mineral quantitative optimization image, the result value, and the parameters used for measurement are stored (step S108), and the process proceeds to step S9 in FIG.
Specifically, in step S108, a new record is added to the bone mineral quantification DB 332, and the result value and parameters used for measurement (calculated L value, DIP value, MCI, two-point designation coordinates ((X1, Y1), (X2, Y2)), measurement area coordinates (upper left (X3, Y3), lower right (X4, Y4)), detected aluminum slope position coordinates upper left (upper left (X5, Y5), lower right ( X6, Y6)) is written, the bone mineral quantitative optimization image is stored in the image DB 331, and the storage destination path of the processed image of the record of the examination in the image information table 331a is the bone mineral quantitative optimization image. Changed to a path.

Returning to FIG. 6, the control unit 31 creates a graph image and its thumbnail image based on the result value obtained by the measurement (step S9).
The created graph image is stored in the image DB 331, and the storage path of the graph image is stored in the record of the examination in the image information table 331a. Also, a thumbnail image of the graph image is created and stored in the image DB 331, and the storage path of the graph thumbnail image is stored in the record of the examination in the image information table 331a.

When the creation of the graph is completed, the control unit 31 displays the viewer screen 351 displaying the created graph image on the display unit 35 (step S10).
FIG. 14 shows an example of the viewer screen 351 on which a graph is displayed. In the image display field 351a, the graph image created in step S9 and the bone mineral quantitative optimization image serving as the measurement source are displayed side by side.
The doctor can grasp the change in the bone mineral content of the patient by checking the graph screen, and can make the necessity and policy of treatment.
In addition, since the graph and the measurement source image are displayed side by side, if there is a significant change from the previous result, observing the measurement source image to determine whether the result is correct, the shooting conditions (shooting magnification, shooting angle) It is easy to determine whether it is caused by the arrangement of hands or the like.

The control unit 31 determines that the print button 351e has been pressed by the operation unit 34 (step S11), and when the print button 351e is pressed (step S11; YES), the data of the graph image is transmitted to the general-purpose printer 6 by the communication unit 36. The graph image is printed out from the general-purpose printer 6 (step S12). On the other hand, if the print button 351e is not pressed (step S11; NO), the process proceeds to step S13.
Then, the control unit 31 determines whether or not the end button 351i is pressed by the operation unit 34 (step S13). When the end button 351i is pressed (step S13; YES), the diagnosis support process is ended. On the other hand, if the end button 351i is not pressed (step S13; NO), the process proceeds to step S11.

As described above, according to the medical image processing apparatus 3 of the present embodiment, the control unit 31 performs image processing on medical image data obtained by X-ray imaging of the metacarpal bone as a subject together with the standard substance. The image data for interpretation is created by applying the image processing to the image data for interpretation, and the image data for bone mineral quantitative measurement is created, and the bone mineral quantity is determined based on the bone mineral quantitative measurement image data. In the creation of image data for interpretation, the image data in the X-ray irradiation field area is recognized from the medical image data, and the image data in the area outside the recognized irradiation field area is blackened. Apply processing.
For this reason, even if the white image area W is an original image formed around the irradiation field, the white image area W is filled when the image data for interpretation is created, and the image for interpretation is as if there is no white image area W. Data is created, and bone mineral quantitative measurement image data is created using the image data for interpretation.
Therefore, it is possible to prevent the white image region W from being mistaken for the aluminum slope and being erroneously detected during measurement of the bone mineral content.

Further, according to the present embodiment, in the generation of the image data for interpretation, the control unit 31 is in the reference area M when the recognized irradiation field area is within the preset reference area M and Blackening processing is performed on image data in an area outside the irradiation field area.
For this reason, the white image area W in the reference area M is filled and appropriate image data for image interpretation can be obtained.

Further, according to the present embodiment, in creating image data for interpretation, the control unit 31 performs trimming to cut out image data of an area outside the irradiation field area when the irradiation field area is outside the range of the reference area M. Process.
Therefore, the white image area W that protrudes from the reference area M is trimmed, and appropriate image data for image interpretation can be obtained.

Further, according to the present embodiment, the medical image is taken using the irradiation field stop.
For this reason, accurate detection of bone minerals is not possible even for medical image data in which a white image is captured in the field outside the irradiation field by X-ray imaging using the irradiation field stop. Measurement can be performed.

  In the above embodiment, the bone mineral quantitative optimization image is created from the image for interpretation. However, when the original image is sufficiently larger than the reference region M, that is, over the entire reference region M. In the case of an image having a density (see FIG. 8A), an optimized bone mineral content quantitative image may be created from the original image.

  In the above embodiment, the measurement result of the bone mineral amount is displayed on the display unit 35 and output from the general-purpose printer 6 as necessary. However, the measurement result is output to the recording medium M by the media drive 37. Or may be transmitted to the client PC 7 or the like connected to the network 8 via the communication unit 36.

  For example, in the above description, an example in which a hard disk, a semiconductor nonvolatile memory, or the like is used as a computer-readable medium of the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also applied as a medium for providing program data according to the present invention via a communication line.

  In addition, the detailed configuration and detailed operation of the medical image processing apparatus can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Facility system 2 Modality 3 Medical image processing apparatus 4 Reception apparatus 5 Imager 6 General-purpose printer 7 Client PC
8 Network 31 control unit (interpretation image creation means, bone mineral quantitative measurement means, irradiation field recognition means, blackening processing means)
32 RAM
33 storage unit 331 image DB
331a Image information table 332 Bone mineral content determination DB
34 Operation unit 35 Display unit 351 Viewer screen 352 Bone mineral determination screen 36 Communication unit 37 Media drive 38 Timekeeping unit 39 Bus

Claims (3)

Image interpretation means for creating image data for image interpretation by performing image processing on medical image data obtained by X-raying the metacarpal bone as a subject together with a standard substance;
Creating bone mineral quantitative measurement image data based on image processing by the image interpretation image creating means, and measuring bone mineral quantitative measurement means based on the bone mineral quantitative measurement image data;
A medical image processing apparatus comprising:
The image interpretation image creating means includes:
Irradiation field recognition means for recognizing image data of an X-ray irradiation field region from the medical image data;
Blackening processing means for performing blackening processing on image data of an area outside the irradiation field area recognized by the irradiation field recognition means;
A medical image processing apparatus comprising:   The blackening processing means, when the irradiation field area recognized by the irradiation field recognition means is within a preset reference area, an image of an area within the reference area and outside the irradiation field area The medical image processing apparatus according to claim 1, wherein blackening processing is performed on the data. The medical image data, a medical image processing apparatus according to claim 1 or 2, characterized in that it is taken using an irradiation field stop.

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