Medical image processing apparatus, X-ray CT apparatus, MRI apparatus, ultrasound diagnostic imaging apparatus, and medical image processing method

A medical image processing apparatus has a parameter calculating unit, a storage unit, and an image generating unit. The parameter calculating unit analyzes data of a plurality of time-series medical images, each containing an image of an organ having a functional blood vessel and a feeding blood vessel, and calculates a parameter based on at least a blood volume in the feeding blood vessel. The storage unit stores in advance a table that associates parameters with degrees of a cancer progression of the organ. The image generating unit refers to the table, obtains a degree of the cancer progression corresponding to the calculated parameter, and generates an image to which the obtained degree is applied on a region-by-region basis.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical image processing apparatuses, an X-ray computed tomography (CT) apparatus, a magnetic resonance imaging (MRI) apparatus, an ultrasound diagnostic imaging apparatus, and a medical image processing method used to examine hepatic functions with perfusion technique.

2. Description of the Related Art

As an example of techniques used to examine hepatic functions with an X-ray CT apparatus, there is a CT-perfusion technique which involves quantifying parameters of a hepatic blood flow using an iodine contrast agent as a tracer. Examples of images obtained by calculation based on the CT-perfusion technique are shown inFIG. 3.

As a hepatocellular cancer progresses, a hepatic blood flow slows down and a hepatic arterial fraction (i.e., hepatic arterial blood volume/(hepatic arterial blood volume+portal venous blood volume)) increases, as shown inFIG. 4. The increase in hepatic arterial fraction indicates that although a decrease in portal venous blood volume leads to a decrease in total hepatic blood volume, the decrease is compensated for by the increase in blood volume in the hepatic artery serving as a feeding blood vessel, the increase being caused by the effect of the hepatocellular cancer.

Nutrients are supplied to normal hepatic cells at a hepatic-arterial-blood-volume to portal-venous-blood-volume ratio of 2:8, that is, at a hepatic arterial fraction of 20%. However, it has been reported that in early stages of cancer, such as a regenerative nodule stage and an adenoma stage, a portal venous blood volume and a hepatic arterial blood volume decrease (ischemia occurs) in the affected area, and as a stage (degree of cancer progression) progresses and a plethoric hepatocellular cancer stage approaches, the hepatic arterial blood volume increases while the portal venous blood volume decreases in the affected area (see, e.g., a following Document 1).

Document 1: Makiko Hayashi, Osamu Matsui, et al. “Correlation Between the Blood Supply and Grade of Malignancy of Hepatocellular Nodules Associated with Liver Cirrhosis: Evaluation by CT During Intraarterial Injection of Contrast Medium” AJR: 172, April 1999: 969-976

Thus, since the hepatic arterial fraction increases as the plethoric hepatocellular cancer stage approaches, it is possible to diagnose a cancer in advanced stages, such as an early liver cancer stage and a plethoric hepatocellular cancer stage, because an apparent increase in hepatic arterial fraction can be observed.

However, in the early stages, such as the regenerative nodule stage and the adenoma stage, since there is an occurrence of ischemia in which the portal venous blood volume and the hepatic arterial blood volume decrease at substantially the same rate, the hepatic arterial fraction tends to be determined to be 20%, which is the same as that in normal (unaffected) areas. As a result, it is difficult to make early detection of hepatic tumor and stage determination of cancer in early stages.

SUMMARY OF THE INVENTION

The present invention has been made in view of the circumstances described above. An object of the present invention is to provide a medical image processing apparatus, an X-ray CT apparatus, an MRI apparatus, an ultrasound diagnostic imaging apparatus, and a medical image processing method for improved diagnostic accuracy in determining the degree of the cancer progression.

To solve the above-described problems, the present invention provides the medical image processing apparatus has: a parameter calculating unit configured to analyze data of a plurality of time-series medical images, each containing an image of an organ having a functional blood vessel and a feeding blood vessel, and to calculate a parameter based on at least a blood volume in the feeding blood vessel; a storage unit configured to store in advance a table that associates parameters with degrees of a cancer progression of the organ; and an image generating unit configured to refer to the table, to obtain a degree of the cancer progression corresponding to the calculated parameter, and to generate an image to which the obtained degree is applied on a region-by-region basis.

To solve the above-described problems, the present invention provides the X-ray CT apparatus has the medical image processing apparatus.

To solve the above-described problems, the present invention provides the MRI apparatus has the medical image processing apparatus.

To solve the above-described problems, the present invention provides the ultrasound diagnostic imaging apparatus has the medical image processing apparatus.

To solve the above-described problems, the present invention provides the medical image processing method has: a parameter calculating step of analyzing data of a plurality of time-series medical images, each containing an image of an organ having a functional blood vessel and a feeding blood vessel, and of calculating a parameter based on at least a blood volume in the feeding blood vessel; a storing step of storing in advance a table that associates parameters with degrees of a cancer progression of the organ; and an image generating step of referring to the table, of obtaining a degree of the cancer progression corresponding to the calculated parameter, and of generating an image to which the obtained degree is applied on a region-by-region basis.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of a medical image processing apparatus, an X-ray CT apparatus, an MRI apparatus, an ultrasound diagnostic imaging apparatus, and a medical image processing method according to the present invention will now be described with reference to the attached drawings.

FIG. 1is a schematic diagram showing a configuration of the medical image processing apparatus of the present embodiment.

FIG. 1shows a workstation terminal100as an example of a medical image processing apparatus10of the present embodiment. The workstation terminal100mainly includes basic hardware components, such as a central processing unit (CPU)11serving as a control device, a memory12, a hard disk (HD)13, an input device14, a display device15, a recording media drive16, and an interface (IF)17. The CPU11and other components included in the workstation terminal100are connected to each other via a bus B serving as a common signal transmission path.

The CPU11is a control device configured as a large-scale integrated circuit (LSI) formed by enclosing a semiconductor electronic circuit in a package having a plurality of terminals. The CPU11executes a program stored in the memory12. Alternatively, a program stored in the HD13, or a program transferred from a network N, received by the IF17, and installed on the HD13may be loaded into the memory12and executed by the CPU11.

The memory12is a storage device serving as a read-only memory (ROM), a random-access memory (RAM), etc. The memory12is used for initial program loading (IPL), and for storing a basic input/output system (BIOS) and data. Additionally, the memory12serves as work memory of the CPU11and a temporary data storage area.

The HD13is a storage device having a configuration where metal disks to which magnetic material is applied or evaporated are unremovably placed inside a reader (not shown). The HD13stores programs (including an operating system (OS) as well as application programs) installed onto the workstation terminal100. At the same time, the HD13causes the OS to provide a graphical user interface (GUI). The GUI allows information containing many graphical elements to be displayed to the operator, so that the operator can perform basic operations with the input device14.

The input device14includes pointing devices (e.g., a keyboard and a mouse) that are operable by the operator, such as a person who performs diagnostic examinations.

The display device15is a cathode ray tube (CRT) display, a liquid crystal display, or the like.

The recording media drive16is configured to allow insertion and removal of a portable recording medium. The recording media drive16reads data (including a program) recorded in a recording medium and outputs the read data to the bus B. Also, the recording media drive16writes data supplied via the bus B to the recording medium. Examples of the recording medium include a flexible disk (FD), a compact disk-read only memory (CD-ROM), a compact disk recordable (CD-R), a compact disk rewritable (CD-RW), a magneto-optical (MO) disk, a digital versatile disk (DVD), a digital versatile disk-recordable (DVD-R), and a magnetic disk.

The IF17is a connector that conforms to parallel connection specifications or serial connection specifications. The IF17performs communication control in accordance with an appropriate standard. The IF17thus allows the workstation terminal100to be connected to the network N.

FIG. 2is a block diagram showing functions of the medical image processing apparatus10of the present embodiment.

When the CPU11shown inFIG. 1executes a program, the workstation terminal100, which is the medical image processing apparatus10, functions as a medical image obtaining unit21, an analysis image generating unit22, an interface unit23, a reference pixel setting unit24, a blood volume calculating unit25, a parameter calculating unit26, and a diagnostic image generating unit27. Alternatively, the workstation terminal100may include the medical image obtaining unit21, the analysis image generating unit22, the interface unit23, the reference pixel setting unit24, the blood volume calculating unit25, the parameter calculating unit26, and the diagnostic image generating unit27as a circuit.

The medical image obtaining unit21uses, for example, patient information (such as a patient ID) and the name of a body part as keys to obtain data of a plurality of time-series medical images, via the IF17, from an image server (not shown) included in picture archiving and communication systems (PACS). For example, when a liver is selected, for a patient, as an organ having a functional blood vessel and a feeding blood vessel, the medical image obtaining unit21obtains data of a plurality of time-series medical images, each containing an image of the liver. The following description will discuss the case where the medical image obtaining unit21obtains data of a plurality of time-series medical images, each containing an image of a liver having a portal vein serving as a functional blood vessel and a hepatic artery serving as a functional blood vessel. Note that examples of an organ having a functional blood vessel and a feeding blood vessel include a lung field as well as a liver.

The analysis image generating unit22analyzes data of a plurality of time-series CT images obtained by the medical image obtaining unit21, and generates a hepatic blood flow (HBF) image, a hepatic blood volume (HBV) image, a mean transit time (MTT) image, and a hepatic arterial fraction (HAF) image serving as functional images. The CT images obtained by the medical image obtaining unit21and the functional images generated by the analysis image generating unit22are displayed via the interface unit23on the display device15.

FIG. 3is a diagram showing examples of functional images generated by the analysis image generating unit22.

The functional images shown inFIG. 3are obtained by assigning one of 256 colors in a color gradation chart (from blue to red) G1 depending on a largeness of a one-dimensional parameter every pixel, and arranging a selected color of the colors in the pixel. An HAF image is generated by assigning one of 256 colors in the color gradation chart G1 to a hepatic arterial fraction (i.e., hepatic arterial blood volume/(hepatic arterial blood volume+portal venous blood volume)) obtained for every pixel of a CT image.

The interface unit23shown inFIG. 2is an interface, such as the GUI. The GUI allows information containing many graphical elements to be displayed on the display device15to the user, so that the use can perform basic operations with the input device14.

The reference pixel setting unit24sets a reference pixel (or region representing a reference pixel) selected from a group of pixels constituting the function image such as the HAF image generated by the analysis image generating unit22. The selection of a reference pixel is made by the operator using the input device14. Specifically, while viewing CT images and functional images displayed on the display device15, the operator selects a reference pixel by clicking (input) on a displayed HAF image via the interface unit23. Thus, the reference pixel is set in response to the operator's clicking (input). Generally, of pixels constituting the HAF image, a pixel which is assumed to contain the image of normal hepatic cells in the multistage carcinogenic process is selected as a reference pixel by the operator. Alternatively, the reference pixel setting unit24may set a reference pixel by converting a pixel selected on a 3D image or a multi-planar reconstruction (MPR) image obtained by the medical image obtaining unit21into that on the HAF image.

The blood volume calculating unit25calculates a hepatic arterial blood volume and a portal venous blood volume for the reference pixel set by reference pixel setting unit24. At the same time, the blood volume calculating unit25calculates a hepatic arterial blood volume and a portal venous blood volume for every non-reference pixel (or region representing every non-reference pixel), which is not the reference pixel set by the reference pixel setting unit24.

The parameter calculating unit26compares, for each of the non-reference pixels, the hepatic arterial blood volume calculated for the non-reference pixel by the blood volume calculating unit25with the hepatic arterial blood volume calculated for the reference pixel by the blood volume calculating unit25, so as to determine a hepatic arterial blood volume comparison value (i.e., a hepatic arterial blood volume ratio or a hepatic arterial blood volume difference). For example, for each of the non-reference pixels, the parameter calculating unit26calculates a hepatic arterial blood volume ratio indicating a ratio of the hepatic arterial blood volume for the non-reference pixel to that for the reference pixel.

Also, the parameter calculating unit26compares, for each of the non-reference pixels, the portal venous blood volume calculated for the non-reference pixel by the blood volume calculating unit25with the portal venous blood volume calculated for the reference pixel by the blood volume calculating unit25, so as to determine a portal venous blood volume comparison value (i.e., a portal venous blood volume ratio or a portal venous blood volume difference). For example, for each of the non-reference pixels, the parameter calculating unit26calculates a portal venous blood volume ratio indicating a ratio of the portal venous blood volume for the non-reference pixel to that for the reference pixel.

Note that the parameter calculating unit26calculates a hepatic arterial blood volume ratio and a portal venous blood volume ratio in the examples described above, the parameter calculating unit26may calculate a hepatic arterial blood volume difference indicating a difference between the hepatic arterial blood volume for the reference pixel and that for each of the non-reference pixels, or may calculate a portal venous blood volume difference indicating a difference between the portal venous blood volume for the reference pixel and that for each of the non-reference pixels.

A storage device, such as the memory12, stores in advance a table that associates two-dimensional parameters with corresponding 256 colors in a color gradation chart G2 (from blue to red) representing the multistage carcinogenic process shown inFIG. 4, the two-dimensional parameters each representing a hepatic arterial blood volume ratio and a portal venous blood volume ratio.

FIG. 4is a diagram showing a relationship between the multistage carcinogenic process and the color gradation chart G2 representing the multistage carcinogenic process.

As shown inFIG. 4, for example, when a two-dimensional parameter represents a hepatic arterial blood volume ratio and a portal venous blood volume ratio that are both substantially one, the two-dimensional parameter is associated with blue (stage: normal hepatic cell) in the color gradation chart G2. For example, when a two-dimensional parameter represents a portal venous blood volume ratio of substantially “0” and a hepatic arterial blood volume ratio of substantially “2”, the two-dimensional parameter is associated with red (stage: plethoric hepatocellular cancer) in the color gradation chart G2.

The diagnostic image generating unit27shown inFIG. 2refers to a two-dimensional parameter representing the hepatic arterial blood volume ratio and the portal venous blood volume ratio calculated for each of the non-reference pixels by the parameter calculating unit26, the two-dimensional parameter being contained in the table stored in the storage device, obtains from the color gradation chart G2 a color corresponding to the two-dimensional parameter for each of the non-reference pixels, and generates a diagnostic image representing the multistage carcinogenic process on the basis of the obtained color. The diagnostic image generating unit27assigns an appropriate color to every non-reference pixel to generate the diagnostic image. As for the reference pixel, both a hepatic arterial blood volume ratio and a portal venous blood volume ratio are set to “1” (blue). The diagnostic image generated by the diagnostic image generating unit27is displayed via the interface unit23on the display device15.

Nutrients are supplied to normal hepatic cells at a hepatic-arterial-blood-volume to portal-venous-blood-volume ratio of 2:8. However, in early stages of cancer, such as a regenerative nodule stage and an adenoma stage, the portal venous blood volume and the hepatic arterial blood volume decrease (ischemia occurs) in the affected area. Then, as a stage (degree of cancer progression) progresses and the plethoric hepatocellular cancer stage approaches, the hepatic arterial blood volume increases and the portal venous blood volume decreases in the affected area. In early stages, such as in the regenerative nodule stage and the adenoma stage, since there is an occurrence of ischemia in which the portal venous blood volume and the hepatic arterial blood volume decrease at substantially the same rate, the hepatic arterial fraction tends to be determined to be 20%, which is the same as that in normal (unaffected) areas. As a result, it is difficult to make early detection of hepatic tumor and stage determination of cancer in early stages, on the basis of an HAF image obtained by assigning colors in the color gradation chart G1 shown inFIG. 3representing the multistage carcinogenic process to corresponding hepatic arterial fractions.

Thus, a hepatic arterial blood volume in hepatic cells in a normal stage is compared with that in another stage, and a portal venous blood volume in hepatic cells in a normal stage is compared with that in another stage. These comparisons show that in early stages, such as the regenerative nodule stage and the adenoma stage, the hepatic arterial blood volume and the portal venous blood volume decrease as the multistage carcinogenic process proceeds from the normal hepatic cell stage. Therefore, the medical image processing apparatus10determines the ratio of a hepatic arterial blood volume for a non-reference pixel in an HAF image corresponding to the normal hepatic cell stage to a hepatic arterial blood volume for a reference pixel in the HAF image, and also determines the ratio of a portal venous blood volume for the non-reference pixel to a portal venous blood volume for the reference pixel. Then, the medical image processing apparatus10generates and displays a diagnostic image by assigning appropriate colors in the color gradation chart G2 representing the multistage carcinogenic process to two-dimensional parameters, each representing the ratios determined as described above. Thus, on the basis of the diagnostic image generated by the medical image processing apparatus10, it is possible to make early detection of hepatic tumor and stage determination of cancer in early stages, such as the regenerative nodule stage and the adenoma stage in the multistage carcinogenic process.

FIG. 5is a block diagram showing a first modification of the medical image processing apparatus10shown inFIG. 2.

When the CPU11shown inFIG. 1executes a program, the workstation terminal100, which is the medical image processing apparatus10, functions as the medical image obtaining unit21, the analysis image generating unit22, the interface unit23, a blood volume calculating unit25A, a parameter calculating unit26A, and a diagnostic image generating unit27A. Alternatively, the workstation terminal100may include the medical image obtaining unit21, the analysis image generating unit22, the interface unit23, the blood volume calculating unit25A, the parameter calculating unit26A, and the diagnostic image generating unit27A as a circuit.

The blood volume calculating unit25A calculates a hepatic arterial blood volume and a portal venous blood volume for every pixel (or region representing every pixel) constituting the functional image generated by the analysis image generating unit22.

The parameter calculating unit26A calculates, for each pixel, a product of the hepatic arterial blood volume and the portal venous blood volume calculated by the blood volume calculating unit25A.

A storage device, such as the memory12, stores in advance a table that associates one-dimensional parameters with corresponding colors in the color gradation chart G2 representing the multistage carcinogenic process shown inFIG. 4, the one-dimensional parameters each representing a product of the hepatic arterial blood volume and the portal venous blood volume.

The diagnostic image generating unit27A refers to a one-dimensional parameter representing a product of the hepatic arterial blood volume and the portal venous blood volume calculated for each pixel by the parameter calculating unit26A, the one-dimensional parameter being contained in the table stored in the storage device, obtains from the color gradation chart G2 a color corresponding the one-dimensional parameter for the pixel, and generates a diagnostic image representing the multistage carcinogenic process on the basis of the obtained color. The diagnostic image generating unit27A assigns an appropriate color to every pixel to generate the diagnostic image. The diagnostic image generated by the diagnostic image generating unit27A is displayed via the interface unit23on the display device15.

FIG. 6is a block diagram illustrating a second modification of the medical image processing apparatus10shown inFIG. 2.

When the CPU11shown inFIG. 1executes a program, the workstation terminal100, which is the medical image processing apparatus10, functions as the medical image obtaining unit21, the analysis image generating unit22, the interface unit23, a parameter calculating unit26B, and a diagnostic image generating unit27B. Alternatively, the workstation terminal100may include the medical image obtaining unit21, the analysis image generating unit22, the interface unit23, the parameter calculating unit26B, and the diagnostic image generating unit27B as a circuit.

The parameter calculating unit26B calculates a hepatic arterial blood volume for every pixel (or region representing every pixel) constituting the functional image generated by the analysis image generating unit22.

A storage device, such as the memory12, stores in advance a table that associates one-dimensional parameters with corresponding colors in the color gradation chart G2 representing the multistage carcinogenic process shown inFIG. 4, the one-dimensional parameters each representing a hepatic arterial blood volume.

The diagnostic image generating unit27B refers to a one-dimensional parameter representing a hepatic arterial blood volume calculated for each pixel by the parameter calculating unit26B, the one-dimensional parameter being contained in the table stored in the storage device; obtains from the color gradation chart G2 a color corresponding the one-dimensional parameter for the pixel; and generates a diagnostic image representing the multistage carcinogenic process on the basis of the obtained color. The diagnostic image generating unit27B assigns an appropriate color to every pixel to generate the diagnostic image. The diagnostic image generated by the diagnostic image generating unit27B is displayed via the interface unit23on the display device15.

As described above, the workstation terminal100serving as the medical image processing apparatus10of the present embodiment is capable of generating and displaying a visible diagnostic image of a liver in early stages of the multistage carcinogenic process, such as the regenerative nodule stage and the adenoma stage. It is thus possible to achieve improved accuracy in diagnosing hepatocellular cancer.

FIG. 7is a schematic diagram showing a configuration of a medical imaging apparatus including the medical image processing apparatus10of the present embodiment.

FIG. 7shows an X-ray CT apparatus30as an example of the medical imaging apparatus including the medical image processing apparatus10of the present embodiment. As shown, the X-ray CT apparatus30includes the medical image processing apparatus10and an imaging system31. The imaging system31of the X-ray CT apparatus30is configured to generate projection data for generating data of a plurality of time-series CT images of a target body part of a patient (object to be examined) O, the target body part being a subject of imaging. Note that the medical imaging apparatus is not limited to the X-ray CT apparatus30, but may be an MRI apparatus or an ultrasound diagnostic imaging apparatus for which the perfusion technique can be used.

The imaging system31includes an X-ray tube41, an X-ray detector42, a limiter43, a data acquisition system44, a high-voltage generator45, a limiter driver46, a rotation driver47, a main controller48, an IF49, a table-top50, and a table-top driver51.

The X-ray tube41, the X-ray detector42, the limiter43, and the data acquisition system44are provided in a rotating unit R on a mount device (not shown) of the imaging system31. The rotating unit R is configured such that the X-ray tube41and the X-ray detector42can move about the patient O while being located opposite each other.

The X-ray tube41generates X-rays in accordance with tube voltage supplied from the high-voltage generator45.

The X-ray detector42is a two-dimensional array detector, which may also be referred to as a multi-slice detector. Each X-ray detecting element of the X-ray detector42has, for example, a 0.5-mm-by-0.5-mm square detection surface. In the X-ray detector42, for example, 916 X-ray detecting elements are arranged in a channel direction and at least 64 rows of the X-ray detecting elements are arranged in parallel along a slicing direction (i.e., along the direction of rows of the X-ray detector42).

The limiter43adjusts, in the slicing direction, the range of X-rays to which the patient O is exposed. The limiter43performs this adjustment under the control of the limiter driver46. In other words, the limiter driver46adjusts the opening of the limiter43to change the range of X-ray exposure in the slicing direction.

The data acquisition system44is generally referred to as a DAS. The data acquisition system44amplifies a signal output from the X-ray detector42for each channel, and converts the amplified signal into a digital signal. The resulting raw data (RAW data) obtained by the conversion is supplied via the IF49of the imaging system31to the medical image processing apparatus10outside the imaging system31.

The main controller48controls the data acquisition system44, the high-voltage generator45, the limiter driver46, the rotation driver47, and the table-top driver51on the basis of control signals input from the medical image processing apparatus10via the IF49.

The table-top50is a table on which the patient O is placed.

The table-top driver51causes the table-top50to move in the slicing direction. The rotating unit R has an opening at the center, through which the patient O placed on the table-top50is inserted. Note that a direction parallel to the central rotation axis of the rotating unit R is defined as a Z-axis direction (slicing direction), and directions of planes orthogonal to the Z-axis direction are defined as an X-axis direction and a Y-axis direction.

Note that in the medical image processing apparatus10of the X-ray CT apparatus30shown inFIG. 7, components identical to those of the medical image processing apparatus10shown inFIG. 1are assigned the same reference numerals and their description is omitted. The IF17shown inFIG. 7is connected to the IF49of the imaging system31and communicates with the imaging system31.

FIG. 8is a block diagram showing functions of the X-ray CT apparatus30including the medical image processing apparatus10of the present embodiment.

When the CPU11shown inFIG. 7executes a program, the X-ray CT apparatus30ofFIG. 8functions as a CT image generating unit61, an analysis image generating unit62, the interface unit23, the reference pixel setting unit24, the blood volume calculating unit25, the parameter calculating unit26, and the diagnostic image generating unit27. Alternatively, the X-ray CT apparatus30may include the CT image generating unit61, the analysis image generating unit62, the interface unit23, the reference pixel setting unit24, the blood volume calculating unit25, the parameter calculating unit26, and the diagnostic image generating unit27as a circuit.

To use the CT-perfusion technique, the CT image generating unit61controls the imaging system31to perform imaging of a liver of the patient O to which a contrast agent has been given, the liver being a target body part. Thus, the CT image generating unit61generates data of a plurality of time-series CT images of the liver of the patient O.

The analysis image generating unit62analyzes the data of the plurality of time-series CT images generated by the CT image generating unit61, and generates a hepatic blood flow image, a hepatic blood volume image, a mean transit time image, and a hepatic arterial fraction image serving as functional images. The CT images generated by the CT image generating unit61and the functional images generated by the analysis image generating unit62are displayed via the interface unit23on the display device15.

In the X-ray CT apparatus30shown inFIG. 8, components identical to those of the medical image processing apparatus10shown inFIG. 2are assigned the same reference numerals and their description is omitted.

When the CPU11shown inFIG. 7executes a program, the X-ray CT apparatus30may function as the CT image generating unit61shown inFIG. 8, the analysis image generating unit22, the interface unit23, the blood volume calculating unit25A, the parameter calculating unit26A, and the diagnostic image generating unit27A shown inFIG. 5. Alternatively, when the CPU11shown inFIG. 7executes a program, the X-ray CT apparatus30may function as the CT image generating unit61shown inFIG. 8, the analysis image generating unit22, the interface unit23, the parameter calculating unit26B, and the diagnostic image generating unit27B sown inFIG. 6.

The X-ray CT apparatus30including the medical image processing apparatus10of the present embodiment is capable of generating and displaying a visible diagnostic image of a liver in early stages of the multistage carcinogenic process, such as the regenerative nodule stage and the adenoma stage. It is thus possible to achieve improved accuracy in diagnosing hepatocellular cancer.