X-ray or gamma ray systems or devices – Electronic circuit – With display or signaling
Reexamination Certificate
1999-07-02
2001-03-06
Bruce, David V. (Department: 2882)
X-ray or gamma ray systems or devices
Electronic circuit
With display or signaling
C378S004000, C378S901000
Reexamination Certificate
active
06198797
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray CT (computed tomography) apparatus and an image diagnostic apparatus, and more particularly to an X-ray CT apparatus and an image diagnostic apparatus which enable diagnosis of corpulence of the internal organs in a practical level and are useful for diagnosis of corpulence of the internal organs.
Conventional X-ray CT apparatuses have the following functions:
(1) Density Contour: a function of extracting a region which is composed of continuous pixels having CT values within a threshold range specified by a human operator and contains a measurement start point specified by the operator, and displaying the region in a discriminable mode;
(2) Density Mask: a function of extracting pixels having CT values within a threshold range specified by an operator, and displaying them in a discriminable mode; and
(3) Histogram: a function of calculating a histogram of CT values.
By sequentially applying the above-listed functions, the conventional X-ray CT apparatuses may serve to diagnose corpulence of the internal organs.
However, such apparatuses involve inconvenience that they do not provide simultaneous display of the respective screens for these functions, and visceral fat must be manually calculated, causing difficulty in the diagnosis of corpulence of the internal organs in a practical level.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an X-ray CT (computed tomography) apparatus and an image diagnostic apparatus which enable diagnosis of corpulence of the internal organs in a practical level and are useful for diagnosis of corpulence of the internal organs.
In accordance with a first aspect of the invention, there is provided an X-ray CT apparatus for successively acquiring data at different view angles while rotating an X-ray tube (or an X-ray tube and a detector) around a subject, and producing a tomographic image for display by means of a reconstruction operation (or interpolation and reconstruction operations), comprising: threshold range defining means for specifying CT values for a fat portion in the tomographic image to define a threshold range; measurement start point specifying means for specifying one point in a subcutaneous fat region on the image; subcutaneous fat pixel retrieving means for retrieving pixels within a region on the tomographic image that is composed of continuous pixels having CT values within the threshold range and contains the measurement start point, and identifying these pixels as subcutaneous fat pixels; visceral fat pixel retrieving means for retrieving pixels on the tomographic image that have CT values within the threshold range and are not the subcutaneous fat pixels, and identifying these pixels as visceral fat pixels; fat region image display means for displaying at least either of the subcutaneous fat pixels or the visceral fat pixels in a discriminable mode; area ratio calculating means for calculating the ratio of the area of the subcutaneous fat pixels and the area of the visceral fat pixels; histogram generating means for generating at least one of a histogram of the pixel values of the subcutaneous fat pixels and a histogram of the pixel values of the visceral fat pixels; and composite screen display means for displaying the area ratio and the histograms along with the fat region image on the same screen.
According to the X-ray CT apparatus of the first aspect, the operator is only required to specify minimum and maximum CT values for the fat portion or specify a central CT value and a CT value width for the fat portion, and specify one point in the subcutaneous fat region on the screen. Then the subcutaneous fat pixels and the visceral fat pixels are automatically retrieved, the area ratio thereof is automatically calculated, and the histograms of their pixel values are automatically generated. Next, the fat region image, the area ratio and the histograms are displayed on the same screen. Thus, the diagnosis of corpulence of the internal organs is facilitated.
In accordance with a second aspect of the invention, there is provided the X-ray CT apparatus as described regarding the first aspect, comprising: fat pixel extracted image display means for displaying a fat pixel extracted image which enables discrimination between pixels having CT values within the threshold range and other pixels; separation line input means for allowing an operator to input a separation line in the image; region separation means for identifying continuous pixels having CT values within the threshold range and lying across the separation line as discontinuous.
For some subjects or under some conditions, the subcutaneous fat region and the visceral fat region may be apparently continuous on a tomographic image. In this case, statistical calculations such as those for finding the area ratio of the subcutaneous fat region and the visceral fat region cannot be performed.
According to the X-ray CT apparatus of the second aspect, even when the subcutaneous fat region and the visceral fat region are apparently continuous, these regions can be separated by the separation line input by the operator. The calculations such as those for finding the area ratio of the subcutaneous fat region and the visceral fat region are thus enabled.
In accordance with a third aspect of the invention, there is provided an image diagnostic apparatus for displaying an image and extracting features of a region of interest in the image, comprising: threshold range defining means for specifying pixel values of pixels of interest in the image to define a threshold range; measurement start point specifying means for specifying one point in a local region on the image; local pixel-of-interest retrieving means for retrieving pixels within a region on the image that is composed of continuous pixels having pixel values within the threshold range and contains the measurement start point, and identifying these pixels as local pixels of interest; residual pixel-of-interest retrieving means for retrieving pixels on the image that have pixel values within the threshold range and are not the local pixels of interest, and identifying these pixels as residual pixels of interest; pixel-of-interest region image display means for displaying at least either of the local pixels of interest or the residual pixels of interest in a discriminable mode; area ratio calculating means for calculating the ratio of the area of the local pixels of interest and the area of the residual pixels of interest; histogram generating means for generating at least one of a histogram of the pixel values of the local pixels of interest and a histogram of the pixel values of the residual pixels of interest; and composite screen display means for displaying the area ratio and the histograms along with the pixel-of-interest region image on the same screen.
According to the image diagnostic apparatus of the third aspect, the operator is only required to specify minimum and maximum pixel values for the pixels of interest or specify a central pixel value and a pixel value width for the pixels of interest, and specify one point in the local region on the screen. Then the local pixels of interest and the residual pixels of interest are automatically retrieved, the area ratio thereof is automatically calculated and the histograms of their pixel values are automatically generated. Next, the pixel-of-interest region image, the area ratio and the histograms are displayed on the same screen. Thus, the features of the pixels of interest can be easily observed. For example, diagnosis of corpulence of the internal organs is facilitated.
In accordance with a fourth aspect of the invention, there is provided the image diagnostic apparatus as described regarding the third aspect, comprising: pixel-of-interest extracted image display means for displaying a pixel-of-interest extracted image which enables discrimination between pixels having pixel values within the threshold range and other pixels; separation line input means for allowing an operator t
Azemoto Shogo
Majima Kaoru
Minami Manabu
Sato Shoko
Bruce David V.
GE Yokogawa Medical Systems Limited
Kojima Moonray
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