Hitachi Medical Corporation

Hitachi, Ltd.

Taiga Goto

Koichi Hirokawa

Hisashi Takahashi

Osamu Miyazaki

Yoshiaki Sugaya

Takayuki Kadomura

Hideaki Fujii

Tsuyoshi Suzuki

Tetsuo Nakazawa

Hiroto Kokubun

Fuyuhiko Teramoto

Yasuo Omi

Yuko Aoki

Toshiyuki Irie

Even a windmill artifact including a high-frequency component in a plane perpendicular to a rotation axis can be reduced and a boundary of an organ can be made to be clear to maintain the contrast. The invention relates to a medical image processing device and includes an image acquiring unit that acquires a 3D volumetric image, a Z high-frequency image generating unit that generates a Z high-frequency image which is a high-frequency component in a rotation axis direction from the 3D volumetric image, an organ component extracting unit that extracts an organ component from the Z high-frequency image, an artifact component extracting unit that extracts an artifact component on the basis of the Z high-frequency image and the organ component, and a corrected image generating unit that generates a corrected image by subtracting the artifact component from the 3D volumetric image.

Medical image processing device and X-ray CT device provided with same, and medical image processing method

In order to determine noise intensity more accurately by a projection data division method using data after fan-parallel conversion, a plurality of projection data obtained by irradiating a scan object with radiations are received and subjected to prescribed data conversion; data after the conversion is divided into two or more sets; a reconstructed image is generated for each set of data; and the generated reconstructed image for each of the sets is subtracted to generate a difference image. An index indicating pixel value variation for at least one prescribed region on the difference image is calculated, the value of the index is corrected by a previously calculated correction value, and the corrected index value is regarded as noise intensity of the region.

Image reconstruction device, X-ray CT device, and image reconstruction method

A reconstruction image is generated with a small number of updates, with the use of an iterative approximation method. A specified tomographic image of a subject is received, and a process is performed two or more times, where an update process is performed according to the iterative approximation method, using the tomographic image as an initial image and an update image is obtained. Then, an update vector corresponding to a difference between thus generated update images of the update process performed twice is multiplied by predetermined coefficients, so as to generate an estimated update vector. Using this vector, an update image is generated. Then, this update image is used as a new initial image, and a process is repeated where the update process is performed according to the iterative approximation method and an update image is obtained, thereby generating a tomographic image of the subject.

Image computing device, image computing method, and tomograph

In order to provide a data processing device and the like, capable of performing highly accurate reference correction even in a case where an object protrudes in reference channels in most of the measurement views, an image processing device (data processing device) of an X-ray CT apparatus calculates a unit air calibration reference value which is a value per unit tube current of an air calibration reference value which is reference data measured during air calibration, calculates a reference value (estimated reference value) corresponding to an X-ray condition in the main scanning on the basis of an output tube current value in the main scanning and a unit air calibration reference value, and corrects normalized reference data obtained by normalizing a measured reference value in the main scanning with the estimated reference value, to be included in an allowable error range, so as to remove the influence of protrusion.

Data processing device, X-ray CT apparatus, and reference correction method

In order to provide an X-ray CT apparatus which can reconstruct a tomographic image with less unevenness in image quality at a high speed on the basis of projection data which is obtained by irradiating an object with X-rays, the X-ray CT apparatus of the invention includes an inverse projection phase width setting unit that sets an inverse projection phase width which is an angular width of projection data used for reconstruction, for each tomographic image, and a view weight calculation unit that calculates a view weight which is a weight coefficient multiplied by projection data within the inverse projection phase width and is a function of a view angle, for each position of a pixel of a tomographic image.

X-ray CT apparatus, image processing device and image reconstruction method

In order to reduce a metal artifact using a short process, without causing image quality deterioration, when a subject containing metal is imaged in an X-ray CT apparatus, the invention is such that a high frequency component is extracted utilizing the fact that a high frequency component is a structure in error projection data, which are a difference between primary corrected projection data wherein at least one portion of an artifact component caused by metal has been removed and photographed projection data acquired by imaging. The high frequency component, extracted while carrying out weighting in order to suppress the metal artifact, is restored to the primary corrected projection data, after which an image is reconstructed. Also, metal projection data used when compiling the primary corrected projection data are calculated from a value that is a CT value corresponding to soft tissue subtracted from a CT value of a metal region.

X-ray CT apparatus, reconfiguration arithmetic apparatus, and X-ray CT image generation method

In a case where helical scanning, etc., is performed in an X-ray CT apparatus, upsampled projection data that more approximates to an observed value is obtained. There is provided an X-ray CT apparatus that improves spatial resolution of an overall effective field of view without reducing rotation speed, in an FFS method of acquiring projection data through moving of an X-ray focus position to a plurality of positions. The X-ray CT apparatus: converts projection data acquired through helical scanning into projection data of normal scanning performed by one rotation; generates a virtual-counter-data space in which virtual counter data are acquired on substantially coincident X-ray transmission path in the converted projection data; performs upsampling in a view direction; and similarly upsamples FFS projection data in the view direction for focus-shifted projection data obtained by performing the helical scanning while causing the X-ray focus position to shift (virtual counter data space generation).

X-ray CT apparatus, upsampling method of projection data, and image reconstruction method

An X-ray CT apparatus includes an extraction unit that acquires air data measured using the X-ray CT apparatus and the measurement data obtained by scanning the object, that extracts sensitivity variation data which is a sensitivity variation component of a detection element from the air data, and that extracts blank data from which the sensitivity variation component is removed, and a projection data generation unit that removes the sensitivity variation component and noise which are included in the measurement data, based on the sensitivity variation data, and that uses the blank data so as to perform a correction process of the measurement data from which the sensitivity variation component and the noise are removed.

X-ray CT apparatus, data processing device, and projection data generation method

In order to provide a technique capable of restoring measured data from projection data with high accuracy and removing system noise included in the measured data, a signal processing device obtains measured data x including signal values of 0 or less by processing an output signal from a data acquisition system, and performs a conversion process on the measured data x by using a predefined function including a logarithmic function so as to generate projection data (logarithmically converted data z), in which the predefined function is a function of which an inverse function is present for values of a predetermined negative number s or more, and the measured data x including signal values of 0 or less within a predetermined range is restored from the projection data by applying the inverse function to the projection data.

X-ray CT apparatus and image calculating device for X-ray CT apparatus

In order to provide a technique for reducing system noise from an output signal value (measurement data), an X-ray CT apparatus includes an X-ray generation unit that irradiates X-rays to an object, an X-ray detector that detects the X-rays transmitted through the object, a correction processing unit that corrects an output signal from the X-ray detector, and a reconstruction calculating unit that reconstructs an image on the basis of an output from the correction processing unit, in which the X-ray detector includes arranged detection elements, and in which the correction processing unit maintains an average value of output signal values of a plurality of predetermined detection elements centering on a focused detection element among the detection elements, and also reduces a variance of the output signal values of the plurality of predetermined detection elements centering on the focused detection element.

X-ray CT apparatus and correction processing device

In order to provide an image processing device and the like making it possible to generate a target image in which edges of a structure are upheld and from which streaking artifacts are removed, a computation device determines a shape of a non-linear function on the basis of feature amounts of an original image and a smoothed image (S). Next, the computation device calculates a condition coefficient of the original image and the smoothed image by using the non-linear function for which the shape was determined in S(S). Next, the computation device uses the condition coefficients calculated in Sto calculate a weighting coefficient for each of the pixels of the original image and the smoothed image (S). Next, the computation device adds weighting to the original image and the smoothed image to generate the target image (S).

Image processing device and image processing method

To generate a reconstructed image suitable to characteristics of a bilaterally symmetric site and possible to an appropriate image diagnosis, a computation device: computes a back projection phase width at a rotational center and distance between the rotational center location which is a reference location and a pixel to be reconstructed; according to the distance between the rotational center location and the pixel to be reconstructed, sets a function (f) changing the back projection phase width; computes a back projection phase width in the pixel to be reconstructed, substituting a value of the distance between the rotational center location and a pixel to be reconstructed in the function (f); computes a view weighting, on the basis of the back projection phase width in the post-correction pixel to be reconstructed and a slope width of a view weighting function; and reconstructs a CT image, using the view weighting.

X-ray CT apparatus and image reconstruction method

In order to provide a technique of obtaining an image having high diagnosability without degrading the operability in an X-ray CT apparatus that suppresses the amount of exposure of an object by controlling the amount of radiation by setting a target image SD and determining the imaging conditions (tube current) satisfying the target image SD, there is provided an X-ray CT apparatus that controls the amount of radiation according to the size of an object in consideration of the contrast by simply inputting one image quality level as a reference of the image quality level that the operator desires. The input image quality level is set as a target image SD when scanning an object having a standard size with a standard tube voltage.

X-ray CT apparatus and tube current determination method

To provide an image reconstruction device capable of creating an image with image quality matching the operator's request when a cross-sectional image is reconstructed through a repeated calculation, the image reconstruction device which performs a repeated calculation on the basis of a difference between calculated projection data and measured projection data, the calculated projection data being obtained by performing a forward projection calculation on a reconstructed image which is reconstructed based on the measured projection data, includes an input section to which an image quality parameter which is considered to be important by an operator is input, a weight calculation section that calculates a weighting coefficient on the basis of the image quality parameter, and a repeated calculation section that performs a repeated calculation on the basis of a value obtained by weighting and adding a pixel value obtained in the previous iteration to a pixel value obtained from now using the weighting coefficient.

Image reconstruction device and image reconstruction method configured to perform iteratively reconstructed image using weight coefficient

With respect to projection data covering a plurality of sites, in order to create a medical image in which a uniform noise reduction effect is achieved for all sites within the projection data, an arithmetic device () determines one or more of proper subsets on the basis of scanning conditions and reconstruction conditions (step). Next, the arithmetic device () calculates a penalty-term weight for each proper subset on the basis of a detector output weight corresponding to a set element contained in the proper subset (step). Then, the arithmetic unit () performs an iterative approximation by using the penalty-term weight for each proper subset (step).

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Tokyo, Japan

Taiga Goto