Hitachi, Ltd.

Hitachi Medical Corporation

Fujifilm Healthcare Corporation

Keisuke Yamakawa

Shinichi Kojima

Yasutaka Konno

Yushi Tsubota

Hironori Ueki

Fumito Watanabe

Hisashi Takahashi

Shinji Kurokawa

Tadashi Nakamura

Isao Takahashi

Akio Yoneyama

Keiko Takahashi

Taiga Gotou

Toshiyuki Irie

Rika Baba

Mariko Yamamoto

Noise is reduced for a medical image for which noise cannot be quantified by a general-purpose image quality evaluation index. An image processor has a preprocessor that generates input images including an original image and one or more images with reduced noise compared with the original image; and a noise reduction processor outputs an image, which is obtained by reducing noise from the original image based on the input images, by applying a learned network. The learned network used in the noise reduction processor is constructed by performing deep learning using a plurality of learning sets in which one or more of a medical image including noise, a noise-reduced image obtained by performing noise reduction processing on the medical image, and an intermediate image obtained during the noise reduction processing are input images and a correct image is obtained based on the input images an output image.

Image processing apparatus, image processing method, and X-ray CT apparatus

An X-ray tomosynthesis apparatus accurately extracts a region of a small high absorber in a subject on 2D measurement projection data. When pieces of the 2D measurement projection data for each of a plurality of projection angles are arranged in a projection angle direction, the 2D measurement projection data is shifted in a 2D plane so that part or all of a range of a high absorber region included in the 2D measurement projection data overlaps at least a range of the high absorber region included in 2D measurement projection data at an adjacent projection angle in an in-plane direction of the 2D plane. The 2D measurement projection data for each of the plurality of projection angles after shifting is arranged in the projection angle direction to obtain 3D measurement projection data, and a 3D region is obtained from a first start point by a region expansion process.

X-ray tomosynthesis apparatus, image processing apparatus, and program

This X-ray CT device uses iterative reconstruction to obtain a CT image with the desired noise reduction or X-ray reduction ratio. An iterative approximation reconstruction unit () is provided which, from measured projection data obtained by an X-ray detection unit of the X-ray CT device, iteratively reconstructs a CT image in a reconstruction range of a subject, and iteratively corrects the CT image such that calculated projection data, calculated through forward projection of a CT image, is the same as the difference between measured projection data detected by the X-raw detection unit and calculated projection data. The iterative approximation reconstruction unit is provided with a parameter determination unit (), an iterative correction unit (), and a table unit () which calculates in advance the relation between each parameter used in the iterative reconstruction, and noise reduction or X-ray reduction ratio in the CT image. The parameter determination unit () determines the parameters from a calculation table in the table unit () depending on the desired reduction ratio.

X-ray CT device and processing device

Provided is a photon counting CT device for estimating an exposure dose to a subject, precisely in a simple configuration, irrespective of a spectrum shape of X-rays being applied. An exposure dose derived from the X-rays with predetermined intensity is obtained in every energy range provided in advance, and held as exposure per band data. When an imaging condition is provided, X-rays are applied in accordance with the imaging condition thus provided, and a photon count (intensity) of the incident X-rays as to each energy range is obtained, in the shape of spectrum of the X-rays applied to a detector without placing the subject. The intensity of the incident X-rays is multiplied by the exposure per band, and the results as to all the energy ranges are added up. Accordingly, the exposure dose caused by the X-rays being applied in accordance with the provided imaging condition is estimated.

Photon counting CT device and estimated exposure level computation method

High-quality image and low radiation exposure are achieved without increasing man-hours and data amount to be held. A table of iterative correction parameters optimized in the representative imaging conditions is held and an iterative correction parameter optimized in the actual imaging conditions is determined from the iterative correction parameters held in the table. In addition to the parameter table, a reference weight is also held and is reflected to generate the iterative correction parameter for each pixel position.

X-ray CT device and sequential correction parameter determination method

An object of the present invention is to non-destructively obtain, in an X-ray imaging apparatus, a sectional image of a subject with spatial resolution higher than spatial resolution of an image detector. In the present invention, the image detector is two-dimensionally moved with respect to an incident X-ray for each half (180&#xb0;) rotation of the subject, and a plurality of image groups (CT data sets) is obtained at different positions of the image detector. An image (sinogram) is synthesized from each image group thus obtained, which image is equal to an image obtained with a detector whose pixel size is smaller than the pixel size constituting the above described image detector. From this synthesized image, a sectional image with high spatial resolution is calculated by reconstruction calculation.

X-ray imaging apparatus and X-ray imaging method

A change of X-ray radiation quality due to a material existing between an X-ray source and a detection element is estimated and corrected. Accordingly, deterioration of material discrimination ability in a dual energy imaging method can be prevented. An X-ray imaging apparatus is provided with an inherent filtration calculator configured to use measured data obtained by imaging air at two or more types of different tube voltages to calculate a deviation from a reference radiation quality, as a transmission length (inherent filtration) of a predetermined reference material. A reference-material transmission-length conversion is applied to the measured data according to the dual energy imaging method, thereby calculating the reference material transmission length (inherent filtration). When a subject is imaged, the dual energy imaging is performed by adding the inherent filtration calculated as to each detection element, and this produces an image with the change of radiation quality having been corrected.

X-ray image pickup apparatus, X-ray image pickup method, and X-ray image pickup apparatus monitoring method

Provided is a technique in an X-ray imaging apparatus for implementing data interpolation approximating an ideal point response trajectory interpolation, along with reducing calculation load. A method is provided to perform interpolation at high speed, in a direction along the point response trajectory. Sinograms are interpolated in advance from measured data, as to representative angles (e.g., 0&#xb0;, &#xb1;30&#xb0;, &#xb1;60&#xb0;, and 90&#xb0;) only. When a pixel targeted for back projection is determined at the time of reconstruction, a slope of the point response trajectory is determined as to each view. According to the slope of the trajectory, each representative sinogram is added with weight, whereby interpolation data in association with any angle can be obtained.

X-ray image pickup device and image reconstruction method

Noise of a CT image is reduced with good accuracy by using noise information obtained from the CT image. An X-ray CT apparatus comprises a successive approximate reconstruction part that reconstructs a CT image for a reconstruction area of an imaging object from measured projection data obtained by an X-ray detection part of the X-ray CT apparatus, and successively corrects the CT image so that calculated projection data obtained by forward projection of the CT image performed by calculation and the measured projection data detected by the X-ray detection part become equal to each other. The successive approximate reconstruction part comprises a noise measurement part that calculates noise intensity in the CT image at least for a predetermined region of interest, and successively corrects the CT image of the region of interest by using the calculated noise intensity.

X-ray CT apparatus

The present invention is capable of distinguishing four types or more of substances such as air, water (soft tissues), contrast medium, and bones (calcification) to diagnose progress of atherosclerotic sites using dual energy imaging. A subject is imaged with two types of different tube voltages and an image obtained by image reconstruction is binarized to carry out a reprojection process; thereby, the distance of penetration of air is estimated, the contribution of air in measurement projection data is determined, and the amount of reduction by the air is deducted from the projection data so as to enable distinction between four or more substances such as air, water (soft tissues), contrast medium, and bones (calcification).

X-ray CT device and processing method

The background projection data of a background region CT image in the X-ray emission path is calculated. Using measurement projection data and background projection data, the measurement projection data of local regions is calculated. Local region CT images are calculated on the basis of local measurement projection data, and the projection data of a local region CT image in the X-ray emission path is calculated. On the basis of local calculation projection data and local measurement projection data, local CT images are iteratively corrected. When creating background region CT images or calculating background projection data, the cause of calculation accuracy deterioration is eliminated by the use of processing such as smoothing, and without deterioration of CT value accuracy in regions other than the target region, a high-quality CT image is obtained.

X-ray CT device, and method

Difference of resolution depending on imaging position in one reconstructed image generated in the FFS method is reduced to improve measurement accuracy. The X-ray CT device interpolates missing data of the projection data obtained by the FFS method with view direction interpolation processing using real data of the projection data lining up along the angular direction of the rotational movement, and channel direction interpolation processing using real data of the projection data lining up along the channel direction, and generates a reconstructed image, in which contribution ratios of the projection data having been subjected to the view direction interpolation processing and the projection data having been subjected to the channel direction interpolation processing differ according to position of pixel in the reconstructed image.

X-ray CT device, and image reconfiguration method

An X-ray detector (), configured to have X-ray detecting elements () arranged in array, detects the intensity of X-rays that are radiated from the X-ray tube () and have passed through a subject (). A data processing device () executes steps of: arranging scan data, which is based on the intensity of X-rays, in an array sequence of the X-ray detecting elements () or in a time sequence, to detect an anomalous scan data; associating a weight greater than '1' with scan data adjacent to the anomalous scan data, and associating a weight of '1' with other imaging data; calculating an update amount of a pixel vector that reflects these weights; and performing an iterative operation using the update amount to generate an X-ray CT image of the subject ().

X-ray CT apparatus and X-ray CT image-generating method

The present invention is directed to improve the precision of a CT image of a local region (small FOV image) that is obtained by applying the extensive reconstruction technique to the iterative approximate reconstruction method. A first CT image relating to a first reconstruction range is reconstructed from the projection data of a subject, the projection data being detected by the X-ray detector of the X-ray CT apparatus, and the first CT image is corrected iteratively so that the first calculated projection data obtained from the first CT image according to projection calculation, becomes equal to the projection data of the subject. The first CT image thus iteratively corrected is used to extract local measured projection data in association with the second reconstruction range. A second CT image is reconstructed in the second reconstruction range and the second CT image is iteratively corrected so that the extracted local measured projection data becomes equal to the second calculated projection data that is obtained from the second CT image according to the projection calculation.

X-ray CT apparatus and X-ray CT image processing method

A view image of high time resolution acquired in an imaging process of X-ray CT is displayed. In this display, by subtracting a background image obtained by forward projection calculation of a CT image from the view image, background is removed from the view image, and only a focused site is imaged. A transmission image of the focused site showing high display contrast and not easily influenced by a motion artifact can be thereby obtained. Thereby, in an X-ray CT device for diagnostic imaging, degradation of diagnostic ability due to motion artifacts can be prevented.

Growing community of inventors

Tokyo, Japan

Keisuke Yamakawa