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4903705 Digital radiography apparatus
111
New Patents
heights. Prior to tomosynthesis, the projection images are weighted by a weighting function which falls off towards shallower angles of the xray tube during acquisition, in order to improve the reconstructability of between-plane structures. A matrix of blurring functions is then determined, describing the blurring of structures in all planes for every tomosynthesis reconstruction. Actual patient structures are then reconstructed by solving a matrix equation containing the matrix of tomosynthesized images and the matrix of blurring functions. The patient structure images are then improved by a hybrid correction routine which combines low spatial frequencies from a wide swing of the x-ray source with high and mid spatial frequencies from a narrow swing of the x-ray source. The data, once hybrid corrected, is further corrected using an interative technique to improve the reconstruction of low spatial frequencies. This iterative technique corrects each column of each image by sequentially determining if errant frequency components are present at the edge of the images where the patient is not present. If errant frequency components are found, they are subtracted from the entire image column. Lastly, a DC level correction is performed which corrects for errant zero frequency components by adding a constant value to each image column to force the edge of each image to zero. The data is finally displayed on a display monitor. An interleaving technique is used to vary reconstructed plane heights in order to permit improved interplane resolution.
4903703 CONVERSATION DEVICE OF MR IMAGING APPARATUS Yoshik Igarashi, Tuyosi Shudo, assigned to Hitachi Ltd
Katsuta,
Japan
The conversation device of an MR imaging apparatus including a magnet for generating a static magnetic field, a gradient field coil disposed between pole pieces of the magnet and used for endowing an NMR signal with positional information, a high-frequency coil disposed in the gradient field coil for transmitting an electromagnetic wave and for detecting the NMR signal, and a bed disposed in the high-frequency coil for holding a person to be inspected, is disclosed. In this conversation device, a bone conduction microphone insensitive to a magnetic field and surrounding noise is mounted on an auxiliary member (which is used for placing the to-be-inspected person at a pre-
determined position on the bed) so that the bone conduction microphone can be kept in contact with that part of the to-be-inspected person which can conduct the voice of the to-beinspected person by a bone.
4903705 DIGITAL RADIOGRAPHY APPARATUS Kazushi Imamura, Masami Kamiya, Kashiwa, Japan assigned to Hitachi Medical Corporation A device for obtaining an image of a subject including a signal generating device including, for example, an X-ray generator for obtaining a signal representative of the subject, a detecting device for detecting a predetermined phase such as the R-wave of the electrocardiographic waveform of the subject, and an actuating device responsive to the detecting device for actuating the X-ray generator in substantial synchronism with the occurrence of the predetermined phase of the electrocardiographic waveform to thereby obtain the image of the subject. The device may include control circuitry for operating the detecting device, the actuating device and X-ray generator in the foregoing order to obtain a mask image of the subject, a device for storing the mask image, a device for injecting a contrast medium into the subject; a device for repeating the above operation of the detecting device, the actuating device, and the X-ray generator in the foregoing order to obtain a live image of the subject, and a device for subtracting the mask image and the live image with respect to each other to obtain a subtraction image to thereby eliminate motion-artifacts due to heartbeats of the subject, although subtraction angiography need not be employed. Different modes of operation of the device are also disclosed.
4905699 METHOD AND APPARATUS NMR IMAGING Koich Sano, Tetsuo Koizumi, Sagamihara, Hitachi Ltd
FOR
Yokoyama, Hideaki Japan assigned to
In order to permit the detection of a respiratory motion and an imaging synchronized with the respiration by an NMR imaging apparatus itself without any special hardware, a sequence for
New Patents
heights. Prior to tomosynthesis, the projection images are weighted by a weighting function which falls off towards shallower angles of the xray tube during acquisition, in order to improve the reconstructability of between-plane structures. A matrix of blurring functions is then determined, describing the blurring of structures in all planes for every tomosynthesis reconstruction. Actual patient structures are then reconstructed by solving a matrix equation containing the matrix of tomosynthesized images and the matrix of blurring functions. The patient structure images are then improved by a hybrid correction routine which combines low spatial frequencies from a wide swing of the x-ray source with high and mid spatial frequencies from a narrow swing of the x-ray source. The data, once hybrid corrected, is further corrected using an interative technique to improve the reconstruction of low spatial frequencies. This iterative technique corrects each column of each image by sequentially determining if errant frequency components are present at the edge of the images where the patient is not present. If errant frequency components are found, they are subtracted from the entire image column. Lastly, a DC level correction is performed which corrects for errant zero frequency components by adding a constant value to each image column to force the edge of each image to zero. The data is finally displayed on a display monitor. An interleaving technique is used to vary reconstructed plane heights in order to permit improved interplane resolution.
4903703 CONVERSATION DEVICE OF MR IMAGING APPARATUS Yoshik Igarashi, Tuyosi Shudo, assigned to Hitachi Ltd
Katsuta,
Japan
The conversation device of an MR imaging apparatus including a magnet for generating a static magnetic field, a gradient field coil disposed between pole pieces of the magnet and used for endowing an NMR signal with positional information, a high-frequency coil disposed in the gradient field coil for transmitting an electromagnetic wave and for detecting the NMR signal, and a bed disposed in the high-frequency coil for holding a person to be inspected, is disclosed. In this conversation device, a bone conduction microphone insensitive to a magnetic field and surrounding noise is mounted on an auxiliary member (which is used for placing the to-be-inspected person at a pre-
determined position on the bed) so that the bone conduction microphone can be kept in contact with that part of the to-be-inspected person which can conduct the voice of the to-beinspected person by a bone.
4903705 DIGITAL RADIOGRAPHY APPARATUS Kazushi Imamura, Masami Kamiya, Kashiwa, Japan assigned to Hitachi Medical Corporation A device for obtaining an image of a subject including a signal generating device including, for example, an X-ray generator for obtaining a signal representative of the subject, a detecting device for detecting a predetermined phase such as the R-wave of the electrocardiographic waveform of the subject, and an actuating device responsive to the detecting device for actuating the X-ray generator in substantial synchronism with the occurrence of the predetermined phase of the electrocardiographic waveform to thereby obtain the image of the subject. The device may include control circuitry for operating the detecting device, the actuating device and X-ray generator in the foregoing order to obtain a mask image of the subject, a device for storing the mask image, a device for injecting a contrast medium into the subject; a device for repeating the above operation of the detecting device, the actuating device, and the X-ray generator in the foregoing order to obtain a live image of the subject, and a device for subtracting the mask image and the live image with respect to each other to obtain a subtraction image to thereby eliminate motion-artifacts due to heartbeats of the subject, although subtraction angiography need not be employed. Different modes of operation of the device are also disclosed.
4905699 METHOD AND APPARATUS NMR IMAGING Koich Sano, Tetsuo Koizumi, Sagamihara, Hitachi Ltd
FOR
Yokoyama, Hideaki Japan assigned to
In order to permit the detection of a respiratory motion and an imaging synchronized with the respiration by an NMR imaging apparatus itself without any special hardware, a sequence for