Abstract: Mode selection switches (76, 96, 98) selectively interconnect a sensor line shift timing generator (76) with one of three signal sources - (1) a conventional raster scan timing signal from a raster scan sync generator (70), (2) variable speed external timing signals from a tachometer (32), and (3) fixed speed timing signals developed from the horizontal timing signals of the raster scan sync generator. In a time delay and integration mode, the sensor line shift timing generator causes the CCD arrays of an image section (22) and storage section (24) to shift pixel values down the CCD arrays at a rate commensurate with the external timing signal. As a spot of light emanating from a portion of an object moving through an examination region moves along the CCD array, a corresponding pixel charge is shifted through the CCD array at the same speed such that the same pixel charge integrates light from the same spot as it moves the entire length of the CCD array.

Abstract: A magnetic resonance imaging apparatus (A) generates a uniform magnetic field, causes gradient fields transversely thereacross, excites resonance in nuclei within the image region, receives radio frequency signals from resonating nuclei, and reconstructs images representative thereof. Electrodes (30) monitor the cardiac cycle of a patient (B) being imaged and an expansion belt (32) monitors the respiratory cycle. During a magnetic resonance imaging scan, noise signal wave forms or spikes are superimposed on the cardiac cycle signal. A noise spike detector detects noise spikes. Specifically, a comparator (48) compares each wave form received from the electrodes with properties of a cardiac signal, such as the slope. When the comparator determines that a noise wave form is being received, it gates a track and hold circuit (52). The track and hold circuit passes the received signal except when gated by the comparator.

Abstract: A planar gradient magnetic field assembly (20) selectively causes gradient magnetic fields linearly across the examination region (12) of a magnetic resonance imaging apparatus. The gradient coil assembly includes a pair of planar y gradient coils (22a, 22b) and a pair of planar x gradient coils (24a, 24b). On each plane, the gradient coil winding includes a pair of larger, outer coil loop arrays (60, 62). A pair of smaller inner coil loop arrays (66, 68) produce a first order gradient field correction to improve the accuracy of the gradient field. The coil loop arrays are symmetric relative to the z axis and relative to an (x,y) plane of symmetry perpendicular to the z axis.

Abstract: A radio frequency pulse (32), a gradient pulse (34), and a first frequency offset pulse (38a) are applied to cause the presaturation region (36a) adjacent one face of an imaging volume (30) such that material flowing into the imaging volume from that face is saturated. An imaging sequence is applied which generates magnetic resonance image data that has non-saturated flow in the imaging volume identified by a characteristic phase modulated intensity. The saturation and gradient pulses are applied again with a second frequency offset pulse (38b) to position the saturation region (36b) adjacent the opposite face of the image volume. The exact same imaging sequence is applied to generate a second set of image data in which non-saturated flowing material is identified by a characteristic phase modulated intensity. Magnitude values from these two data sets are reconstructed (72, 74) into image representations that are subtractively combined (76), to form a difference image representation.

Abstract: A magnetic resonance method comprising the steps of exciting magnetic resonance in nuclei in a planar region of a body, applying a first gradient magnetic field having a periodically reversing gradient in a first direction across the region in conjunction with a series of pulses of a second gradient magnetic field in a second direction across the region orthogonal to the first direction, progressively decreasing the time between successive pulses of the second gradient, sensing resonance signals from the nuclei, and subjecting the resonance signals to a two-dimensional Fourier Transform process to acquire data relating to the region of the body. In the method the time between successive pulses of the second gradient is decreased in such a manner as to avoid acquisition of data in respect of areas in the corners of a rectangular matrix defined by the first and second gradient fields.

Abstract: A deformable, inner ring (22) is mounted by spokes (24) to internal structure (26) of a CT scanner. A plurality of circuit boards (32) are bent in a circular arc that is concentric with an inner circular surface of the first ring and secured to the first ring such that the arcuate bend is maintained. Bending the flexible circuit boards into an arc stresses them such that they are cantilevered outward from the first ring, yet are held along the circular arc. A second ring (44) is connected to the outer ends of the circuit boards to assure that both ends of the circuit board are held in like diameter parallel circles. Brackets (52) hold the side edges of the circuit boards straight and linear. In this manner, the circuit boards on which radiation detectors (36) are mounted become a rigid, circular mounting assembly for the radiation detectors and provide the sole support for the second ring.

Abstract: A patient is disposed within a scan circle or examination region (62) of a CT scanner (B). As the patient starts breathing air from a xenon gas supply (A), a flow image and a lambda image are created and stored in a flow image memory (90) and a lambda image memory (92). The flow and lambda images, as well as a standard CT image, are displayed in quadrants of a video monitor (102). A joystick (106) enables the operator to designate a region of interest on the displayed image representations. Corresponding flow and lambda values are retrieved from the flow and lambda image memories for each spatial location or pixel within the region of interest. The flow and lambda values are loaded into a flow vs. lambda image memory (112) which is addressed in one direction by the flow values and in another by the lambda values to create a count of the flow and lambda value pairs. The information in the flow vs. lambda image memory is displayed as a histogram in one quadrant of the video display.

Abstract: A method of reducing the effects of eddy currents produced by a gradient magnetic field pulse pattern applied to a body in a magnetic resonance method by selecting the rates of change of magnetic flux produced during the edges of the or each pulse of the pulse pattern in relation to the times elapsing between the edges and the time constants of the eddy currents.

Abstract: A patient receiving region (12) is defined within a stationary CT scanner frame (A). An x-ray tube (B) is mounted on a rotating frame portion (40) for rotation about the patient receiving region on an annular bearing (44, 46, 48). A fluidic slip ring (60) is mounted between the rotating and stationary frames adjacent the bearing for conveying cooling fluid between the x-ray tube and a stationarily mounted, preferably off-site, chiller (D). The fluidic slip ring enables large amounts of heat to be removed from the x-ray tube to maintain the x-ray tube at proper operating temperatures without overheating the interior of the CT scanner, the CT scanner room, or the like.

Abstract: RF and gradient pulse combinations (30, 32, 36, 38) are applied to limit or define a region of interest in two dimensions (42) by pre-saturating surrounding regions (34a, 34b, 40a, 40b). A 90.degree. RF pulse (50) is applied in the presence of a slice select gradient (60) to excite selected dipoles in a slice or slab, defining the region of interest or voxel in the third dimension. Phase encoding gradients (62) and (64) are applied to encode spatial position in two dimensions of the slice. A binomial refocusing pulse (52) suppresses the water and refocuses the metabolite resonance into an echo which is acquired (68) by a receiver (26). A Fourier transform means (72, 74) transforms the received magnetic resonance signals to create a two dimensional array (76) or matrix of spectra (78) corresponding to a two dimensional array of spatial positions within the slice.

Abstract: A support stand (B) adjustably supports either (i) a localized coil assembly or (ii) a portion of a patient within an image region of a magnetic resonance imager (A). A vertical member (42) extends upward from a base (40). A follower (44) is selectively positionable along the vertical member. In one embodiment, a universal joint (48) adjustably mounts a bracket (50) to the follower (FIG. 2). In another embodiment, the follower includes an arm (70) which receives a mounting pin (72) of the supported device. The supported device may be a surface coil (22) or an orthopedic appliance such as a knee support (80) or limb support (90). Every part of the support stand and the supported orthopedic structure, including screws and fasteners are constructed of a material which is invisible in the magnetic resonance images generated by the imager and which is a dielectric to avoid patient shock from induced currents.

Abstract: A CT scanner (10) generates views of data such as equal angular increment detector fan views (FIG. 2A) which are convolved or filtered by an array processor (24). A combined backprojector and forward projector (28) backprojects the data from the array processor into an output memory (30) and forward projects lines of image representation data from an input memory (26) to the output memory. Each view representation may again be an equal angular increment detector fan format view (FIG. 2A), a parallel ray format view (FIG. 2B), an equal linear increment source fan format view (FIG. 2D), a source fan format view (FIG. 2C), an equal angular incremental detector fan format (FIG. 2E), an equal linear increment detector fan format (FIG. 2F), or an equal angular increment source fan format (FIG. 2G). In a backprojector mode, the projector is addressed by line and row addresses of a pixel of the output memory. A look-up table (76) and a multiplier (82) generate a weighting function W.

Abstract: An x-ray tube is disclosed whose cathode cup is battery biased at a low level, approximately 30 volts DC, to inhibit "wings" on the focal spot of electrons bombarding the anode. The battery for providing bias, floats at the DC electrical potential applied to the cathode, many KV below ground potential. Geometric modifications to the filament/focusing cup arrangement are also included. The geometrical characteristics partially inhibit the dispersion of electrons, inhibiting the formation of "wings" on the x-ray focal spot, particularly at high current levels. At lower current levels, the low DC battery bias enhances the anti-dispersion effects of the geometrical characteristics to inhibit wing formation even at these lower current levels.

Abstract: A customized random access memory circuit is provided to allow the processing of extremely high amounts of data in an area of very small physical size. The chip contains a group of interconnected registers with a set of input ports and a set of output ports. The input ports have individual write enable signals to allow them to write to selected address locations. A switching circuit is provided to ensure that the proper data from the proper input port goes to the chosen address location. A first and second set of latches are provided where the first set of latches are connected to a multiplexor first and the second set of latches are connected to a second multiplexor. The chip also contains a cycle skipping chip to allow the data to maintain its position and not be transferred through at least one clock cycle. Selected data sets which are going to be outputted have the data internally swapped to prepare it for use in floating point operations.

Abstract: An x-ray tube (A) is powered by a control circuit (C) for selectively irradiating a sheet of x-ray film (B). An operator selects the operating anode current mA for the x-ray tube, an exposure or dose value (preferably an mAs value), and a tube voltage kV on a keyboard (20). For a fixed operating voltage and selected mAs value, the film should be exposed to the same density regardless of whether a low mA and a long time or a high mA and a short time are selected. Particularly in single phase inverter control circuit and power supplies, the high current and short time exposure tend to be underdeveloped relative to low mA and long time exposures for the same mAs value. To standardize the exposure for any current and time combination of the selected mAs value, a look up table (60) is provided. The look up table is addressed by the selected kV, mA, and mAs values to retrieve an appropriate current boost value which boosts the actual current such that the film is exposed to the selected density.

Abstract: A cardiac monitor (62, 64) monitors the cardiac cycles of a patient in an examination region (10). Each cardiac cycle includes an R-wave (40) at the beginning of the end-diastole. A conditioning pulse trigger (74) enables a preconditioning pulse control (34) to generate a conditioning pulse (42) at a time selected in accordance with the R-wave (40.sub.n-1) of one cardiac cycle. More specifically, an R-wave predictor (72) predicts when the next R-wave (40.sub.n) will occur and the conditioning pulse trigger enables the application of the conditioning pulse (42.sub.n) a selected duration before the next predicted R-wave (40.sub.n). An imaging sequence trigger (78) enables an image sequence controller (24) to start an imaging sequence in an imaging window (44.sub.n) in conjunction with the R-wave (40.sub.n). Preferably, the imaging sequence starts immediately with the R-wave (40.sub.n) such that the end-diastole stage of the heart is imaged.

Abstract: A medical diagnostic imaging apparatus (A) creates an image representation which is stored in an image memory (24). A video processor (26) generates a monochrome video signal from the data stored in the image memory. A monochrome to color video signal converter (B) converts the gray scale designations of the monochrome video signal to hue scale designations of a color video signal. More specifically, the gray scale values of the monochrome signal are digitized by an analog-to-digital (32) and used as addresses for a plurality of look up tables (36r, 36g, 36b, 64r, 64g, 64b). Each set of three look up tables (30, 60, 66) is preprogrammed with appropriate transfer functions, such as the transfer functions (40, 42, 44) of FIG. 2. Each look up table puts out an appropriate intensity designation for one of the three color components of the video signal. A digital-to-analog converter (50) converts the look up table outputs to three components of an RGB or other appropriate color video signal.

Abstract: Light box assembly (10) has a removably mountable viewing panel (30), a cabinet (20), and a film media hanging means (40). Upon insertion, the viewing panel (30) is maintained in position by pressure applied by a stopping surface (70) a second surface opposite a camming surface (60) of an arm (62), along with a bottom panel positioner (72). Naturally resilient film (52) is inserted into a film receiving means (50). The film is guided along a guide surface (74) such that the leading edge of the film (52) follows the camming surface (60). Upon reaching film receiving bight (66), the operator releases the film. Due to the film's natural resiliency and the relative positions of the film receiving bight (66), the engaging edge (58), and an outer edge of the viewing panels' notch (32), the film is maintained in a secured position without the need of any moving parts. Such a configuration allows films of various thickness is to be secured.

Abstract: A patient (B) is disposed in a region of interest of a magnetic resonance apparatus (A). During an imaging sequence, changing magnetic field gradients and radio frequency pulses are applied to the region of interest. The changing magnetic field gradients induce a corresponding electrical response in the patient. Electrodes (40) of a cardiac monitor (C) sense the electrocardiographic signal of the patient as well as the electrical response to the magnetic field gradient changes and produces an output signal having a cardiac component and a noise component. The bandwidth of the noise component varies in accordance with the changes of the magnetic field gradients. An adaptive filter (80) filters the output signal to remove the changing magnetic field gradient induced noise. The bandwidth of the filter function with which the output signal is filtered is varied or adjusted in accordance with the magnetic field gradient changes.

Abstract: A network (A) carries large image blocks among medical diagnostic equipment (20, 22, 24), archive computer (26), and data handling and display stations (28, 30). Four kilobyte packets of 4 megabyte image blocks are moved from transmit buffers (38) to queuing buffers (42). The order in which packets from the queuing buffers are transmitted on the network medium (10) is determined by a combination of an assigned priority, duration in the buffer, and a statistical availability of the addressed receiving node. A data link (52) at the receiving node includes an elasticity buffer (122) which stores a small plurality bits, e.g. 5, to accommodate for variances in the clock speed of the transmitting and receiving nodes. A buffer table (60) monitors memory addresses at which preceding data packets corresponding to the same image are stored and provides address information to send each subsequently received packet.