Abstract: A contact sensor apparatus with improved sensitivity is provided. A frame defining a surface upon which contact detection is desired has two electrically conductive sheets held in spaced parallel relationship by a plurality of electrically non-conductive insulating spacers attached to the face thereof. A contact force distributor is sandwiched between the outside electrically conductive sheet and a graphics layer. Contact forces on the graphics layer, that are in alignment with the spacers, are redistributed to areas between adjacent spacers by the contact distributor.

Abstract: Superconducting magnets (10) of a magnetic resonance imager create static magnetic fields through an examination region (12). Gradient magnetic field coils (30) under control of a gradient magnetic field control (42) generate gradient magnetic fields across the examination region (12), as a whole. A plurality of surface coils (36, 38) receive radio frequency signals from each of two distinct subregions within the examination region (12). The two receiver coils are connected with separate receivers (60.sub.1, 60.sub.2) which demodulate the received magnetic resonance signals. The magnetic resonance signals are reconstructed (76) into an image representation (80, 82) of the first and second subregions. In the embodiment of FIGS. 1 and 2, a radio frequency transmitter (40) and a whole body coil (32) generate and manipulate the magnetic resonance signals within the first and second subregions. In the embodiment of FIGS. 3 and 4, a plurality of transmitters (40.sub.1, 40.sub.2, . . .

Abstract: A CT scanner (A) non-invasively examines a volumetric region of a subject and generates volumetric image data indicative thereof. An object memory (B) stores the data values corresponding to each voxel of the volume region. An affine transform algorithm (60) operates on the visible faces (24, 26, 28) of the volumetric region to translate the faces from object space to projections of the faces onto a viewing plane in image space. An operator control console (E) includes operator controls for selecting an angular orientation of a projection image of the volumetric region relative to a viewing plane, i.e. a plane of the video display (20). A cursor positioning trackball (90) inputs i- and j-coordinate locations in image space which are converted (92) into a cursor crosshair display (30) on the projection image (22). A depth dimension k between the viewing plane and the volumetric region in a viewing direction perpendicular to the viewing plane is determined (74).

Abstract: In a magnetic resonance system, four primary loop circuits (50, 52, 54, 56) are inductively coupled to a resonator coil (32) at 90.degree. intervals around its circumference. The loop circuits are over-coupled to the resonator coil, i.e. they present more than the characteristic resistance of the associated cabling system which causes the maximum current transfer between the loop circuits and the resonator coil to be offset (f.sub.N) in equal amounts in each direction from a natural resonance frequency (f.sub.0) of the resonator coil. In one embodiment, two adjacent primary loop circuits provide for quadrature radio frequency transmission to and from the resonator coil at a first frequency and the other two primary loop circuits provide for quadrature radio frequency transmission to and from the resonator coil at a second resonance frequency. Each of the primary loop circuits includes a tank circuit (62) for blocking the passage of the frequency of the other quadrature primary loop circuit pair.

Abstract: A magnetic resonance imaging system (A) generates an image (16) of a slice or other region of an examined subject. A smoothing filter (B) smooths the generated image to create a smoothed or filtered image representation (30). The filtering of the image, unfortunately, tends to smooth or blur the edges. An edge detecting means (C.sub.1) views the region around each sampled pixel of the filtered image to determine an amount of deviation in the pixel values. A large deviation indicates an edge; whereas, substantial homogeneity indicates the lack of an edge. Analogously, the direction of the maximum deviation is orthogonal to the direction of the edge. A plurality of soft edge directional filters (54) operate on the filtered image data to create a plurality of soft edge directionally filtered image representations (62). A plurality of hard edge directional filters (56) operate on the filtered image data to create a plurality of hard edge directionally filtered image representations (64).

Abstract: A patient's cardiac cycle is monitored (34) for a characteristic point (54) of the cardiac cycle. Following or in response to the characteristic point, a series of field echo sequences (FIG. 3 ) are applied to generate magnetic resonance echoes (50a, 50b, 50c, etc.) at about 10 millisecond intervals (TR=10 ms) following the characteristic point. The echoes are phase encoded (44) such that echoes phase encoded in a lowest frequency or central most segment (I) of k-space are generated at regular intervals. Between temporal consecutive segment (I) echoes, echoes with higher frequency phase encoding from segments (II) and (III) (FIG. 4 ), segments (II-IV) (FIGS. 5A, 5B), etc. are generated. The views are sorted (60) into data sets (62a, 62b, 62c, etc.) such that the central most views are sent to only a single data set and at least some of the higher frequency views are conveyed to two data sets, i.e., the high frequency views are shared or commonly used by two data sets.

Abstract: A sequence controller (30) controls gradient pulse amplifiers (20) and a digital transmitter (24) to apply a conventional magnetic resonance imaging or spectroscopy sequence. One or more of the resonance excitation pulses includes a series of very small tip angle RF pulses (52, 70) applied in rapid succession substantially within the time interval of a normal RF excitation pulse (e.g. 10 msec.). A series of gradient pulses (58x, 58y, 72y, 72z) with linearly diminishing amplitudes and a repetition cycle that is an integer multiple of the duration of the very small tip angle RF pulses are applied such that an excitation trajectory in k-space follows a piecewise linear square spiral (FIG. 3 ) when gradients are applied along two axes or an octahedral spiral (FIG. 6 ) when a series of gradient pulses are applied along three axes. The subregion of resonance excitation is selectively shifted along one of the axes by applying a series of frequency offset pulses (66, 76) along one or more of the axes.

Abstract: A magnetic resonance imaging magnet, gradient coil, and RF coil assembly is controlled by a workstation (40). The workstation (40) includes an operator input (46, 48) and a display system (58) including a video monitor (44) for displaying human-readable images reconstructed from magnetic resonance data. A scan/reconstruction rack (50) includes a scan processor (60) which controls scan parameters and a reconstruction processor (64) and associated hardware for reconstructing received magnetic resonance signals into the image representation. A scan sequencer (52) includes a master microcode board (90) which controls the scan sequencer in accordance with instructions received from the scan processor (60). The scan processor loads a series of codes describing gradient and RF waveform profiles into memories (130) of each of a plurality of profile channels (100, 102, 104, 106, 110, 112, 114).

Abstract: The magnetic field assembly of a magnetic resonance imaging device includes an annular superconducting magnet (10) which is mounted within a toroidal vacuum vessel (24). A cylindrical member (26) defines a central bore (12) through which the superconducting magnets generate a uniform, static magnetic field. A cylindrical, dielectric former (46) is mounted in the bore displaced by an annular gap (58) from the cylindrical member. A shimset (60) for shimming the uniformity of the magnetic field is mounted in the gap (58). A radio frequency coil (32) is mounted within the cylindrical member defining a patient receiving examination region. An RF shield (34) is mounted around the exterior peripheral surface of the former. Primary gradient coils (50, 52, 54) are mounted around and potted to the exterior of the dielectric former around the RF shield. Gradient shield or secondary coils (74, 76, 78) are potted around an exterior of the cylindrical member within the vacuum chamber.

Abstract: A high frequency voltage generator (10) produces a high positive voltage and a high negative voltage. A parallel connected coil (26) and diode (30) are connected between the high voltage supply and a target (44) of an x-ray tube (40). A second parallel connected coil (28) and diode (32) are connected between the negative voltage and an electron source (42) of the x-ray tube. The coils are preferably a multiple pancake design (FIG. 3 ). When the tube starts to arc, the sudden increase in current flow through the coil is converted and stored in a magnetic field leaving only a small current to contribute to arcing. The coils are sized such that the current which passes to the x-ray tube is sufficiently small that the arcing is usually extinguished without an avalanche phenomenon occurring.

Abstract: An RF pulse sequence (40, 42, 44) is applied to generate magnetic resonance in which a dipolar or bound spin system component of the magnetic resonance has a quadrature or 90.degree. phase offset from a Zeeman or free spin system component of the magnetic resonance. The resultant resonance signal is encoded with magnetic field gradients (50, 52, 54) and sampled during a dipolar spin system resonance echo (46). The process is repeated altering the relative phase of the three RF pulses (40', 42', 44') and of a digital radio frequency receiver (28) such that the sampled dipolar and Zeeman spin system components are again in quadrature, but 90.degree. offset in the opposite sense. The two resonance signals with their Zeeman components out of phase in the opposite sense are combined (64) such that the dipolar spin system components add and the Zeeman spin system components cancel.

Abstract: An RF device (A) under test is connected with ports or jacks (14, 16) of an S-parameter test set (B). An RF input jack (18) is connected with an RF tracking signal output (20) of a spectrum analyzer (C) to receive an RF tracking signal. An output jack (22) is connected with a receiver input (24) of the spectrum analyzer. A mode control (30) internal to the test set is controlled by a programmable control sequence generator (34) of the spectrum analyzer. The mode control controls a switch array (32), preferably PIN diodes, which interconnect the RF input jack (18), the RF output jack (22), the two jacks (14, 16) that are connected to the device under test, and a 50 Ohm termination (54) in four modes to make reflection measurements and two transmission measurements. DC bias jacks (26, 28) are connected with a DC power for injecting a DC component into the RF signals applied to the device under test.

Abstract: A positive portion (52) of k-space and a negative portion (56) are both divided into n segments (FIG. 2 ). In each cardiac cycle, a multiplicity of field echoes (106) are generated, which multiplicity of gradient echoes are divided into groups of n contiguous echoes. Within each group, the echoes are all from either the positive portion of k-space or the negative portion of k-space. Preferably, every group of each cardiac cycle has the same views in the same order to generate like, time displaced frames of a cine image sequence. Within each group, the views from the central-most segment n are collected in the middle of the group, views from progressively less central, higher frequency segments are progressively less centrally located within each group with views of the most peripheral, highest frequency segments being collected at the ends of the group. The total number of segments is an integer multiple of four times the number of views per group to facilitate 0.degree.-180.degree. phase cycling.

Abstract: Magnetic resonance imaging hardware (A) defines a patient receiving region (20) that is surrounded by a bore liner (22). A socket (50) is mounted in the bore liner with an appropriate receptacle for receiving a standard plug (52) of a conventional pulse oximetry system. Conventional pulse oximetry systems include a sensor unit (54) connected with a cable (56) having the plug (52) at one end thereof. A notch filter (62) attenuates currents near the resonance frequency of the imager. A preamplifier (60) amplifies signals from the sensor unit. Within the shielding (66) of the preamplifier, a low pass filter (68) is provided to remove induced radio frequency components from the preamplified sensor unit signal. A radio frequency filter (70) mounted at the shield of the shielded room (B) prevents radio frequency signals from reaching an exterior processing and display unit (E) and prevents radio frequency signals from a clock (72) of the processing and display unit from being conveyed into the shielded room (B).

Abstract: A video processing system includes a plurality of identical video switch modules (A). Each of the video switch modules has matching inputs and outputs such that received signals can be passed through unchanged, enabling the modules to be connected in a daisy chain or series relationship. Each of the modules further includes inputs and outputs for receiving video signals from and sending video signals to procedure rooms (B). Preferably, each of the procedure rooms includes medical diagnostic apparatus (10-18) which produce one or more unprocessed video signals, a first video monitor (22) for displaying first processed video signals, a second monitor (24) for displaying second processed video signals, and a VCR (20) for recording and playing back second processed video signals. The daisy chain of video switch modules is interconnected at one end with a shared digital image processing system (C).

Abstract: A DMA control device (10) is connected with an n-bit address bus (12) by way of a bidirectional internal n-bit bus (14). The m most significant bits of signals received on the bidirectional bus (14) are reserved for carrying codes which identify or enable the DMA device to respond, to generate a load signal, to generate a count signal, and to generate an output signal. The remaining bits are reserved for address data. The load signal causes the remaining bit addresses to be loaded into counters (22) or registers (40). The count signal causes the counters (22) or a latched incrementor (44) to increment. The output signal controls three-state buffers (24, 42, 46) which cause the current address to be outputted on the bidirectional bus. In this manner, the DMA control device has only a single bus and in the embodiment of FIG. 2 replaces the counter array with a register array.

Abstract: In a fast scanning technique in which the repeat time TR is less than the T2 relaxation time, a first generation component (34), a second generation component (52), and a third generation component (62) are each phase encoded by a phase encode gradient (36). The persisting second and third generation components are encoded with the sum of the phases with which they have been encoded in the present and prior repetitions. A composite data line is sampled during each echo and includes a first component (44), a second component (54), and a third component (64), each component having an independent phase encoding. The data lines are each stored in a first data set memory (80) in accordance with the phase encoding of the first generation component, in a second data set memory (82) in accordance with the phase encoding of the second component and in a third data set memory means (84) in accordance with the phase encoding of the third generation component.

Abstract: An imaging system comprised of a source of penetrative radiation 14, an image intensifier tube 18 and a video camera 38 is provided. The intensifier tube is comprised of a input screen 22 and an output screen 24. The intensifier tube converts radiation 20 impinging on the input screen into a visible light image 36 on the output screen 24. The video camera is operatively positioned to view the output screen of the intensifier. A light sampler 50 is operatively disposed in the visible light path between the image intensifier output screen 24 and the video camera input 38. The light sampler is comprised of a mirror 52, a focusing lens 54, a beam splitter 56, an aperture 58, a light source 78, a photo receptor 60 and an optical aligner 64.

Abstract: In imaging an internal region of the human body, using optical or NMR techniques, a high resolution image is produced by imaging a layer of material formed on the region of interest which conforms to the surface of the region. The material is preferably a lipid, introduced into the body and positioned adjacent the region of interest using a probe.

Abstract: A toroidal x-ray tube (I) is supported (II) for rotation about a horizontal axis (170), translation along a vertical axis (172), and translation along a horizontal axis (174). The x-ray tube includes a toroidal housing (A), an annular anode (B), and a cathode (0) which rotates a beam of electrons around the annular anode. A plurality of parallel connected voltage sources (90.sub.1, 90.sub.2, . . . , 90.sub.n) provide a sufficiently high bias voltage between the electron source and the anode that x-rays are generated. The x-ray beam passes through a compensator crystal (62), an annular window (20), a collimator (132), through a subject received in a central bore (26) of the x-ray tube, and impacts an arc segment of radiation detectors (130). The x-ray detectors are stationarily mounted outside of the plane of the annular window (FIGS. 2 and 7), nutate into the plane of the windows opposite of the origin of the x-ray beam (FIG. 6 ), rotate in part (FIG. 9 ) or rotate in full (FIG.