Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A free flow mitigating device for a fluid administration set includes a pump driver mechanism having a locator pin attached and positioned to register with a locator hole on the administration set, for example in a cassette. The locator pin has a surface area. A compressible material is attached to at least a portion of the surface area of the locator pin. The compressible material has a thickness such that it is frictionally received within the locator hole of the cassette sufficient to provide a retaining force to resist cassette movement during closing of a flow regulator valve of the cassette.

Abstract: A medical device includes a housing, a power supply, a thermally conductive mounting clamp, a heat shield, and at least one fastener. The housing includes a handle. The power supply is disposed within the housing. The thermally conductive mounting clamp is attached to an outer surface of the housing. The heat shield is disposed within the housing adjacent to the power supply. The heat shield is disposed against at least one interior surface of the handle. The at least one fastener passes through at least one opening in the housing and is in thermally conductive contact with the thermally conductive mounting clamp. Heat generated by the power supply is configured to dissipate from the power supply, through the heat shield, through the at least one fastener, and into the thermally conductive mounting clamp.

Abstract: A free flow mitigating device for a fluid administration set includes a pump driver mechanism having a locator pin attached and positioned to register with a locator hole on the administration set, for example in a cassette. The locator pin has a surface area. A compressible material is attached to at least a portion of the surface area of the locator pin. The compressible material has a thickness such that it is frictionally received within the locator hole of the cassette sufficient to provide a retaining force to resist cassette movement during closing of a flow regulator valve of the cassette.

Abstract: A digital lowpass filter design for filtering nuclear magnetic resonance (NMR) signals in a magnetic resonance imaging (MRI) system supports multiple frequencies and is highly configurable without sacrificing speed and performance. The first FIR filter stage of a synchronized multirate digital filter is selected from a database of filter coefficient/parameter sets which are loaded at start time and used in place. Second (and later) FIR filter stages are fixed in the example. A large number of different filter frequencies can be selected rapidly without changing the parameterized filter program reducing the amount of time to start up the MRI system and allowing "on-the-fly" filter changes in real-time between echoes and/or A/D samples. For example, filter preselection by the host can be performed in less than 100 .mu.s, and, one of several lowpass filters can be selected by the sequencer "on-the-fly" with a latency of less than 10 .mu.s.

Abstract: A control interface for a magnetic resonance imaging (MRI) system provides extended, improved linker syntax/techniques that maximize reuse of program segments, allow optimal compromise between detailed representation and efficient sequence program design and maintenance, and permit uniform application of the loop syntax to link commands for MRI sequencers with a wide range of hardware implementations.

Abstract: A multi-rate sample MRI (magnetic resonance imaging) digital receiver maintains synchronization of digitally processed signals. This multi-rate sample data system is used to demodulate and filter a digitized MRI RF signal. A phase/timing relationship is established between the signal received and processed by the digital receiver, and the physical nuclear magnetic resonance (NMR) process the body being imaged is undergoing. Once established, the phase/timing relationship is maintained for the duration of the particular NMR experiment being performed. Special logic in the digital system ensures that the data output is synchronized with an external synchronous signal controlling data acquisition within the MRI system. Optimum signal processing is performed to minimize the time between the end of the acquisition control signal and the last output from the digital signal processing system.

Abstract: A sequencer controller for nuclear magnetic resonance imaging includes a level-sensitive external gating arrangement. When a sequencer microcode WAIT instruction is executed, the gating arrangement operates differently depending on the level of the signal existing at the external gating input. If the external gating signal level is at one level, the gating arrangement causes the sequencer to wait until the external gating input changes level----thus permitting an external gating event (e.g., closure of a breath switch or the like) to interact with and control the timing of the NMR sequence. If the external gating signal is at a different level when the WAIT instruction is first executed, however, the sequencer does not "wait" at all but instead ignores the WAIT instruction and goes to the next sequencer state.

Abstract: An extremely fast and efficient Linker for a Magnetic Resonance Imaging (MRI) system Nuclear Magnetic Resonance (NMR) pulse control sequencer efficiently derives subsequent blocks of microcode to be loaded by using the contents of a memory buffer containing previously loaded microcode as a template, Most of the template is reused "as is". Only the relatively few field values in the microinstructions which change from one signal generation process, or cycle, to the next are replaced with new values. Offsets are tabulated of instructions which have associated multi-entry cycle indexed program change table (PCT) values. When further code is to be linked and loaded, the linker accesses the PCTs based on the table and to inserts new values into the appropriate instruction fields. The microcode memory image may be continuously maintained in a host memory buffer and re-edited successive times.

Abstract: A local frequency generator employing a single crystal oscillator, latches and direct digital synthesizer circuits digitally produces all signals needed in the transmitter channel of a MRI system to generate MRI transmitter RF pulses. The local frequency generator is operable in both the single side band and double side band modes and has the capability of switching between the modes. The generator is constructed with a phase resetting capability for providing the plural output frequencies needed for making plural MRI slices.

Abstract: A sequencer controller for nuclear magnetic resonance imaging includes a level-sensitive external gating arrangement. When a sequencer microcode WAIT instruction is executed, the gating arrangement operates differently depending on the level of the signal existing at the external gating input. If the external gating signal level is at one level, the gating arrangement causes the sequencer to wait until the external gating input changes level--thus permitting an external gating event (e.g., closure of a breath switch or the like) to interact with and control the timing of the NMR sequence. If the external gating signal is at a different level when the WAIT instruction is first executed, however, the sequencer does not "wait" at all but instead ignores the WAIT instruction and goes to the next sequencer state.

Abstract: In a multi-slice magnetic resonance imaging system which employs a train of plural RF NMR nutation pulses, the frequency spectrum and/or magnetic gradient employed for succesive pulses is controlled so as to effect more nearly equal full-width-half-magnitude (FWHM) or other spatial dimensions of actual nuclei nutation variation versus distance curves for all of the slice selective nutation pulses. The result is a reduction of any "gap" of non-imaged volume disposed between the succession of selected MRI slice volumes.

Abstract: An assembler/linker process utilizes predetermined control program segments ("templates" defining a sub-sequence of magnetic resonance imaging (MRI) states) together with predetermined program-change tables of MRI parameter values. At least some of the program segments are referenced by predetermined symbolic addresses and include pointer-references to corresponding ones of the table entries. The assembler/linker process machine replicates a predetermined set of such slice/specific program segments in a predetermined order while also simultaneously indexing corresponding symbolic addresses and referenced table entries in a predetermined sequence so as to maintain proper correspondence between slice-specific main programs and subroutines for each replicated program segment.

Abstract: An imaging NMR scanner generates multi-dimensional NMR spin echo responses from selected sub-volumes of an object. 90.degree. and 180.degree. r.f. nutation pulses are used together with a variable amplitude gradient between these nutation pulses to phase encode a second dimension in the spin echo response which is already phase-encoded in a first dimension by use of a magnetic gradient during signal readout. Two-dimensional Fourier transforms or multiple angle projection reconstruction processes are then used to generate an array of pixel value data signals representing a visual image of the point-by-point spatial distribution of nutated nuclei within the object. Image artifacts potentially caused by relatively moving elements of the object are avoided by selecting the spin echo generating sub-volumes to avoid the moving elements. High resolution images of sub-volumes of interest can be obtained by selection of a sub-volume of interest in conjunction with these reconstruction techniques.

Abstract: An imaging NMR scanner obtains plural spin echo signals during each of successive measurement cycles permitting determination of the T2 parameter for each display pixel after but a single measurement sequence. The amplitude of the NMR spin echo responses is dependent on an "a" machine parameter (the elapsed time between initiation of a given measurement cycle and the occurrence of the NMR response) and upon a "b" machine parameter (the elapsed time between initiation of successive measurement cycles). These a and b machine time parameters are selectively controlled to enhance resultant image contrast between different types of tissue or other internal structures of an object under examination. Special phase control circuits ensure the repeatability of relative phasing between successive NMR responses from the same measured volume and/or of reference RF signals utilized to frequency translate and synchronously demodulate the NMR responses in the successive measurement cycles of a complete measurement sequence.

Abstract: An imaging NMR scanner obtains plural spin echo signals during each of successive measurement cycles permitting determination of the T2 parameter for each display pixel after but a single measurement sequence. The amplitude of the NMR spin echo responses is dependent on an "a" machine parameter (the elapsed time between initiation of a given measurement cycle and the occurrence of the NMR response) and upon a "b" machine parameter (the elapsed time between initiation of successive measurement cycles). These a and b machine time parameters are selectively controlled to enhance resultant image contrast between different types of tissue or other internal structures of an object under examination. Special phase control circuits ensure the repeatability of relative phasing between successive NMR responses from the same measured volume and/or of reference RF signals utilized to frequency translate and synchronously demodulate the NMR responses in the successive measurement cycles of a complete measurement sequence.