John C Hoenninger

US Patent:

57396914, Apr 14, 1998

Filed:

Nov 28, 1995

Appl. No.:

8/563239

Inventors:

John C. Hoenninger - Oakland CA

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

G01V 300

US Classification:

324322

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.

US Patent:

54653614, Nov 7, 1995

Filed:

Dec 13, 1993

Appl. No.:

8/165534

Inventors:

John C. Hoenninger - Oakland CA

Assignee:

The Regents of the University of California - Berkeley CA

International Classification:

G06F 930

US Classification:

395700

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. The Fast Linker provided by the present invention is capable of continually loading microcode into a sequencer writable control store, and is fast enough to run under a time shared operating system at the same time a higher priority data acquisition and display process is executing.

US Patent:

54366003, Jul 25, 1995

Filed:

Jul 29, 1994

Appl. No.:

8/283050

Inventors:

John Van Heteren - San Francisco CA
Mitsuaki Arakawa - Hillsborough CA
Lawrence E. Crooks - Richmond CA
John C. Hoenninger - Oakland CA
Thomas McDermott - Redwood City CA
Keiji Furui - Otawara, JP

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H03B 2800
H03C 152
H03C 160
G01R 3324

US Classification:

332167

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.

US Patent:

56062583, Feb 25, 1997

Filed:

Mar 17, 1993

Appl. No.:

8/032647

Inventors:

John C. Hoenninger - Oakland CA
Lawrence E. Crooks - Richmond CA

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

G01V 300

US Classification:

324309

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. The control interface provides, among other features, generalized loops at the link level; loop symbols representing loop identity can be associated with scope and/or range (with some kind of limited grammar in the link command itself that supports identification of scope and/or range); parameter tables that can be associated with loop symbols (any given table can be associated with N loop symbols in order to provide multidimensional sequences); multiple levels of loop nesting; and directed limited syntax that provides limited grammar, and range and syntax checking and requires the user to explicitly enter information into the interface.

US Patent:

43180434, Mar 2, 1982

Filed:

Feb 12, 1980

Appl. No.:

6/120875

Inventors:

Lawrence E. Crooks - Richmond CA
John C. Hoenninger - Berkeley CA
Mitsuaki Arakawa - San Mateo CA

Assignee:

The Regents of the University of California - Berkeley CA

International Classification:

G01N 2700

US Classification:

324309

Abstract:

Densities of resonant nuclei within elemental volumes along a line are measured using the nuclear magnetic resonance phenomenon called "spin echo". A first planar volume of nuclei is selectively excited to nutate spins by approximately 90. degree. Thereafter a second planar volume of nuclei, transverse to the first planar volume, is selectively excited to nutate spins by approximately 180. degree. The nuclei in the line volume common to both of the planar volumes thereafter generate characteristic spin echo signals. A magnetic gradient is established along this line volume during the spin echo read out so that the resultant spin echo signals can be processed to determine the respective densities of resonant nuclei along the line volume. Appropriate phasing of the excitations enables interference with the spin echo signals by the free induction decay to be eliminated. To enable rapid development, successive line volumes are read out which do not lie in previously excited planes.

US Patent:

45995656, Jul 8, 1986

Filed:

Jul 19, 1983

Appl. No.:

6/515117

Inventors:

John C. Hoenninger - Oakland CA
Lawrence E. Crooks - Richmond CA
Mitsuaki Arakawa - San Mateo CA
Jerome R. Singer - Berkeley CA

Assignee:

The Regents of the University of Calif. - Berkeley CA

International Classification:

G01N 2700

US Classification:

324309

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. Solutions for possible aliasing artifacts are also presented as are three-dimensional reconstruction techniques using NMR spin echo responses from such selected sub-volumes.

US Patent:

47076615, Nov 17, 1987

Filed:

Jul 29, 1986

Appl. No.:

6/890364

Inventors:

John C. Hoenninger - Oakland CA
Lawrence E. Crooks - Richmond CA

Assignee:

The Regents of the University of California - Berkeley CA

International Classification:

G01R 3320

US Classification:

324309

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. In addition, certain of the replicated program segments may be defined having predetermined symbolic addresses which are not indexed thus further conserving the number of program instructions which need to be replicated and stored in the assembly/linkage process. A subset of slice-specific program segments can be further designated for replication as a unit before following program segments are utilized.

US Patent:

54817447, Jan 2, 1996

Filed:

Nov 5, 1993

Appl. No.:

8/147552

Inventors:

John C. Hoenninger - Oakland CA

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

G06F 900

US Classification:

395800

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. Such level sensitive external gating permits microcode sequences including WAIT instructions to be executed when external gating is desired and also when external gating is not desired, thus reducing the amount of code that needs to be maintained.