Patents by Inventor James W. Kristoff

James W. Kristoff has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5757189
    Abstract: A multimode radio frequency coil (50.sub.1) receives resonance signals from a region of interest while allowing arbitrary placement of the coil. A peripheral electrical conductor (62) is divided into four symmetric segments by capacitors (76), (78), (80), (82). A pair of crossing conductors (64, 66) are connected between 90.degree. offset diagonally opposite portions of the peripheral loop (62). The crossing conductors include capacitors (68, 70) when not connected and include capacitors (68, 70, 86, 88) when connected at their midpoints. With this configuration, the coil supports orthogonal modes (72, 74) within the plane of the coil and, additionally, a third orthogonal mode (84) perpendicular to the plane of the coil. To image an extended region, a plurality of coils are overlapped to minimize mutual inductance relative to a first mode. An adjustable capacitor (90) across one of the coils adjusts mutual inductance relative to the second mode.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: May 26, 1998
    Assignee: Picker International, Inc.
    Inventors: David A. Molyneaux, William O. Braum, James W. Kristoff
  • Patent number: 5594339
    Abstract: A resonance exciting coil (C) disposed in an image region in which a main magnetic field and transverse gradients have been produced. A flexible receiving coil (D) includes a flexible plastic sheet (40) on which an electrically continuous flexible foil strip (36) is adhered to receive signals from the resonating nuclei. The coil also includes components (24), mounted on the flexible plastic sheet (40), which may amplify the received signals before they are transmitted along a cable (22). A first soft material layer (44) is mounted on the flexible plastic sheet (40) for providing comfort to the patient. A flexible mechanical structure (50) on which two flexible receiving coils (F, G) adjusts an overlap between the coils (F, G) as the coils are flexed to adjust interaction properties of the coils (FIGS. 4 A, 4B).
    Type: Grant
    Filed: July 11, 1995
    Date of Patent: January 14, 1997
    Assignee: Picker International, Inc.
    Inventors: Robert G. Henderson, James W. Kristoff, David A. Molyneaux