Abstract: Systems and methods for image segmentation using a deformable atlas are provided. One method includes obtaining one or more target images, obtaining one or more propagated label probabilities for the one or more target images, and segmenting the one or more target images using a cost function of a deformable atlas model. The method further includes identifying segmented structures within the one or more target images based on the segmented one or more target images.

Abstract: Systems and methods for image segmentation using a deformable atlas are provided. One method includes obtaining one or more target images, obtaining one or more propagated label probabilities for the one or more target images, and segmenting the one or more target images using a cost function of a deformable atlas model. The method further includes identifying segmented structures within the one or more target images based on the segmented one or more target images.

Abstract: The present invention comprises a whole body RF coil system for use with an open magnetic resonance (MR) imaging system. The RF coil system comprises first and second quadrature RF coil sets positioned on opposing sides of an imaging volume. Each RF coil set comprises similarly-structured, multiple RF coils. Each quadrature RF coil comprises a first and second plurality of primary path conductor segments, and first and second return path conductors, symmetrically disposed about a centerline at specified distances. The first and second plurality of primary path conductor segments are positioned in a first plane that is substantially spaced apart from a second plane, further from the imaging volume, containing the first and second return path conductors. The conductors within each of the first and second set of primary path conductor segments are adapted to have a predetermined current amplitude ratio.

Abstract: Magnetic field gradient coils, such as those typically employed in magnetic resonance (MR) imaging employ folded loop current paths in which a first section carries current along a path close to an imaging volume. This produces a magnetic field gradient within the imaging volume. A second section, being a further radial distance from the imaging volume, carries current in a return path, in a substantially opposite current direction as the first section, thereby reducing stray magnetic fields outside of the second section. The second preferable has the same current pattern, but is slightly larger to contain magnetic fields at the fringes. A third section connects each turn of the coils in the first section to a corresponding turn of coils in the second section. This third section is disposed in a partially radial direction to connect the first and second sections.

Abstract: A tracking system in which radiofrequency signals emitted by an invasive device such as a catheter, are detected and used to measure the position and orientation of the invasive device. The invasive device has a transmit coil attached near its end and is driven by a low power RF source to produce a dipole electromagnetic field that can be detected by an array of receive coils distributed around a region of interest. The position and orientation of the device as determined by the tracking system are superimposed upon independently acquired Medical Diagnostic images, thereby minimizing the radiographic exposure times. One or more invasive devices can be simultaneously tracked.

Abstract: A magnetic resonance (MR) imaging system for use in a medical procedure employs an open main magnet allowing access to a portion of a patient within an imaging volume, for producing a main magnetic field over the imaging volume; a set of open gradient coils which provide magnetic fields gradients over the imaging volume without restricting access to the imaging volume; a radiofrequency coil set for transmitting RF energy into the imaging volume to nutate nuclear spins within the imaging volume and receive an MR response signal from the nuclear spins; and a pointing device for indicating the position and orientation of a plane in which an image is to be acquired; an image control means for operating power supplies for the gradient coils and the RF coils to acquire an MR signal from the desired imaging plane; and a computation unit for constructing an image of the desired imaging plane.

Abstract: A tracking system in which radiofrequency signals emitted by an invasive device such as a catheter are detected and used to measure the position and orientation of the invasive device within a subject. Detection of the radiofrequency signals is accomplished with coils having sensitivity profiles which vary approximately linearly with position. The invasive device has a transmit coil attached near its end and is driven by a low power RF source to produce a dipole electromagnetic field that can be detected by an array of receive coils distributed around a region of interest of the subject. The position and orientation of the device as determined by the tracking system are superimposed upon independently acquired Medical Diagnostic images, thereby minimizing the diagnostic exposure times. One or more invasive devices can be simultaneously tracked.

Abstract: An antenna for NMR imaging of the eye of a patient includes a small circular or oval surface coil which is locatable immediately adjacent to the eye of the patient and supported by a member having a shape contoured to fit in the region between the zygomatic and supra-orbital arches of the face. The supporting member may be a disc supporting a whole-eye surface coil anterior of the eye, or may be a contact-lens-like member supporting a fine wire surface coil substantially in contact with the anterior orbital aspect.

Abstract: Apparatus for detecting movement of an anatomical sample undergoing NMR imaging uses at least one optical sensor, each having an output responsive to the intensity of received illumination and each directed to view a selected portion of sample; and apparatus for monitoring the output of each sensor to detect a change therein responsive to movement of the sample.

Abstract: A magnetic resonance system for both imaging and spectroscopy of a sample of non-magnetic material (such as a portion of the human anatomy and the like) at one static magnetic field magnitude in excess of 0.7 Tesla (T), utilizes a superconducting magnet having a room-temperature bore of diameter sufficiently large to place therein not only the desired sample but also a set of gradient magnetic field-producing coils and at least one radio-frequency coil for exciting and/or receiving response signals from the sample to be examined. The entire magnetic system has suitably-small temporal and positional field variations to allow imaging to be accomplished at the resonant frequencies of nuclei including .sup.1 H, .sup.13 C, .sup.19 F, .sup.23 Na and .sup.31 P. The system includes a novel interface subsystem, itself including a novel gradient signal switching circuit, for acquiring imaging data in relatively short time intervals.

Abstract: In one embodiment, referred to as the "high-pass" version, the radio frequency (RF) coil is made up of two conductive loop elements, each including serially-connected capacitors. The loop elements are electrically interconnected by axial conductive segments having inherent inductances associated therewith. Electrically, the coil can be viewed as a slow wave delay line structure wrapped around a cylinder and connected to itself. The coil can be energized by connecting a source of RF power across one of the capacitors in the loop elements. In another embodiment, termed the "band-pass" version, the axial conductive segments, as well as the conductive loop elements, are provided with capacitors.

Abstract: In the production of nuclear magnetic resonance images, it is necessary to provide various magnetic fields with specified orientations and configurations in particular relationships with respect to a cylindrical coil form on which the RF and gradient coils are generally disposed. In particular, it is necessary to produce so-called transverse gradient fields which are oriented transversely with respect to the cylindrical form. It is necessary to produce a component parallel to the axis of the cylinder, but which component varies linearly in intensity in the direction transverse to the axis. That is to say, it is desirable to produce a magnetic field component within the cylinder such that surfaces on which this component is constant are parallel and are generally oriented parallel to the axis of the cylinder. Furthermore, for the purpose of providing proper spatial definition and resolution, it is necessary that this transverse field exhibit a highly linear variation in intensity inside the cylinder.

Abstract: A radio-frequency coil, for nuclear magnetic resonance imaging at Larmor frequencies associated with a magnetic field of greater than about 0.5 Tesla, comprises a slotted-tube radio-frequency resonator having an elliptical cross-section. First and second complementary outer resonator portions have central bands connecting juxtaposed wing structures; the end of each of the four wings is spaced from a complementary wing portion of the other outer portion and capacitively coupled thereto. An inner structure has a pair of elliptical guard rings placed substantially in registration with the elliptical portions of the outer structure wing portions. The eccentricity ratio of the elliptical cross-section of the resonator and the resonator dimensions are arranged to provide an interior volume into which a human head or body extremity can be placed for imaging purposes.

Abstract: A cylindrical coil for providing a magnetic field having a substantially linear gradient in an axial direction within the volume of the cylinder, as can be utilized in NMR apparatus, includes a cylindrical coil support structure and electrically conductive winding turns wound on the outer surface of the support structure. The winding turns are electrically insulated from each other and are located such that the axial density of the winding turns increases linearly from the center of the coil to each axial end thereof. Preferably, the winding turns are located so that the angular position .phi. of the spiral path of the windings on the surface of the cylindrical support structure satisfies the relationship determined by the equation ##EQU1## The coil may also include additional electrically conductive winding turns for compensating for variations in the linearity of the magnetic field gradient which are due to the coil being of finite length.

Abstract: A field effect transistor including conventional source and drain electrodes employs, in the gate region, a layer of antibody specific to a particular antigen. An electrolyte solution such as 0.155 Normal sodium chloride atop the antibody layer provides a predetermined drain current versus drain voltage characteristic for the device. Replacement of the electrolyte solution with another electrolyte solution containing the antigen alters the charge of the protein surface layer due to the antigen-antibody reaction, thus affecting charge concentration in a semiconductor inversion layer in the transistor. The time rate of change of drain current thus provides a measure of the antigenic protein concentration in the replacement solution.