By using a multiple receiving coil composed of receiving coils, an imaging portion of a subject is subjected to a first pulse sequence to create n sensitivity images (701 to 703) fewer than the examination images. When these sensitivity images are created, an NMR signal is measured for only the low-frequency region of the k space. A second pulse sequence from which a phase encode step is removed is conducted to create m (m>n) examination images (704, 705) of the subject by using the receiving coils. When sensitivity distributions (707, 708) of the receiving coils are determined for the sensitivity images (701 to 703), and if there are no sensitivity distributions corresponding to the slice positions of the examination images (704, 705), they are determined by slice interpolation using the sensitivity distributions (701 to 703), and the aliasing artifacts of the examination images (704, 705) are removed by matrix operation by using the sensitivity distributions (707, 708).

Magnetic resonance imaging device

Magnetic resonance imaging apparatus

Magnetic resonance information acquired by a movable magnetic resonance instrument is used to monitor hyperthermia treatments such as tissue ablation. The instrument may include both the magnetic resonance equipment and an energy applicator such as a high intensity focused ultrasound unit. The treatment can be conducted under automatic control after the operator marks a treatment volume on an image of the subject, such as a magnetic resonance image acquired using the movable magnetic resonance instrument. The automatic treatment can be based on interpolation of tissue response curves at plural test points near the treatment volume. The system can also provide automatic supervisory control during manual operation, to prevent application of heat to sensitive anatomical structures.

MRI-guided therapeutic unit and methods

Methods and apparatuses for displaying and using a shaped field of a repositionable magnet to move, guide, and/or steer a magnetic seed or catheter in living tissue for medicinal purposes. A moveable magnet assembly and a portion of a patient's body undergoing magnetically-aided surgery are both provided with fiducial markers. The portion of the patient's body is fixed in a location in which the fiducial markers are sensed and located by a set of localizers. The positions of the fiducial markers are determined by a processor, which operates on a stored representation of the magnetic field of a magnet in the magnet assembly to provide a display of the present magnetic field of the magnet. This display may be superimposed over an MRI, X-ray or CAT image during surgery. The repositionable magnet can be an electromagnet. In some embodiments, a computer calculates orientations and currents for an external electromagnet to move the implanted magnetic object in the patient's body through a desired path. The display can provide real-time imaging of the implanted magnetic object in comparison to the desired path as the object is moved.

Method and apparatus using shaped field of repositionable magnet to guide implant

A method and apparatus for effectuating transmission, reception, and processing of source program signals representative of a multimedia program between a remote multimedia server and a plurality of local set-top control systems are disclosed. The multimedia server processes stored digitally compressed multimedia programs preferably by parsing a selected multimedia program into a customized series of discrete program segments, and transmitting the compressed program segments to a local set-top control system, which buffers and decompresses the compressed program segments for presentation on a local display monitor. A local set-top control system preferably includes a direct access storage device adapted to buffer a predetermined number of compressed program segments received from a multimedia server, some of which may be non-sequentially ordered and others of which may be sequentially ordered. A novel formatting methodology provides for the sequential presentation of the program segments asynchronously distributed on one or more data storage disks disposed in the direct access storage device. A user-definable presentation control window for performing local VCR-type presentation control functions for the portion of a multimedia program buffered in the direct access storage device is also provided through the novel formatting methodology. The novel formatting methodology also provides concurrent presentation and buffering of program segments received from the multimedia server for on-demand viewing of a selected multimedia program.

Media-on-demand communication system and method employing direct access storage device

A magnetic resonance imaging (MRI) device for imaging a volume is provided with at least one main magnet for generating a magnetic field, and at least one gradient coil for manipulating the magnetic field generated by the at least one main magnet to image the volume. The magnetic fields generated by the at least one gradient coil are substantially unshielded.

Conduction cooled passively-shielded MRI magnet

An open magnet having two magnet assemblies arranged in a spaced-apart, parallel relationship to define a working space therebetween is provided for magnetic resonance imaging. Each assembly has an annular superconductive coil and a ferromagnetic field enhancer encircled by the superconductive coil. The field enhancers are substantially cylindrical ferromagnetic pole pieces which are encircled by a respective one of the superconductive coils. The magnet assemblies are attached to a C-shaped support frame which is rotatively mounted to a pedestal member. The frame can thus be rotated between vertical and horizontal imaging positions. The field enhancers are shaped so as to maximize homogeneity in the imaging volume while keeping their weight and volume to a minimum. The specific shape of the field enhancers is determined with a nonlinear optimization design method.

Open (non-enclosed) magnets for magnetic resonance imaging

A magnetic resonance imaging (MRI) magnet having an annularly cylindrical-shaped vacuum enclosure with a longitudinal axis, first and second longitudinal ends, a first larger diameter bore extending from the first towards the second longitudinal end, and a second smaller diameter bore extending from the second longitudinal end to the first bore. First and second superconductive coils are placed in the vacuum enclosure with the first coil generally circumferentially surrounding the first bore and the second coil circumferentially surrounding the second bore, wherein the radial distance of the radially innermost portion of the second coil from the axis is smaller than the radius of the first bore. The second longitudinal end of the vacuum enclosure fits on a patient's shoulders with the patient's head passing through the second bore and extending into the first bore for MRI brain imaging.

On-shoulder MRI magnet for human brain imaging

A shielded and open magnetic resonance imaging (MRI) magnet having two spaced-apart, generally toroidal-shaped superconductive coil assemblies. Each coil assembly has a coil housing containing a generally annular-shaped superconductive main and a radially-outwardly spaced-apart shielding coil carrying electric currents in opposing directions. Preferably, supplemental shielding is provided with the addition of: a generally annular permanent magnet configuration internal to, or external of, the coil housings; a generally-non-permanently-magnetized external ferromagnetic shield having at least a portion positioned longitudinally between the coil housings, an external resistive coil; or combinations thereof.

Shielded and open MRI magnet

A planar magnetic resonance imaging (MRI) magnet having a superconductive coil assembly including a toroidal-shaped coil housing which surrounds a bore, has a longitudinal axis, and contains at least three concentric, annular-shaped superconductive coils coaxially aligned with the axis. The coils produce a magnetic resonance imaging volume having a center located outside the bore. Preferably, the bore is generally completely filled with magnetic material, and the magnetic resonance imaging volume is located completely outside the bore which provides for improved patient and physician access during MRI-guided biopsy as well as during MRI imaging.

Michele Dollar Ogle

Papers

Conduction cooled passively-shielded MRI magnet

Open (non-enclosed) magnets for magnetic resonance imaging

On-shoulder MRI magnet for human brain imaging

Shielded and open MRI magnet

Planar superconducting MRI magnet