Abstract: Devices and methods are provided for shutting down a magnet system. The device includes a portable housing, a communication unit, and a switch on the portable housing. The portable housing encloses a field shutdown initiation circuitry. The communication unit is disposed at least partially in the portable housing and the communication unit is configured to establish communication between the field shutdown initiation circuitry and the magnet system. The switch is configured to turn on the field shutdown initiation circuitry to initiate a magnet field shutdown in the magnet system.

Abstract: Devices and methods are provided for shutting down a magnet system. The device includes a portable housing, a communication unit, and a switch on the portable housing. The portable housing encloses a field shutdown initiation circuitry. The communication unit is disposed at least partially in the portable housing and the communication unit is configured to establish communication between the field shutdown initiation circuitry and the magnet system. The switch is configured to turn on the field shutdown initiation circuitry to initiate a magnet field shutdown in the magnet system.

Abstract: A method and system of obtaining information by interrogating an information mark attached to a device implanted in a body of a patient by transmitting a non-ionizing pulse through the body of the patient, receiving, from the information mark, a response to the transmitted non-ionizing pulse, the response including encoded information, and extracting the encoded information from the response.

Abstract: A magnetic resonance imaging (MRI) system magnet includes at least one main electromagnet winding disposed within a first radius of the magnet and at least one bucking electromagnet winding disposed within a second radius, larger than the first radius of the magnet and configured to provide self-shielding magnetic fields that substantially reduce fringe magnetic fields outside the magnet produced by the main electromagnet winding. The combination of magnetic fields produced by both the main and bucking electromagnet windings inside the magnet conform to MRI requirements within at least an imaging volume. The main and bucking electro-magnet windings are configured so as to create a net fringe field outside the magnet within the range of 50-100 gauss at a distance within a range of 3-5 meters axially and 2-3 meters radially from a center of the magnet.

Abstract: A magnetic resonance imaging (MRI) system magnet includes at least one main electromagnet winding disposed within a first radius of the magnet and at least one bucking electromagnet winding disposed within a second radius, larger than the first radius of the magnet and configured to provide self-shielding magnetic fields that substantially reduce fringe magnetic fields outside the magnet produced by the main electromagnet winding. The combination of magnetic fields produced by both the main and bucking electromagnet windings inside the magnet conform to MRI requirements within at least an imaging volume. The main and bucking electro-magnet windings are configured so as to create a net fringe field outside the magnet within the range of 50-100 gauss at a distance within a range of 3-5 meters axially and 2-3 meters radially from a center of the magnet.

Abstract: A bi-directional communications link between an active implanted medical device (AIMD) and a magnetic resonance imaging (MRI) machine enables information to be exchanged to determine whether an operational mode of the AIMD and MRI is acceptable. For example, the bi-directional communications link enables information to be exchanged to determine whether the AIMD and MRI machine are acceptably operating within at least one operational limit. An operation of the MRI machine may be permitted if the operation is acceptably within the operational limit and may be stopped if not.

Abstract: A communications link between an active implanted medical device (AIMD) and a magnetic resonance imaging (MRI) machine enables an information exchange including data relating to a configuration of a lead of the AIMD as installed in the patient and/or an operational parameter limit of the MRI machine determined from the data. The data relating to the configuration of the lead in the patient may include a size and/or position of an effective loop area enclosed by the lead. The data relating to the configuration of the lead in the patient may include data corresponding to a pictorial representation, such as an x-ray of the patient having the AIMD, of the lead and at least part of the patient's body. An operation of the MRI machine may be stopped or a warning/alarm initiated if the operational parameter limit (e.g., maximum power limit of a gradient or RF field) determined from the data relating to the configuration of the lead in the patient is exceeded.

Abstract: Described herein is a medical imaging technique that includes directing ultrasound waves into a portion of a body of interest during at least a portion of a time period during which an MR imaging process is simultaneously performed on the portion of the body of interest such that the MR signal is altered by the application of the ultrasound waves. The ultrasound waves may be applied continually during the MR imaging process, or only during a portion thereof. The frequency of the ultrasound waves may be substantially the same as, or different than that of the MR signals. Images may be produced from only the MR imaging process or both the MR imaging process and the application of ultrasound waves prior to the imaging sessions.

Abstract: Described herein is a process for patient localization within a medical imaging system, having a first and second signal means for identifying patient position. The patient is manually positioned on a patient table at an initial position outside the system. A first signal means is manually positioned adjacent an area of interest on the patient in the initial position and the first signal means communicates that initial patient position to a detection means. The second signal means communicates a desired final patient position location to the detection means. The detection means either essentially continuously monitors and compares said initial and subsequent positions to the final position, or calculates the distance between the initial position and the final position and causes the patient to move from the initial position to the final position when the positions are not essentially the same.

Abstract: Described herein is a radiofrequency receive coil system for a magnetic resonance imaging (MRI) system that includes an array of a plurality of individual coils arrayed around the outer limits of the imaging volume that is defined by a main magnet and a gradient coil, positioned tangentially down the length of said volume, with the plurality of individual coils each having an initial position with relation to the patient to be imaged; and mechanical support for the individual coils. The individual coils may be dynamically repositioned for optimal imaging. A further embodiment of the system includes an array of individual coils positioned radially on the vertical plane around the patient table, which may advance into the gantry before imaging. The method for use of the receive coil system is also described.

Abstract: Described herein is a radiofrequency receive coil system for a magnetic resonance imaging (MRI) system that includes an array of a plurality of individual coils arrayed around the outer limits of the imaging volume that is defined by a main magnet and a gradient coil, positioned tangentially down the length of said volume, with the plurality of individual coils each having an initial position with relation to the patient to be imaged; and mechanical support for the individual coils. The individual coils may be dynamically repositioned for optimal imaging. A further embodiment of the system includes an array of individual coils positioned radially on the vertical plane around the patient table, which may advance into the gantry before imaging. The method for use of the receive coil system is also described.

Abstract: Described herein is a medical imaging technique that includes directing ultrasound waves into a portion of a body of interest during at least a portion of a time period during which an MR imaging process is simultaneously performed on the portion of the body of interest such that the MR signal is altered by the application of the ultrasound waves. The ultrasound waves may be applied continually during the MR imaging process, or only during a portion thereof. The frequency of the ultrasound waves may be substantially the same as, or different than that of the MR signals. Images may be produced from only the MR imaging process or both the MR imaging process and the application of ultrasound waves prior to the imaging sessions.

Abstract: Described herein is a method for the automatic selection of elements within at least one radiofrequency coil used for imaging at least one slice of a volume using a magnetic resonance imaging system which includes performing a one-dimensional projection for at least one angle for each element of an initial selection of multiple elements; and using the at least one projection in selecting and/or deselecting at least one element from the group of multiple elements for imaging of the volume. Noise scans can also be utilized to set the receiver channel gain for imaging as part of the method. The elements can also be ranked, commonly using the element's signal to noise ratio, with selection and/or deselection based on the ranking.

Abstract: Described herein is a magnet system for use in imaging a volume that includes a main magnet and at least one magnet coil assembly positioned between the main magnet and the imaging volume. A gradient coil assembly including an inner primary gradient coil alone or with the addition of an outer secondary gradient coil may also exist between the main magnet and imaging volume. The magnet coil assembly may then be positioned between the inner primary gradient coil and the imaging volume, between the inner primary gradient coil and outer secondary gradient coil, or in both positions. Also described herein is an MRI system incorporating the magnet system with additional magnet coil assemblies, and the process for improving the homogeneity of a magnet system using the additional magnet coil assemblies.

Abstract: A target treatment apparatus for treating a target region (130) within a subject (140) is provided. The apparatus includes an MRI apparatus (100) for generating MR images during an MR scan of the subject disposed within an examination region (110). The apparatus further includes an MRI localizer (150) for receiving the image data from the MRI apparatus wherein the target (130) is localized and a reference marker localizer (160, 160?) for non-invasively receiving reference data from a plurality of reference points disposed in proximity to the target wherein the reference points are localized. A tracking processor (300) is also included in the apparatus for receiving localized data from the MRI localizer wherein a relationship between the reference markers and the target region is generated.

Abstract: Described herein is a process for patient localization within a medical imaging system, having a first and second signal means for identifying patient position. The patient is manually positioned on a patient table at an initial position outside the system. A first signal means is manually positioned adjacent an area of interest on the patient in the initial position and the first signal means communicates that initial patient position to a detection means. The second signal means communicates a desired final patient position location to the detection means. The detection means either essentially continuously monitors and compares said initial and subsequent positions to the final position, or calculates the distance between the initial position and the final position and causes the patient to move from the initial position to the final position when the positions are not essentially the same.

Abstract: An open MRI or other diagnostic imaging system (A) generates a three-dimensional diagnostic image representation, which is stored in an MRI image memory (26). A laser scanner or other surface imaging system (B) generates a volumetric surface image representation that is stored in a surface image memory (34). Typically, the volume and surface images are misaligned and the magnetic resonance image may have predictable distortions. An image correlating system (C) determines offset, scaling, rotational, and non-linear corrections to the magnetic resonance image representation, which are implemented by an image correction processor (48). The corrected magnetic resonance image representation and the surface image representation are combined (50) and stored in a superimposed image memory (52). A video processor (54) generates image representations from selected portions of the superimposed image representation for display on a human-readable monitor (56).

Abstract: A three-dimensional fast spin echo (FSE) scan is performed by stepping (220) through a plurality of phase encode k-space views from a computed view list (210). The view list is computed such that (i) magnetic resonance echoes having a selected image contrast are encoded in the center of k-space, (ii) adjacent data lines in k-space have similar contrast, and (iii) common planes of data lines in k-space are completed at regular intervals. As each data line is read, it is Fourier transformed (230) and stored (240) within a fast-access memory (52). Once a plane of data lines is acquired, it is Fourier transformed (250) along a second direction using a plurality of parallel processors (54). The twice-transformed data is stored (260) in conventional memory (56). Once all of the phase encode views on the view list are acquired, a final Fourier transform (60) along a third direction is performed (270), rendering a volumetric image representation.

Abstract: The present invention is directed to an MRI apparatus. It includes a main magnet 12 that generates a substantially uniform temporally constant main magnetic field, B0, through an examination region 14 wherein an object being imaged is positioned. A magnetic gradient generator produces magnetic gradients in the main magnetic field across the examination region 14. A transmission system includes an RF transmitter 24 that drives an RF coil 26 which is proximate to the examination region 14. A sequence control 40 manipulates the magnetic gradient generator and the transmission system to produce an MRI pulse sequence, such as an FSE pulse sequence. The MRI pulse sequence induces magnetic resonance echos 66 from the object. A reception system includes a receiver 30 that receives and demodulates the echos 66 at varying sample rates and varying bandwidths.

Abstract: A method for shimming main magnetic field in a magnetic resonance imaging apparatus is provided. The method includes generating a radio frequency pulse sequence (200) while a subject is in an examination region (14) of the magnetic resonance imaging apparatus. A reference signal (EC1) which is immune to shim errors is then acquired. Thereafter, a field echo (EC3a) signal is acquired which is sensitive to shim errors. The field echo (EC3a) signal is acquired at a timed interval (T) equal to a multiple of an amount of time it takes for fat and water signals to become in phase. The temporal position of the maximum of the field echo signal is compared to its predicted temporal position (EC3) relative to the reference signal (EC1). The shim term is calculated based on the preceding comparison and an electrical current is applied to one of a gradient offset and a shim coil such that the main magnetic field is adjusted according to the shim term.