Abstract: An MR system features an intracavity probe and associated interface device. The probe includes a shaft, a balloon at one end thereof, and a coil loop within the balloon. The loop has two drive capacitors and a tuning capacitor, all of which in series. A junction node between the drive capacitors serves as a ground for electrically balancing the loop. Diametrically opposite the node, the tuning capacitor enables the loop to resonate at the operating frequency of the MR system. The interface allows the MR system to couple the loop to a port of the MR system during a receive cycle thereof and decouple it from the port during a transmit cycle thereof. With its balloon inserted and inflated within a cavity of a patient, the probe allows the MR system to generate images and/or spectra of the region of interest using the MR signals received by the loop.

Abstract: A tracking device (20, 20?) for tracking a tip (14) of an interventional instrument such as a catheter (10) during an interventional procedure performed on an associated subject (12) and monitored by magnetic resonance imaging includes a resonant circuit (22) disposed at the tip (14) of the catheter (10). The resonant circuit (22) includes a coil (32, 32?) having a coil inductance and a light-sensitive metal-insulator-semiconductor capacitor (30) optically coupled with an optical fiber (36) and having a selected capacitance determined by an intensity of light delivered by the optical fiber (36). A selected resonance frequency of the resonant circuit (22) is determined by the coil inductance and the selected capacitance. The resonance frequency is adjusted by modulating the intensity of light delivered to the light-sensitive metal-insulator-semiconductor capacitor (30).

Abstract: The present invention is directed to an MRI enhancing device deployable in a body. In one embodiment, the MRI enhancing device is formed of a wire loop and a capacitor that is at least partially formed by the wire used in forming the wire loop.

Abstract: A deflectable tip catheter that is safe and effective for use in a magnetic resonance imaging environment. The deflectable tip catheter is configured such that it includes a built-in antenna, such as a loopless antenna or a loop antenna. The built-in antenna permits the deflectable tip catheter to be actively tracked and/or visualized. Depending upon the specific configuration of the deflectable tip catheter, the catheter may be tracked and/or visualized as a single unit, it may be tracked and/or visualized separate and independent of other components or instruments associated with the catheter, such as pull wires, injection needles, surgical instruments, and the like. The catheters described herein include injection type catheters and/or guidance type catheters.

Abstract: The present invention realizes a medical device guidance system capable of improving propulsion control characteristic.

Abstract: A system and method of MR imaging is disclosed that includes reconstruction of MR images with uniform or homogeneous fat suppression. An imaging process is performed using partial asymmetric acquisitions in conjunction with zero-filling of k-space for dynamic contrast-enhanced imaging. Data acquisition is carried out in a relatively short period of time which reduces scan time, reduces the likelihood of subject discomfort and motion-induced artifacts, and increases patient throughput.

Abstract: A medical device includes a sensor for sensing for an MRI gradient magnetic field and a microprocessor for responding to the detected gradient magnetic field by switching from a first electrical signal processing mode to a second electrical signal processing mode, such that electrical signals induced by the gradient magnetic field and an associated RF burst are not counted as cardiac events.

Abstract: The invention is directed to techniques in which magnetic resonance imaging (MRI) is coordinated with the operation of an implantable medical device (IMD). By using an IMD to sense conditions, MRI can be improved because the sensed conditions can accurately define timing for application of electromagnetic radiation bursts. Moreover, by applying stimulation pulses specifically to coordinate the electromagnetic radiation bursts, the MRI may also be improved.

Abstract: An endoscope-like image taking method includes providing at least one peculiar index, which can be discriminated from other portions on an MR image, at the tip of a catheter, previously inserting a metal guide wire for guiding the catheter into a body cavity of a patient inserting the catheter into the body cavity along the guide wire, executing an MR imaging sequence of a plurality of sliced images intersecting the guide wire, reconstructing three-dimensional image data based upon the nuclear magnetic resonance signals, which are received by the guide wire, and determining the tip position and the inserting direction of the catheter by detecting the peculiar index provided at the tip of the catheter based upon the three-dimensional image data, and reconstructing the center projected image using the three-dimensional image data and setting the tip position and the inserting direction of the catheter as a view point and a line-of-sight direction and displaying the center projected image on a display means.

Abstract: In a capsule 3 as a medical apparatus inserted into a body cavity, the lengthwise direction of the capsule 3 is used as an insert axis, a manipulation/input device 8, which is magnetized in a direction orthogonal to the insert axis, is disposed at the center position of the insert axis. A magnetic field generation device 4, which is disposed outside of a body, is caused to generate a vibration magnetic field in a direction parallel with the insert axis of the capsule 3 by turning on a vibration (ON/OFF) switch 8f of a manipulation/input device 8 so that couples having lines of action, which are in parallel with the insert axis, are exerted on the capsule 3, thereby the capsule 3 executes a swiveling motion about the insert axis and smoothly travels along a cavity organ.

Abstract: Apparatus for driving current in a power circuit of a medical device inserted into a body of a subject includes a power transmitter, which is adapted to generate, in a vicinity of the body, an electromagnetic field having a predetermined frequency capable of inductively driving the current in the power circuit. A passive energy transfer amplifier, having a resonant response at the frequency of the electromagnetic field is placed in proximity to the medical device so as to enhance the current driven in the power circuit by the electromagnetic field.

Abstract: Systems, methods, and other embodiments associated with remotely controlling a catheter configured with a 3D array of steering coils are described. One example magnetic resonance imaging (MRI) apparatus may include logic to remotely control a catheter. The 3D array of coils may include, for example, one axial coil and two side coils. The MRI apparatus may independently control current provided to members of the 3D array of coils. The MRI apparatus may also selectively produce different pulse sequences to mitigate and/or take advantage of signal voids present in an acquired image due to susceptibility effects from a field(s) generated by a member(s) of the 3D array of coils. Independently controlling the current provided to the 3D array of coils facilitates bending the catheter in a desired position as a result of a magnetic torque associated with a magnetic moment induced in a member of the 3D array of coils.

Abstract: A system and method to perform parallel MR imaging are disclosed. The system comprises an MR imaging machine and a probe having at least two MR RF reception coils. Each coil of the probe is operationally connected to a separate receiver channel of the MR imaging machine. The MR imaging machine implements a partially parallel acquisition method to excite precessing nuclear spins, in and around an internal segment of a patient into which the probe is inserted, and to use the coils of the catheter to simultaneously sample a plurality of response signals to form reduced k-space data sets for each of the coils. The plurality of response signals represent nuclear magnetic resonance signals arising from the precessing nuclear spins. The reduced k-space data sets are further processed by the MR imaging machine to generate a full volume dataset of a region in and around the vessel.

Abstract: A medical apparatus, includes a medical instrument with an acquisition unit for a magnetic resonance signal, the acquisition unit exhibiting a non-constant sensitivity profile in the azimuthal direction relative to an axis of the medical instrument. An azimuthal orientation of the medical apparatus is determined by an evaluation unit from magnetic resonance signals received by the acquisition unit.

Abstract: Systems and methods for the evaluation of the urethra and periurethral tissues may involve an MRI coil adapted for insertion into the male, female or pediatric urethra. The MRI coil may be in electrical communication with an interface circuit made up of a tuning-matching circuit, a decoupling circuit and a balun circuit. The interface circuit may also be in electrical communication with a MRI machine. In certain practices, the present invention provides methods for the diagnosis and treatment of conditions involving the urethra and periurethral tissues, including disorders of the female pelvic floor, conditions of the prostate and anomalies of the pediatric pelvis.

Abstract: A probe suitable for attachment to, or incorporation in, a medical interventional device, such as a catheter, and which may be employed for tracking, imaging, or both, includes a first material having an MR resonance frequency distinct from a resonance frequency of a second material adjacent to the first material. The probe may include one or more coils, or it may be wireless, that is, it may have no coils. Some probe configurations are directed at tracking or imaging of vascular vessels or tissue, and configurations allow both tracking and imaging.

Abstract: Apparatus for performing a medical procedure on a tissue within a body of a subject includes a wireless tag configured to be fixed to the tissue and adapted to emit radiation, thereby causing first signals to be generated indicative of a location of the tag in the body. An invasive medical tool includes a probe, which is adapted to penetrate into the body so as to reach the tissue. A handle is fixed proximally to the probe, for manipulation by an operator of the tool. A display, mounted on the handle, presents a visual indication to the operator of an orientation of the probe relative to the tag. A processing unit processes the first signals so as to determine coordinates of the tag relative to the probe, and drives the display responsive to the coordinates.

Abstract: A device is presented including a medical device adapted to be inserted in an anatomy. The medical device has many target markers. A magnetic resonance imaging (MRI) system will not detect or will disregard the medical device as noise without information obtained on the plurality of target markers prior to insertion of the medical device into the anatomy. Also presented a method including inserting a medical device into an anatomy. The medical device has many target markers. Scanning a magnetic resonance image (MRI) of the anatomy. Processing the scanned image by a MRI processor connected to a memory. Determining a location and orientation of the medical device in relation to the anatomy based on the target markers. And displaying a precise image of the medical device within the anatomy. The medical device is not detectable or disregardable as noise for MRI systems.

Abstract: A system and method for active MR tracking includes a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, an RF coil assembly positioned in the bore, and a pulse module. The MRI system also includes a polarization reversal switch controlled by the pulse module to transmit RF signals to the RF coil assembly coupled to the polarization reversal switch and an RF switch controlled by the pulse module to transmit the RF signals to the polarization reversal switch.

Abstract: The invention describes a system, method, and means for an MRI transseptal needle that can be visible on an MRI, can act as an antenna and receive MRI signals from surrounding subject matter to generate high-resolution images and can enable real-time active needle tracking during MRI guided transseptal puncture procedures.

Abstract: MRI compatible localization and/or guidance systems for facilitating placement of an interventional therapy and/or device in vivo include: (a) a mount adapted for fixation to a patient; (b) a targeting cannula with a lumen configured to attach to the mount so as to be able to controllably translate in at least three dimensions; and (c) an elongate probe configured to snugly slidably advance and retract in the targeting cannula lumen, the elongate probe comprising at least one of a stimulation or recording electrode. In operation, the targeting cannula can be aligned with a first trajectory and positionally adjusted to provide a desired internal access path to a target location with a corresponding trajectory for the elongate probe. Automated systems for determining an MR scan plane associated with a trajectory and for determining mount adjustments are also described.

Abstract: Imaging a device in a magnetic resonance imaging system includes inserting a device having a conductive coil assembly thereon into a subject, obtaining a magnetic resonance image of the subject that includes signal phase variations, determining a position of the device based on discontinuities in the signal phase variations, and displaying an image representation of the device superimposed on a reference image based upon the determined position.

Abstract: An intracavity probe for use with an MR system allows images or spectra of a region of interest within a cavity of a patient to be obtained. The probe includes a shaft, a balloon at one end thereof, and a coil loop within the balloon. The coil loop preferably includes two drive capacitors and a tuning capacitor, all of which in series. A junction node between the drive capacitors serves as a ground for electrically balancing the coil loop. Diametrically opposite the junction node, the tuning capacitor enables the coil loop to resonate at the operating frequency of the MR system. Across each drive capacitor is connected an output cable having an electrical length of SL+n(?/4). The output cables terminate in a plug that is used to connect the coil loop to an interface device for the intracavity probe.

Abstract: The present invention relates to an elongate intravascular device adapted to be advanced through a vessel of a subject. The present invention further includes an antenna which is disposed on an inflatable member such that the antenna can be increased or decreased in size to more accurately tune the system in which it is employed.

Abstract: Medical devices incorporate therein imaging materials having selected MRI detectable nuclei to provide useful magnetic resonance images of the medical devices and proximate body tissue. Also, a method generates MRI images of such a medical device, and involves performing first and second MRI processes on a body portion including at least a portion of the medical device to obtain, respectively, first and second image data. The first MRI process is adapted to detect MRI detectable nuclei present in the proximate body tissue, and the second MRI process is adapted to detect the selected MRI detectable nuclei contained in the device's imaging material. The selected MRI detectable nuclei incorporated in the imaging material is not the same nuclei that the first MRI process is adapted to detect. The second image data are combined with the first image data to produce image data for the medical device and the proximate body tissue.

Abstract: Systems and methods for radio frequency identification and tagging of implantable medical devices and their components are disclosed. A preferred embodiment includes tagging a device and its components with manufacturing information relating to the device and it components and with information identifying a patient using the device. The information can be automatically transmitted or extracted from the device when the device or its components come into communication range of an external programmer or other device adapted to read or sense the RFID information. Some embodiments of a system disclosed herein can also be configured as a component of an Advanced Patient Management System that helps better monitor, predict and manage chronic diseases.

Abstract: A rectal probe adapted for ultrasound and magnetic resonance imaging of the prostate, comprising: a) an ultrasound imaging probe; b) an MRI probe comprising a first magnetic field source for creating a static magnetic field in an MRI imaging region outside the rectal probe, a second magnetic field source for creating a time-varying magnetic field which excites nuclei in the MRI imaging region, and a receiver for receiving NMR signals from the excited nuclei and generating MRI imaging data indicative thereof; and c) a link joining the ultrasound probe and the MRI probe.

Abstract: Systems and methods for a resonator with an adjustable capacitance for a medical device. In one embodiment, a resonator system includes a resonator device with an LC resonator circuit that has an adjustable capacitance, an inductor coil in series with the adjustable capacitance, and an adjustable capacitance control that can control the adjustable capacitance to obtain different particular capacitance values. This embodiment also includes a medical device, positioned with the resonator device, so that at least a portion of the inductor coil surrounds a space that is surrounded by at least a portion of the medical device.

Abstract: An improved method of tracking a catheter's position within a human body does not rely on x-rays, but instead calculates the position of the catheter's imaging head by analyzing image data. Such an analysis is able to determine the position of the imaging head in 3 dimensional space, relative to an arbitrarily selected reference image. An image is compared with the reference image, correlation data between corresponding points on the two images are gathered, and a correlation loss rate in a particular direction is determined. This correlation loss rate is modeled to an exponential function, which is evaluated to estimate an angle of separation between the image and the reference image. One or more angles of separation are used to determine a position in three dimensional space of the image, relative to the reference image. By repeating this process for a series of images being gathered by a catheter, the position of the catheter can be determined.

Abstract: An assembly for delivering optical signals comprising a nuclear magnetic resonance system comprised of magnets, an NMR programmable logic unit, a signal input channel, and a command output channel; an optical interface assembly electrically connected to the nuclear magnetic resonance system, the optical interface assembly comprising a first laser modulated so as to produce laser optical signals, an interface optical to electrical signal convertor; and a catheter assembly connected to said optical interface assembly, the catheter assembly comprising a proximal end, a distal end, a fiber optic cable assembly, an electronics assembly disposed at the distal end comprised of a catheter electrical to optical signal convertor and a catheter optical to electrical signal convertor, and a first receiving coil disposed at the distal end.

Abstract: The present invention relates to an implantable chamber (1) with a connecting element (2), comprising a connecting sleeve (6) and a surrounding contact surface (7), an insert element (3), comprising an insert sleeve (8) and a surrounding abutment surface (9). The insert sleeve (8) is inserted into the connecting sleeve (6) of the connecting element (2). The implantable chamber (1) further comprises a cap (4) with a surrounding edge (11), the cap (4) partly covering the connecting element (2) and the insert element (3), leaving an opening (13) on one side. The implantable chamber (1) contains a passive resonance circuit (14) with an inductance and a capacitance, the passive resonance circuit (14) surrounding at least part of a cavity (15) inside the insert element (3).

Abstract: We present, in exemplary embodiments of the present invention, a system combining anatomical imaging technologies (e.g., MR) with molecular imaging technologies (e.g., ultrasound). The system can be used for a variety of applications, including, but not limited to, (1) cancer diagnosis and staging; (2) image guidance; and (3) radiation therapy planning. Image guidance may include guiding a biopsy. For example, a prostatectomy potentially has severe side effects, such as impotence and incontinence. Thus, a histologically-confirmed diagnosis, such as one provided from a biopsy, may prevent unnecessary prostatectomy. Image guidance may also include guiding minimal invasive therapy, such as brachytherapy focused ultrasound. The present invention may be used to plan radiation therapy, for example, by detecting, and thus sparing, healthy tissue from radiation exposure.

Abstract: Disclosed is a device for nuclear magnetic resonance examination of intracorporal sections of a person's body, the device having a coil arrangement which can be placed in immediate vicinity of an intracorporal section of the body which a stationary magnetic polarization field B0 and a radio-frequency alternating field penetrate. A coil arrangement is integrated in an encapsulated, self-sufficient unit having a shape and size that a person is able to swallow it and a transmitter unit, is connected to the coil arrangement which transmits induction signals coming from the coil arrangement wirelessly to an extracorporal receiving unit, which is integrated in the encapsulated self-sufficient unit.

Abstract: In vivio deep brain medical probe systems include: (a) an NMRI compatible cannula comprising a plurality of concentric axially extending tubes with a receiving bore; and (b) an elongate antenna member with a conductor and an insulating layer configured to slidably advance through cannula bore to define an MRI receive antenna.

Abstract: Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

Abstract: An apparatus, system and method of a resonator device with an adjustable capacitor for allowing the resonance frequency (F) of the resonator device to continue to be matched to the Larmor frequency of the MRI system. The resonator device includes an inductor coil, a conductive member, a sleeve having first and second sockets that receive at least portions of the inductor coil and the conductive member as electrodes to provide a capacitor structure. Dielectric material can be positioned between at least the first and second sockets, where changes in the cross sectional area defined by the induction coil cause changes in the capacitance value (C) as one or more of the electrodes move within the socket. Changes in the inductance and the capacitance values allow for the resonance frequency (F) of the resonator device to continue to be matched to the Larmor frequency of the MRI system.

Abstract: Herein is disclosed a magnetic resonance imaging antenna, including an inner conductor, an outer shield slideably displaceable with respect to the inner conductor, and an insulator electrically insulating the inner conductor from the outer shield. Herein is disclosed a biopsy needle antenna, including a magnetic resonance imaging antenna, having an outer shield, and an inner conductor electrically insulated from the outer shield by a dielectric; and a biopsy needle electrically connected to the inner conductor and electrically insulated from the outer shield by the dielectric. Herein is disclosed a method of obtaining a sample with magnetic resonance imaging guidance, including providing a sampling needle magnetic resonance imaging antenna, advancing the antenna to a structure from which the sample is to be taken, detecting magnetic resonance data by the antenna, and coupling the sample to the antenna.

Abstract: A method supplies a dynamic vector map of properties within a region or a unified suite of quantification functionality for property functions, such as density functions, conduction functions (e.g., thermal conduction, electrical conduction, atomic or subatomic mass conduction, macromolecular mass conduction), defined on, defined in or defining a three-dimensional space, which functions may optionally vary in time.

Abstract: A magnetic resonance imaging apparatus is provided with one or more electrical accessory devices, for example, catheters (10) or RF body coils (6), which are intended for use during the examination of an object, as well as with a connection lead (13) which is arranged so as to extend through an examination zone (1) of the magnetic resonance imaging apparatus, which zone can be exposed to an RF field, and to connect the accessory device to a connection unit (12). In order to avoid heating of the connection lead (13) due to currents induced in the connection lead by the RF field, which currents could lead to injury of a patient or damage of the accessory device or the connection unit (12), the connection lead (13) comprises at least one lead segment (131, 132, . . . ) which has a length which is limited by at least one inductive coupling element, e.g. a transformer (141, 142, . . . ; 161, 162, . . . ) and is unequal to n*/2, where denotes the RF wavelength and n=1, 2, 3, . . . .

Abstract: Apparatus for performing a medical procedure on a tissue within a body of a subject includes a wireless tag which is fixed to the tissue and includes a first sensor coil. A second sensor coil is fixed to a medical device for use in performing the procedure. An integral processing and display unit includes a plurality of radiator coils, along with processing circuitry and a display. The radiator coils generate electromagnetic fields in a vicinity of the tissue, thereby causing currents to flow in the sensor coils. The processing circuitry processes the currents so as to determine coordinates of the tag relative to the medical device. The display is driven by the processing circuitry so as to present a visual indication to an operator of the medical device of an orientation of the device relative to the tag.

Abstract: The invention relates to an MR arrangement which includes a medical instrument (3), an RF arrangement (17) which is provided thereon and in which at least one microcoil (1) and a capacitor (2) are connected so as to form a resonant circuit, and also an optical signal lead (4) via which a light signal is applied to the RF arrangement. In order to achieve simple and fast determination of the position of the medical instrument (3) within the examination zone of an MR apparatus, the invention proposes to provide a modulator (20) for modulating the light signal applied to the RF arrangement and also an optoelectrical converter (5) which converts the modulated light signal into an electrical signal and is coupled to the resonant circuit in such a manner that the resonant circuit is triggered by the electrical signal from the optoelectrical converter (5) so as to emit an RF field.

Abstract: Systems and methods for the orientation of soft tissue such as breast tissue for enhanced accuracy of imaging and/or procedures such as a biopsy or excision are disclosed. The system for orientating and maintaining the orientation of soft tissue generally includes a frame defining an opening, the frame being configured to orient and immobilize an area of soft tissue positioned on one side of the opening, an attachment mechanism to secure the frame to an attachment region defined by the area of soft tissue or by a skin surface overlying the area of soft tissue, to facilitate orienting and immobilizing the area of soft tissue, and an imaging device to image the area of soft tissue. The opening may allow a probe of the imaging device or imaging energy transmitted by the imaging device to be movable therein for image scanning of the soft tissue. The probe, e.g., an ultrasound transducer can be rotated within the frame such that the probe scans at least either of two perpendicular directions within the frame.

Abstract: A magnetic resonance probe may include a plurality of center conductors, at least some center conductors including a conductive core and an insulator disposed at least partially about the core along at least a portion of the core, a first dielectric layer disposed at least partially about the plurality of center conductors in a proximal portion of the probe, an outer conductive layer at least partially disposed about the first dielectric layer, and a plurality of electrodes, at least one electrode being coupled to one of the center conductors and disposed at least partly on a probe surface.

Abstract: A method for functional magnetic resonance imaging (fMRI) uses steady-state free precession (SSFP) to image changes in blood oxygenation between two time periods. A center frequency of the SSFP sequence is placed between the different resonant frequencies for oxyhemoglobin and deoxyhemoglobin whereby the signals have a phase difference of 180° and tend to cancel. By repeating the SSFP imaging sequence at different times, the difference in the measured signals provides a measure of change in oxyhemoglobin. RF flip angle of the SSFP sequence is chosen to maximize signal level in the frequency range from that of water in the presence of oxyhemoglobin and that of water in the presence of deoxyhemoglobin.

Abstract: A method and apparatus for collecting and processing physical space data used while performing image-guided surgery is disclosed. Physical space data is collected by probing physical surface points of surgically exposed tissue. The physical space data provides three-dimensional (3-D) coordinates for each of the physical surface points. Based on the physical space data collected, point-based registrations used to indicate surgical position in both image space and physical space are determined. In one embodiment, the surface of surgically exposed tissue of a living patient is illuminated with laser light. Light reflected from the illuminated surface of the exposed tissue is received and analyzed. In another embodiment, one or more magnetic fields of known shape and size are established in the proximity of the exposed tissue. Data associated with the strength of the magnetic fields is acquired and analyzed.

Abstract: A catheter is used for medical treatments within an organism. The catheter comprises at least one lumen. Within the at least one lumen are at least two microcatheters, with at least one of the at least two microcatheters being connected to a source of liquid material to be delivered to the organism and another of the at least two microcatheters being connected to a system capable of effecting a medical treatment other than delivery of the liquid.

Abstract: An interventional magnetic resonance method and apparatus utilizing a microcoil which enable localization of an interventional instrument by detecting magnetic resonance signals from the surroundings of the microcoil under the influence of magnetic field gradients. The outstanding reliability and the high speed of the method are due to the application of spatially non-selective RF pulses in conjunction with a sequence of gradient pulses in non-colinear directions. The localization method can be used inter alia for angiography wherein the signal intensity is used to determine the amount of blood present in the blood vessel.

Abstract: A method of localizing a medical device inside a patient's body, the method comprising: transmitting ac magnetic signals between a plurality of points of known location outside of the patient's body and a plurality of points on the medical device inside the patient's body, the signals transmitted between at least some of the points comprising at least two different frequencies; and receiving the transmitted ac magnetic signals and processing the received signals to determine the position of the points on the medical device, and thus the location of the medical device, this processing including correcting for the affects of metal in the vicinity by using the transmitted and received signals at different frequencies. In an alternate embodiment, a reference device is provided inside the patients' body, and the medical device is localized relative to the reference catheter.

Abstract: The vest provides a simple and intuitive coil support assuring proper alignment of the coils with the patient and providing support for coil elements encircling the opposed arms. A coil for receiving and/or transmitting radio-frequency signals for magnetic resonance imaging of the chest, and particularly for ventilation studies of the lungs, is supported in a flexible vest having arm holes locating the coil elements about the patient.

Abstract: A medical appliance for use in magnetic resonance imaging procedures. A guidewire for vascular procedures is formed by a coaxial cable acting as antenna in a magnetic resonance imaging system.