Abstract: The invention sets forth an RF-safe invasive device which is intended to cooperate with a magnetic resonance imaging apparatus and which contains at least one long conductor for a specific purpose, e.g., the localization of the RF-safe device in an object under test. It is known that in such devices with long conductors during RF transmission of the magnetic resonance apparatus a standing RF wave along the conductors may build up which causes dangerous heating of the device and surrounding tissue. It is the object of the invention to provide a construction applicable to such devices such that the heating of the conductor and surrounding tissue is avoided.

Abstract: A system for and method of determining and compensating for the effect of a field influencing object on a field sensor, preferably a coil, that is within a navigational domain. The navigational domain contains navigational magnetic energy and disturbing magnetic energy, and the field influencing object produces the disturbing magnetic energy in response to the navigational magnetic energy. The correction system includes a first transmitter for projecting into the navigational domain field energy in a first waveform sufficient to induce a first signal value in the sensing coil. The system also includes a second transmitter for projecting into the navigational domain field energy in a second waveform sufficient to induce a second signal value in the sensing coil. The system further includes a signal processor for receiving the first signal value and for receiving the second signal value to determine the effect of the electrically conductive object on the field senior.

Abstract: A microcoil configuration, preferably on a medical device to be inserted into a patient, has an opposed pair of microcoils. At least one or each microcoil of the opposed pair of microcoils has at least a region where a diameter circumscribed by a first winding is greater than the diameter circumscribed by at least one complete second winding, especially an adjacent winding displaced from the first winding along an axis or core of the medical device or an axis of the microcoil. The second winding is nearer to or farther from an intermediate region between the microcoils that define the pair of microcoils. For example, it is common to have a connecting (usually straight or non-wound) lead between the two microcoils, and this lead may be used to define an intermediate region.

Abstract: A method is provided for operating a magnetic resonance apparatus comprising a magnetic stimulation device, the method comprising bearing a region of a central nervous system of a living examination subject in an imaging volume of the magnetic resonance apparatus, whereby this region is to be imaged, operating the magnetic stimulation device for stimulating at least one prescribable location of the examination subject outside of the region to be imaged and generating a functional magnetic resonance image of the region to be imaged for imaging a neuronal activity of the central nervous system, whereby said neuronal activity is initiated by the stimulation.

Abstract: The invention relates to an interventional magnetic resonance method utilizing a microcoil. The method enables localization of an interventional instrument by detection of 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. The invention also relates to a magnetic resonance apparatus for carrying out the method.

Abstract: An MRI apparatus includes a local endovaginal probe (30) for receiving magnetic resonance in a study of the endopelvic fascia surrounding the female urethra. The probe (30) includes a shaft portion (62) an insert portion (60), the insert portion to be inserted into the vaginal cavity of a female subject. The insert portion (60), in order to have maximum efficiency in imaging the endopelvic fascia, is designed to specific dimensions to achieve the optimum balance between image quality and patient comfort. In an imaging sequence, a main magnet assembly (12) produces a main magnetic field through an imaging region (14). A whole-body RF coil (26) excites and manipulates magnetic resonance in the vicinity of the vaginal cavity. The probe (30) detects the magnetic resonance, which is received and demodulated. The received magnetic resonance is then reconstructed into an image representation of the tissue surrounding the vaginal cavity of the subject.

Abstract: The invention includes a method of coating a substrate, comprising exposing a substrate to an initiator capable of initiating a graft polymerization reaction on the substrate, to generate reactive radical sites on the surface of the substrate; contacting the substrate with a composition comprising one or more monomers in a medium which has different hydrophilicity compared to the substrate, and grafting monomer molecules onto the substrate by forming covalent bonds between monomer molecules and the substrate at reactive radical sites on the substrate surface. With the invention, novel coated articles can be obtained which are particularly useful as medical products such as catheters.

Abstract: A magnetic resonance imaging probe includes a dipole including a first arm and a second arm. The second arm includes an elongate loop coil. In one embodiment, the loop coil is an open coil. In another embodiment, the coil is a twisted coil. The first and second arms are electrically connected to provide a dipole output. The second arm is electrically connected to a loop output.

Abstract: A magnetic resonance image receiving coil includes a first balloon having a longitudinal axis. An internal surface of the first balloon defines an internal inflatable chamber. A second balloon has a longitudinal axis. The second balloon is disposed about the first balloon. A plurality of longitudinally extending grooves are disposed in one of an external surface of the first balloon and the internal surface of the second balloon. A first wire is disposed in at least one of the grooves. A second wire is disposed in at least a second one of the grooves. Each of the first wire and the second wire is adapted to be electrically connected to an MRI apparatus. In accordance with an alternate embodiment, the first and second wires are disposed in grooves in a sheath which is disposed between the first and second balloons. In accordance with a further alternate embodiment, the first and second wires are disposed in guide tubes that are connected to the external surface of a balloon.

Abstract: A method for detecting body condition using nano and microdevices is disclosed. The microdevice or nanodevice is inserted into a fluid stream within a body, and used in detecting a bodily condition. The bodily condition may be myocardial infarction, stroke, sickle cell anemia, phlebitis, or a vascular aneurysm. The micro or nano device may be detected using electron paramagnetic resonance (EPR), electron spin resonance (ESR), and nuclear magnetic resonance (NMR).

Abstract: The invention relates to a method and a device for determining the position of a medical instrument (3) that is introduced into an object (1) to be examined and for imaging the vicinity of the medical instrument (3).

Abstract: A method of transesophageal magnetic resonance analysis of a patient, such as an animal or human, includes providing a loopless antenna formed from a flexible coaxial cable having an extended center conductor at the distal end thereof. A distal portion of the loopless antenna is secured within a Levin-type gastric tube. The gastric tube which receives the loopless antenna is inserted in the esophagus of the patient. A tuning, matching and decoupling circuit for the loopless antenna is employed external to the patient. The tuning, matching and decoupling circuit is electrically connected to a magnetic resonance imaging scanner. The magnetic resonance imaging scanner is employed to display an image of the aorta of the patient.

Abstract: A microcoil is manufactured by rolling a trace unit in such a way as to form at least one winding. The trace unit is comprised of a conductive trace attached to a flexible insulating film. A preferred embodiment of the microcoil contains both a first winding and a second winding electrically connected and spaced apart by a joining portion. The microcoil may be used for internal magnetic resonance imaging of patient by attaching the microcoil to a catheter.

Abstract: The invention relates to an MR method which utilizes a microcoil without connection leads which causes an increase of or a change in phase of an external RF magnetic field in its direct vicinity within an object to be examined. This increase can be used to localize the coil, to image the direct vicinity, or to track the propagation of a liquid flow passing through the direct vicinity.

Abstract: The present invention provides a method of magnetic resonance investigation of a sample, preferably of a human or non-human animal body, said method comprising:

Abstract: A magnetic resonance imaging system for interventional MR imaging involving operations to insert a device such as a catheter into an object. According to the system, a tip position of the catheter is detected, data indicative of moved loci of the catheter are produced from data indicative of the detected tip position, and the produced movement locus data are displayed. In addition, even when an operator changes the progress direction of the device such as a puncture needle, an imaging cross section automatically tracks movements of the device. Appropriate preoperative plan means are also provided.

Abstract: A coil for magnetic resonance imaging includes at least two spaced electrodes positionable within an object in proximity to a region of interest with feed wires coupling the electrodes to a signal detector. The electrodes and feed wire cooperatively function with tissue and fluid of the object to form an RF signal detecting coil. The electrodes can be needles or rings around the circumference of a catheter or electrodes which extend from and are retractable within a catheter.

Abstract: A medical instrument, for use in relation to an MR scanner, comprising body portion having mounted thereon a plurality of positioning elements each of which comprises a reservoir containing a liquid and at least two spaced tuned MR auxiliary receiver coils positioned coaxially with respect to one another and carried by the reservoir, and means for electrically connecting the said auxiliary coils to separate receiver channels of the MR scanner. Flux enhancement is used to enable the positioning elements to be rapidly located without disturbing the magnetization of the patient and thereby permit the position of the medical instrument and the image of the patient to be rapidly cycled between.

Abstract: The apparatus, systems and methods of the present invention provide for MRI sleeves, probes, and combinations thereof adapted for insertion into a subject, in order to internally image regions of the subject.

Abstract: The present invention provides systems and methods for the evaluation of the urethra and periurethral tissues using 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: 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: Nuclear magnetic resonance spectroscopy catheter probe comprising a permanent magnet arrangement (1,2,3,4) for generating a static magnetic field of suitable intensity and homogeneity for analyzing a sample of fluid flowing into a catheter (6) traversing the permanent magnet arrangement. The probe further comprises an arrangement of electronic circuits (8,9) responsible for the excitation and detection of the nuclear magnetic resonance signal and at least one coil (7) to expose the fluid sample to the excitation signal and to collect the returned nuclear magnetic resonance signal.

Abstract: The invention relates to a magnetic resonance imaging process for the imaging and determination of the position of a stent introduced into an examination object as well as to the stent so utilized. According to the invention, the stent has at least one passive resonance circuit with an inductance and a capacitance whereby its resonance frequency is essentially equal to the resonance frequency of the applied high-frequency radiation of the magnetic resonance system. A changed signal response is thus produced in a locally defined area in or around the stent which is imaged in spatial resolution.

Abstract: This invention relates to a method for MR imaging using a moveable RF receiving coil assembly that is swept over the region of interest to be imaged during the imaging protocol.

Abstract: The present invention comprises a device and method for targeted drug delivery, and especially intracranial inflsion or retroperfusion drug delivery using nonlinear magnetic stereotaxis in combination with magnetic resonance (MR) imaging and/or X-ray visualization. An MR-visible and/or X-ray visible drug delivery device is positioned by non-linear magnetic stereotaxis at a site such as an intracranial target site, its location is verified via MR imaging, and it is then used to deliver a biologically active material such as a diagnostic or therapeutic drug solution into that site (such as the brain) at constant or variable rates. The spatial distribution kinetics of the injected or infised drug agent may be monitored quantitatively and non-invasively using real-time MR-imaging such as water proton directional diffusion MR imaging, to establish the efficacy of targeted drug delivery.

Abstract: The present invention provides several embodiments of methods of making magnetic resonance catheter coils which include employing a flexible electrically insulative base member, depositing an electrically conductive material on the base member in a predetermined pattern to create at least one pair of generally parallel electrically conductive coil elements which are electrically connected to each other. A catheter is provided over the coil assembly. In one embodiment, a second pair of generally parallel electrically conductive coil elements are provided in order to create a quadrature coil. In this latter embodiment, the electrically insulative base member may have the first pair of coil elements created on one surface thereof and a second pair on the other with the base member subsequently being deformed to create a tubular coil having one pair of coil elements on the outside and the other pair on the inside. In some embodiments, tuning and matching circuits and decoupling circuits may be provided.

Abstract: An RF coil structure for intra-cavity use includes a pair of conductors (7, 8) separated by a support such as a web (9) which come together at positions separated along the length of the coil structure such as (A, B). Previous coils have included two parallel conductors. If the conductors (7) and (8) were parallel, while the structure could be flexed transverse to the plane of the web (9) about the arrow (10), it could not be flexed in the plane of the web (9) about arrows (12, 13). Because the conductors come together at points (A) and (B), it can be so flexed. A second coil may be provided including conductors (4, 5) and flexing about the same points as for the first coil is still possible because the points of closest approach for one pair come between those for the other pair.

Abstract: The invention relates to a method of navigating a magnetic object (11) within an object (1) which is exposed to a magnetic field, as well as to a magnetic resonance device in which this method can be carried out. The method according to the invention is particularly suitable for navigating a catheter or a flexible endoscope within the body of a patient. The magnetic object (11), preferably being provided in or on such a medical instrument (10), has a controllable magnetic moment for this purpose and the direction of movement of the object is determined by control of the magnetic moment. In the case of a magnetic resonance device whose static magnetic field is used, the object (11) is preferably includes as a coil system.

Abstract: An invasive probe for mapping the walls of a lumen employs a real-time tracking means and a wall distance measurement means. As the probe is advanced within the lumen, the real-time tracking means provides three-dimensional coordinates of the probe's position and orientation. Concurrent with probe localization, the distance between the probe and the lumen walls is measured. Both the probe position and the wall distance measurement are sent to a data acquisition system which in turn provides a graphic or numeric display to the operator. Probe tracking can be performed with radio-frequency, magnetic resonance, ultrasonic techniques or the like. If desired, lumen wall distance measurements can be performed with magnetic resonance or ultrasound methods. Lumen wall distance measurements can also be performed with mechanical devices such as balloons and/or expanding structures.

Abstract: A non-invasive device for evaluating circulatory state parameters, and specifically, a pulsewave analysis device capable of evaluation by separating blood vessel compliance and blood vessel resistance into central and peripheral components of the arterial system is provided. Microcomputer 4 detects the waveform at a test subject's radius artery via pulsewave detector 1, and uptakes the stroke volume in the test subject which is measured by a stroke-volume measurer. Next, based on the measured stroke volume, microcomputer 4 adjusts the values of each element in a lumped five parameter model made up of an electrical circuit which models the arterial system from the center to the periphery of the body, so that the response waveform obtained when an electric signal corresponding to the pressure waveform at the proximal portion of the aorta in a test subject is provided to the electric circuit coincides with the waveform at the radius artery.

Abstract: A radio frequency coil (12, 19) adapted for use in interventional magnetic resonance imaging consists of a loop of an elongated electric conductor arranged to form a twisted wire pair (12, 19) and means associated with it for operating the coil both in transmit and receive mode, in order that the coil does not image anything but tracks its own path on an MR image, without affecting the magnetization in the main bulk of the body being imaged.

Abstract: In a method for the location determination of a positionable object in an examination subject by means of magnetic resonance and apparatus for the implementation of the method a reference image is acquired from at least one slice of the examination subject. The current position of the subject is determined by at least one radio-frequency reception coil attached to the object. A slice position in which the reference image is updated is determined on the basis of this current position.

Abstract: The use of devices in procedures, especially medical procedures where the events take place under view of Magnetic Resonance Imaging (MRI) systems is becoming more important. Although some general and specific structures have been discussed in the literature and commercialized, little has been done effectively to design devices for MRI procedures for specific tasks. The present invention describes a device for use within an organism, said device comprising an element having at least one pair of opposed RF receiver microcoils having a space between each microcoil of said pair of microcoils, the coils of said microcoils may have diameters of less than 2.4 mm.

Abstract: An MR system for interventional procedures, includes an MR device and an invasive device. The MR device is arranged to acquire images of a part of an object. A part of the invasive device can be imaged in an MR image by providing a coil or a conductor loop which has two non-magnetic conductors which are situated at some distance from one another underneath the surface of the invasive device. A reduction of artefacts due to the movement of a patient or the invasive device can be obtained by sampling an MR signal, whereby an auxiliary magnetic field is periodically applied during the time in which the plurality of lines in k-space are scanned.

Abstract: A catheter apparatus for use in determining the location of a tip of a catheter inside biological tissue is disclosed. The apparatus includes a catheter, a detector positioned within the catheter, and a polyimide sheath containing the detector and forming a detector assembly. The sheath is comprised of a first member, a polyimide layer, and a second member having an undulating outer surface sandwiched therebetween. The detector assembly may be removed from the catheter without damage thereto once the tip of the catheter is in its desired location inside biological tissue.

Abstract: The invention provides a method for magnetic resonance imaging and spectroscopic analysis of a specimen which includes positioning the specimen within a main magnetic field and introducing an antenna having a loopless antenna portion in close proximity to the specimen. Radio frequency pulses are provided to the region of interest to excite magnetic resonance signals, gradient magnetic pulses are applied to the region of interest with the antenna receiving magnetic resonance signals and emitting responsive output signals. A processor processes the responsive output signals to provide image information for display in a desired manner. The method in a preferred form involves employing a flexible antenna. The method in another preferred form involves employing an impedance matching circuit electrically interposed between the loopless antenna and the processor to enhance radio frequency power transfer and magnetic resonance signal-to-noise ratio from the loopless antenna to the processor.

Abstract: An invasive device which is intended to cooperate with a magnetic resonance imaging apparatus is provided with an RF coil which is situated near a distal part of the invasive device. The RF coil is used so as to visualize the position of a distal end of the invasive device, introduced into an object, in an image of the object. Current induced by an RF field to be generated by the magnetic resonance imaging apparatus develops heat in the electric connection between the RF coil and a control unit, which may be annoying to a patient. In order to counteract the development of heat in the invasive device, the invasive device is provided with a hollow carrier. The electric connection extends through said carrier which is provided with an electrically conductive shield with an additional resistance.