Abstract: A fiducial marker assembly (30) is tracked using a magnetic resonance scanner (10). At the tracked position of the fiducial marker assembly, local B0 magnetic field inhomogeneity is measured. A warning is issued if the measured local B0 magnetic field inhomogeneity satisfies a warning criterion. A noise figure of merit of the tracking is also determined, and the warning is also issued if the noise figure of merit satisfies a noise-based warning criterion.

Abstract: A magnetic resonance imaging (MRI) system includes an interventional instrument and a switched, segmented transmission (Tx) line which ensures safety during an MRI protocol while the interventional instrument is located in the system. The transmission line includes at least two electrically conductive Tx line segments separated by a non-conductive gap. An electrically conductive bridge, having an open and a closed state, and a parallel connected impedance bridge, having a known impedance which suppresses RF current between the line segments, bridge the non-conductive gap. A measurement unit measures the impedance across the Tx line while the conductive bridges are open. The line segments are verified to be decoupled if the measured impedance of the line is substantially equal to that of the impedance bridge.

Abstract: An apparatus for applying energy within an object includes an energy applying unit having an energy emitting element or outputting energy within the object and an energy storage unit locatable within the object and coupled to the energy emitting element. The apparatus further includes an electrical control line coupled to the energy applying unit for controlling the application of energy within the object by controlling transmission of energy from the energy storage unit to the energy emitting element.

Abstract: A catheter comprising:-a transmission line (104, 106, 924, 1202, 1302, 1902,), wherein the transmission line comprises a plurality of radio frequency traps (118, 318, 418, 518, 618, 718, 818, 918, 1018, 1202, 1404,); and-a cooling line (104, 304, 1200, 1900) for cooling the plurality of radio frequency traps with a fluid.

Abstract: A magnetic tracking system is particularly adapted for a combination with an imaging system, for example with a rotational X ray device. The magnetic tracking system includes pairs of first and second field generators that are disposed on opposite sides of a measuring volume. The first field generators may particularly be attached to a radiation source and the second field generators to a detector of the X ray device. Moreover, the first and second field generators may be constituted by coils with opposite magnetic polarity. Due to the attachment of the field generators to the X ray device, motions of the X ray device do not disturb the magnetic field in a frame of reference fixed to the imaging system.

Abstract: An electrically conductive transmission cable for supplying a DC signal safely to an electrical device in the presence of radio-frequency (RF) fields in a magnetic resonance (MR) is disclosed herein. The transmission cable comprises a transmission line (STL) comprising at least a first segment (S1) and a second segment (S2), wherein the first and second segments are electrically connected to each other by a reactive coupling unit (103), and a rectifier unit (101) connected to the transmission line and configured to extract the DC signal (203) from the modulated DC signal (201). The extracted DC signal may be supplied to an electrical device or used for cardiac pacing. The transmission cable finds application in auxiliary devices used in an MR environment, for example an interventional catheter with or without an active tracking circuit (301).

Abstract: The invention relates to a magnetic resonance imaging system comprising a main magnet coil (2) for generating a uniform, steady magnetic field within an examination volume, a number of gradient coils (4, 5, 6) for generating switched magnetic field gradients in different spatial directions within the examination volume, at least one cardiac RF coil (11) for transmitting RF pulses to and/or receiving MR signals from the chest region of a body (10) of a patient positioned in the examination volume, a control unit (13) for controlling the temporal succession of RF pulses and switched magnetic field gradients, and a reconstruction unit (15) for reconstructing a MR image from the MR signals.

Abstract: The present invention relates to a catheter (2) for applying energy to an object (6) and a magnetic resonance imaging system (1) for localizing the catheter (2). The catheter (2) comprises an energy application element for applying energy to the object (6), and a cavity for providing a magnetic resonance fluid from which magnetic resonance signals generated by the magnetic resonance imaging system (1) are receivable, wherein the cavity is adapted for providing a cooling fluid as the magnetic resonance fluid for cooling the energy application element. The catheter (2) comprises further a tracking coil (15) for tracking the catheter (2), wherein the tracking coil (15) is adapted to receive the magnetic resonance signals from the magnetic resonance fluid. Thus, the magnetic resonance fluid fulfils at least two functions, providing magnetic resonance signals for tracking the catheter (2) and cooling the energy application element.

Abstract: A magnetic resonance method comprises: performing (C1) a magnetic resonance procedure on a calibration subject including an implant device; detecting (C2) a pick-up coil (PUC) signal at least during a radio frequency transmit phase of operation (C1); performing (C3) three dimensional temperature mapping of the calibration subject using a magnetic resonance sequence configured to detect any temperature change induced in any part of the implant device by operation (C1); generating (C4) an unsafe condition criterion (30) for the detected PUC signal based on correlating a PUC signal characteristic detected by operation (C2) with a temperature change detected by operation (C3); performing (M5) the magnetic resonance procedure on a subject containing an implant device; detecting (M6) a PUC signal at least during a radio frequency transmit phase of operation (M5); and monitoring (M7) for an unsafe condition indicated by the PUC signal detected in operation (M6) satisfying the unsafe condition criterion (30).

Abstract: The invention relates to a method of MR imaging of a moving portion (22) of a body (10) of a patient placed in an examination volume of a MR device (1). For the purpose of enabling improved interventional MR imaging with motion compensation, the invention proposes that the method comprises the steps of: a) collecting tracking data from an interventional instrument (19) introduced into the portion (22) of the body (10), b) subjecting the portion (22) of the body (10) to an imaging sequence for acquiring one or more MR signals therefrom, wherein parameters of the imaging sequence are adjusted on the basis of the tracking data, c) acquiring a MR signal data set by repeating steps a) and b) several times, d) reconstructing one or more MR images from the MR signal data set.

Abstract: A transformer line (46) extends through a catheter or other interventional instrument (30) that is to be used in the examination region (14) of a magnetic resonance imaging apparatus (10). The transformer line includes pairs of transformer windings (28) which are tuned in order to adjust the operating frequency and the maximum attenuation frequencies. Eccentric cams or other tuning elements (50, 64) are disposed in the transformer windings. Rotating the eccentric cams mechanically changes the geometry of the transformer windings, changing their inductive properties, and thus the frequency to which each is tuned.

Abstract: The invention relates to electrophysiology catheter systems and their use, such as in an MRI environment, and in particular to analysis of electric signals from such. An electrophysiology (EP) catheter with a plurality of electrically isolated electrode segments arranged in longitudinally spaced bands around the catheter is used to detect electric signals. A workstation receives the electrical signals which are then processed by a processing unit. Electric signals from electrode segments can be used to determine roll angle information of the catheter in relation to patient anatomy by determining signals from electrode segments in contact with tissue. Also, electric signals can be used to extract a reference signal that can be used to correct for gradient induced artefacts.

Abstract: An interventional instrument (24) for use in performing an interventional procedure includes: a balloon (30) disposed proximate to a tip of the interventional instrument that inflates and anchors in a lumen of a fluid conduit during the interventional procedure; and one or more susceptibility markers (34) disposed proximate to the tip of the interventional instrument. A magnetic resonance scanner (10) is configured to image at least the tip of the interventional instrument during the interventional procedure using a magnetic resonance imaging sequence in which fluid flow (40) through the fluid conduit past the inflated balloon produces an extended magnetic resonance image artifact (42).

Abstract: A handpiece (32) defines a bore (62) in which a proximal end (56) of a catheter or other interventional instrument (30) is received. An insulating support (70) supports an interventional instrument which carries an interventional instrument winding (54) in, but spaced from, the internal bore (62). A handpiece winding (64) disposed along the bore interacts with the transmission line winding (54) to form an inductive coupling with the transmission line. After the handpiece is slid axially to adjust the inductive coupling between the windings (54, 64), a locking mechanism functions in such a manner that the interventional instrument is inhibited from axial sliding motion relative to the handpiece while permitting rotation of the interventional instrument relative to the handpiece thus maintaining the inductive coupling while allowing optimal handling of the device.

Abstract: The present invention relates to a device (100) and method for interfacing a signal transmission/reception device (200) and a catheter (300). A signal transmitted by the signal transmission/reception device (200) and supplied to the device (100) via a first interface (102, 104, 106, 108) can be sensed by a first sensor (114). The sensed signal may be adjusted by an adjustment unit (116). The adjusted signal can be output via a second interface (110, 112) and supplied to the catheter (300). In this way, a resistance loss caused by a conductor (302, 304) of the catheter (300) may be compensated for.

Abstract: A system and method for determining the location of a remote object connected to an induction coil using a magnetic tracking sensor. The system and method include locating a magnetic core asymmetrically disposed within the induction coil located near the remote object, and operably connecting a single DC electrical circuit o ends defining the induction coil. The DC electrical circuit provides a DC current to the induction coil while the induction coil is disposed in an external AC magnetic field. The DC current adjusts the level of saturation of the magnetic core, and hence varies a response signal of the induction coil disposed in the external AC magnetic field to provide magnetic tracking of the induction coil.

Abstract: A magnetic resonance method comprises applying a radio frequency excitation in an examination region (14), measuring a magnetic resonance signal generated by the applied radio frequency excitation in a subject (16) in the examination region, monitoring a radio frequency parameter during the applying, and evaluating subject safety based on the monitoring. A magnetic resonance safety monitor (40) comprises an analyzer (42, 44, 46, 50) configured to (i) receive a radio frequency signal during magnetic resonance excitation, (ii) extract a radio frequency parameter from the received radio frequency signal, and (iii) evaluate subject safety based on the extracted radio frequency parameter, and a remediation module (54) configured to perform a remediation of the magnetic resonance excitation responsive to the evaluation (iii) indicating a potentially unsafe condition.

Abstract: A transmission cable for use in an elongate medical device (420) such as a catheter, guide wire, etc., wherein the transmission cable is capable of being switched to an MR-safe mode only when necessary, while retaining its optimal electrical transmission properties otherwise, is disclosed herein. The transmission cable comprises a transmission line including at least two electrically conductive line segments (104a, 104b) separated by a non-conductive gap (106a), a bridging unit comprising at least one electrically conductive bridge segment (108a) capable of bridging the non-conductive gap, and a switching unit (112) arranged to move the bridging unit and/or the transmission line to electrically connect the two line segments by closing the non-conductive gap using the bridge segment or to electrically disconnect the two line segments by opening the non-conductive gap.

Abstract: The present invention relates to an electrically conductive transmission line for transmitting RF signals, in particular for transmitting MR signals between a transmission and/or receiving coil (11) and a transmitting and/or receiving unit (12), by which separate known matching networks can be avoided or reduced. A transmission line is proposed comprising a plurality of lead segments (31) coupled only by transformers (32, 33) having a transformer impedance ZL placed between two neighbouring lead segments, wherein for power matching of the two transformers (32, 33) placed at opposite ends of a lead segment (31) said lead segment (31) has a low lead segment impedance Zo and/or a high dielectric constant ?r and wherein said lead segment (31) has a short length 1. Thus, the lead segments themselves provide the matching of the transformers, and separate matching circuits are no longer needed.

Abstract: The invention relate to an interventional device (I2) conceived to be positioned in a body and comprising an electrically operable unit (E1, E2) conceived to carry out an interaction with the body upon a receipt of electric power, wherein the device further comprises a sensor (2) arranged for wirelessly receiving electromagnetic energy from a remote source, the said sensor being arranged as a resonant circuit (2a, 2b) and being conceived to convert the received electromagnetic energy into the said electric power. The electrically operable device may comprise a diagnostic and/or therapeutic module.