摘要:
The present invention relates to an element configuration within an RF coil for use for MRI. The invention provides for an inherently electromagnetically decoupled solenoid element pair for receiving radio frequency magnetic resonance signals within a vertical field MRI system. The elements of the solenoid element pair described herein are typically positioned in a coplanar, side-by-side position. The decoupling of the solenoid pair can be accomplished through numerous methods including but not limited to an overlapping between the elements of the solenoid pair, use of a capacitor shared between the elements of the solenoid pair, or the use of overlapped inductors between the elements of the solenoid pair.
摘要:
An MRI system includes a receive coil having a coil element. Two preamplifiers are used in relation to the coil element, thus placing a large impedance in series with the coil element. The optimal noise impedance of each preamplifier is matched to that of the other preamplifier.
摘要:
The present invention relates to an element configuration within an RF coil for use for MRI. The invention provides for an inherently electromagnetically decoupled solenoid element pair for receiving radio frequency magnetic resonance signals within a vertical field MRI system. The elements of the solenoid element pair described herein are typically positioned in a coplanar, side-by-side position. The decoupling of the solenoid pair can be accomplished through numerous methods including but not limited to an overlapping between the elements of the solenoid pair, use of a capacitor shared between the elements of the solenoid pair, or the use of overlapped inductors between the elements of the solenoid pair.
摘要:
A low profile radio frequency coil (32, 44, 441, 442, 443) for use in a magnetic resonance imaging system includes a low profile antenna (34, 102, 202, 302) that is configured to resonate at about a magnetic resonance frequency of the magnetic resonance imaging system. A generally planar inductor (110, 112, 210, 240, 310) is electrically connected or coupled with the low profile antenna. The generally planar inductor provides selected frequency filtering of a radio frequency signal received by or transmitted by the low profile antenna.
摘要:
A magnetic resonance imaging scanner (10) includes a main magnet (20) generating a spatially uniform main magnetic field at least over a field of view, a plurality of gradient coils (30) selectively generating magnetic field gradients at least over the field of view, and a radio frequency coil (32, 34) for performing at least one of exciting and detecting magnetic resonance at the selected resonance frequency in an imaging subject disposed in the field of view. A radio frequency trap (60, 60′) connected with the radio frequency coil (32, 34) includes helically grooved dielectric formers (62, 62) around which a coaxial cable (64) is wrapped. A plurality of electrically conductive tuning elements such as screws or rods (84, 90) are selectively inserted into the dielectric formers (62, 62) to tune the radio frequency trap (60, 60) to a selected resonance frequency by adjusting the inductance of the trap.
摘要:
A split-top RF coil is provided. The split-top RF coil includes a first housing (80) having a first RF coil portion (41) disposed therein and a second housing (84) having a second RF coil portion (42) disposed therein. A plurality of slides (100) disposed on at least one of the housings and a plurality of slide tracks (101) are disposed the housing opposite the slides for receiving the slides. The first and second housings are mechanically coupled via the slides and slide tracks. The RF coil also includes a plurality of electric connector pins (110) disposed on at least one of the housings and a plurality of pin receivers (111) disposed on the housing opposite the pins for receiving the conductor pins. Electric connections between the first and second coil RF coil portions are made via the pins and receivers.
摘要:
A birdcage coil (16) used in conjunction with a magnetic resonance imaging apparatus includes a first conductive loop (81, 581), a second conductive loop (82, 582), and a plurality of first conductor rungs (80, 580) disposed between the first and second conductive loops. A third conductor (83, 83″, 583) is coupled to the second conductive loop at resonance frequencies, such as by second conductor rungs (84, 84″, 584). The birdcage coil also includes switches (590) for switching the birdcage coil at least among: 1) an RF transmit mode to operate as an RF transmit coil; and 2) an RF receive mode to operate as an RF receive coil.
摘要:
A magnetic resonance imaging apparatus creates images by exciting magnetic resonance in selected nuclei disposed within an image region. Through the image region a main magnetic field (B0) is applied and transverse gradients are produced. At selected times a high power RF pulse is applied to the imaging region causing the selected nuclei to resonate. These magnetic resonance signals are detected by a receive coil (D1, D2) and converted into an image representation viewable on a display (24). Images are obtained by repeating the transmit and receive portions until enough image data is received to produce an image. The receive coil (D1, D2) includes first decoupler circuits (28) arranged about the coil. During the transmit portion of the cycle, the decoupler circuits sense the high power RF pulse and decouple the coil. High speed switching diodes or PIN diodes are excited by the transmit RF pulse to switch inductors (40) into the coil to decouple the receive coil. During a receive portion of a cycle in which the coil is not used, a DC bias is selectively applied to the coil forcing the diodes on, actively decoupling the coil. The DC bias also biases a diode switch (50, 50′) to short the input of a preamplifier element (48, 48′) providing protection.
摘要:
Mortgage fraud detection systems and methods are provided. A fraud detection system can generally comprise a database operator, a database manager, one or more users, and a database. Database components can be implemented as hardware, software, or a combination of both. A fraud detection method can generally comprise providing a database for maintaining a plurality of records. Data records can be continually received by a database in batchwise or single submission protocols. Records can be compared to determine whether they contain common data in one or more predetermined fields. If records contain common data in one or more predetermined fields, records can be examined for inconsistencies in one or more other data fields. Discovered inconsistencies and magnitudes of inconsistencies can be warning signs of fraud. Results of comparisons can be reported to system users to enable such users to investigate additional circumstances. Other embodiments and features are also claimed and described in the application.
摘要:
A magnetic resonance imaging apparatus includes a main magnet (12) for generating a main magnetic field in an examination region (14), a plurality of gradient coils (22) for setting up magnetic field gradients in the main field, an RF transmit coil for transmitting RF signals into the examination region to excite magnetic resonance in a subject disposed therein, and an RF receive coil (16) for receiving RF signals from the subject. The RF receive coil includes a first loop (101) and a second loop (102), the first and second loops being disposed substantially in a similar plane (x-z). Also included is a signal combiner (120) for combining the signals received by the first and second loops in quadrature.