Patent classifications
G01R33/3854
Low field magnetic resonance imaging methods and apparatus
According to some aspects, a laminate panel is provided. The laminate panel comprises at least one laminate layer including at least one non-conductive layer and at least one conductive layer patterned to form at least a portion of a B.sub.0 coil configured to contribute to a B.sub.0 field suitable for use in low-field magnetic resonance imaging (MRI).
Noise suppression methods and apparatus
According to some aspects, a method of suppressing noise in an environment of a magnetic resonance imaging system is provided. The method comprising estimating a transfer function based on multiple calibration measurements obtained from the environment by at least one primary coil and at least one auxiliary sensor, respectively, estimating noise present in a magnetic resonance signal received by the at least one primary coil based at least in part on the transfer function, and suppressing noise in the magnetic resonance signal using the noise estimate.
ELECTROMAGNETIC SHIELDING FOR MAGNETIC RESONANCE IMAGING METHODS AND APPARATUS
According to some aspects, a portable magnetic resonance imaging system is provided, comprising a Bo magnet configured to produce a Bo magnetic field for an imaging region of the magnetic resonance imaging system, a noise reduction system configured to detect and suppress at least some electromagnetic noise in an operating environment of the portable magnetic resonance imaging system, and electromagnetic shielding provided to attenuate at least some of the electromagnetic noise in the operating environment of the portable magnetic resonance imaging system, the electromagnetic shielding arranged to shield a fraction of the imaging region of the portable magnetic resonance imaging system. According to some aspects, the electromagnetic shield comprises at least one electromagnetic shield structure adjustably coupled to the housing to provide electromagnetic shielding for the imaging region in an amount that can be varied. According to some aspects, substantially no shielding of the imaging region is provided.
Apparatus for magnetic resonance imaging
A method for reducing a tendency of a thermal radiation shield for a superconducting magnet of a magnetic resonance imaging system to vibrate. A mass per unit area of the material of the thermal radiation shield is locally modified in a random or pseudo-random pattern.
NOISE SUPPRESSION METHODS AND APPARATUS
According to some aspects, a method of suppressing noise in an environment of a magnetic resonance imaging system is provided. The method comprising estimating a transfer function based on multiple calibration measurements obtained from the environment by at least one primary coil and at least one auxiliary sensor, respectively, estimating noise present in a magnetic resonance signal received by the at least one primary coil based at least in part on the transfer function, and suppressing noise in the magnetic resonance signal using the noise estimate.
Systems and methods for magnetic resonance imaging
A method for magnetic resonance imaging (MRI) may include cause, based on a pulse sequence, a magnetic resonance (MR) scanner to perform a scan on an object. The pulse sequence may include a steady-state sequence and an acquisition sequence that is different from the steady-state sequence. The steady-state sequence may correspond to a steady-state phase of the scan in which no MR data is acquired. The acquisition sequence may correspond to an acquisition phase of the scan in which MR data of the object is acquired. The method may also include generating one or more images of the object based on the MR data.
Gradient Coil Unit Comprising Two Hollow Cylinder Regions
A gradient coil unit may include a hollow cylinder surrounding a cylinder axis, delimited perpendicularly to the cylinder axis by a first longitudinal end and a second longitudinal end opposing the first longitudinal end. The hollow cylinder may include a first hollow cylinder region and a second hollow cylinder region separated from the first hollow cylinder region by a sectional plane perpendicular to the cylinder axis. The first hollow cylinder region may be delimited by the first longitudinal end and the second hollow cylinder region by the second longitudinal end. The gradient coil unit may also include a conductor structure configured to generate magnetic field gradients in three mutually different directions. The gradient coil unit may have a length corresponding to a distance between the first longitudinal end and the second longitudinal end of at least 140 cm.
Acoustic shield for a magnetic resonance imaging magnet assembly
The invention provides for a magnetic resonance imaging system component. The magnetic resonance imaging system component comprises an acoustic shield (124) for a magnetic resonance imaging cylindrical magnet assembly (102). The acoustic shield comprises a cylindrical portion (125) configured for being inserted into a bore (106) of the magnetic resonance imaging cylindrical magnet assembly and for completely covering the bore of the magnetic resonance imaging system. The cylindrical portion comprises a smooth exposed surface (126) configured for facing away from the magnetic resonance imaging cylindrical magnet assembly. The cylindrical portion further comprises an attachment surface (127). The acoustic shield further comprises an acoustic metamaterial layer (128) attached to the attachment surface.
RADIO-FREQUENCY COIL SIGNAL CHAIN FOR A LOW-FIELD MRI SYSTEM
Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.
APPARATUS FOR MAGNETIC RESONANCE IMAGING, AND METHODS FOR THE DESIGN AND MANUFACTURE THEREOF
A device for use in magnetic resonance imaging (MRI) systems may include a superconducting main magnet coil; and a thermal radiation shield that encloses the superconducting main magnet coil. The shield may include an inner cylindrical bore tube, an outer cylindrical wall, and annular end walls welded between the annular cylindrical bore tube and the outer cylindrical wall to form a closed, hollow cylindrical vessel. A distribution of a position and length of welds that affix the annular end walls to the inner cylindrical bore tube may include a predetermined arrangement of welds of varying lengths interspersed with gaps of varying lengths.