Fonar Corporation

Terry Morrone

Raymond V Damadian

Gordon T Danby

Hank T Hsieh

John W Jackson

Timothy Damadian

Rajendra K Shenoy

David Hertz

Jan V Votruba

Robert B Wolf

Sudhir Moolky

Mark E Hamberger

Through advancing the phase of radio frequency (RF) excitation with each phase-encoding level, a method, apparatus and article thereof increases the effectiveness of a Magnetic Resonance Imaging (MRI) device by correcting for main magnetic field inhomogeneities without noticeably decreasing the signal-to-noise (SNR) ratio. Increased effectiveness of fast imaging with steady precession (FISP) scans and using FISP scans to image multiple slices. In an MRI device, a patient is subjected to a constant magnetic field, and RF pulses are used to excite the nuclei in the patient's body, which release a corresponding RF signal as the nuclei relax, which is measured and mapped into a visual display. The RF pulses used to excite the nuclei cooperate with a slice select gradient and a phase-encoding gradient. When the RF pulse is phase shifted with each phase-encoding gradient level, improved SNR ratios are observed.

System and method for multislice fast magnetic resonance imaging

Multi-slice fast magnetic resonance imaging

According to a method of detecting and compensating for MRI scan errors, MRI scan data are received. At least one statistical boundaries is determined for the generated data. The data are observed in K-space. The observed K-space data are compared to the determined statistical boundary. Data that are likely undesirable, based on the comparison, are removed. The removed data are replaced with substitute data to modify the data set. Images are generated from the modified data set.

Method of detecting and compensating for faults in an MRI process

Through advancing the phase of radio frequency (RF) excitation with each phase-encoding level, a method and apparatus increases the effectiveness of a Magnetic Resonance Imaging (MRI) device by correcting for main magnetic field inhomogeneities without noticeably decreasing the signal-to-noise (SNR) ratio. Increased effectiveness of fast imaging with steady precession (FISP) scans and using FISP scans to image multiple slices. In an MRI device, a patient is subjected to a constant magnetic field, and RF pulses are used to excite the nuclei in the patient's body, which release a corresponding RF signal as the nuclei relax, which is measured and mapped into a visual display. The RF pulses used to excite the nuclei cooperate with a slice select gradient and a phase-encoding gradient. When the RF pulse is phase shifted with each phase-encoding gradient level, improved SNR ratios are observed.

A self-shielded gradient adapted to be disposed within a main magnet field of an MRI scanner includes a gradient coil having a shield current distribution Jbased on current density components &#x3c6;on a gradient surface where The current distribution is a predetermined value within a volume defined by a periphery of the gradient coil. The current distribution is substantially zero outside the periphery of the gradient coil. According to a method of producing a self-shielded gradient, a shield current distribution Jis determined based on current density components &#x3c6;on a gradient surface where by using an optimization technique, and a gradient coil is constructed according to the shield current distribution. The current distribution is a predetermined value within a volume defined by a periphery of the gradient coil. The current distribution is substantially zero outside the periphery of the gradient coil.

Self-shielded gradients and method of designing and producing self-shielded gradients

Through advancing the phase of radio frequency (RF) excitation with each phase-encoding level, a method and apparatus increases the effectiveness of a Magnetic Resonance Imaging (MRI) device by correcting for main magnetic field inhomogeneities without noticeably decreasing the signal-to-noise ratio. The present invention also increases the effectiveness of fast imaging with steady precession (FISP) scans and allows FISP scans to image multiple slices. In an MRI device, a patient is subjected to a constant magnetic field, and RF pulses are used to excite the nuclei in the patient's body. The nuclei release a corresponding RF signal as the nuclei relax, which can be measured and mapped into a visual display. The RF pulses used to excite the nuclei in the body cooperate with a slice select gradient and a phase-encoding gradient. When the RF pulse is phase shifted with each phase-encoding gradient level, improved signal-to-noise ratios are observed.

Magnetic resonance imaging

In one embodiment, a ferromagnetic frame for use in an MRI system comprises first and second opposing ferromagnetic elements magnetically coupled by a flux return path. First and second poles are provided, separated by a distance to define an imaging volume therebetween. The first pole is movably supported with respect to the first ferromagnetic element to vary the distance between the first and second poles. The first pole may have a first, imaging position and a second position wherein the first pole is farther from the second pole than in the first position. When the first pole is in the first, imaging position, a gap is provided between the first pole and the first ferromagnetic element. The second pole is supported by the second ferromagnetic element. When the first pole is in the second position, the imaging volume is made larger, providing room for medical personnel to access a patient. Performance of medical procedures on the patient is thereby facilitated. The flux return path may be two or more opposing ferromagnetic posts or plates, for example. Magnet assemblies, MRI systems, methods of conducting an MRI procedure and methods of conducting a medical procedure are also disclosed.

MRI system

A process of providing a gradient field includes providing a pair of opposing magnets and associated magnet poles, which are divided into zones. For each zone, a target current density is determined, and is modeled after a mathematical series, at least two of which are different. Gradient coils are formed from wires disposed on the magnet poles along paths corresponding to the mathematical series. A current source is connected to the gradient coils to provide the gradient field. A magnetic resonance imaging system includes a pair of opposing magnets and magnet poles, and a pair of gradient coils. The gradient coils are formed from wires disposed along paths on each magnet pole, which are divided into zones defined by a shape of the wire path in that zone. The shape in each zone corresponds to a mathematical series, which are different in at least two of the zones.

Gradient coils for MRI systems having multiple current density zones

A magnetic field produced by a magnet is measured and modeled as a sum of additive components, each having a different symmetry with respect to the three-dimensional field. The sum of all the additive components completely describes the measured magnetic field, without approximation due to truncation of terms. The degree of non-homogeneity in the measured field is determined by examining the additive components individually. A shim is designed to correspond to a magnitude change of an additive component in order to improve the homogeneity of the magnetic field, such as in an MRI application. The shim is placed in a predetermined location against a metal plate that is connected to or placed near a pole of the magnet, and a plastic plate is attached to the metal plate to hold the shim in place. Grooves are machined into corresponding symmetrical plate locations to complement the shim effect.

Method and apparatus for shimming a magnet to control a three-dimensional field

NMR apparatus for achieving construction of improved patient access desirably including a generally C-shaped yoke, and devices for reducing the field asymmetry caused by the C-shaped yoke.

Nuclear magnetic resonance apparatus and methods of use and facilities for incorporating the same

NMR apparatus for achieving construction of improved patient access. Facilities and methods of mobile and fixed site scanning.

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Greenlawn, NY, United States of America

Terry Morrone