University of Minnesota

Shalom Michaeli

Silvia Mangia

Michael G Garwood

Dennis J Sorce

Timo Liimatainen

Matthew D Johnson

Lauri Lehto

Julia Slopsema

Gregory F Molnar

Kamil Ugurbil

John Thomas Vaughan

Simeng Zhang

Artem Shatillo

Olli Gröhn

Olli Grohn

Hanne Laakso

The present disclosure provides a method for using a magnetic resonance system to measure magnetization data from a region of interest in a subject having a spin system that includes at least a first labile spin species and a second labile spin species experiencing chemical exchange. The method includes applying periodic radiofrequency irradiation to the spin system using a frequency swept pulse sequence having frequency and amplitude modulation functions, wherein sweeping a frequency of the RF irradiation together with amplitude modulation generates a magnetic field component having an effective field. The method further includes generating off resonance side bands in a frequency domain positioned adjacent the resonant frequency of the first labile spin species or the second labile spin species by applying the periodic RF irradiation to induce the instantaneous flip of the effective field with periodicity of RF irradiation tuned to the chemical shift difference of the exchanging sites.

Systems and methods for utilizing periodic irradiation to enhance sensitivity of magnetic resonance detection

Systems and methods are provided for neuromodulation with simultaneous stimulation and reception of neuronal response. A closed-loop control system provides the ability to modulate any combination of at least five parameters of stimulation (magnitude, frequency, amplitude, time, and phase) based on any combination of at least five parameters of received signals. The neuromodulation is well-suited for deep brain stimulation (DBS) applications.

System and method for feedback-driven neuromodulation

Described here are bioelectric modulation systems and methods for generating rotating or spatially-selective electromagnetic fields. A modulation system includes a multichannel electrode with independently controllable electrode channels that can be operated to generate rotating electromagnetic fields that stimulate cells regardless of their orientation, or to generate spatially-selective electromagnetic fields that preferentially stimulate cells oriented along a particular direction. The bioelectric modulation system may be implemented for stimulation of neurons or other electrically active cells. The bioelectric modulation described here may be used for a variety applications including deep brain stimulation (DBS), spinal cord and vagus nerve stimulation, stimulation of myocardial (heart) tissue, and directional stimulation of muscles.

Bioelectrical modulation using rotating or spatially-selective electromagnetic fields

A method includes acquiring a signal intensity from a spin system after applying the radio frequency preparation pulses prior to the imaging readout or spectroscopic localization, and acquiring signal intensity starting with magnetization initially rotated to a certain angle by applying an initial pulse before the preparation scheme, and processing the data to generate an image or spectra corresponding to the spin system. The imaging or spectroscopy sequence is configured to provide data based on magnetization transfer or an off-resonance effect.

Magnetization transfer and off-resonance protocols in NMR

A system includes a driving module, a processor, and a readout module. The driving module is configured to apply a perturbation to a sample. The processor is configured to define a plurality of different rotating frames relative to the perturbation, wherein each frame has a corresponding fictitious field. The readout module is coupled to the processor and is configured to generate an output based on relaxation of the sample as a function of the perturbation.

Magnetic resonance relaxation along a fictitious field

A system includes a signal generator and a processor. The signal generator is configured to couple with a magnetic resonance transmitter coil. The processor is configured to execute instructions to control the signal generator. The instructions include forming a sequence of waveforms. The sequence is configured to generate spin relaxation in a fictitious field in a third rotating frame of reference based on at least one magnetic field component that arises based on an effective field in a second rotating frame of reference. The third rotating frame of reference is of a higher order than the second rotating frame of reference and the second rotating frame of reference is of a higher order than the first rotating frame of reference.

Magnetic resonance contrast using fictitious field relaxation

This document discusses, among other things, a system and method for modulating transverse and longitudinal relaxation time contrast in a rotating frame based on a train of radio frequency pulses.

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Saint Paul, MN, United States of America

Shalom Michaeli