Yeda Research and Develpment & Co. Ltd

Lucio Frydman

Shimon Michael Lustig

Zhiyong Zhang

Assaf Tal

Boaz Shapira

A method for MRI imaging of a subject includes spatially encoding spins in a slice of the subject in orthogonal first and second directions. The encoding includes applying a chirped radiofrequency (RF) pulse concurrently with application of a magnetic field gradient pulse along the first direction. After applying of the RF pulse, a second chirped RF pulse is applied concurrently with application of a second magnetic field gradient pulse, with polarity opposite that of the first gradient pulse. An encoding magnetic field gradient, constant from applying the first RF pulse until the end of applying the second RF pulse, is concurrently applied along the second direction. Following the encoding, a spin signal is measured concurrently with application of a constant readout magnetic field gradient.

Cross-term spatiotemporal encoding for magnetic resonance imaging

A method and apparatus for treating a sample for acquiring high-definition magnetic resonance images (MRI images) or high resolution nuclear magnetic resonance (NMR) spectra even in the presence of magnetic field distortions within one or multiple scans. The spatial nature and temporal dependence of the field inhomogeneities are determined a priori using any of several literature procedures. A static or oscillating magnetic field gradient is applied on the sample so as to endow spins at different positions within the sample with different resonance frequencies. A phase- and amplitude-modulated radiofrequency (RF) pulse is applied in unison with the magnetic field gradient so as to endow spins at different positions within the sample with a homogeneous excitation/inversion profile. The nature of the spatially-selective RF irradiation is tailored in such a way that, when added on top of the effects of the inhomogeneities, the spins' evolution phases and their signal amplitudes at the time of the acquisition become independent of the inhomogeneities. The spin signals thus created are captured and decoded, so as to obtain the spins' response as if the inhomogeneity was not present. The collected data is processed to a suitable rearrangement and Fourier analysis procedure to retrieve a final undistorted image or spectrum. The magnetic field gradient can be oscillated to impose this kind of inhomogeneity corrections on multiple spatial dimensions sequentially, or simultaneously.

Method and apparatus for acquiring high resolution spectral data or high definition images in inhomogeneous environments

Method and apparatus for treating a sample to acquire multidimensional spectra within a single scan that partitions a sample into a set of independent subensembles endowed with different resonance frequencies. A polychromatic irradiation of the sample is implemented whereby the various subensembles are selectively manipulated by a time-incremented series of excitation or refocusing sequences. Thereafter, a homogeneous sequence capable of generating an observable spectral signal from each of the subensembles is applied with simultaneous monitoring of the observable signals arising from the various subensembles in a resolved fashion. The observable signals acquired in this manner are processed into a complete multidimensional spectral data set.

Method and apparatus for acquiring multidimensional spectra and improved unidimensional spectra within a single scan

Method and apparatus for treating a sample to acquire multidimensional spectra within a single scan that partitions a sample into a set of independent subensembles endowed with different resonance frequencies. A polychromatic irradiation of the sample is implemented whereby the various subensembles are selectively manipulated by a time-incremented series of excitation or refocusing sequences. Thereafter, a homogeneous sequence capable of generating an observable spectral signal from each of the subensembles is applied with simultaneous monitoring of the observable signals arising from the various subensembles in a resolved fashion the observable signals acquired in this manner are processed into a complete multidimensional spectral data set.

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Rehovot, Israel

Lucio Frydman