Leland Stanford Junior University

Elfar Adalsteinsson

Daniel Mark Spielman

Gary H Glover

Adolf Pfefferbaum

Edith V Sullivan

Dong-Hyun Kim

Pablo Irarrazabal

A non-invasive longitudinal method that is sensitive and objective for quantifying progressive loss of neurons in normal aging brains and brains that suffer from a neurodegenerative disease is provided. The method also provides clinicians, patients and drug companies with a method for evaluating the efficacy of various treatments and interventions by assessing a change in brain integrity. The method determines and localizes a change in brain integrity in a compartment of a brain from at least structural images and metabolite brain images, which are acquired for at least two time instances. The time period between two time instances is dependent on the disease pathology and disease progression and could, for instance, be at least 3 months between time instances as well as at least 6 or 12 months between time instances.

Magnetic resonance spectroscopic imaging method to monitor progression and treatment of neurodegenerative conditions

Disclosed is a method for regularized high-order shimming of a magnetic field in an MRI system. In one application a spiral pulse sequence is used to acquire field maps, and based on the user selection a shimming region, a least squares calculation of shim currents is performed that minimizes the root mean square (RMS) value of the B in homogeneity-over the volume of interest. The singular value decomposition (SVD) is used to enable regularized methods for solving the least squares problem. The regularization allows arbitrary regions to be shimmed without the divergence of shim currents.

High order shimming of MRI magnetic fields using regularization

Disclosed is a rapid data acquisition method that applies spiral-based k-space trajectories to spectroscopic imaging. In contrast to conventional acquisition methods, this technique offers independent control over imaging time and spatial resolution. The rapid scan enables the acquisition of spectroscopic data from three spatial dimensions in the same time that conventional methods acquire a single slice. This three-dimensional acquisition delivers an order of magnitude more data than the conventional methods, with no loss in SNR. In addition to three-dimensional spectroscopic imaging, other applications of the rapid k-space scanning with spiral trajectories are described. Sophisticated acquisition methods based on multiple-quantum editing can be incorporated into spectroscopic imaging sequences without a loss in SNR. These editing methods have shown particular promise in the detection of the important lactate signal in the presence of strong, undesired lipid signals. More generally, any combination of RF and gradient waveforms can precede the spectroscopic readout, as long as it excites transverse magnetization for the desired metabolites and suppresses the undesired water and lipid resonances. Rapid scans to acquire chemical-shift inhomogeneity information are also described, where a separate acquisition of the water and lipid signal is used to collect a robust and reliable map of the main field inhomogeneities.

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Palo Alto, CA, United States of America

Elfar Adalsteinsson