The United States of America as Represented by the Department of Health

The United States of America as Represented by the Secretary, Department

Denis LeBihan

Peter J Basser

Stefan Posse

Jose Delannoy

James H Mattiello

Ronald L Levin

A method and system for providing prelocalization of a volume of interest and for rapidly acquiring a data set for generating spectroscopic images. Spatial prelocalization of a volume of interest is achieved by providing a presuppression sequence before a stimulated echo (STE) sequence and a suppression sequence during the mixing time (TM) interval of the STE sequence. The presuppression sequence includes a spatial suppression sequence to selectively saturate slices that intersect the plane selected by the STE sequence in order to define a boundary for the volume of interest, and this spatial suppression sequence is substantially repeated during the TM interval of the STE sequence. Spectroscopic imaging data is acquired by an oversampled echo planar spatial-spectral imaging sequence in which the gradient reversal frequency is a integer factor of n greater than the gradient reversal frequency required to sample the spectral width. Each RF pulse of the STE sequence excites spins in substantially the same plane, and an adaptation of this STE sequence provides for acquiring multiple echoes at different effective echo times without compromising spatial localization of the different echoes.

Method and system for multidimensional localization and for rapid

A method and system for measuring the effective diffusion tensor for spin labeled particles, and generating images therefrom. The effective diffusion tensor is related to the echo intensity in an NMR spin-echo experiment. This relationship is used to design experiments from which the diffusion tensor components are estimated. Estimation of Deff provides the theoretical basis for a new MRI modality, diffusion tensor imaging. Diffusion ellipsoids may be used for generating images representative of physical characteristics of the observed object. Scalar invariants of the diffusion tensor are also used for imaging.

Method and system for measuring the diffusion tensor and for diffusion

A method of determining and imaging the temperature or temperature change of a liquid or solid object by NMR placing the object in a magnetic field B.sub.o at a temperature T.sub.o.sup.i, subjecting the object or a limited volume thereof to a first series of NMR imaging sequences to obtain first numerical values or images of molecular diffusion coefficients D.sub.o for individual points of the object or the limited volume thereof and recording the first series of images, maintaining the object or limited volume thereof at a temperature T.sup.i or waiting for a spontaneous change to the temperature, subjecting the object to a second series of magnetic resonance imaging sequences to obtain second numerical values or images of molecular diffusion coefficients D.sup.i for the same points of the object or the limited volume thereof and recording the second series of images, comparing point-by point the values or images of the diffusion coefficients D.sub.o.sup.i with the values or images of the diffusion coefficients D.sup.i to generate a third series of values or images representing temperature changes dT.sub.i and recording the third series of images for each point of the object or limited volume thereof from the formula

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Rockville, MD, United States of America

Denis LeBihan