The United States of America, as Represented by the Secretary, Department of Health and Human Services

Anthony H Aletras

Han Wen

Robert S Balaban

Kathleen M Ward

Image contributions produced by an untagged specimen magnetization component in magnetic resonance imaging are controlled by applying one or more radiofrequency (RF) pulses that invert at least a portion of the untagged specimen magnetization. In an example, a specimen is tagged with a spatially modulated magnetization that is used to produce an image signal that includes a contribution associated with the tagged magnetization and an untagged magnetization. The untagged magnetization is substantially along an axial direction defined by an applied axial magnetic field. The untagged magnetization increases in magnitude because of so-called Trelaxation. A contribution to the image signal increases for a predetermined time or to a predetermined magnitude, and a 180-degree pulse is applied to invert at least a portion of the untagged magnetization. The untagged magnetization is then antiparallel with respect to the applied axial magnetic field. Additional inversion recovery causes the untagged magnetization to increase from a negative value to zero and then becomes positive. As a result, signal contributions associated with the untagged magnetization are reduced. Additional 180-degree pulses can be applied whenever the untagged magnetization becomes larger than a predetermined value so that image contrast can be maintained. When the tagged magnetization decreases to a predetermined level, an initial specimen magnetization is reestablished for subsequent imaging.

Magnetic resonance imaging methods and apparatus for time-series motion tracking with inversion recovery compensation

Magnetic resonance imaging method and apparatus are provided for mapping the internal or bulk motion of an object by labeling the phase of a specimen magnetization with a selected spatial function and measuring changes in the phase of the magnetization. The spatial function is selectable to provide magnetization phase modulation corresponding to displacements in a selected direction, such as a radial or azimuthal direction. Methods and apparatus for producing images based on magnetization phase modulation acquire image data based on stimulated echos and stimulated anti-echos. In an embodiment, a series of 180 degree pulses produces alternating stimulated and stimulated anti-echos that are measured and assigned to respective images.

Methods and apparatus for mapping internal and bulk motion of an object with phase labeling in magnetic resonance imaging

Method for determining in vivo concentration of a metabolite that includes administering a contrast agent to a subject, allowing the contrast agent to disperse to tissue of interest, performing CEDST MRI analysis of the subject, and comparing the results to known in vitro results to determine metabolite concentration.

Method for determining in vivo concentration of a metabolite

A method for obtaining an image by MRI, comprising: administering at least one contrast agent to a subject in amounts effective to perform CEDST MRI analysis; and performing CEDST MRI analysis to produce an image of the subject. A number of different contast agents can be used to practice the present method including, without limitation, sugars, animo acids, nitrogen-containing heterocycles, purines and pyrimidines, nucleosides; imidazole and derivatives thereof, imino acids, barbituric acid and analogs thereof, and miscellaneous materials, such as guanidine hydantoin, parabanic acid, and biologically active salts thereof.

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Rockville, MD, United States of America

Anthony H Aletras