Mayo Foundation for Medical Education and Research

University of Minnesota

Clifford R Jack, Jr

Stephen J Riederer

Michael G Garwood

Armando Manduca

Joseph F Poduslo

Edward Brian Welch

Thomas M Wengenack

Roger C Grimm

Heidi A Ward

Peter C O'Brien

Amyloid plaque in the brain of a subject is imaged in an MRI system with or without the use of a contrast agent. Contrast is achieved using a spin-echo pulse sequence that is both respiratory gated and cardiac gated to reduce motion artifacts at the very high image resolution required to see plaque. A preparatory pulse sequence is used to insure longitudinal magnetization remains constant for all the acquired views even if the effective TR changes during the scan due to irregular breathing.

Magnetic resonance imaging of amyloid plaque in the brain

A method for classifying tissue in a magnetic resonance image, and particularly for measuring a volume of pathological tissue such as white tissue hyperintensity (leukoaraiosis) in the brain based on the segmentation of the intensity histogram of fluid attenuated inversion recovery (FLAIR) images is described. A magnetic resonance image of the brain of a subject is acquired, and a pixel intensity histogram is constructed from the image. A statistically-based regression analysis is applied to the histogram to determine upper and lower threshold values, which define different types of brain tissue, particularly normal brain, cerebral spinal fluid (CSF), or lesion.

Histogram segmentation of FLAIR images

A series of fMRI image frames are acquired along with interleaved navigator signals. The navigator signals are acquired while three orthogonal readout gradients are applied such that a spherical surface is sampled in k-space. The navigator signals are analyzed to measure subject rotational and translational motion during the scan.

Reduction of motion artifact in NMR images using spherical navigator signals

An fMRI scan is performed with an MRI system in which a series of single shot EPI pulse sequences are performed to acquire a series of images. A shim navigator pulse sequence is interleaved with the EPI pulse sequence to acquire data with which the MRI system polarizing magnetic field can be measured. Measured changes in the polarizing field during the scan are employed to calculate corrective changes in the scan parameters that offset phase errors caused by changes in the polarizing field.

Real-time shimming of polarizing field in magnetic resonance system

Growing community of inventors

Rochester, MN, United States of America

Clifford R Jack, Jr