Patent ID: 6597935
Filing Date: 2003-07-22
Classification: G01R

Abstract:
A method of measuring three-dimensional motion of an object by harmonic phase magnetic resonance imaging comprising:applying a first tag pulse sequence to spatially modulate a region of said object within a short axis plane; acquiring a first spectral peak from the Fourier domain of said spatially modulated object; computing the inverse Fourier transform information of said acquired first spectral peak; computing a first harmonic phase image; applying a second tag pulse sequence to spatially modulate a region of interest of said object in a direction perpendicular to said first tag pulse sequence within a short axis plane; acquiring a second spectral peak from the Fourier domain of said spatially modulated object; computing the inverse Fourier transform information of said acquired second spectral peak; computing a second harmonic phase image; creating tagged images of circumferential and radial strains by combining said first harmonic phase image and said second harmonic phase image; applying a third tag pulse sequence in a third direction generally perpendicular to said first and second tag pulse sequences through said region of interest of said object, and creating a third harmonic phase image therefrom; applying a fourth tag pulse sequence of a different strength than said third tag pulse sequence in a fourth direction generally perpendicular to said first and second tag sequences and generally in said third direction and creating a fourth harmonic phase image therefrom; and determining longitudinal strain by combining said third and fourth harmonic phase images to determine strain in a longitudinal direction.