The present invention relates to a method of measuring motion of an object such
as a heart by magnetic resonance imaging. A pulse sequence is applied to spatially
modulate a region of interest of the object and at least one first spectral peak
is acquired from the Fourier domain of the spatially modulated object. The inverse
Fourier transform information of the acquired first spectral-peaks is computed
and a computed first harmonic phase image is determined from each spectral peak.
The process is repeated to create a second harmonic phase image from each second
spectral peak and the strain is determined from the first and second harmonic phase
images. In a preferred embodiment, the method is employed to determine strain within
the myocardium and to determine change in position of a point at two different
times which may result in an increased distance or reduced distance. The method
may be employed to determine the path of motion of a point through a sequence of
tag images depicting movement of the heart. The method may be employed to determine
circumferential strain and radial strain.
