Patent ID: 8588890

Claim:
A magnetic resonance imaging (MRI) apparatus comprising: an MRI gantry including a static magnet, a set of gradient magnets, at least one radio frequency (RF) coil, an RF transmitter, an RF receiver and control circuits including at least one computer configured to detect a magnetization vector having an amplitude and relative phase angle which correspond to orthogonal real and imaginary vector components for each of a large number of pixel positions in an imaging region including at least part of a subject, the magnetization vector being excited to have a phase angle difference between (a) pixel positions from a flow portion of the imaging region in which a fluid flows and pixel positions from a static portion of the imaging region in which tissues are static or (b) between pixel positions from a normal tissue portion of the imaging region and pixel positions from an abnormal tissue portion of the imaging region having a difference in susceptibility from the normal tissue portion; determine a first pixel value for each pixel position as a value proportional to an absolute value of the amplitude of the magnetization vector detected for that pixel position; and correct, on the basis of a real part of the magnetization vector detected for each pixel position, the first pixel value to generate a corrected second pixel value by enhancing magnetization vector phases to make the phase angle for pixel positions representing a blood vessel or abnormal tissue more closely approaches ±180° while the phase angle for pixel positions representing other static or normal background portions approaches zero so that the contrast difference of the corrected second pixel values is increased between (a) the flow portion or the abnormal portion and (b) the static portion or the normal portion.