In magnetic resonance imaging (MRI), quantitative susceptibility mapping (QSM) is known in which tissue susceptibility is generated from phase signals.
As a method for generating susceptibility from a phase image that represents a distribution of phase signal data, inverse transform of an equation representing the relation between susceptibility and phase signal data is known. However, this method is an inverse problem with no unique solution, thereby failing to uniquely generate a correct susceptibility value.
To generate such a susceptibility value, estimating a susceptibility image representing a distribution of approximate susceptibility by using, for example, regularization is widely implemented. However, generating the susceptibility value using regularization is also an inverse problem with no unique solution at or near the magic angle in the frequency space of the susceptibility image. The magic angle is an angle of 55 or 135 degrees relative to the static magnetic field direction from the center (DC position) of the frequency space. This results in streak artifacts (or radial artifacts) having different widths on the susceptibility image mainly in accordance with the size of the noise region on the phase image.