Static-magnetic-field shimming coil system for magnetic resonance imaging

A method of designing a static-magnetic-field shimming coil system (SCS) for magnetic resonance imaging, comprising the steps of:

• a) for each member of a cohort of magnetic resonance imaging subjects (S1, S2, S3):
• a1) acquiring a map of a static magnetic field (FM1, FM2, FM3) within a region of interest (ROI), common to all members, comprising a bodily portion (HH) of the member;
• a2) determining a corrective static magnetic field such that a sum of the acquired static magnetic field and the corrective static magnetic field is equal to a target static magnetic field within the region of interest;
• a3) determining a stream function (I, I1, I2, I3, I4), defined on a reference surface (RS, RS1) enclosing the region of interest (ROI) and corresponding to a current density distribution on said surface, minimizing either a cost function representative at least of a difference between the corrective static magnetic field and a static magnetic field generated by said current density distribution, or a cost function representative at least of an electric parameter of the coil system subject to at least one constraint representative of said difference;
• b) performing a Principal Component Analysis of the stream functions determined for at least a plurality of members of the cohort;
• and
• c) determining at least one coil wiring pattern (WP1) defined on said reference surface (RS1) by discretizing at least a most significant principal component (I1SVD) of said stream functions;
• steps a2), a3), b) and c) being carried out using a computer.