A planar MRI system is disclosed. The system has an open magnet configuration
that
produces a magnetic field having a remote region of substantial magnetic field
homogeneity. Spatial encoding gradient coils and a rf coil provide MRI data for
image reconstruction. The open magnet configuration has a ferromagnetic core with
a substantially planar core surface layer and a longitudinal axis, and a unipolar
current wire pair on a side of the ferromagnetic core adjacent the planar core
surface layer. The wire pair is separated along the longitudinal axis and extends
in a direction substantially perpendicular to the axis and substantially parallel
to the planar core surface layer. The current wire pair provides a magnetic field
having a maximum between the current wire pair along a direction perpendicular
to the planar core surface layer and in the remote region of substantial magnetic
field homogeneity. The planar core surface layer of the ferromagnetic core provides
an orthogonal refractory effect in the form of mirror imaging current wires having
the same polarity as the current wire pair that substantially increases the resulting
magnetic field compared to a magnetic field generated by the current wire pair
in free space.
