Single shim coil design for b0 shimming

A magnetic resonance imaging (MRI) system comprising an MRI knee coil, wherein the MRI knee coil comprises:

• a housing comprising an opening, wherein the opening is configured so that a knee of a patient is positionable in the opening;
• an electromagnetic coil disposed in the housing, wherein the electromagnetic coil is a transmit coil or a receive coil or both, wherein the electromagnetic coil arcs circumferentially around a central axis in a direction from a first radial angle to a second radial angle, and wherein the central axis extends laterally though the opening;
• and
• a local shim coil disposed in the housing and spaced from the electromagnetic coil, wherein the local shim coil arcs circumferentially around the central axis in the direction from a third radial angle to a fourth radial angle, wherein a separation between the first and second radial angles in the direction is greater than a separation between the third and fourth radial angles in the direction, wherein the local shim coil is disposed on a semi-cylindrical surface, wherein the local shim coil generates a local shimming magnetic field that has a same magnitude and an opposite phase as a localized magnetic field inhomogeneity, and wherein the localized magnetic field inhomogeneity is caused by a susceptibility artifact disposed in the patient.

A method for magnetic resonance imaging (MRI) comprising:

• providing an MRI knee coil comprising:
• a housing comprising an opening, wherein the opening extends laterally in a first direction through the housing such that a knee of a patient is positionable within the opening;
• an electromagnetic coil disposed in the housing, wherein the electromagnetic coil is a transmit coil or a receive coil or both;
• a local shim coil disposed in the housing and spaced from the electromagnetic coil, wherein the local shim coil comprises one or more conductors, wherein each of the one or more conductors of the local shim coil is disposed on a semi-cylindrical surface, and wherein the semi-cylindrical surface extends laterally in the first direction;
• positioning the knee of the patient within the opening, such that the knee of the patient is bent at an angle and disposed between opposite sides of the housing;
• providing a first current to the local shim coil to generate a local shimming magnetic field that reduces a localized magnetic field inhomogeneity caused by a susceptibility artifact disposed in the knee of the patient;
• and
• performing an MRI process on the patient using the MRI knee coil, wherein the MRI process generates an image of the patient.