Image shown depicts the generation of a gradient in B0 in the Z direction. Image shown depicts the generation of a gradient in B0 in the Z direction. For a standard clinical MR system, this is accomplished using two coils in which the current flowing through them runs in opposite directions to each other (the so-called Maxwell pair type). The magnetic field at the centre of one coil adds to the B0 field while the magnetic field at the centre of the other subtracts from B0, thus creating a gradient in the B0 field.29 X and Y gradient coils (not shown) generally have a figure-8 configuration. (These designs have started to be superseded by ‘thumb-print’ designs, which produce the desired gradients over the patient, but minimise any interfering field interacting with the main magnet's coils and containers.)‏ Stuart Currie et al. Postgrad Med J 2013;89:209-223 Copyright © The Fellowship of Postgraduate Medicine. All rights reserved.