In MR imaging of a body part of a patient in an intra-operative procedure, the body part is supported using gel pads where the gel material is arranged such that the presence of the gel material does not generate an image in the analysis of the RF signal from the location so that the pad is invisible in the MR image. This can be obtained by using a water based gel material and providing an additive such as manganese chloride to reduce the relaxation time of the water molecules to a value which is sufficiently short that the molecules relax before the acquisition of the signals by the RF receive coil. This can be achieved by using a non-water based gel or a heavy water based gel.