Abstract: A method of magnetic resonance imaging a flowing liquid flowing through a rectangular cross-section column of space, wherein imaging readings are obtained from points throughout the column by utilizing a frequency encoding gradient to define the position of a reading point in the direction of the long axis of the column; defining the position of a reading point in a plane normal to the long axis of the column using one of phase encoding gradients and echo-planar blips; using one of phase encoding gradients and echo-planar blips with odd echoes and even echoes to acquire readings in two distinct regions of k-space; and obtaining readings in each plane normal to the long axis of the column from a 32×32 matrix of reading points using 16 phase encoding steps and 8 echo planar interleaves. Alternatively, the step of obtaining may be accomplished by varying the velocity phase sensitivity of the frequency encoding gradient to achieve a continuously varying phase sensitivity across k-space.

Abstract: In Magnetic Resonance Imaging Apparatus, it is necessary to switch the radio frequency electric coils which are positioned around the patient in the imaging volume very rapidly. The present invention achieves such switching using switching devices which are sensitive to control signals other than electrical signals. This removes the need to pass additional electrical conductors, which could carry interfering signals, into the imaging volume and this reduces image degradation. In particular the switching devices may be photodiodes which function in response to optical signals carried by optical fibres.