A SIMPLE DEVICE FOR RESPIRATORY GATING FOR THE MRI OF LABORATORY-ANIMALS

Respiratory motion must be overcome if MRI of the abdomen, even at the lowest resolution, is to be performed satisfactorily. A simple and re liable respiratory gating device, based on the interruption of an infr ared (IR) optical beam is described. This device has the advantage tha t gating is based on the position of the chest as opposed to its veloc ity, and that it can be used without degrading the radiofrequency isol ation of a Faraday cage. Its use in animal MRI is illustrated by high resolution (200 mum) images of in vivo rat liver and kidney.