Introduction to How MRIs Work

By: John Scampini

Abstract: This tutorial explains how magnetic resonance imaging (MRI) systems use the reaction of hydrogen atoms moving in a magnetic field to yield a detailed medical image. The types of magnetic fields typically used are described. The note explains why today's higher resolution MRI systems rely on super-conducting magnets. The note also discusses the formation of 3-D images by proper alignment of gradient coils and their interaction with RF signaling. A functional block diagram of a typical MRI system is presented.