The Extended Phase
Graph (EPG) calculus can be understood as a solution of the Bloch
equation using its k‑space representation. The ability to represent
magnetization in phase state configurations frequently enables an intuitive and
pictorial understanding of echo formation and assignment. A class of functions
that allows for the easy calculation and simulation of EPGs for arbitrary MR
sequences was developed (EPGspace)
and its key points are presented. The EPGspace source code is made publically available for download in the internet.