The Phase Encoding Gradient

Abstract

The y gradient is applied in the direction perpendicular to the coronal plane. Now it would seem that we could be able to use frequency in this direction just as we did for the x axis. However, if we did that, then we would not be able to uniquely specify whether a given frequency belonged to the x or the y axis, and the computer would get confused and render us an improper image reconstruction. So we must do something else, and in fact, all commercial scanners available today make use of “phase encoding”. This rather difficult concept will now be explained in depth.