"Dost thou love life? Then do not squander time, for that's the stuff
life is made oj': Benjamin Franklin This book describes the technical
principles and applications of echo-planar imaging (EPI) which, as much
as any other technique, has shaped the develop- ment of modern magnetic
resonance imaging (MRI). The principle of EPI, namely, the acquisition
of multiple nuclear magnetic resonance echoes from a single spin
excitation, has made it possible to shorten the previously time-con-
suming MRI data acquisition from minutes to much less than a second.
Interest- ingly, EPI is one of the oldest MRI techniques, conceived in
1976 by Sir Peter Mansfield only 4 years after the initial description
of the principles of MRI. One of the inventors of MRI himself, Mansfield
realized that fast data acquisition would be paramount in bringing
medical applications of MRI to full fruition. The technological
challenges in implementing EPI, however, were formidable. Until the end
of the 1980s few people believed that EPI would be clinically useful,
since its complexity was far greater than that of "conventional" MRI
methods.