It is demonstrated that the stability of the Carr-Purcell-Meiboom-Gill
(CPMG) sequence reflects the existence of a steady state solution to
the Bloch equations in the absence of T-2 and T-1 decay. The steady st
ate theory is then used to evaluate the performance of low flip angle
RARE imaging sequences with both constant and optimally varied refocus
ing flip angles. The theory is experimentally verified in phantoms and
then optimized, single shot, low flip angle RARE is used to obtain ar
tifact-free images from the brain of a normal volunteer.