Original Jpn J Radiol Technol 1999 ; 55 (10) :
Proton T2 Relaxation Effect of Superparamagnetic Iron Oxide on Fast Spin Echo Sequence: Influence of Echo Number(Even or Odd)
of Effective TE

TOSHIO TSUCHIHASHI, ISAO FUJITA,1) TOSHIO MAKI, MATSUO KITAGAWA, and TAKESHI SUZUKI
Department of Radiology, Nippon Medical School Main Hospital
1)Department of Radiology, Urawa Municipal Hospital
Received Feb. 4, 1998; Revision accepted July 7, 1999; Code No. 261
Summary
The T2 relaxation effect of the fast spin echo sequence(FSE)was investigated using superparamagnetic iron oxide(SPIO)particles. When even echoes were used as the effective TE of FSE, the signal intensity ratio [signal intensity of FSE/signal intensity of conventional spin echo sequence(CSE)] of FSE and CSE increased, whereas the T2 relaxation effect of SPIO with FSE was reduced. However, when odd echoes were used, neither signal intensity changed, and weakening of the T2 relaxation effect, considered a problem with FSE, was reduced. This phenomenon was not observed when the refocusing flip angle was changed to 30 and 60 degrees. However, it was observed when the refocusing flip angle was 120 and 150 degrees. Thus, this phenomenon can be considered to be related to oscillation in longitudinal magnetization when using the Carr-Purcell-Meiboom-Gill(CPMG)technique.
Key words: Fast spin echo, Susceptibility, T2 relaxation effect, Superparamagnetic iron oxide(SPIO), Carr-Purcell-Meiboom-Gill(CPMG)