Design of self-refocused pulses under short relaxation times

Bashar Issa

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The effect of using self-refocused RF pulses of comparable duration to relaxation times is studied in detail using numerical simulation. Transverse magnetization decay caused by short T2 and longitudinal component distortion due to short T1 are consistent with other studies. In order to design new pulses to combat short T1 and T2 the relaxation terms are directly inserted into the Bloch equations. These equations are inverted by searching the RF solution space using simulated annealing global optimization technique. A new T2-decay efficient excitation pulse is created (SDETR: single delayed excursion T2 resistive) which is also energy efficient. Inversion pulses which improve the inverted magnetization profile and achieve better suppression of the remaining transverse magnetization are also created even when both T1 and T2 are short. This is achieved, however, on the expense of a more complex B1 shape of larger energy content.

Original languageEnglish
Pages (from-to)151-159
Number of pages9
JournalJournal of Magnetic Resonance
Issue number2
Publication statusPublished - Jun 2009


  • Bloch equations
  • Radio frequency pulse
  • Relaxation
  • Selective excitation
  • Simulated annealing

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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