Effect of off-resonance on T1 saturation recovery measurement in inhomogeneous fields

Chong Duan; Colm Ryan; Shin Utsuzawa; Yi-Qiao Song; Martin D Hürlimann

doi:10.1016/j.jmr.2017.05.003

Effect of off-resonance on T₁ saturation recovery measurement in inhomogeneous fields

J Magn Reson. 2017 Aug:281:31-43. doi: 10.1016/j.jmr.2017.05.003. Epub 2017 May 10.

Authors

Chong Duan¹, Colm Ryan², Shin Utsuzawa³, Yi-Qiao Song⁴, Martin D Hürlimann⁵

Affiliations

¹ Schlumberger-Doll Research, Cambridge, MA 02139, USA; Department of Chemistry, Washington University, Saint Louis, MO 63110, USA. Electronic address: duanchong@wustl.edu.
² Schlumberger-Doll Research, Cambridge, MA 02139, USA; Raytheon BBN Technologies, Cambridge, MA 02138, USA. Electronic address: colm@colmryan.org.
³ Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: sutsuzawa@slb.com.
⁴ Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: ysong@slb.com.
⁵ Schlumberger-Doll Research, Cambridge, MA 02139, USA. Electronic address: hurlimann@slb.com.

PMID: 28544910
DOI: 10.1016/j.jmr.2017.05.003

Abstract

Saturation-recovery measurements with Carr-Purcell-Meiboom-Gill sequences are commonly employed to measure the longitudinal relaxation time constant, T₁, in grossly inhomogeneous fields. We show that in general the off-resonant effect generates unexpected extra signals in the T₁ measurement. In the present study, we derive a modified T₁ kernel that accounts for this off-resonance effect quantitatively. The new kernel has been tested with numerical simulations and experiments, and excellent agreement is found.

Keywords: Dynamic equilibrium; Off-resonance; Saturation recovery.