On resonance phase alternated CWFP sequences for rapid and simultaneous measurement of relaxation times

[Display omitted] •New CWFP sequences for determination of both relaxation times are proposed.•The sequences with π phase alternation can be performed on resonance.•The Carr–Purcell sequence with π/2 pulses (CP-CWFPx−x) shows the best performance.•CP-CWFPx−x shows the highest dynamic range independe...

Full description

Saved in:
Bibliographic Details
Published in:Journal of magnetic resonance (1997) 2015-10, Vol.259, p.174-178
Main Authors: Monaretto, Tatiana, Andrade, Fabiana Diuk, Moraes, Tiago Bueno, Souza, Andre Alves, deAzevedo, Eduardo Ribeiro, Colnago, Luiz Alberto
Format: Article
Language:English
Subjects:
CP-CWFP
CWFP
Phase alternation
SSFP
TD-NMR
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:[Display omitted] •New CWFP sequences for determination of both relaxation times are proposed.•The sequences with π phase alternation can be performed on resonance.•The Carr–Purcell sequence with π/2 pulses (CP-CWFPx−x) shows the best performance.•CP-CWFPx−x shows the highest dynamic range independent of T1/T2 ratio. T1 and T2 relaxation times have been frequently used as probes for physical–chemical properties in several time-domain NMR applications (TD-NMR) such as food, polymers and petroleum industries. T2 measurements are usually achieved using the traditional Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence because it is a fast and robust method. On the other hand, the traditional methods for determining T1, i.e., inversion and saturation recovery, are time-consuming, driving several authors to develop rapid 1D and 2D methods to obtain T1 and T2 or T1/T2 ratio. However, these methods usually require sophisticated processing and/or high signal to noise ratio (SNR). This led us to develop simple methods for rapid and simultaneous determination of T1 and T2 using Continuous Wave Free Precession (CWFP) and Carr–Purcell Continuous Wave Free Precession (CP-CWFP) pulse sequences. Nevertheless, a drawback of these sequences is that they require specific adjustment of the frequency offset or the time interval between pulses (Tp). In this paper we present an alternative form of these sequences, named CWFPx−x, CP-CWFPx−x, where a train of π/2 pulses with phases alternated by π enable performing the experiments on-resonance and independently of Tp, when Tp
ISSN:1090-7807
1096-0856
DOI:10.1016/j.jmr.2015.08.013