NEW AND RAPID D-T1 CORRELATION MEASUREMENTS AND DIRECT NMR T1 DISTRIBUTION MEASUREMENT METHOD

Vol 1, 2021 - 140746
Invited Lecturer
Favoritar este trabalho
Como citar esse trabalho?
Resumo

The presentation mainly approaches two articles published in the Journal of Magnetic Resonance. In the first article [1], we studied four D-T1 sequences for TD-NMR combining Stejskal-Tanner Pulse Gradient Spin Echo (PGSE) diffusion measurement with Inversion-Recovery (IR), Saturation-Recovery (SR), Small-Angle Continuous Wave Free Precession (CWFP-T1), and Small-Angle Flip-Flop (SAFF) for T1 measurement. The results show that rapid D-T1 measurements can be obtained with single shot CWFP-T1 and SAFF sequences. The two sequences were two and eight times faster than sequences based on SR and IR, respectively. Although the two fast sequences yield lower signal-to-noise ratio, they can be as fast as the traditional D-T2 experiment, or even faster, because it is not necessary to wait a recycle delay of 5 T1. Another advantage of the CWFP-T1 and SAFF methods, when compared to the ones based on SR or CPMG (for D-T2) are the low specific absorption rate (SAR) of these sequences due to the low flip angles employed, which reduce sample heating problems. In the second article [2], a new method to measure T1 without using ill-posed fitting methods is introduced. The usual Nuclear Magnetic Resonance (NMR) experiments for measuring spin–lattice relaxation time (T1) distributions are Inversion-Recovery (IR) and Saturation-Recovery (SR), followed by data processing based on ill-posed multi-exponential curve fitting methods. Recently, a new method combining SR and IR, called Saturation-Inversion-Recovery (SIR), has been proposed to obtain sharper T1-dependences than IR and SR. In this work, we propose an appropriate combination of SIR signals to directly obtain T1 distributions without using any multi-exponential fitting methods.

Compartilhe suas ideias ou dúvidas com os autores!

Sabia que o maior estímulo no desenvolvimento científico e cultural é a curiosidade? Deixe seus questionamentos ou sugestões para o autor!

Faça login para interagir

Tem uma dúvida ou sugestão? Compartilhe seu feedback com os autores!

Instituições
  • 1 Department of Chemical and Biological Physics, Weizmann Institute of Science, Israel
  • 2 Centre National de La Recherche Scientifique, France
  • 3 Embrapa Instrumentation, Brazil
  • 4 São Carlos Institute of Physics, University of São Paulo, Brazil
Palavras-chave
longitudinal relaxation
Diffusion
D-T1 correlation