Two-dimensional semi-LASER correlation spectroscopy with well-maintained cross peaks.
Magn Reson Med
; 72(1): 26-32, 2014 Jul.
Article
em En
| MEDLINE
| ID: mdl-24123233
ABSTRACT
PURPOSE:
To demonstrate that the limited bandwidth of the second 90° radiofrequency (RF) pulse in two-dimensional (2D) localized correlation spectroscopy (L-COSY) induces spatially dependent magnetization transfer that results in attenuated cross-peaks, and to propose a new 2D semi-adiabatically localized COSY sequence to solve this problem. METHODS AND THEORY A semi-localization by adiabatic selective refocusing (semi-LASER or sLASER) method was incorporated into the COSY sequence with the slice-selective first 90° RF pulse and the non-slice-selective second 90° RF pulse to form a new 2D sLASER localized COSY sequence, named "sLASER-first-COSY," to solve the problem of spatially dependent magnetization transfer. Experiments were performed to verify the feasibility and advantages of sLASER-first-COSY sequence over a recently reported other sLASER COSY sequence with a slice-selective second 90° RF pulse, named "sLASER-last-COSY".RESULTS:
Phantom, ex vivo, and in vivo human brain experiments demonstrated that sLASER-first-COSY yielded stronger cross peaks and higher ratios of cross peak volumes to diagonal peak volumes than sLASER-last-COSY.CONCLUSION:
As COSY relies on the cross peaks to obtain larger dispersion of peaks for quantification, the new sLASER-first-COSY sequence yielding well-maintained cross peaks will facilitate more reliable and accurate quantification of metabolites with coupled spin systems.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Química Encefálica
/
Espectroscopia de Ressonância Magnética
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article