1H NMR relaxation measurements of human tissues in situ by spatially resolved spectroscopy

Abstract

Spatially resolved spectroscopy (SPARS) is a method for obtaining high-resolution NMR spectra of well-defined volumes of human tissues in situ. This method was combined with the Carr-Purcell-Meiboom-Gill multiple-echo sequence for T₂, and with inversion recovery for T₁ relaxation measurements. Relaxation times obtained by SPARS were compared with standard CPMG and IR relaxation measurements and with imaging methods, using a number of relaxation phantoms. Spectroscopically resolved relaxation data of human bone marrow, muscle, and adipose tissue in situ were obtained. T₂ measurements of human adipose tissue gave different results when using single-echo measurements rather than the CPMG method. This difference was interpreted as a J modulation effect, which shows up in fatty acid proton resonances. This J modulation effect influences the intensity of adipose tissue in routine ¹H NMR images. © 1987 Academic Press, Inc.