Refocused insensitive nucleus enhancement by polarization transfer (RINEPT) from protons (1H) to a J-coupled phosphorus (31P) has been incorporated into three-dimensional (3D) chemical-shift-imaging (CSI) sequence on a clinical imager. The technique is demonstrated on a phantom and in in vivo human brain. The polarization-transfer efficiency (~1.2) is lower than the theoretical maximum of γ1(H)/γ31(P) ≃ 2.4 resulting from 1H- 1H homonuclear J couplings of similar magnitude competing with the 1H → 31P transfer. Nevertheless, compared with direct 31P Ernst-angle excitation, signal gains of up to x1.8 were obtained mainly as a result of T1 differences between 31P and the 1H. Spectral interpretation is simplified by editing out all non-proton-coupled 31P signals. The duration, ~50 min, and power deposition, ~1 W · kg-1, make the application suitable for human studies.
- 3D CSI
- polarization transfer
- proton decoupling
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology