A method is proposed for carrying out chemical-shift imaging simultaneously on several nuclei (1H and 31P in this example), using a commercial clinical NMR imager fitted with a second RF channel and a dual-tuned birdcage coil to fit the human head. Nuclei of different γ are examined at the same field of view by exciting each nucleus successively at times proportional to γ during the same phase-encoding gradient waveform. Thus, each higher-γ nucleus is exposed to a smaller area of the gradient. Additionally, since in vivo protons typically have a shorter T1 and roughly an order of magnitude higher sensitivity than phosphorus, it is possible to interleave 1H-only acquisitions between the simultaneous 1H, 31P observations while the lower-γ nucleus relaxes. Consequently, additional information is obtained with either higher spatial resolution or greater sensitivity (more signal averaging) without lengthening the duration of the examination.
ASJC Scopus subject areas