Interleaved 31P MRS imaging of human frontal and occipital lobes using dual RF coils in combination with single-channel transmitter-receiver and dynamic B0 shimming

In vivo(31)P magnetic resonance spectroscopy (MRS) provides a unique tool for the non-invasive study of brain energy metabolism and mitochondrial function. The assessment of bioenergetic impairment in different brain regions is essential to understand the pathophysiology and progression of human brain diseases. This article presents a simple and effective approach which allows the interleaved measurement of P-31 spectra and imaging from two distinct human brain regions of interest with dynamic B-0 shimming capability. A transistor-transistor logic controller was employed to actively switch the single-channel X-nuclear radiofrequency (RF) transmitter-receiver between two P-31 RF surface coils, enabling the interleaved acquisition of two P-31 free induction decays (FIDs) from human occipital and frontal lobes within the same repetition time. Linear gradients were incorporated into the RF pulse sequence to perform the first-order dynamic shimming to further improve spectral resolution. The overall results demonstrate that the approach provides a cost-effective and time-efficient solution for reliable P-31 MRS measurement of cerebral phosphate metabolites and adenosine triphosphate (ATP) metabolic fluxes from two human brain regions with high detection sensitivity and spectral quality at 7T. The same design concept can be extended to acquire multiple spectra from more than two brain regions or can be employed for other magnetic resonance applications beyond the P-31 spin.