Evaluation of the brain pH using a phosphorus magnetic resonance spectroscopy technique – a comparison of women and men

What is it about?

Intracellular pH provides information about the homeostatic mechanisms in neuronal cells. To use the phosphorus magnetic resonance spectroscopy (PMRS) determination of the pH in the diagnostics, it is essential to define its reference value for healthy subjects. The aim of this study was to determine the reference value of pH in healthy women and men using the PMRS technique and then to determine if there are sex differences in these values. The brains of 65 volunteers were examined - 31 women (mean age 24.4 ± 2.2 years) and 34 men (mean age 24.5 ± 2.1 years). MR system with a field strength of 1.5 T (Signa Excite, GE) and the CSI FID sequence (TR = 4000 ms, FA = 90 °, NEX = 2) were used. The analysis of the raw data was carried out in the SAGE (GE). Based on the chemical shift of the inorganic phosphate (Pi) relative to phosphocreatine (PCr) the intracellular pH was calculated separately in the group of women and a group of men. In both cases the average pH was slightly alkaline (respectively 7,10 and 7,08). The results were compared using t-test. The computed pH values are not statistically significantly different from each other (p<0.05). In this study no statistically significant sex difference in brain pH was found. Thus, in case if this method is used to estimate possible brain pathology, it is not needed to take the gender factor into consideration.

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Why is it important?

The study was to define any sex differences in pH in the largest possible volume of the brain. To our knowledge this is the first report on non-localized determination of such variability in young, healthy men and women. Its results can be helpful while estimating possible brain pathology using this technique.