In situ determination of pH in brain tissue using postmortem 1H-MRS

Postmortem, relatively low pH values have been described and reported to be dependent on the cause of death and the duration of the agonal phase. Using 1H-MRS on decedents and subsequent control pH measurements in collected samples, we investigated to what extent the pH dependence of peak positions of acetate and lactate are suitable to detect such low pH values non-invasively. We found that the measured chemical shift of acetate and corresponding pH value follow a simulated titration curve. Hence, acetate is a promising candidate to detect low postmortem brain pH for forensic investigations.