In situ postmortem ethanol quantification in the cerebrospinal fluid by non‐water‐suppressed proton MRS

Abstract

Determination of the ethanol concentration in corpses with MRS would allow a reproducible forensic assessment by which evidence is collected in a noninvasive manner. However, although MRS has been successfully used to detect ethanol in vivo, it has not been applied to postmortem ethanol quantification in situ. The present study examined the feasibility of the noninvasive measurement of the ethanol concentration in human corpses with MRS. A total of 15 corpses with suspected alcohol consumption before demise underwent examination in a 3 T whole body scanner.To address the partial overlap of the ethanol and lactate signal in the postmortem spectrum, non-water-suppressed single voxel spectra were recorded in the cerebrospinal fluid (CSF) of the left lateral ventricle via the metabolite cycling technique. The ethanol signals were quantified using the internal water as reference standard, as well as based on a reference signal acquired in a phantom. The measured values were compared with biochemically determined concentrations in the blood (BAC) and CSF (CSFAC). In 8 of the 15 corpses a BAC above zero was determined (range 0.03-1.68 g/kg). In all of these 8 corpses, ethanol was measured in CSF with the proposed MRS protocol. The two applied MRS calibration strategies resulted in similar concentrations. However, the MRS measurements generally overestimated the ethanol concentration by 0.09 g/kg (4%) to 0.72 g/kg (45%) as compared with the CSFAC value. The presented MRS protocol allows the measurement of ethanol in the CSF in human corpses and provides an estimation of the ethanol concentration prior to autopsy. Observed deviations from biochemically determined concentrations are mainly explained by the approximate correction of the relaxation attenuation of the ethanol signal.

NMR in forensics

“…[ 1a ] Zoelch et al used 1 H “magnetic resonance spectroscopy” for the post‐mortem quantification of ethanol in cerebrospinal fluid using internal water and a signal acquired from a phantom as reference standards. [ 13 ] Locci et al utilized NMR metabolomics for the diagnosis of asphyxial death in an animal model and found evidence that metabolomics provided additional evidence beyond that obtained by histology and immunohistochemistry in the differential diagnosis of pre‐ and post‐asphyxiation cardiac arrest. [ 14 ] Chighine et al demonstrated that metabololic profiling by NMR of infant urine was useful in the determination of fatal acute methadone intoxication in a case study of a suspicious claim of sudden infant death syndrome.…”