Cerebral proton and phosphorus-31 magnetic resonance spectroscopy in patients with subclinical hepatic encephalopathy

Background/Aims: In vivo magnetic resonance spectroscopy can be used to stu dy cerebral metabolism non-invasively. We aimed to correlate H-1 and P-31 m agnetic resonance spectral abnormalities in the brains of patients with sub clinical hepatic encephalopathy. Methods: Eighteen patients were studied at 1.5T, with combined H-1 and P-31 magnetic resonance spectra obtained from multiple voxels in the cerebral cortex and basal ganglia. Peak area ratios of choline, glutamine/glutamate, relative to creatine in the H-1 spectra an d percentage phosphomonoesters, phosphodiesters and beta NTP signals relati ve to total P-31 signals in the P-31 spectra were measured. Results: Six pa tients did not complete the full examination - P-31 results are available f rom 12 patients only. Relative to creatine, there were reductions in cholin e and elevations in glutamine/glutamate, varying across the brain with chol ine significantly reduced in occipital cortex (p<0.05) and glutamine/glutam ate most significantly elevated in temporo-parietal cortex (p<0.0001). Perc entage phosphomonoester (p<0.05), phosphodiester (p<0.05) and beta NTP (p<0 .005) signals were significantly decreased in basal ganglia spectra. No cor relation was found between the magnitude of H-1 and P-31 MRS changes, excep t between percentage phosphodiester decrease and glutamine/glutamate to cre atine increase in occipital cortex. Conclusion: The results of this study p oint to a multifactorial aetiology for this condition.