Brain edema dynamics in patients with overt hepatic encephalopathy A magnetic resonance imaging study.

The aim of our study was to investigate the dynamics of brain water content assessed by magnetic resonance imaging (MRI) applications in patients with cirrhosis and overt episodic hepatic encephalopathy (HE).

METHODS

Twenty-four patients with cirrhosis and overt HE, 9 healthy controls and 9 controls with cirrhosis but without HE were included. All patients underwent laboratory analysis, MRI and (1)H MRS in the first 24h after the diagnosis of encephalopathy. Five of them were studied again 5days after the resolution of HE.

RESULTS

The values of glutamine/glutamate (Glx) increased progressively (healthy controls: 1.8; cirrhotic controls: 2.4; HE: 4.4; p=0.0001). Values of myo-inositol were lower among cirrhotics than in healthy controls (healthy: 0.6; cirrhotic: 0.3; HE: 0.4; p=0.01). Patients with overt HE showed a decrease in MTR in several brain locations. A significant correlation was observed between MTR values and Glx/creatine ratios (r=-0.54; P=0.004). Five days after the resolution of HE, there were no changes in brain Glx/Cr or MTR but a significant decrease of median ADC in parietal grey matter was observed (acute HE: 121.9 vs. 5days later: 100.5; p<0.05).

CONCLUSIONS

Cirrhotic patients with overt HE have a disturbance in the brain osmolyte homeostasis, reflecting a low-grade brain edema. Shortly after the clinical resolution of the episode of HE low-grade brain edema still persists, but there is a decrease in the ADC value in the parietal grey matter, suggesting water flux from extracellular to intracellular compartments and the existence of a vasogenic brain edema.