Comparative Evaluation of Signal Hyperintensity in Pallidal Structures of Patients with Liver Cirrhosis

Teimuraz Kodua, Ketevan Lashkhi, Mamuka Gurgenidze, Teimuraz Ioseliani, Maia Meparidze, Maka Moistsrapishvili, Nino Shervashidze, Sopho Lobzhanidzee 

Tbilisi State Medical University; Research Institute of Medical Radiology, Georgia

Clinical, laboratorial, morphologic and magnetic resonance imaging (MRI) observations indicate accumulation of paramagnetic substance (manganese - Mn and/or copper - Cu) in the brain of patients with hepatoencephalopathy (HE). Pallidal index (PI) - semi-quantitative indicator of brain manganese concentration in vivo is calculated as a ratio of globus pallidus to subcortical frontal white matter signal intensity in sagittal T1-weighted MRI planes multiplied by 100. Signal intensity in other regions of the brain (putamen, subthalamic area, amygdala etc.) also represents an area of interest. Significant correlations have been shown between blood Mn content, liver enzyme activity, brain MRI changes and signs of parkinsonism in cirrhotic patients. Recently it has been showed that in the diagnostics of HE psychometric tests are as valuable as neuroimaging. The goal of our study was to reveal correlations between signal intensity and severity of HE measured by number connection test part - A. The signal intensity was defined in the areas of globus pallidus, putamen and prefrontal white matter. Some correlations were calculated between PI, HE degree and in blood and 24 hour urine manganese and copper contents. The study covered 17 patients suffering from HE. Hyperintense T1 signal was revealed in all 17 cases. Maximal signal intensity was obtained in the pallidal area, less - in putamen and very low - in the prefrontal white matter. The brain manganese deposition is explained by the following hypothesis: hyperammonemia and lack of substrate - glutamate leads to the saturation and decrease of glutaminesynthetase activity. Imbalance in the distribution of metal co-enzyme Mn ions in mitochondria and cytosol occurs. Needless and thus unused free manganese ions released from mitochondria in cytosol, accumulate and create paramagnetic deposits.

Keywords:  liver cirrhosis, hepatoencephalopathy, paramagnetic substances, manganese, copper, pallidal index