title: Regional differences in cerebral blood flow and cerebral ammonia metabolism in patients with cirrhosis.
abstract: Clinical and histopathological findings hint at regional differences in the brain's sensitivity to metabolic changes in cirrhosis. The aim of the present study was to examine regional differences in cerebral ammonia metabolism in patients with cirrhosis and grade 0-to-I hepatic encephalopathy (HE). (13)N-ammonia, (15)O-water positron emission tomography (PET) and magnetic resonance imaging (MRI) were performed. Quantitative values of cerebral blood flow (CBF) and the initial cerebral ammonia uptake rate (K1) were derived for several regions of interest from images of the desired parameters after interactive coregistration with the patients' MRI-studies. CBF (mL/mL/min), K1 (mL/mL/min), and the ammonia extraction fraction (K1/CBF) showed marked regional variance with the highest levels in the thalamus, the lenticular nucleus, and the cerebellum. In conclusion, the regional differences in cerebral ammonia uptake correspond to the distribution of histopathological changes in the brain of patients with cirrhosis as well as clinical features of HE, characterized by signs of basal ganglia and cerebellar dysfunction with corresponding signs of functional impairment, especially of the frontal cortex and cingulate gyrus.
authors.affiliation: Department of Neurology, Medizinische Hochschule Hannover, Hannover, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Ahl
authors.forename: Karin
authors.initials: K
authors.lastname: Weissenborn
authors.forename: Jörg
authors.initials: J
authors.lastname: van den Hoff
authors.forename: Daniela
authors.initials: D
authors.lastname: Fischer-Wasels
authors.forename: Herbert
authors.initials: H
authors.lastname: Köstler
authors.forename: Hartmut
authors.initials: H
authors.lastname: Hecker
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Burchert
mesh_terms: D000328:Adult; D000368:Aged; D000641:Ammonia / Q000493:pharmacokinetics*; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D002560:Cerebrovascular Circulation; D003342:Corpus Striatum / Q000378:metabolism; D005260:Female; D006501:Hepatic Encephalopathy / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013788:Thalamus / Q000378:metabolism; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
chemical_list: D000641:Ammonia