Diffusion MRI shows increased water apparent diffusion coefficient in the brains of cirrhotics

Background: Brain edema and increased intracranial pressure worsen prognosis in patients with end-stage chronic cirrhosis. Objective: To use diffusion-weighted imaging (DWI) to quantify water apparent diffusion coefficient ( ADC) in different brain regions of patients with chronic liver failure with or without hepatic encephalopathy. Methods: The authors studied 14 patients with viral liver cirrhosis and 12 sex- and age-matched healthy volunteers. Seven patients had no clinical evidence of hepatic encephalopathy; six had grade I hepatic encephalopathy; and one had grade II hepatic encephalopathy. Brain DWI was obtained using a single-shot echo-planar imaging sequence, and four gradient strengths (b values = 0, 300, 600, and 900 s/mm(2)) were applied to calculate the average diffusivity maps. Results: Mean ADC values in the brains of patients with cirrhosis were significantly increased in all selected regions of interest ( caudate, putamen, and pallidus nuclei; occipital, parietal, and frontal lobe white matter) except in the thalamus. Venous ammonia was linearly related to ADC values in deep gray and white matter regions of interest. Conclusions: Brain water apparent diffusion coefficient is increased in patients with chronic liver disease and may be useful in monitoring patients with hepatic encephalopathy.