Identification of Minimal Hepatic Encephalopathy in Patients with Cirrhosis Based on White Matter Imaging and Bayesian Data Mining

Abstract

BACKGROUND AND PURPOSE:White matter abnormalities have been demonstrated to play an important role in minimal hepatic encephalopathy. In this study, we aimed to evaluate whether WM diffusion tensor imaging can be used to identify minimal hepatic encephalopathy among patients with cirrhosis.

A longitudinal study of patients with cirrhosis treated with L-ornithine L-aspartate, examined with magnetization transfer, diffusion-weighted imaging and magnetic resonance spectroscopy

“…However, the interpretation of these results is confounded because no healthy control data were provided. Chen and colleagues studied 65 patients with cirrhosis, 29 of whom had minimal HE, while the remaining 36 had no evidence of neuropsychiatric impairment (Chen et al 2015). The mean FA was significantly reduced in multiple cerebral regions and the changes in FA values were found, after adjustment for the degree of hepatic dysfunction, to be predictive of survival over the next 18 months.…”

“…Study protocols differ appreciably and so do the methods of data analysis and the variables selected for study; thus direct comparisons are difficult, if not impossible to make. Chen and colleagues, for example, interpreted the increase they observed in cerebral mean diffusivity (MD), in patients with minimal HE, as indicating intracerebral oedema and the reduction in cerebral FA as reflecting impaired microstructural integrity, but without further elaboration (Chen et al 2015). Ahluwalia and colleagues interpreted their findings, in patients with minimal HE, of an increase in cerebral FA following treatment with rifaximin in the absence of any change in cerebral MD as indicative of a treatment–related correction of intracellular oedema (Ahluwalia et al 2014).…”

“…Studies in patients with cirrhosis and varying degrees of HE have reported increased regional cerebral ADCs (Lodi et al 2004; Sugimoto et al 2008), with a degree of reversibility observed following treatment for HE (Ahluwalia et al 2014; Chen et al 2015; Kale et al 2006). These findings have been attributed to: (i) increased brain water content (Lodi et al 2004); (ii) reversible interstitial oedema (Kale et al 2006); (iii) minimal cellular oedema with an increase in membrane permeability and intracellular diffusivity, and changes in the viscosity of the cytoplasm (Sugimoto et al 2008).…”

“…Chen et al (2015) reported significant reductions in mean FA throughout the cerebral white matter in patients with minimal HE, compared to their neuropsychiatrically unimpaired counterparts, but data from healthy controls were not included for comparison. Ahluwalia et al (2015), reported significant increases in mean FA in patents with minimal HE following 2 months of treatment with rifaximin; however, no healthy controls were included and so the FA data before treatment are not easily interpreted.…”

“…Although there is some evidence that cerebral MR might be useful to detect minimal HE (Chen et al 2015; Rai et al 2015) and to determine the effects of treatment (Ahluwalia et al 2014; Rai et al 2015), relatively few well-controlled studies are available, to date. The aim of this study was to determine if measures of cerebral volume, water content and metabolite concentrations, obtained using cerebral MR imaging and spectroscopy, can be used to differentiate patients with minimal HE from their neuropsychiatrically unimpaired counterparts and/or to monitor treatment effects.…”