Evaluation of early cerebral metabolic, perfusion and microstructural changes in HCV-positive patients: a pilot study

Abstract

Background & aims: The aim of the study was to evaluate early metabolic perfusion, and microstructural cerebral changes in patients with the hepatitis C virus (HCV) infection and normal appearing brain on plain MR using advanced MR techniques, as well as to assess correlations of MR measurements with the liver histology activity index (HAI).

Methods: Fifteen HCV-positive patients and 18 control subjects underwent single voxel MR spectroscopy (MRS), perfusion weighted imaging (PWI), and diffusion tensor imaging (DTI), using a 1.5T MR unit. MRS metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr) were calculated. PWI values of relative cerebral blood volume (rCBV) were assessed from 8 areas including several cortical locations, basal ganglia, and fronto-parietal white matter. DTI fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained from 14 white matter tracts.

Results: Compared to controls, HCV-positive patients showed significantly (p < 0.05) lower NAA/Cr ratios within frontal and parietal white matters, lower rCBV values within frontal and temporo-parietal cortices, decreased FA values, as well as increased ADC values in several white matter tracts. We also found elevated rCBV values in basal ganglia regions. The increase in mI/Cr and Cho/Cr ratio was correlated with a higher HAI score.

Conclusions: The results of advanced MR techniques indicate neurotoxicity of HCV reflected by neuronal impairment within white matter, cortical hypoperfusion, and disintegrity within several white matter tracts. Hyperperfusion in basal ganglia may be an indicator of brain inflammation in HCV patients. Our findings may suggest a biologic link between HCV-related liver disease and cerebral dysfunction.

Keywords: ACG; ADC; BG; CNS; Cerebral metabolism; Cerebral perfusion; Cerebral white matter; Cho; Cr; DSC-MR; DTI; DWI; Diffusion tensor imaging; FA; FLAIR; FWM; GCC; HAI; HCV; HIV; IDU; IFOF; ILF; MCP; MR; MRS; Magnetic resonance spectroscopy; N-acetylaspartate; NAA; NAGM; NAWM; PCG; PLIC; PWI; PWM; Perfusion-weighted imaging; SCC; SLF; SVS; Single Voxel Spectroscopy; WSCT; Wisconsin Card Sorting Test; anterior cingulate gyrus; apparent diffusion coefficient; basal ganglia; central nervous system; choline; creatine; diffusion tensor imaging; diffusion-weighted imaging; dynamic susceptibility contrast MR imaging; fluid-attenuated inversion recovery sequence; fractional anisotropy; frontal white matter; genu of the corpus callosum; hepatitis C virus; histology activity index; human immunodeficiency virus; inferior fronto-occipital fasciculus; inferior longitudinal fasciculus; intravenous drug users; mI; magnetic resonance; magnetic resonance spectroscopy; middle cerebellar peduncle; myo-inositol; normal appearing gray matter; normal appearing white matter; parietal white matter; perfusion weighted imaging; posterior cingulate gyrus; posterior limb of internal capsule; rCBV; relative cerebral blood volume; splenium of the corpus callosum; superior longitudinal fasciculus, PC, posterior cingulum.