Design: Prospective interventional study.
Chronic HCV infected patients who are going to initiate a DAA-based antiviral regimen according to clinical practice will be recruited to participate in the study. Patients will be treated according to the current national and international guidelines for the treatment of HCV chronic hepatitis. The participation in the study will not influence neither the indication for de treatment nor the type of treatment prescribed. The only intervention in this study refers to the performance of extraordinary neuro-psychological evaluations and MRI studies at different times along the study.
Patients and methods:
This study will be performed in a cohort of 80 patients with CHC (≤ F3). The number of subjects required to test effects with sufficient power over the entire cortex varies between cortical measures (cortical thickness: N=39, surface area: N=21, volume: N=81; 10mm smoothing, power=0.8, α =0.05). For subcortical regions this number is between 16 and 76 subjects, depending on the region (Liem et al., 2015). Sample size calculations performed for functional magnetic resonance using values of medium Cohen's d effect size of 0.6 and 0.7 yield sample sizes of 88, 66 respectively to achieve 80% power at a significance level of 0.05 (Guo et al., 2012). Therefore, the sample size estimated in this project would yield enough power to detect small and medium effects size.
The following studies will be conducted:
1. \- Cognitive assessment: The assessment with widely-used neuropsychological test batteries may yield summary scores for the domains: attention and reaction time (Continuous Performance Test (CPT), working memory (digits forward and backward WAIS-III subtest), information processing speed (digit symbol WAIS-III subtest and Trail making test Part A), verbal fluency (letter FAS and category animals subtest), learning and memory (Rey Auditory 2.- Verbal Learning Test (RAVLT) and Rey Copy Figure(RCF)), motor functioning (Grooved Pegboard) and executive functions (Tower of London, Trail making test Part B and Stroop color-word test).
2. \- MRI scanning: Imaging data will be acquired at the neurorradiology section of the Hospital Marques de Valdecilla, on a 3T MRI scanner (Achieva, Philips Medical Systems, Best, The Netherlands) at the Neuroradiology Department of "Marques de Valdecilla" University Hospital. Subjects will undergo a 30 minutes protocol that will include a high resolution T1- weighted image, a 64 directions DWI sequence and A BOLD resting state fMRI sequence.
3. \- MRI data analysis: It will involve structural, diffusion and functional MRI analyses. These analyses will be conducted by Neuroimaging Platform at the IDIVAL.
3.1.- Structural MRI: we will use the software FreeSurfer (http://freesurfer.net/) to quantify the volume of subcortical structures (amygdala, hippocampus, thalamus, putamen, globus pallidus, and caudate nucleus) and the area, thickness, and volume of 34 cortical structures (Desikan-Killiany atlas).
3.2.- Diffusion MRI: we will use FSL's TBSS and Probtracx tools http://www.fmrib.ox.ac.uk/fsl/index.html) to compare fractional anisotropy values (a measure based on restricted movement of water molecules) in whole brain voxelwise analysis and identify regions (clusters) where white matter is more disorganized.
Also we will perform fiber tracking and study connectivity between different brain areas.
3.3.- Functional MRI (fMRI): resting state fmri will be used to evaluate regional interactions that occur when non performing and specific task. This analysis will be carried out with using SPM software http://www.fil.ion.ucl.ac.uk/spm/) and the toolbox PRONTO (http://www.mlnl.cs.ucl.ac.uk/pronto ).
