Definition of White Matter Brain Regions and of the Basal Ganglia for the Analysis of [11C] (R)-PK11195 Binding in People with Schizophrenia and in Normal Subjects

Abstract

Abstract Background Schizophrenia is a common, mental chronic disease that is associated with typical psychotic symptoms such as disorganised speech and behaviour, schizophrenia affects around 1% of the world’s population and is more common in men than in women. Several studies have investigated the 18 k Da translocator protein (TSPO) in vivo by using Positron Emission Tomography (PET) in order to see the activation of microglia, which is an indication of neuroinflammation in the brain with schizophrenia. Objective This study aims to a reanalysis of PK11195 data from Conen et al. First aim was to see whether there was an evidence of increase the brain inflammation in WM in recent-onset schizophrenia patients. The second aim was to determine the extent to which using manually defined restricted ROIs could reduce variation in VTR values by reducing contamination from other tissue compartments. Method 10 controls and 20 recent-onset schizophrenia patients had a MRI scan and PET by intravenous injection of [11C] (R)-PK11195. All MR images were co-registered with PET images into one template space, than transfer the brain template into individual PET space by using SPM8 in order to segment the ROI and create the Ratio of Volume of Distribution in WM regions. The GM regions were defined manually in the template brain twice in order to measure VTR in standard and restricted ROI. Result Lower VTR values in WM regions (temporal lobe, cingulate, prefrontal, orbital, occipital, and parietal) and the corpus callosum of the brain were found in recent-onset schizophrenia patients compared with controls. There was no significant differences between standard and restricted in GM regions except the right caudate for both standard and restricted view (0.022 and 0.0082) respectively.

Conclusion There was no evidence for increasing TSPO binding in six regions of WM regions and the corpus callosum in recent-onset schizophrenia patients, and there was no difference between the variations in restricted view and standard view in the ROI.