Search

The Eplus-260 primate PET is an animal PET imaging system developed by the Institute of High Energy Physics, Chinese Academy of Sciences, which is designed to image non-human primates, especially the brain of large non-human primates. The system consists of 48 block detectors arranged in two 24-sided rings with a ring diameter of 263 mm and an axial extent of 64 mm. Each block detector is composed of a 16 × 16 cerium-doped lutetium-yttrium orthosilicate crystal array with a pixel size of 1.9 × 1.9 × 10 mm3. This article presents a performance evaluation of the PET scanner according to the National Electrical Manufacturers Association NU-4 2008 standards. All measurements were made for an energy window of 360-660 keV and a coincidence timing window of 2 ns. In terms of the FWHM, the FBP reconstructed spatial resolution results in all three directions at the radial position of 5 mm were better than or approached to 2 mm, and remained below 3.0 mm within the central 5 cm diameter of the FOV. The peak absolute sensitivity of the scanner was measured 1.80%. For a monkey-sized phantom, the scatter fraction was 34.2% and the peak noise equivalent count rate (NECR) was 26.5 kcps at 64.3 kBq/cc. The overall imaging capabilities of the scanner were also assessed using in vivo imaging study of a rhesus macaque. The performance measurements demonstrate that the Eplus-260 primate PET scanner has the potential ability to obtain good quality and high-contrast images for non-human primates, especially the brain of large non-human primates and could be considered as one technologically advanced dedicated non-human primate PET scanner available today.

Purpose Positron emission tomography (PET) is a non-invasive imaging tool for the evaluation of brain function and neuronal activity in normal and diseased conditions with high sensitivity. The macaque monkey serves as a valuable model system in the field of translational medicine, for its phylogenetic proximity to man. To translation of non-human primate neuro-PET studies, an effective and objective data analysis platform for neuro-PET studies is needed. Materials and methods A set of stereotaxic templates of macaque brain, namely the Institute of High Energy Physics & Jinan University Macaque Template (HJT), was constructed by iteratively registration and averaging, based on 30 healthy rhesus monkeys. A brain atlas image was created in HJT space by combining sub-anatomical regions and defining new 88 bilateral functional regions, in which a unique integer was assigned for each sub-anatomical region. Results The HJT comprised a structural MRI T1 weighted image (T1WI) template image, a functional FDG-PET template image, intracranial tissue segmentations accompanied with a digital macaque brain atlas image. It is compatible with various commercially available software tools, such as SPM and PMOD. Data analysis was performed on a stroke model compared with a group of healthy controls to demonstrate the usage of HJT. Conclusion We have constructed a stereotaxic template set of macaque brain named HJT, which standardizes macaque neuroimaging data analysis, supports novel radiotracer development and facilitates translational neuro-disorders research.

Structural brain abnormalities have been widely reported in major depressive disorder (MDD). However, many previous results cannot exclude the interferences of medication or multiple recurrent episodes. In this study, we examined structural brain abnormalities by comparing 68 drug-naïve first-episode adult-onset MDD and 68 healthy controls (HCs). Structural magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) methods were used. The mean values of grey matter volume/white matter volume (GMV/WMV) were calculated, then the differences between MDD and HCs were analyzed, and the associations of the differences with clinical characteristics of depression were discussed. The whole brain GMV/WMV did not differ between MDD patients and HCs; however, the regional GMV of the right pre-supplementary motor area (pre-SMA) was smaller in MDD patients. The GMV of both hippocampi was positively correlated with symptom severity and lower in patients with long durations. These results indicate the GMV reduction of the pre-SMA at an early stage of depression, whereas the GMV of the hippocampus is associated with depressive characteristics. Moreover, the whole brain GMV/WMV was negatively related to the duration of depression, supporting that volume loss could become progressive during the development of disease. These results may suggest the importance of identifying and intervening depression at an early stage, especially the first year after onset, to prevent volume loss in the brain.

Purpose To automatically extract regions of interest (ROIs) and simultaneously preserve the anatomical characteristics of each individual, we developed a new atlas-based method utilizing a pair of coregistered brain template and digital atlas. Materials and Methods Unlike the previous atlas-based method, this method treats each individual as the target image, and the template and atlas are each transformed to register with the individual. To evaluate the accuracy of this method we implemented it in extracting the hippocampus from two groups of T2-weighted structural images with different spatial resolutions and a group of T2*-weighted functional images. Furthermore, the results were compared against a manually segmented hippocampus and an atlas-derived hippocampus. Results Jaccard similarity (JS) reached 84.7%–90.5%, and relative error in volume (RV) was 4.8%–12.7%. The consistency observed between the results of the proposed method and manual drawing was therefore considerable. Conclusion We developed a new atlas-based method for ROI extraction that can automatically extract ROI and simultaneously preserve each individual's unique anatomical characteristics. J. Magn. Reson. Imaging 2010;32:830–835. © 2010 Wiley-Liss, Inc.

Objective.The central nervous system (CNS) is often affected by systemic lupus erythematosus (SLE), but assessment of CNS outcomes using noninvasive cerebral structural measures remains in its infancy. Magnetic resonance imaging (MRI) with expert visual interpretation is critical to diagnosis, but does not permit quantitative measurements. Our pilot study investigated whether quantitative brain volumetric analyses could be used to detect white-matter (WM) abnormalities and responses to treatment in SLE (ClinicalTrials.gov: NCT00703742).Methods.Forty-two pairs of SLE patients and healthy controls underwent high-resolution 3-dimensional structural MRI scans. Combining voxel-based morphometry and region of interest analyses, subtle WM volume abnormalities in whole brains from SLE patients were identified, and regional WM volume was calculated. Associations between WM volume and symptom severity, as well as the effects of immunosuppressive therapy, were then investigated.Results.The WM volume of the SLE group was significantly decreased in the bilateral posterior and anterior crus of the internal capsule (PIC and AIC, respectively), the subgyral right frontal lobe, and left temporal lobe (p < 0.001). Regional WM volume (left PIC and right AIC) was correlated with SLEDAI scores. The WM volume of patients treated with immunosuppressive therapy was greater than that of patients who were never treated with immunosuppressive therapy.Conclusion.Quantitative brain volumetric analyses detect brain injuries in WM for SLE that are not obvious by conventional MRI, and may be adequately sensitive and quantitative to measure the effect of therapeutic interventions in preventing brain injury and outcomes in SLE.