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Duan H.-F.,Mental Diseases Prevention and Treatment Institute of PLA | Gan J.-L.,Mental Diseases Prevention and Treatment Institute of PLA | Yang J.-M.,Center for Medical Imaging | Cheng Z.-X.,Mental Diseases Prevention and Treatment Institute of PLA | And 5 more authors.
Behavioural Brain Research | Year: 2015

Hippocampal pathology has been considered to underlie clinical, functional and cognitive impairments in schizophrenia. While longitudinal magnetic resonance imaging (MRI) studies have demonstrated progressive gray matter reduction of the hippocampus during the early phases of schizophrenia (SCZ), very little is known about whether functional connectivity (FC) between the hippocampus and other brain regions also exhibit progressive changes. In this study, resting state functional MRI (fMRI) was used to examine changes in hippocampal connectivity at baseline and follow-up scans comparing 68 patients with first episode SCZ and 62 matched controls. At baseline and follow-up, in the bilateral hippocampal network, SCZ mainly showed decreased FC with bilateral cerebellum posterior lobe, frontal gyrus temporal gyrus, precuneus, and cingulate cortex compared to controls. Furthermore, in the bilateral hippocampus, there was a significant interaction effect of group and time for FC with cerebellum posterior lobe, temporal gyrus, frontal gyrus, and posterior cingulate cortex. Interestingly, longitudinal changes of bilateral hippocampal connectivity with right middle frontal gyrus negatively correlated with positive symptom scores in SCZ. These results provide novel evidence for the progressive changes of FC between hippocampus and other brain regions in SCZ. It further suggests that longitudinal changes of bilateral hippocampal connectivity with right middle frontal gyrus can contribute to the formation and emergence of positive symptom of SCZ. © 2015 Elsevier B.V. Source


Gan J.-L.,Mental Diseases Prevention and Treatment Institute of Chinese PLA | Cheng Z.-X.,Mental Diseases Prevention and Treatment Institute of Chinese PLA | Duan H.-F.,Mental Diseases Prevention and Treatment Institute of Chinese PLA | Yang J.-M.,Center for Medical Imaging | And 2 more authors.
Psychiatry Research - Neuroimaging | Year: 2014

Early onset schizophrenia (EOS) is often associated with poorer outcomes, including lack of school education, higher risk of mental disability and resistance to treatment. But the knowledge of the neurobiological mechanism of EOS is limited. Here, using proton magnetic resonance spectroscopy, we investigated the possible neurochemical abnormalities in prefrontal cortex (PFC) and thalamus of first-episode drug-naïve patients with EOS, and followed up the effects of atypical antipsychotic treatment for 6 months on neurochemical metabolites and clinical symptoms. We measured the ratios of N-acetylaspartate (NAA), choline (Cho) to creatine (Cr) in 41 adolescents with first episode of EOS and in 28 healthy controls matched for age, gender, and years of education. The EOS patients presented with abnormally low NAA/Cr values in the left PFC and left thalamus with a reduced tendency in the right PFC compared with healthy controls. No significant differences were detected between groups for Cho/Cr in PFC and thalamus in any hemisphere. After atypical antipsychotic treatment for 6 months, the reduced NAA/Cr in the left PFC and left thalamus in EOS patients was elevated to the normal level in healthy controls, without any alteration in Cho/Cr. We also found that there was no significant correlation between the neurochemical metabolite ratios in the PFC and thalamus in patients with EOS, and clinical characteristics. Our results suggest that there was neurochemical metabolite abnormalities in PFC and thalamus in EOS patients, atypical antipsychotic treatment can effectively relieve the symptoms and restore the reduced NAA in PFC and thalamus. © 2014 Elsevier Ireland Ltd. Source


Tremoulheac B.,University College London | Atkinson D.,Center for Medical Imaging | Arridge S.R.,University College London
Proceedings - International Symposium on Biomedical Imaging | Year: 2013

Higher spatial and temporal resolution of dynamic MR imaging can be achieved by sparse and sub-Nyquist sampling of (k-t)-space. However, direct inversion of this inverse problem can result in artefact in reconstructed images. In combination with a golden angle pseudo-radial acquisition, we propose in this paper to use prior information based on the rank to regularize the problem. The iterative scheme to reconstruct the dynamic imaging series is based on an accelerated proximal gradient algorithm designed for large-scale low-rank matrix completion. The method is tested on simulated and clinical datasets and, besides being simple, proves to be fast and efficient for high acceleration factors. © 2013 IEEE. Source


Menys A.,Center for Medical Imaging | Makanyanga J.,Center for Medical Imaging | Plumb A.,Center for Medical Imaging | Bhatnagar G.,Center for Medical Imaging | And 3 more authors.
Inflammatory Bowel Diseases | Year: 2016

Background: Inflammation-related enteric dysmotility has been postulated as a cause for abdominal symptoms in Crohn's disease (CD). We investigated the relationship between magnetic resonance imaging-quantified small bowel (SB) motility, inflammatory activity, and patient symptom burden. Methods: The Harvey-Bradshaw index (HBI) and fecal calprotectin were prospectively measured in 53 patients with CD (median age, 35; range, 18-78 years) the day before magnetic resonance enterography, which included a dynamic (cine), breath-hold motility sequence, repeated to encompass the whole SB volume. A validated registration-based motility quantitation technique produced motility maps, and regions of interest were drawn to include all morphologically normal SB (i.e., excluding diseased bowel). Global SB motility was correlated with calprotectin, HBI, and symptom components (well-being, pain, and diarrhea). Adjustment for age, sex, smoking, and surgical history was made using multivariate linear regression. Results: Median calprotectin was 336 (range, 0-1280). Median HBI, motility mean, and motility variance were 3 (range, 0-16), 0.33 (0.18-0.51), and 0.01 (0.0014-0.034), respectively. Motility variance was significantly negatively correlated with calprotectin (rho-0.33, P 0.015), total HBI (rho-0.45, P < 0.001), well-being (rho-0.4, P 0.003), pain (rho-0.27, P 0.05), and diarrhea (rho-0.4, P 0.0025). The associations remained highly significant after adjusting for covariates. There was no association between mean motility and calprotectin or HBI (P > 0.05). Conclusions: Reduced motility variance in morphologically normal SB is associated with patient symptoms and fecal calprotectin levels, supporting the hypothesis that inflammation-related enteric dysmotility may explain refractory abdominal symptoms in CD. © 2016 Crohn's & Colitis Foundation of America, Inc. Source


Menys A.,Center for Medical Imaging | Menys A.,University College London | Hamy V.,Center for Medical Imaging | Hamy V.,University College London | And 9 more authors.
Physics in Medicine and Biology | Year: 2014

At present, registration-based quantification of bowel motility from dynamic MRI is limited to breath-hold studies. Here we validate a dual-registration technique robust to respiratory motion for the assessment of small bowel and colonic motility. Small bowel datasets were acquired in breath-hold and free-breathing in 20 healthy individuals. A pre-processing step using an iterative registration of the low rank component of the data was applied to remove respiratory motion from the free breathing data. Motility was then quantified with an existing optic-flow (OF) based registration technique to form a dual-stage approach, termed Dual Registration of Abdominal Motion (DRAM). The benefit of respiratory motion correction was assessed by (1) assessing the fidelity of automatically propagated segmental regions of interest (ROIs) in the small bowel and colon and (2) comparing parametric motility maps to a breath-hold ground truth. DRAM demonstrated an improved ability to propagate ROIs through free-breathing small bowel and colonic motility data, with median error decreased by 90% and 55%, respectively. Comparison between global parametric maps showed high concordance between breath-hold data and free-breathing DRAM. Quantification of segmental and global motility in dynamic MR data is more accurate and robust to respiration when using the DRAM approach. © 2014 Institute of Physics and Engineering in Medicine. Source

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