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The ability to identify biomarkers of psychosis risk is essential in defining effective preventive measures to potentially circumvent the transition to psychosis. Using samples of people at clinical high risk for psychosis (CHR) and Healthy controls (HC) who were administered a task fMRI paradigm, we used a framework for labelling time windows of fMRI scans as 'integrated' FC networks to provide a granular representation of functional connectivity (FC). Periods of integration were defined using the 'cartographic profile' of time windows and k-means clustering, and sub-network discovery was carried out using Network Based Statistics (NBS). There were no network differences between CHR and HC groups. Within the CHR group, using integrated FC networks, we identified a sub-network negatively associated with longitudinal changes in the severity of psychotic symptoms. This sub-network comprised brain areas implicated in bottom-up sensory processing and in integration with motor control, suggesting it may be related to the demands of the fMRI task. These data suggest that extracting integrated FC networks may be useful in the investigation of biomarkers of psychosis risk., (© 2020 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Purpose: To investigate the magnetic susceptibility artifact associated with pigmented intraorbital prosthetics when performing magnetic resonance imaging (MRI) and computed tomography (CT). Potential artifact reduction techniques were also investigated., Study Design: Prospective study., Methods: Five different-colored 20-millimeter small animal silicone intraorbital prosthetics and two equine prosthetics were evaluated using 0.3 and 1.5 Tesla (T) MRI and CT. MRI sequences included T1- (T1WI) and T2-weighted spin echo (T2WI), T2 gradient echo (T2*), short tau inversion recovery (STIR), and fluid-attenuated inversion recovery (FLAIR). When present, artifact size was measured using computerized software by three separate observers. Artifact reduction techniques included alterations in receiver bandwidth, field of view, slice thickness, and matrix size., Results: The ferrous brown-pigmented prosthetic resulted in a magnetic susceptibility artifact with MRI. No artifact was observed on CT images. Interobserver variability was not statistically significant. For both the 0.3T and 1.5T MRI, the T2* sequence exhibited the largest artifact surface area followed by T2WI, T1WI, STIR, and FLAIR. Decreasing slice thickness showed a decrease in artifact size; however, this difference was not statistically significant., Conclusions: The ferrous substances in the brown intraorbital prosthetic resulted in a significant magnetic susceptibility artifact when performing MRI. Artifact reduction techniques did not significantly decrease artifact surface area. The use of ferrous brown-pigmented prosthetics and their potential to affect future MR imaging studies should be adequately discussed with pet owners., (© 2013 American College of Veterinary Ophthalmologists.)

A 9 yr old spayed female German shepherd dog was referred for MRI of the thoracic and lumbar spine because she had clinical signs of chronic neurogenic bladder dysfunction of an unknown cause. Transverse T2-weighted images identified a type II split cord malformation (i.e., diastematomyelia) in the thoracic spine. Split cord malformations are forms of spinal dysraphism where the abnormal development of spinal cord results in sagittal splitting of a portion of the cord into two hemicords. The location of the lesion in the thoracic spine was consistent with the dog's clinical signs of an upper motor neuron bladder. Split cord malformations that occur in humans have similar MRI characteristics and can result in similar clinical signs as those identified in the dog described in this report.

Background: Several studies have indicated that people with prodromal signs of psychosis show alterations in the structure and function of the brain when they first present to clinical services. However, the longitudinal course of these abnormalities, and how they relate to subsequent clinical and functional outcome is relatively unclear., Methods: A cohort of subjects at ultra high risk of psychosis were studied using functional magnetic resonance imaging (fMRI) in conjunction with the N-Back task, and volumetric MRI at first clinical presentation and again after one year. Levels of psychopathology and global functioning were assessed at the same time points using the CAARMS, PANSS, and the GAF scale., Results: At baseline, the high risk group showed reduced activation during the task in the left middle frontal gyrus, supramarginal gyrus and inferior parietal lobule, and reduced gray matter volume in the left middle and medial frontal gyri, left insula and the right anterior cingulate gyrus. Within the high-risk group, there was a positive correlation between the magnitude of the functional and structural alterations in the left middle frontal gyrus. Between presentation and follow up, the severity of perceptual disorder and thought disorder (rated by the CAARMS), and of general psychopathology (rated by the PANSS general score) decreased, and the level of global functioning improved. This clinical and functional improvement was associated with a longitudinal increase in activation in the anterior cingulate and right parahippocampal gyrus. The change in anterior cingulate response was directly correlated with the improvement in the GAF score., Conclusions: In subjects presenting with prodromal signs of psychosis, reduced prefrontal activation during a working memory task is associated with a reduction in gray matter volume in the same area. Changes in anterior cingulate activation were correlated with functional improvement in this group, consistent with the role of this region in multiple cognitive and social processes., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: Neurocognitive impairments in executive and mnemonic domains are already evident in the pre-psychotic phases. The longitudinal dynamic course of the neurofunctional abnormalities underlying liability to psychosis and their relation to clinical outcomes is unknown., Methods: In this study we used functional magnetic resonance imaging (fMRI) in a cohort of subjects at ultra high clinical risk for psychosis (with an "At Risk Mental State", ARMS) and in healthy controls. Images were acquired at baseline and again after one year on a 1.5 Tesla Signa, while patients were performing a visuospatial working memory task. Psychopathological assessment of the prodromal symptoms was conducted at the same time points by using the CAARMS and the PANSS instruments., Results: There were no significant differences between the ARMS and control groups with respect to age or IQ. Although both groups performed the PAL task with a high degree of accuracy, the ARMS showed an increased latency in answers during the most demanding level of the task. At baseline, such cognitive impairment was associated with reduced activation in the left precuneus, left superior parietal lobule, right middle temporal gyrus in the ARMS as compared to controls. In addition, the ARMS failed to activate parietal areas with increasing difficulty of the task. Between presentation and follow-up the overall clinical status of the ARMS sample improved, despite 2 out of the 15 subjects having developed a full-blown psychosis: the CAARMS (perceptual disorder and thought disorder subscales) and the PANNS general scores decreased, while the GAF score increased. Such clinical amelioration was associated with a longitudinal compensatory increase in occipitoparietal regions., Conclusions: The prodromal phase of psychosis is associated with functional alterations in parietal and temporal networks subserving visuospatial working memory which are more evident under high cognitive loads. The clinical improvement at one year is associated with a compensatory increase in occipitoparietal regions., (Copyright © 2010 Elsevier B.V. All rights reserved.)