Center for Advanced Imaging

Roanoke, VA, United States

Center for Advanced Imaging

Roanoke, VA, United States
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Blokland G.A.M.,Queensland Institute of Medical Research | Blokland G.A.M.,Center for Advanced Imaging | Blokland G.A.M.,University of Queensland | McMahon K.L.,Center for Advanced Imaging | And 5 more authors.
Journal of Neuroscience | Year: 2011

Although key to understanding individual variation in task-related brain activation, the genetic contribution to these individual differences remains largely unknown. Here we report voxel-by-voxel genetic model fitting in a large sample of 319 healthy, young adult, human identical and fraternal twins (mean ± SD age, 23.6 ±1.8 years) who performed an n-back working memory task during functional magnetic resonance imaging (fMRI) at a high magnetic field (4 tesla). Patterns of task-related brain response (BOLD signal difference of 2-back minus 0-back) were significantly heritable, with the highest estimates (40 - 65%) in the inferior, middle, and superior frontal gyri, left supplementary motor area, precentral and postcentral gyri, middle cingulate cortex, superior medial gyrus, angular gyrus, superior parietal lobule, including precuneus, and superior occipital gyri. Furthermore, high test-retest reliability for a subsample of 40 twins indicates that nongenetic variance in the fMRI brain response is largely due to unique environmental influences rather than measurement error. Individual variations in activation of the working memory network are therefore significantly influenced by genetic factors. By establishing the heritability of cognitive brain function in a large sample that affords good statistical power, and using voxel-by-voxel analyses, this study provides the necessary evidence for task-related brain activation to be considered as an endophenotype for psychiatric or neurological disorders, and represents a substantial new contribution to the field of neuroimaging genetics. These genetic brain maps should facilitate discovery of gene variants influencing cognitive brain function through genome-wide association studies, potentially opening up new avenues in the treatment of brain disorders. © 2011 the authors.

Regenbogen C.,University of Bremen | Regenbogen C.,RWTH Aachen | Herrmann M.,University of Bremen | Herrmann M.,Center for Advanced Imaging | And 2 more authors.
Social Neuroscience | Year: 2010

Studies investigating the effects of violent computer and video game playing have resulted in heterogeneous outcomes. It has been assumed that there is a decreased ability to differentiate between virtuality and reality in people that play these games intensively. FMRI data of a group of young males with (gamers) and without (controls) a history of long-term violent computer game playing experience were obtained during the presentation of computer game and realistic video sequences. In gamers the processing of real violence in contrast to nonviolence produced activation clusters in right inferior frontal, left lingual and superior temporal brain regions. Virtual violence activated a network comprising bilateral inferior frontal, occipital, postcentral, right middle temporal, and left fusiform regions. Control participants showed extended left frontal, insula and superior frontal activations during the processing of real, and posterior activations during the processing of virtual violent scenarios. The data suggest that the ability to differentiate automatically between real and virtual violence has not been diminished by a longterm history of violent video game play, nor have gamers' neural responses to real violence in particular been subject to desensitization processes. However, analyses of individual data indicated that grouprelated analyses reflect only a small part of actual individual different neural network involvement, suggesting that the consideration of individual learning history is sufficient for the present discussion. © 2009 Psychology Press.

Chiang M.-C.,National Yang Ming University | Chiang M.-C.,University of California at Los Angeles | Barysheva M.,University of California at Los Angeles | McMahon K.L.,Center for Advanced Imaging | And 8 more authors.
Journal of Neuroscience | Year: 2012

A major challenge in neuroscience is finding which genes affect brain integrity, connectivity, and intellectual function. Discovering influential genes holds vast promise for neuroscience, but typical genome-wide searches assess approximately one million genetic variants one-by-one, leading to intractable false positive rates, even with vast samples of subjects. Even more intractable is the question of which genes interact and how they work together to affect brain connectivity. Here, we report a novel approach that discovers which genes contribute to brain wiring and fiber integrity at all pairs of points in a brain scan. We studied genetic correlations between thousands of points in human brain images from 472 twins and their nontwin siblings (mean age: 23.7 2.1 SD years; 193 male/279 female).Wecombined clustering with genome-wide scanning to find brain systems withcommongenetic determination.Wethen filtered the image in a new way to boost power to find causal genes. Using network analysis, we found a network of genes that affect brain wiring in healthy young adults. Our new strategy makes it computationally more tractable to discover genes that affect brain integrity. The gene network showed small-world and scale-free topologies, suggesting efficiency in genetic interactions and resilience to network disruption. Genetic variants at hubs of the network influence intellectual performance by modulating associations between performance intelligence quotient and the integrity of major white matter tracts, such as the callosal genu and splenium, cingulum, optic radiations, and the superior longitudinal fasciculus. ©2012 the authors.

Durschmid S.,Helen Wills Neuroscience Institute | Durschmid S.,Leibniz Institute of Neurobiology | Zaehle T.,Leibniz Institute of Neurobiology | Zaehle T.,Otto Von Guericke University of Magdeburg | And 13 more authors.
Cerebral Cortex | Year: 2016

Rapid changes in the environment evoke a comparison between expectancy and actual outcome to inform optimal subsequent behavior. The nucleus accumbens (NAcc), a key interface between the hippocampus and neocortical regions, is a candidate region for mediating this comparison. Here, we report event-related potentials obtained from the NAcc using direct intracranial recordings in 5 human participants while they listened to trains of auditory stimuli differing in their degree of deviation from repetitive background stimuli. NAcc recordings revealed an early mismatch signal (50-220 ms) in response to all deviants. NAcc activity in this time window was also sensitive to the statistics of stimulus deviancy, with larger amplitudes as a function of the level of deviancy. Importantly, this NAcc mismatch signal also predicted generation of longer latency scalp potentials (300-400 ms). The results provide direct human evidence that the NAcc is a key component of a network engaged in encoding statistics of the sensory environmental. © 2014 The Author. Published by Oxford University Press. All rights reserved.

Joshi A.A.,University of California at Los Angeles | Lepore N.,University of California at Los Angeles | Lepore N.,University of Southern California | Joshi S.H.,University of California at Los Angeles | And 10 more authors.
NeuroReport | Year: 2011

We analyzed brain MRI data from 372 young adult twins toidentify cortical regions in which gray matter thickness and volume are influenced by genetics. This was achieved using an A/C/E structural equation model that divides the variance of these traits, at each point on the cortex, into additive genetic (A), shared (C), and unique environmental (E) components. A strong genetic influencewas found in frontal and parietal regions. Inaddition, we correlated cortical thickness with full-scale intelligence quotient for comparison with the A/C/E maps, and several regions where cortical structure was correlated with intelligence quotient are under genetic control. These cortical measures may be useful phenotypes to narrow the searchfor quantitative trait lociinfluencing brain structure.© 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Ortiz O.,Winthrop University | Mathis J.M.,Center for Advanced Imaging
Neuroimaging Clinics of North America | Year: 2010

Vertebral augmentation techniques use image guidance for the percutaneous placement of spinal implants that stabilize a painful osteoporotic or pathologic vertebral compression fracture. The initial implant, acrylic bone cement, was injected through a bone needle into the vertebral body, a procedure referred to as vertebroplasty. A modification of this procedure, kyphoplasty, entails the temporary use of an inflatable balloon tamp before cement injection. Other techniques and the equipment required to perform these vertebral augmentation procedures have evolved significantly during the past two decades. It is now possible to perform vertebral body reconstruction in patients with painful fractures of compromised vertebrae with excellent outcomes in terms of sustainable pain relief and marked reduction in patient morbidity. © 2010 Elsevier Inc.

Undheim E.A.B.,Institute for Molecular Bioscience | Undheim E.A.B.,Center for Advanced Imaging | Hamilton B.R.,Materials Health Services | Hamilton B.R.,University of Queensland | And 5 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Venom represents one of the most extreme manifestations of a chemical arms race. Venoms are complex biochemical arsenals, often containing hundreds to thousands of unique protein toxins. Despite their utility for prey capture, venoms are energetically expensive commodities, and consequently it is hypothesized that venom complexity is inversely related to the capacity of a venomous animal to physically subdue prey. Centipedes, one of the oldest yet least-studied venomous lineages, appear to defy this rule. Although scutigeromorph centipedes produce less complex venom than those secreted by scolopendrid centipedes, they appear to rely heavily on venom for prey capture. We show that the venom glands are large and well developed in both scutigerid and scolopendrid species, but that scutigerid forcipules lack the adaptations that allow scolopendrids to inflict physical damage on prey and predators. Moreover, we reveal that scolopendrid venom glands have evolved to accommodate a much larger number of secretory cells and, by using imaging mass spectrometry, we demonstrate that toxin production is heterogeneous across these secretory units. We propose that the differences in venom complexity between centipede orders are largely a result of morphological restrictions of the venom gland, and consequently there is a strong correlation between the morphological and biochemical complexity of this unique venom system. The current data add to the growing body of evidence that toxins are not expressed in a spatially homogenous manner within venom glands, and they suggest that the link between ecology and toxin evolution is more complex than previously thought. venom evolution , venom-gland morphology , centipede,mass spectrometry imaging ,venom optimization hypothesis.

Bae H.,Spine Institute | Bae H.,Spine Center | Hatten H.P.,Indian River Radiology | Linovitz R.,Core Orthopedic Medical Center | And 8 more authors.
Spine | Year: 2012

STUDY DESIGN.: Randomized, controlled, prospective (AAOS therapeutic level I) trial conducted under Food and Drug Administration Investigational Device Exemption hypothesized noninferiority of a novel bioactive composite material to polymethylmethacrylate (PMMA). OBJECTIVE.: To determine the safety and efficacy of a new, nonresorbable bioactive composite (Cortoss) compared with PMMA, the standard treatment of vertebral compression fractures (VCFs). SUMMARY OF BACKGROUND DATA.: Vertebroplasty with PMMA, the widely adopted treatment for VCFs nonresponsive to conservative care, provides effective, immediate pain relief, but the material has received criticism for its properties. A new bioactive composite material designed specifically for vertebroplasty showed promising results in animals and nonrandomized clinical studies and was subsequently compared with PMMA in a randomized study. This study represents the first prospective study evaluating vertebroplasty comparing PMMA with another material with 24-month follow-up. METHODS.: Using 2:1 randomization, vertebroplasty was performed with Cortoss on 162 patients and PMMA on 94 patients. Inclusion criteria were painful osteoporotic VCFs with a visual analogue scale pain score of at least 50 mm on a 100-mm scale and at least 30% disability as measured by the Oswestry Disability Index. Evaluations at pretreatment, treatment day, and 7 posttreatment intervals out to 24 months included pain, disability, neurological status, adverse events, quality of life, patient satisfaction, analgesic use, and independently reviewed radiographs. RESULTS.: Noninferiority of Cortoss relative to PMMA was observed, with Cortoss-treated patients experiencing significant pain relief at 3 months (P = 0.0395) and better maintenance or improvement in function at 24 months (P = 0.0299). Incidence of serious device-related adverse events was 4.3% in both groups; none were life threatening. CONCLUSION.: Vertebroplasty using either Cortoss or PMMA provides effective, immediate, and lasting pain relief and prevents further loss of function. Both materials performed comparably at most time points; Cortoss demonstrated better results for pain reduction at 3 months and for function at 24 months. © 2012, Lippincott Williams & Wilkins.

Li L.-P.,Center for Advanced Imaging | Li L.-P.,University of Chicago | Lu J.,University of Chicago | Lu J.,NorthShore University HealthSystem | And 5 more authors.
Investigative Radiology | Year: 2015

Objectives: The objective of this study was to assess whether streptozotocin (STZ)-induced diabetic rats develop iodinated contrast-induced acute kidney injury. The intrarenal R2∗ (=1/T2∗) was evaluated continuously before, during, and after contrast administration. Renal injury was confirmed using urinary neutrophil gelatinase-associated lipocalin measurements. Materials and Methods: Six Sprague-Dawley rats were administered with STZ to induce diabetes (group 1). R2∗ was measured before, during, and after administration of iodixanol. R2∗ readings were sampled from 4 renal regions: inner medulla, inner stripe of outer medulla (ISOM), outer stripe of outer medulla, and cortex. Peak R2∗ and initial upslope of R2∗ increase after iodinated contrast were calculated. Data from 12 nondiabetic rats pretreated with nitric oxide synthase and prostaglandin inhibitors to induce susceptibility to contrast-induced acute kidney injury (pretreatment model) from a previous study were reanalyzed for peak R2∗ and initial upslope of R2∗ increase after contrast. Six of these animals received saline (group 2), and the other 6 received furosemide (group 3) before iodixanol. Results: Peak R2∗ and initial upslope of R2∗ increase were used as bloodoxygenation- level-dependent response parameters. R2∗ in ISOM was comparable in all 3 groups before administration of furosemide/saline. Except for the furosemide group, ISOMshowed a rapid increase in R2∗ immediately after contrast administration. Unlike the L-NAME- and indomethacin-treated groups, the diabetic group showed a quick reversal of R2∗ toward baseline measurements after contrast administration. Urinary neutrophil gelatinase-associated lipocalin indicated significant increase in diabetic rats 4 hours after contrast administration. The observed trends with peak R2∗ and initial upslope of R2∗ increase in renal ISOM were in agreement with those of urinary neutrophil gelatinase-associated lipocalin. Conclusions: The STZ-induced diabetic rat may be suitable for studying the effects of iodinated contrast on renal oxygenation status and may mimic human condition closer than the pretreatment model described before. The peak R2∗ value and initial upslope of R2∗ in ISOM appear to be effective magnetic resonance imaging markers to predict renal injury after administration of an iodinated contrast agent. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

PubMed | Mahatma Jyotiba Phule Rohilkhand University, Center for Advanced Imaging, Mayo Medical School and Ben - Gurion University of the Negev
Type: Journal Article | Journal: Journal of the American Heart Association | Year: 2016

Hyper- and hypokalemia are clinically silent, common in patients with renal or cardiac disease, and are life threatening. A noninvasive, unobtrusive, blood-free method for tracking potassium would be an important clinical advance.Two groups of hemodialysis patients (development group, n=26; validation group, n=19) underwent high-resolution digital ECG recordings and had 2 to 3 blood tests during dialysis. Using advanced signal processing, we developed a personalized regression model for each patient to noninvasively calculate potassium values during the second and third dialysis sessions using only the processed single-channel ECG. In addition, by analyzing the entire development groups first-visit data, we created a global model for all patients that was validated against subsequent sessions in the development group and in a separate validation group. This global model sought to predict potassium, based on the T wave characteristics, with no blood tests required. For the personalized model, we successfully calculated potassium values with an absolute error of 0.360.34 mmol/L (or 10% of the measured blood potassium). For the global model, potassium prediction was also accurate, with an absolute error of 0.440.47 mmol/L for the training group (or 11% of the measured blood potassium) and 0.50.42 for the validation set (or 12% of the measured blood potassium).The signal-processed ECG derived from a single lead can be used to calculate potassium values with clinically meaningful resolution using a strategy that requires no blood tests. This enables a cost-effective, noninvasive, unobtrusive strategy for potassium assessment that can be used during remote monitoring.

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