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Restriction spectrum imaging

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https://www.readbyqxmd.com/read/29053874/tau-pathology-and-neurodegeneration-contribute-to-cognitive-impairment-in-alzheimer-s-disease
#1
Alexandre Bejanin, Daniel R Schonhaut, Renaud La Joie, Joel H Kramer, Suzanne L Baker, Natasha Sosa, Nagehan Ayakta, Averill Cantwell, Mustafa Janabi, Mariella Lauriola, James P O'Neil, Maria L Gorno-Tempini, Zachary A Miller, Howard J Rosen, Bruce L Miller, William J Jagust, Gil D Rabinovici
Neuropathological and in vivo studies have revealed a tight relationship between tau pathology and cognitive impairment across the Alzheimer's disease spectrum. However, tau pathology is also intimately associated with neurodegeneration and amyloid pathology. The aim of the present study was therefore to assess whether grey matter atrophy and amyloid pathology contribute to the relationship between tau pathology, as measured with 18F-AV-1451-PET imaging, and cognitive deficits in Alzheimer's disease. We included 40 amyloid-positive patients meeting criteria for mild cognitive impairment due to Alzheimer's disease (n = 5) or probable Alzheimer's disease dementia (n = 35)...
October 7, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29044691/the-role-of-magnetization-transfer-in-the-observed-contrast-in-t1-weighted-imaging-under-clinical-setups
#2
U Eliav, G Navon
In T1 weighted magnetic resonance imaging of brain and spinal cord in the clinical setting, the white matter (WM) appears with greater intensity than the gray matter (GM). This contrast has been assigned to differences in T1 values. In these experiments the RF pulses are too long to excite both the water and the species with restricted motion of the protons (SRMP). In in vitro studies using short RF pulses, the contrast is reversed, with greater intensity for the GM. These results raise the question of whether magnetization transfer (MT) plays a role in the contrast observed in the T1 weighting experiments...
October 18, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/29041200/graphene-metamaterial-spatial-light-modulator-for-infrared-single-pixel-imaging
#3
Kebin Fan, Jonathan Y Suen, Willie J Padilla
High-resolution and hyperspectral imaging has long been a goal for multi-dimensional data fusion sensing applications - of interest for autonomous vehicles and environmental monitoring. In the long wave infrared regime this quest has been impeded by size, weight, power, and cost issues, especially as focal-plane array detector sizes increase. Here we propose and experimentally demonstrated a new approach based on a metamaterial graphene spatial light modulator (GSLM) for infrared single pixel imaging. A frequency-division multiplexing (FDM) imaging technique is designed and implemented, and relies entirely on the electronic reconfigurability of the GSLM...
October 16, 2017: Optics Express
https://www.readbyqxmd.com/read/29020825/the-yield-of-the-prenatal-work-up-in-intrauterine-growth-restriction-and-the-spectrum-of-fetal-abnormalities-detected-postnatally
#4
Rivka Sukenik-Halevy, Adi Katz, Rivka Regev, Ofer Markovitch, Reuven Sharony, Yael Ganor Paz, Tal Biron-Shental
OBJECTIVE: To evaluate the yield of work-up in intrauterine growth restriction (IUGR) pregnancies and their outcomes. MATERIALS AND METHODS: Retrospective data regarding prenatal work-up (serology, genetic testing and imaging), and neonatal outcomes of 198 IUGR pregnancies (estimated fetal weight < 10th percentile) were analyzed. RESULTS: IUGR was isolated in 72. Work-up performed in 158 (80%) cases was positive in 4 (2.5%). No abnormalities were detected in prenatal genetic testing...
October 11, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28981635/linking-entropy-at-rest-with-the-underlying-structural-connectivity-in-the-healthy-and-lesioned-brain
#5
Victor M Saenger, Adrián Ponce-Alvarez, Mohit Adhikari, Patric Hagmann, Gustavo Deco, Maurizio Corbetta
The brain is a network that mediates information processing through a wide range of states. The extent of state diversity is a reflection of the entropy of the network. Here we measured the entropy of brain regions (nodes) in empirical and modeled functional networks reconstructed from resting state fMRI to address the connection of entropy at rest with the underlying structure measured through diffusion spectrum imaging. Using 18 empirical and 18 modeled stroke networks, we also investigated the effect that focal lesions have on node entropy and information diffusion...
July 13, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28981295/3d-imaging-of-gap-plasmons-in-vertically-coupled-nanoparticles-by-eels-tomography
#6
Georg Haberfehlner, Franz-Philipp Schmidt, Gernot Schaffernak, Anton Hörl, Andreas Trügler, Andreas Hohenau, Ferdinand Hofer, Joachim R Krenn, Ulrich Hohenester, Gerald Kothleitner
Plasmonic gap modes provide the ultimate confinement of optical fields. Demanding high spatial resolution, the direct imaging of these modes was only recently achieved by electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). However, conventional 2D STEM-EELS is only sensitive to components of the photonic local density of states (LDOS) parallel to the electron trajectory. It is thus insensitive to specific gap modes, a restriction that was lifted with the introduction of tomographic 3D EELS imaging...
October 10, 2017: Nano Letters
https://www.readbyqxmd.com/read/28941767/a-proton-mr-spectroscopy-study-of-the-thalamus-in-twins-with-autism-spectrum-disorder
#7
John P Hegarty, Meng Gu, Daniel M Spielman, Sue C Cleveland, Joachim F Hallmayer, Laura C Lazzeroni, Mira M Raman, Thomas W Frazier, Jennifer M Phillips, Allan L Reiss, Antonio Y Hardan
Multiple lines of research have reported thalamic abnormalities in individuals with autism spectrum disorder (ASD) that are associated with social communication impairments (SCI), restricted and repetitive behaviors (RRB), or sensory processing abnormalities (SPA). Thus, the thalamus may represent a common neurobiological structure that is shared across symptom domains in ASD. Same-sex monozygotic (MZ) and dizygotic (DZ) twin pairs with and without ASD underwent cognitive/behavioral evaluation and magnetic resonance imaging to assess the thalamus...
September 20, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
https://www.readbyqxmd.com/read/28910681/the-imaging-spectrum-of-posterior-reversible-encephalopathy-syndrome-a-pictorial-review
#8
REVIEW
Emily Brady, Neal S Parikh, Babak B Navi, Ajay Gupta, Andrew D Schweitzer
Posterior reversible encephalopathy syndrome (PRES) is characterized by the acute onset of neurologic symptoms (headache, altered mental status, visual changes, seizures) with accompanying vasogenic edema on brain imaging. Risk factors for PRES include infection, uremia, malignancy, autoimmune disorders, the peripartum state and hypertension. PRES is classically described as being posterior (i.e. parieto-occipital) but radiologic variants are increasingly recognized. This pictorial review demonstrates the heterogeneity of the different radiologic presentations of PRES in reference to lesion distribution, hemorrhage, diffusion restriction, contrast enhancement, and other associated findings...
August 30, 2017: Clinical Imaging
https://www.readbyqxmd.com/read/28864914/nonketotic-hyperglycinemia-spectrum-of-imaging-findings-with-emphasis-on-diffusion-weighted-imaging
#9
Shaimaa Abdelsattar Mohammad, Heba Salah Abdelkhalek
PURPOSE: The purpose of this study was to explore brain abnormalities in nonketotic hyperglycinemia (NKH) using diffusion-weighted imaging (DWI) and when feasible, diffusion tensor imaging (DTI) and tractography. METHODS: Seven patients with confirmed diagnosis of NKH (8 days-2 years) underwent brain MRI. Conventional T1 and T2WI were acquired in all patients, DWI in six and DTI and tractography in two (4 months and 2 years). Measurements of fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD) and Trace from eight white matter regions were compared between the two patients and age-matched controls...
September 1, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28845892/multiple-functional-networks-modeling-for-autism-spectrum-disorder-diagnosis
#10
Tae-Eui Kam, Heung-Il Suk, Seong-Whan Lee
Despite countless studies on autism spectrum disorder (ASD), diagnosis relies on specific behavioral criteria and neuroimaging biomarkers for the disorder are still relatively scarce and irrelevant for diagnostic workup. Many researchers have focused on functional networks of brain activities using resting-state functional magnetic resonance imaging (rsfMRI) to diagnose brain diseases, including ASD. Although some existing methods are able to reveal the abnormalities in functional networks, they are either highly dependent on prior assumptions for modeling these networks or do not focus on latent functional connectivities (FCs) by considering discriminative relations among FCs in a nonlinear way...
August 28, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28839245/hypermasculinised-facial-morphology-in-boys-and-girls-with-autism-spectrum-disorder-and-its-association-with-symptomatology
#11
Diana Weiting Tan, Syed Zulqarnain Gilani, Murray T Maybery, Ajmal Mian, Anna Hunt, Mark Walters, Andrew J O Whitehouse
Elevated prenatal testosterone exposure has been associated with Autism Spectrum Disorder (ASD) and facial masculinity. By employing three-dimensional (3D) photogrammetry, the current study investigated whether prepubescent boys and girls with ASD present increased facial masculinity compared to typically-developing controls. There were two phases to this research. 3D facial images were obtained from a normative sample of 48 boys and 53 girls (3.01-12.44 years old) to determine typical facial masculinity/femininity...
August 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28820624/retinopathy-and-optic-atrophy-expanding-the-phenotypic-spectrum-of-pathogenic-variants-in-the-aars2-gene
#12
Jason H Peragallo, Stephanie Keller, Marjo S van der Knaap, Bruno P Soares, Suma P Shankar
BACKGROUND: Optic atrophy may be the sequela of optic nerve injury due to any insult, including isolated and syndromic genetic diseases. Alanyl-tRNA synthetase 2 (AARS2) pathogenic variants have been reported to cause leukodystrophy with ovarian failure, and cardiomyopathy (#615889) as well as combined oxidative phosphorylation deficiency-8 (#614096). We report a young child who presented with decreased vision due to optic atrophy and was found to harbor missense variants in the AARS2 gene expanding the phenotypic expression of the AARS2 gene...
August 18, 2017: Ophthalmic Genetics
https://www.readbyqxmd.com/read/28764771/sensitivity-of-restriction-spectrum-imaging-to-memory-and-neuropathology-in-alzheimer-s-disease
#13
Emilie T Reas, Donald J Hagler, Nathan S White, Joshua M Kuperman, Hauke Bartsch, Karalani Cross, Richard Q Loi, Akshara R Balachandra, M J Meloy, Christina E Wierenga, Douglas Galasko, James B Brewer, Anders M Dale, Linda K McEvoy
BACKGROUND: Diffusion imaging has demonstrated sensitivity to structural brain changes in Alzheimer's disease (AD). However, there remains a need for a more complete characterization of microstructural alterations occurring at the earliest disease stages, and how these changes relate to underlying neuropathology. This study evaluated the sensitivity of restriction spectrum imaging (RSI), an advanced diffusion magnetic resonance imaging (MRI) technique, to microstructural brain changes in mild cognitive impairment (MCI) and AD...
August 2, 2017: Alzheimer's Research & Therapy
https://www.readbyqxmd.com/read/28720366/the-evolving-role-of-retrograde-intrarenal-surgery-in-the-treatment-of-urolithiasis
#14
REVIEW
Francesco Sanguedolce, Giorgio Bozzini, Ben Chew, Panagiotis Kallidonis, Jean de la Rosette
CONTEXT: Retrograde intrarenal surgery has gained substantial popularity worldwide thanks to continuous improvements in technology and techniques, and is now considered one of the first-line treatment options for active removal of renal stones. OBJECTIVE: To provide a comprehensive synthesis of the main evidences in literature on the current management of kidney stones by means of retrograde intrarenal surgery (RIRS). EVIDENCE ACQUISITION: A review of literature has been conducted using search string "retrograde intrarenal surgery OR flexible ureteroscop* OR ureterorenoscop*", without any language restriction; PubMed, Embase, and Scopus databases were searched in November 2016...
February 2017: European Urology Focus
https://www.readbyqxmd.com/read/28712371/visual-systemizing-preference-in-children-with-autism-a-randomized-controlled-trial-of-intranasal-oxytocin
#15
Lane Strathearn, Sohye Kim, D Anthony Bastian, Jennifer Jung, Udita Iyengar, Sheila Martinez, Robin P Goin-Kochel, Peter Fonagy
Several studies have suggested that the neuropeptide oxytocin may enhance aspects of social communication in autism. Little is known, however, about its effects on nonsocial manifestations, such as restricted interests and repetitive behaviors. In the empathizing-systemizing theory of autism, social deficits are described along the continuum of empathizing ability, whereas nonsocial aspects are characterized in terms of an increased preference for patterned or rule-based systems, called systemizing. We therefore developed an automated eye-tracking task to test whether children and adolescents with autism spectrum disorder (ASD) compared to matched controls display a visual preference for more highly organized and structured (systemized) real-life images...
July 17, 2017: Development and Psychopathology
https://www.readbyqxmd.com/read/28709144/the-spectrum-of-peri-ictal-mri-changes-four-illustrative-cases
#16
Jennifer Williams, Gerard Mullins, Norman Delanty, Bede Peter, Colin P Doherty
PURPOSE: Seizure induced neuronal hyperexcitability and increased unmet metabolic neuronal demand results in failure of the sodium/potassium ATP pump. Sodium and water accumulates intracellularly with cellular swelling and reduced extracellular volume demonstrating hyperintensity on DWI and reduced ADC. The aim of this study was to describe 4 clinical cases where we identified abnormalities in diffusion restriction in the acute peri-ictal period and followed them longitudinally. METHODS: Patients were recruited from the emergency department, clinical consultation service and epilepsy monitoring unit of two tertiary referral centres...
July 6, 2017: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/28630678/on-the-colour-of-wing-scales-in-butterflies-iridescence-and-preferred-orientation-of-single-gyroid-photonic-crystals
#17
Robert W Corkery, Eric C Tyrode
Lycaenid butterflies from the genera Callophrys, Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue-green-yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform...
August 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/28600921/an-exploration-of-the-spectrum-of-peri-ictal-mri-change-a-comprehensive-literature-review
#18
REVIEW
Jennifer A Williams, Peter Bede, Colin P Doherty
PURPOSE: The aim of this review was to identify published studies in the literature relating to ictal induced MRI change and to identify certain common themes, practical points for clinicians and areas for future research. METHODS: We identified 96 articles that satisfied our inclusion criteria yielding 575 cases. All articles were analysed; number of subjects, spectrum of MRI and EEG change, aetiology, and follow-up (both clinical and imaging) were noted. RESULTS: The most frequent imaging changes were restricted diffusion, T2-hyperintensity and reduced ADC values...
May 31, 2017: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/28572226/a-clinical-enigma-of-ongoing-constrictive-pericarditis
#19
Deacon Zhao Jun Lee, Reshma Amin, John Baksi, Robert Gerber
A 59-year-old lady presented with a 1-week history of orthopnoea, paroxysmal nocturnal dyspnoea, night sweats and a productive cough. She had no recent history of travel. Transthoracic echocardiogram revealed preserved left ventricular systolic function with abnormal pericardial thickening and restrictive left ventricular filling consistent with pericardial constriction. Cardiac magnetic resonance imaging confirmed a globally thickened pericardium and showed evidence of pericardial inflammation and constrictive physiology...
June 2017: Clinical Medicine: Journal of the Royal College of Physicians of London
https://www.readbyqxmd.com/read/28533516/asd-restricted-and-repetitive-behaviors-associated-at-17q21-33-genes-prioritized-by-expression-in-fetal-brains
#20
R M Cantor, L Navarro, H Won, R L Walker, J K Lowe, D H Geschwind
Autism spectrum disorder (ASD) is a behaviorally defined condition that manifests in infancy or early childhood as deficits in communication skills and social interactions. Often, restricted and repetitive behaviors (RRBs) accompany this disorder. ASD is polygenic and genetically complex, so we hypothesized that focusing analyses on intermediate core component phenotypes, such as RRBs, can reduce genetic heterogeneity and improve statistical power. Applying this approach, we mined Caucasian genome-wide association studies (GWAS) data from two of the largest ASD family cohorts, the Autism Genetics Resource Exchange and Autism Genome Project (AGP)...
May 23, 2017: Molecular Psychiatry
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