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https://www.readbyqxmd.com/read/29332074/diffusion-tensor-imaging-of-the-basal-ganglia-for-functional-neurosurgery-applications
#1
Francesco Sammartino, Mojgan Hodaie
Since its introduction, diffusion tensor imaging (DTI) has become an important tool in neuroscience given its unprecedented ability to image brain white matter in vivo. The interest in understanding the mechanisms of action of Deep Brain Stimulation in different targets and indications, together with the constant drive towards the improvement in long-term clinical outcomes, has found a logical complement in the application of tractography in this field. Diffusion tensor imaging has been traditionally associated with an increased susceptibility to MRI artifacts, and expensive computational resources...
2018: Progress in Neurological Surgery
https://www.readbyqxmd.com/read/29332063/diffusion-tensor-imaging-investigation-of-uncinate-fasciculus-anatomy-in-healthy-controls-description-of-a-subgenual-stem
#2
Kartik Bhatia, Luke Henderson, Mark Yim, Eugene Hsu, Rajiv Dhaliwal
The uncinate fasciculus is the largest white matter association tract connecting the prefrontal cortex and the anteromedial temporal lobe. The traditional anatomical description outlines a temporal stem that hooks around the posterior insula, a subinsular body, and 2 prefrontal stems extending to the lateral orbital gyri and the frontopolar cortex. Recent imaging studies of the white matter tracts deep to the subgenual cingulate gyrus (Brodmann area 25: BA25) suggest the presence of white matter fibers extending from BA25 to the amygdala, via a route that would run in close proximity to the uncinate fasciculus, that are of functional importance in mood disorders...
January 12, 2018: Neuropsychobiology
https://www.readbyqxmd.com/read/29332032/value-of-conventional-mri-and-diffusion-tensor-imaging-parameters-in-predicting-surgical-outcome-in-patients-with-degenerative-cervical-myelopathy
#3
Canghai Shen, Haiwei Xu, Baoshan Xu, Xiaoguang Zhang, Xiaofeng Li, Qiang Yang, Xinlong Ma
BACKGROUND: In addition to conventional magnetic resonance imaging (cMRI), diffusion tensor imaging (DTI) has been investigated as a potential diagnostic and prognostic tool for patients with degenerative cervical myelopathy (DCM). OBJECTIVE: To assess the efficacy of cMRI and DTI parameters in prediction of surgical outcome in DCM patients. METHODS: One hundred and forty-two patients with DCM who underwent presurgical cMRI and DTI of the cervical spine were included...
December 29, 2017: Journal of Back and Musculoskeletal Rehabilitation
https://www.readbyqxmd.com/read/29331847/longitudinal-hippocampal-and-extra-hippocampal-microstructural-and-macrostructural-changes-following-temporal-lobe-epilepsy-surgery
#4
Cameron A Elliott, Donald W Gross, B Matt Wheatley, Christian Beaulieu, Tejas Sankar
OBJECTIVES: 1) Characterize the evolution of microstructural changes in the contralateral, non-operated hippocampus-using longitudinal diffusion tensor imaging (DTI)-following surgery for temporal lobe epilepsy (TLE). 2) Characterize the downstream extra-hippocampal volumetric changes of the fornix and mammillary bodies after TLE surgery. 3) Examine the relationship between these measures and seizure/cognitive outcome. METHODS: Serial structural and DTI brain MRI scans were collected in 25 TLE patients pre- and post-surgery (anterior temporal lobectomy, ATL - 13; selective amygdalohippocampectomy, SelAH - 12) and in 12 healthy controls...
January 6, 2018: Epilepsy Research
https://www.readbyqxmd.com/read/29331116/tensor-decomposed-vibrational-coupled-cluster-theory-enabling-large-scale-highly-accurate-vibrational-structure-calculations
#5
Niels Kristian Madsen, Ian H Godtliebsen, Sergio A Losilla, Ove Christiansen
A new implementation of vibrational coupled-cluster (VCC) theory is presented, where all amplitude tensors are represented in the canonical polyadic (CP) format. The CP-VCC algorithm solves the non-linear VCC equations without ever constructing the amplitudes or error vectors in full dimension but still formally includes the full parameter space of the VCC[n] model in question resulting in the same vibrational energies as the conventional method. In a previous publication, we have described the non-linear-equation solver for CP-VCC calculations...
January 14, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29331053/renal-flow-and-microstructure-anisotropy-refmap-mri-in-normal-and-peritumoral-renal-tissue
#6
Andrea L Liu, Artem Mikheev, Henry Rusinek, William C Huang, James S Wysock, James S Babb, Thorsten Feiweier, David Stoffel, Hersh Chandarana, Eric E Sigmund
BACKGROUND: Diffusion-weighted imaging (DWI) provides insight into the pathophysiology underlying renal dysfunction. Variants of DWI include intravoxel incoherent motion (IVIM), which differentiates between microstructural diffusion and vascular or tubular flow, and diffusion tensor imaging (DTI), which quantifies diffusion directionality. PURPOSE: To investigate the reproducibility of joint IVIM-DTI and compare controls to presurgical renal mass patients. STUDY TYPE: Prospective cross-sectional...
January 13, 2018: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29328696/symmetry-preservation-and-critical-fluctuations-in-a-pseudospin-crossover-perovskite-lacoo_-3
#7
Yasuhiro Shimizu, Takuya Takahashi, Syunpei Yamada, Ayako Shimokata, Takaaki Jin-No, Masayuki Itoh
Spin-state crossover beyond a conventional ligand-field theory has been a fundamental issue in condensed matter physics. Here, we report microscopic observations of spin states and low-energy dynamics through orbital-resolved NMR spectroscopy in the prototype compound LaCoO_{3}. The ^{59}Co NMR spectrum shows the preserved crystal symmetry across the crossover, inconsistent with d orbital ordering due to the Jahn-Teller distortion. The orbital degeneracy results in a pseudospin (J[over ˜]=1) excited state with an orbital moment observed as ^{59}Co hyperfine coupling tensors...
December 29, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29328099/incoherent-component-of-light-scattered-by-a-monolayer-of-spherical-particles-analysis-of-angular-distribution-and-absorption-of-light
#8
Natalia A Loiko, Alexander A Miskevich, Valery A Loiko
We have derived an analytical solution for an incoherent component of light scattered by a normally illuminated monolayer of homogeneous spherical particles. It is based on the quasi-crystalline approximation of the theory of multiple scattering of waves as well as on the multipole expansion of electromagnetic fields and tensor Green's function in terms of vector spherical wave functions. We apply the solution to a description of scattering and absorption characteristics of partially ordered monolayers and monolayers with imperfect lattices...
January 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/29327688/empirical-optimization-of-dft%C3%A2-%C3%A2-%C3%A2-%C3%A2-u-and-hse-for-the-band-structure-of-zno
#9
Keshab Bashyal, Christopher K Pyles, Sajjad Afroosheh, Aneer Lamichhane, Alexey T Zayak
ZnO is a well-known wide band gap semiconductor with promising potential for applications in optoelectronics, transparent electronics, and spintronics. Computational simulations based on the density functional theory (DFT) play an important role in the research of ZnO, but the standard functionals, like Perdew-Burke-Erzenhof, result in largely underestimated values of the band gap and the binding energies of the Zn3d electrons. Methods like DFT  +  U and hybrid functionals are meant to remedy the weaknesses of plain DFT...
January 12, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/29327368/measurement-of-residual-chemical-shift-anisotropies-in-compressed-pmma-gels-automatic-compensation-of-gel-isotropic-shift-contribution
#10
Fernando Hallwass, Rubens R Teles, Erich Hellemann, Christian Griesinger, Roberto R Gil, Armando Navarro-Vázquez
Mechanical compression of polymer gels provides a simple way for the measurement of Residual Chemical Shift Anisotropies (RCSAs), which then can be employed, on its own, or in combination with Residual Dipolar Couplings (RDCs), for structural elucidation purposes. RCSAs measured using compression devices needed a posteriori correction to account for the increase of the polymer to solvent ratio inside the swollen gel. This correction has been cast before in terms of a single free parameter which, as shown here, can be simultaneously optimized along with the components of the alignment tensor while still retaining discriminating power of the different relative configurations as illustrated in the stereochemical analysis of α-santonin and 10-epi-8-deoxycumambrin B...
January 11, 2018: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/29327000/atomic-charges-for-conformationally-rich-molecules-obtained-through-a-modified-principal-component-regression
#11
Tymofii Yu Nikolaienko, Leonid A Bulavin
A modification of the principal component regression model is proposed for obtaining a fixed set of atomic charges (referred to as dipole-derived charges) optimized for reproducing the dipole moment of a conformationally rich molecule, i.e., a molecule with multiple local minima on the potential energy surface. The method does not require any adjustable parameters and requires the geometries of conformers, their dipole moments and atomic polar tensor (APT) charges as the only input data. The fixed atomic charges generated by the method not only reproduce the molecular dipole moment in all the conformers accurately, but are also numerically close to the APT charges, thereby ensuring accurate reproduction of the dipole moment variations caused by small geometrical distortions (e...
January 12, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29324249/disability-in-progressive-ms-is-associated-with-t2-lesion-changes
#12
C Ammitzbøll, T B Dyrby, M Lyksborg, K Schreiber, R Ratzer, J Romme Christensen, P Iversen, M Magyari, E Garde, P S Sørensen, H R Siebner, F Sellebjerg
BACKGROUND: Progressive multiple sclerosis (MS) is characterised by diffuse changes on brain magnetic resonance imaging (MRI), which complicates the use of MRI as a diagnostic and prognostic marker. The relationship between MRI measures (conventional and non-conventional) and clinical disability in progressive MS therefore warrants further investigation. OBJECTIVE: To investigate the relationship between clinical disability and MRI measures in patients with progressive MS...
December 18, 2017: Multiple Sclerosis and related Disorders
https://www.readbyqxmd.com/read/29323797/relations-between-cortical-thickness-serotonin-1a-receptor-binding-and-structural-connectivity-a-multimodal-imaging-study
#13
Rajapillai L I Pillai, Ashwin Malhotra, Deborah D Rupert, Bennett Weschler, John C Williams, Mengru Zhang, Jie Yang, J John Mann, Maria A Oquendo, Ramin V Parsey, Christine DeLorenzo
Serotonin 1A (5-HT1A ) receptors play a direct role in neuronal development, cell proliferation, and dendritic branching. We hypothesized that variability in 5-HT1A binding can affect cortical thickness, and may account for a subtype of major depressive disorder (MDD) in which both are altered. To evaluate this, we measured cortical thickness from structural magnetic resonance imaging (MRI) and 5-HT1A binding by positron emission tomography (PET) in an exploratory study. To examine a range of 5-HT1A binding and cortical thickness values, we recruited 25 healthy controls and 19 patients with MDD...
February 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29323047/diffusion-tensor-imaging-of-spinal-microstructure-in-healthy-adults-improved-resolution-with-the-readout-segmentation-of-long-variable-echo-trains
#14
Bu-Tian Zhang, Meng Li, Li-Li Yu, Yi-Meng Dai, Shao-Nan Yu, Jin-Lan Jiang
Diffusion tensor imaging plays an important role in the accurate diagnosis and prognosis of spinal cord diseases. However, because of technical limitations, the imaging sequences used in this technique cannot reveal the fine structure of the spinal cord with precision. We used the readout segmentation of long variable echo-trains (RESOLVE) sequence in this cross-sectional study of 45 healthy volunteers aged 20 to 63 years. We found that the RESOLVE sequence significantly increased the resolution of the diffusion images and improved the median signal-to-noise ratio of the middle (C4-6) and lower (C7-T1) cervical segments to the level of the upper cervical segment...
December 2017: Neural Regeneration Research
https://www.readbyqxmd.com/read/29323041/central-post-stroke-pain-due-to-injury-of-the-spinothalamic-tract-in-patients-with-cerebral-infarction-a-diffusion-tensor-tractography-imaging-study
#15
Sung Ho Jang, Jun Lee, Sang Seok Yeo
Many studies using diffusion tensor tractography (DTT) have demonstrated that injury of the spinothalamic tract (STT) is the pathogenetic mechanism of central post-stroke pain (CPSP) in intracerebral hemorrhage; however, there is no DTT study reporting the pathogenetic mechanism of CPSP in cerebral infarction. In this study, we investigated injury of the STT in patients with CPSP following cerebral infarction, using DTT. Five patients with CPSP following cerebral infarction and eight age- and sex-matched healthy control subjects were recruited for this study...
December 2017: Neural Regeneration Research
https://www.readbyqxmd.com/read/29322921/tensor-decomposition-based-unsupervised-feature-extraction-identifies-candidate-genes-that-induce-post-traumatic-stress-disorder-mediated-heart-diseases
#16
Y-H Taguchi
BACKGROUND: Although post-traumatic stress disorder (PTSD) is primarily a mental disorder, it can cause additional symptoms that do not seem to be directly related to the central nervous system, which PTSD is assumed to directly affect. PTSD-mediated heart diseases are some of such secondary disorders. In spite of the significant correlations between PTSD and heart diseases, spatial separation between the heart and brain (where PTSD is primarily active) prevents researchers from elucidating the mechanisms that bridge the two disorders...
December 21, 2017: BMC Medical Genomics
https://www.readbyqxmd.com/read/29322239/the-lateralized-arcuate-fasciculus-in-developmental-pitch-disorders-among-mandarin-amusics-left-for-speech-and-right-for-music
#17
Xizhuo Chen, Yanxin Zhao, Suyu Zhong, Zaixu Cui, Jiaqi Li, Gaolang Gong, Qi Dong, Yun Nan
The arcuate fasciculus (AF) is a neural fiber tract that is critical to speech and music development. Although the predominant role of the left AF in speech development is relatively clear, how the AF engages in music development is not understood. Congenital amusia is a special neurodevelopmental condition, which not only affects musical pitch but also speech tone processing. Using diffusion tensor tractography, we aimed at understanding the role of AF in music and speech processing by examining the neural connectivity characteristics of the bilateral AF among thirty Mandarin amusics...
January 10, 2018: Brain Structure & Function
https://www.readbyqxmd.com/read/29321969/the-two-year-progression-of-structural-and-functional-cerebral-mri-in-amyotrophic-lateral-sclerosis
#18
R A L Menke, M Proudfoot, K Talbot, M R Turner
MRI has emerged as one of several urgently needed candidate disease progression biomarkers for the neurodegenerative disorder amyotrophic lateral sclerosis (ALS), not least due to its unique ability to non-invasively assess structural and functional cerebral pathology. We sought to identify the extent of detectable change in cerebral MRI metrics over a more prolonged period. Analysis of multi-modal MRI data was performed in a cohort of sixteen patients (13 ALS and 3 with primary lateral sclerosis) in whom it was possible to acquire six-monthly images over two years...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29321483/extracellular-total-electrolyte-concentration-imaging-for-electrical-brain-stimulation-ebs
#19
Saurav Z K Sajib, Mun Bae Lee, Hyung Joong Kim, Eung Je Woo, Oh In Kwon
Techniques for electrical brain stimulation (EBS), in which weak electrical stimulation is applied to the brain, have been extensively studied in various therapeutic brain functional applications. The extracellular fluid in the brain is a complex electrolyte that is composed of different types of ions, such as sodium (Na+), potassium (K+), and calcium (Ca+). Abnormal levels of electrolytes can cause a variety of pathological disorders. In this paper, we present a novel technique to visualize the total electrolyte concentration in the extracellular compartment of biological tissues...
January 10, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29320524/patients-with-primary-biliary-cholangitis-and-fatigue-present-with-depressive-symptoms-and-selected-cognitive-deficits-but-with-normal-attention-performance-and-brain-structure
#20
Roman Zenouzi, Janina von der Gablentz, Marcus Heldmann, Martin Göttlich, Christina Weiler-Normann, Marcial Sebode, Hanno Ehlken, Johannes Hartl, Anja Fellbrich, Susanne Siemonsen, Christoph Schramm, Thomas F Münte, Ansgar W Lohse
BACKGROUND: In primary biliary cholangitis (PBC) fatigue is a major clinical challenge of unknown etiology. By demonstrating that fatigue in PBC is associated with an impaired cognitive performance, previous studies have pointed out the possibility of brain abnormalities underlying fatigue in PBC. Whether structural brain changes are present in PBC patients with fatigue, however, is unclear. To evaluate the role of structural brain abnormalities in PBC patients severely affected from fatigue we, therefore, performed a case-control cerebral magnetic resonance imaging (cMRI) study and correlated changes of white and grey brain matter with the cognitive and attention performance...
2018: PloS One
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