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Lorinda A Hart, Colleen T Downs, Mark Brown
The thermoregulatory capacity of a species can determine which climatic niche it occupies. Its development in avian chicks is influenced by numerous factors. Furthermore, it is suggested that altricial chicks develop their thermoregulatory capacity post-hatching, while precocial chicks develop aspects of this in the egg. We investigated the development of thermoregulation of four co-occurring seabird species in the Seychelles; namely white, ground-nesting white-tailed tropicbirds (Phaethon lepturus) and tree-nesting fairy terns (Gygis alba); and dark plumaged, tree-nesting lesser noddies (Anous tenuirostris) and ground- and tree-nesting brown noddies (A...
February 2017: Journal of Thermal Biology
Elizabeth B Hutchinson, Alexandru V Avram, M Okan Irfanoglu, C Guan Koay, Alan S Barnett, Michal E Komlosh, Evren Özarslan, Susan C Schwerin, Sharon L Juliano, Carlo Pierpaoli
PURPOSE: This study was a systematic evaluation across different and prominent diffusion MRI models to better understand the ways in which scalar metrics are influenced by experimental factors, including experimental design (diffusion-weighted imaging [DWI] sampling) and noise. METHODS: Four diffusion MRI models-diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), mean apparent propagator MRI (MAP-MRI), and neurite orientation dispersion and density imaging (NODDI)-were evaluated by comparing maps and histogram values of the scalar metrics generated using DWI datasets obtained in fixed mouse brain with different noise levels and DWI sampling complexity...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Sila Genc, Charles B Malpas, Scott K Holland, Richard Beare, Timothy J Silk
PURPOSE: White matter development during childhood and adolescence is characterised by increasing white matter coherence and organisation. Commonly used scalar metrics, such as fractional anisotropy (FA), are sensitive to multiple mechanisms of white matter change and therefore unable to distinguish between mechanisms that change during development. We investigate the relationship between age and neurite density index (NDI) from neurite orientation dispersion and density imaging (NODDI), and the age-classification accuracy of NDI compared with FA, in a developmental cohort...
January 11, 2017: NeuroImage
Inge Timmers, Alard Roebroeck, Matteo Bastiani, Bernadette Jansma, Estela Rubio-Gozalbo, Hui Zhang
Neurite orientation dispersion and density imaging (NODDI) enables more specific characterization of tissue microstructure by estimating neurite density (NDI) and orientation dispersion (ODI), two key contributors to fractional anisotropy (FA). The present work compared NODDI- with diffusion tensor imaging (DTI)-derived indices for investigating white matter abnormalities in a clinical sample. We assessed the added value of NODDI parameters over FA, by contrasting group differences identified by both models...
2016: PloS One
Björn Lampinen, Filip Szczepankiewicz, Johan Mårtensson, Danielle van Westen, Pia C Sundgren, Markus Nilsson
In diffusion MRI (dMRI), microscopic diffusion anisotropy can be obscured by orientation dispersion. Separation of these properties is of high importance, since it could allow dMRI to non-invasively probe elongated structures such as neurites (axons and dendrites). However, conventional dMRI, based on single diffusion encoding (SDE), entangles microscopic anisotropy and orientation dispersion with intra-voxel variance in isotropic diffusivity. SDE-based methods for estimating microscopic anisotropy, such as the neurite orientation dispersion and density imaging (NODDI) method, must thus rely on model assumptions to disentangle these features...
February 15, 2017: NeuroImage
Samuel Groeschel, Gisela E Hagberg, Thomas Schultz, Dávid Z Balla, Uwe Klose, Till-Karsten Hauser, Thomas Nägele, Oliver Bieri, Thomas Prasloski, Alex L MacKay, Ingeborg Krägeloh-Mann, Klaus Scheffler
OBJECTIVE: We investigate how known differences in myelin architecture between regions along the cortico-spinal tract and frontal white matter (WM) in 19 healthy adolescents are reflected in several quantitative MRI parameters that have been proposed to non-invasively probe WM microstructure. In a clinically feasible scan time, both conventional imaging sequences as well as microstructural MRI parameters were assessed in order to quantitatively characterise WM regions that are known to differ in the thickness of their myelin sheaths, and in the presence of crossing or parallel fibre organisation...
2016: PloS One
Ryusuke Irie, Kohei Tsuruta, Masaaki Hori, Michimasa Suzuki, Koji Kamagata, Atsushi Nakanishi, Kouhei Kamiya, Madoka Nakajima, Masakazu Miyajima, Hajime Arai, Shigeki Aoki
PURPOSE: To evaluate diffusional changes of the corticospinal tract (CST) in patients with idiopathic normal pressure hydrocephalus (iNPH) by neurite orientation dispersion and density imaging (NODDI). MATERIALS AND METHODS: Nineteen patients with iNPH and 12 healthy controls were included. Diffusion MRI data for NODDI were acquired with a 3-T system, using 32 motion-probing gradient directions with six b-values (from 0 to 2500 s/mm(2)). The orientation dispersion index (ODI), intra-cellular volume fraction (Vic), and isotropic volume fraction (Viso) of the CST were calculated by tract-specific analysis in patients and controls...
October 27, 2016: Japanese Journal of Radiology
Ai Wern Chung, Kiran K Seunarine, Chris A Clark
Diffusion models are advantageous for examining brain microstructure non-invasively and their validation is important for transference into the clinical domain. Neurite Orientation Dispersion and Density Imaging (NODDI) is a promising model for estimating multiple diffusion compartments from MRI data acquired in a clinically feasible time. As a relatively new model, it is necessary to examine NODDI under certain experimental conditions, such as change in magnetic field-strength, and assess it in relation to diffusion tensor imaging (DTI), an established model that is largely understood by the neuroimaging community...
December 2016: Human Brain Mapping
Akash P Kansagra, Marc C Mabray, Donna M Ferriero, A James Barkovich, Duan Xu, Christopher P Hess
PURPOSE: This study aims to apply neurite orientation dispersion and density imaging (NODDI) to measure white matter microstructural features during early development. METHODS: NODDI parameters were measured in twelve newborns and thirteen 6-month infants, all with perinatal clinical encephalopathy. RESULTS: Between 0 and 6 months, there were significant differences in fractional anisotropy (FA) for all tracts; in neurite density for internal capsules, optic radiations, and splenium; and in orientation dispersion for anterior limb of internal capsule and optic radiations...
September 2016: Clinical Imaging
Eduardo Caverzasi, Nico Papinutto, Antonella Castellano, Alyssa H Zhu, Paola Scifo, Marco Riva, Lorenzo Bello, Andrea Falini, Aditya Bharatha, Roland G Henry
PURPOSE: Neurite orientation dispersion and density imaging (NODDI) has recently been developed to overcome diffusion technique limitations in modeling biological systems. This manuscript reports a preliminary investigation into the use of a single color-coded map to represent NODDI-derived information. MATERIALS AND METHODS: An optimized diffusion-weighted imaging protocol was acquired in several clinical neurological contexts including demyelinating disease, neoplastic process, stroke, and toxic/metabolic disease...
September 2016: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
Chinthala P Reddy, Yogesh Rathi
Tracing white matter fiber bundles is an integral part of analyzing brain connectivity. An accurate estimate of the underlying tissue parameters is also paramount in several neuroscience applications. In this work, we propose to use a joint fiber model estimation and tractography algorithm that uses the NODDI (neurite orientation dispersion diffusion imaging) model to estimate fiber orientation dispersion consistently and smoothly along the fiber tracts along with estimating the intracellular and extracellular volume fractions from the diffusion signal...
2016: Frontiers in Neuroscience
Claire E Kelly, Deanne K Thompson, Jian Chen, Alexander Leemans, Christopher L Adamson, Terrie E Inder, Jeanie L Y Cheong, Lex W Doyle, Peter J Anderson
BACKGROUND: Very preterm birth (VPT, <32 weeks' gestation) is associated with altered white matter fractional anisotropy (FA), the biological basis of which is uncertain but may relate to changes in axon density and/or dispersion, which can be measured using Neurite Orientation Dispersion and Density Imaging (NODDI). This study aimed to compare whole brain white matter FA, axon dispersion, and axon density between VPT children and controls (born ≥37 weeks' gestation), and to investigate associations with perinatal factors and neurodevelopmental outcomes...
September 2016: Human Brain Mapping
Chandana Kodiweera, Yu-Chien Wu
This article provides NODDI diffusion metrics in the brains of 52 healthy participants and computer simulation data to support compatibility of hybrid diffusion imaging (HYDI), "Hybrid diffusion imaging"[1] acquisition scheme in fitting neurite orientation dispersion and density imaging (NODDI) model, "NODDI: practical in vivo neurite orientation dispersion and density imaging of the human brain"[2]. HYDI is an extremely versatile diffusion magnetic resonance imaging (dMRI) technique that enables various analyzes methods using a single diffusion dataset...
June 2016: Data in Brief
Mauro Zucchelli, Lorenza Brusini, C Andrés Méndez, Alessandro Daducci, Cristina Granziera, Gloria Menegaz
Diffusion weighted magnetic resonance signals convey information about tissue microstructure and cytoarchitecture. In the last years, many models have been proposed for recovering the diffusion signal and extracting information to constitute new families of numerical indices. Two main categories of reconstruction models can be identified in diffusion magnetic resonance imaging (DMRI): ensemble average propagator (EAP) models and compartmental models. From both, descriptors can be derived for elucidating the underlying microstructural architecture...
August 2016: Medical Image Analysis
Fani Deligianni, David W Carmichael, Gary H Zhang, Chris A Clark, Jonathan D Clayden
In Diffusion Weighted MR Imaging (DWI), the signal is affected by the biophysical properties of neuronal cells and their relative placement, as well as extra-cellular tissue compartments. Typically, microstructural indices, such as fractional anisotropy (FA) and mean diffusivity (MD), are based on a tensor model that cannot disentangle the influence of these parameters. Recently, Neurite Orientation Dispersion and Density Imaging (NODDI) has exploited multi-shell acquisition protocols to model the diffusion signal as the contribution of three tissue compartments...
2016: PloS One
Rutger H J Fick, Demian Wassermann, Emmanuel Caruyer, Rachid Deriche
The recovery of microstructure-related features of the brain's white matter is a current challenge in diffusion MRI. To robustly estimate these important features from multi-shell diffusion MRI data, we propose to analytically regularize the coefficient estimation of the Mean Apparent Propagator (MAP)-MRI method using the norm of the Laplacian of the reconstructed signal. We first compare our approach, which we call MAPL, with competing, state-of-the-art functional basis approaches. We show that it outperforms the original MAP-MRI implementation and the recently proposed modified Spherical Polar Fourier (mSPF) basis with respect to signal fitting and reconstruction of the Ensemble Average Propagator (EAP) and Orientation Distribution Function (ODF) in noisy, sparsely sampled data of a physical phantom with reference gold standard data...
July 1, 2016: NeuroImage
Douglas C Dean, Jonathan O'Muircheartaigh, Holly Dirks, Brittany G Travers, Nagesh Adluru, Andrew L Alexander, Sean C L Deoni
Optimal myelination of neuronal axons is essential for effective brain and cognitive function. The ratio of the axon diameter to the outer fiber diameter, known as the g-ratio, is a reliable measure to assess axonal myelination and is an important index reflecting the efficiency and maximal conduction velocity of white matter pathways. Although advanced neuroimaging techniques including multicomponent relaxometry (MCR) and diffusion tensor imaging afford insight into the microstructural characteristics of brain tissue, by themselves they do not allow direct analysis of the myelin g-ratio...
May 15, 2016: NeuroImage
Maira Tariq, Torben Schneider, Daniel C Alexander, Claudia A Gandini Wheeler-Kingshott, Hui Zhang
This paper presents Bingham-NODDI, a clinically-feasible technique for estimating the anisotropic orientation dispersion of neurites. Direct quantification of neurite morphology on clinical scanners was recently realised by a diffusion MRI technique known as neurite orientation dispersion and density imaging (NODDI). However in its current form NODDI cannot estimate anisotropic orientation dispersion, which is widespread in the brain due to common fanning and bending of neurites. This work proposes Bingham-NODDI that extends the NODDI formalism to address this limitation...
June 2016: NeuroImage
Koji Kamagata, Taku Hatano, Shigeki Aoki
No abstract text is available yet for this article.
2016: Expert Review of Neurotherapeutics
Chandana Kodiweera, Andrew L Alexander, Jaroslaw Harezlak, Thomas W McAllister, Yu-Chien Wu
Microstructural changes in human brain white matter of young to middle-aged adults were studied using advanced diffusion Magnetic Resonance Imaging (dMRI). Multiple shell diffusion-weighted data were acquired using the Hybrid Diffusion Imaging (HYDI). The HYDI method is extremely versatile and data were analyzed using Diffusion Tensor Imaging (DTI), Neurite Orientation Dispersion and Density Imaging (NODDI), and q-space imaging approaches. Twenty-four females and 23 males between 18 and 55years of age were included in this study...
March 2016: NeuroImage
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