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MRI theory and use

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https://www.readbyqxmd.com/read/29139161/cognitive-abilities-brain-white-matter-hyperintensity-volume-and-structural-network-connectivity-in-older-age
#1
Stewart J Wiseman, Tom Booth, Stuart J Ritchie, Simon R Cox, Susana Muñoz Maniega, Maria Del C Valdés Hernández, David Alexander Dickie, Natalie A Royle, John M Starr, Ian J Deary, Joanna M Wardlaw, Mark E Bastin
OBJECTIVE: To assess brain structural connectivity in relation to cognitive abilities in healthy ageing, and the mediating effects of white matter hyper-intensity (WMH) volume. METHODS: MRI data were analysed in 558 members of the Lothian Birth Cohort 1936. Brains were segmented into 85 regions and combined with tractography to generate structural connectomes. WMH volume was quantified. Relationships between whole-brain connectivity, assessed using graph theory metrics, and four major domains of cognitive ability (visuospatial reasoning, verbal memory, information processing speed and crystallized ability) were investigated, as was the mediating effects of WMH volume on these relationships...
November 14, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29104148/laminar-fmri-and-computational-theories-of-brain-function
#2
REVIEW
K E Stephan, F H Petzschner, L Kasper, J Bayer, K V Wellstein, G Stefanics, K P Pruessmann, J Heinzle
Recently developed methods for functional MRI at the resolution of cortical layers (laminar fMRI) offer a novel window into neurophysiological mechanisms of cortical activity. Beyond physiology, laminar fMRI also offers an unprecedented opportunity to test influential theories of brain function. Specifically, hierarchical Bayesian theories of brain function, such as predictive coding, assign specific computational roles to different cortical layers. Combined with computational models, laminar fMRI offers a unique opportunity to test these proposals noninvasively in humans...
November 2, 2017: NeuroImage
https://www.readbyqxmd.com/read/29094378/modeling-rater-diagnostic-skills-in-binary-classification-processes
#3
Xiaoyan Lin, Hua Chen, Don Edwards, Kerrie P Nelson
Many disease diagnoses involve subjective judgments by qualified raters. For example, through the inspection of a mammogram, MRI, or ultrasound image, the clinician himself becomes part of the measuring instrument. To reduce diagnostic errors and improve the quality of diagnoses, it is necessary to assess raters' diagnostic skills and to improve their skills over time. This paper focuses on a subjective binary classification process, proposing a hierarchical model linking data on rater opinions with patient true disease-development outcomes...
November 2, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/29084064/new-insights-into-cerebral-small-vessel-disease-and-vascular-cognitive-impairment-from-mri
#4
Eric E Smith, Andrew E Beaudin
PURPOSE OF REVIEW: We review recent MRI research that addresses two important challenges in cerebral small vessel disease (SVD) research: early diagnosis, and linking SVD with cognitive impairment. First, we review studies of MRI measurements of blood flow and blood-brain barrier integrity. Second, we review MRI studies identifying neuroimaging correlates of SVD-related cognitive dysfunction, focusing on brain connectivity and white matter microarchitecture. This research is placed in context through discussion of recent recommendations for management of incidentally discovered SVD, and neuroimaging biomarker use in clinical trials...
October 27, 2017: Current Opinion in Neurology
https://www.readbyqxmd.com/read/29081852/the-aetiology-of-the-non-ossifying-fibroma-of-the-distal-femur-and-its-relationship-to-the-surrounding-soft-tissues
#5
A Goldin, D A Muzykewicz, J Dwek, S J Mubarak
PURPOSE: We aim to retrospectively evaluate patients with non-ossifying fibroma (NOF) of the distal femur by radiographs, CT and MRI, and to provide a theory describing the reasoning for the distal femur NOF's location and aetiology. METHODS: Charts of patients with NOFs between 2003 and 2014 were retrospectively reviewed. Inclusion criteria encompassed a diagnosis of NOF of the distal femur by imaging, and histologically, if available. Radiographs, CT and MRI were used to characterise the relationship of the NOF lesions with the surrounding soft tissues...
October 1, 2017: Journal of Children's Orthopaedics
https://www.readbyqxmd.com/read/29077570/determination-of-mean-ionization-potential-using-magnetic-resonance-imaging-for-the-reduction-of-proton-beam-range-uncertainties-theory-and-application
#6
Atchar Sudhyadhom
The accurate determination of mean ionization potential (I m) has the potential to reduce range uncertainty based margins and therefore allow for more focal treatments in proton radiotherapy. Many methods have been proposed to reduce uncertainty in I m and stopping power ratios (SPR), each with varying degrees of accuracy and issues. In this work, we present a simple parameterized model to determine I m in human biological tissue, allowing for the computation of patient-specific I m at the voxel level using magnetic resonance imaging (MRI)...
October 27, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29034164/aberrant-brain-functional-connectivity-in-newborns-with-congenital-heart-disease-before-cardiac-surgery
#7
Josepheen De Asis-Cruz, Mary T Donofrio, Gilbert Vezina, Catherine Limperopoulos
Newborns with congenital heart disease (CHD) requiring open heart surgery are at increased risk for neurodevelopmental disabilities. Recent quantitative MRI studies have reported disrupted growth, microstructure, and metabolism in fetuses and newborns with complex CHD. To date, no study has examined whether functional brain connectivity is altered in this high-risk population after birth, before surgery. Our objective was to compare whole-brain functional connectivity of resting state networks in healthy, term newborns (n = 82) and in term neonates with CHD before surgery (n = 30) using graph theory and network-based statistics...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29028542/spectral-diffusion-and-dynamic-nuclear-polarization-beyond-the-high-temperature-approximation
#8
W Th Wenckebach
Dynamic Nuclear Polarization (DNP) has proven itself most powerful for the orientation of nuclear spins in polarized targets and for hyperpolarization in magnetic resonance imaging (MRI). Unfortunately, the theoretical description of some of the processes involved in DNP invokes the high temperature approximation, in which Boltzmann factors are expanded up to first order, while the high electron and nuclear spin polarization required for many applications do not justify such an approximation. A previous article extended the description of one of the mechanisms of DNP-thermal mixing-beyond the high temperature approximation (Wenckebach, 2017)...
October 4, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29024242/lanthanide-based-t2ex-and-cest-complexes-provide-new-insights-into-the-design-of-ph-sensitive-mri-agents
#9
Lei Zhang, Andre F Martins, Piyu Zhao, Yunkou Wu, Gyula Tircso, Dean Sherry
A series of Eu3+ and Dy3+ DOTA-tetraamide complexes with four appended primary amine groups were prepared and their CEST and T1/T2 relaxation properties measured as a function of pH. The CEST signals in the Eu3+ complexes show a surprisingly strong CEST signal after the pH was reduced from 8 to 5. The opposite trend was observed for the Dy3+ complexes where the r2ex of bulk water protons increased dramatically from ~1.5 mM-1s-1 to ~13 mM-1s-1, while r1 remained unchanged. A fit of the CEST data (Eu3+ complexes) to Bloch theory and the T2 data (Dy3+ complexes) to Swift-Connick theory provided the proton exchange rates as a function of pH...
October 11, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29023969/calculating-potential-error-in-sodium-mri-with-respect-to-the-analysis-of-small-objects
#10
Robert W Stobbe, Christian Beaulieu
PURPOSE: To facilitate correct interpretation of sodium MRI measurements, calculation of error with respect to rapid signal decay is introduced and combined with that of spatially correlated noise to assess volume-of-interest (VOI) (23) Na signal measurement inaccuracies, particularly for small objects. METHODS: Noise and signal decay-related error calculations were verified using twisted projection imaging and a specially designed phantom with different sized spheres of constant elevated sodium concentration...
October 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29020291/reward-sensitivity-and-waiting-impulsivity-shift-towards-reward-valuation-away-from-action-control
#11
Daisy J Mechelmans, Daniela Strelchuk, Nuria Donamayor-Alonso, Paula Banca, Trevor W Robbins, Kwangyeol Baek, Valerie Voon
Background: Impulsivity and reward expectancy are commonly inter-related. Waiting impulsivity, measured using the rodent 5-Choice Serial Reaction Time (5-CSRT) task, predicts compulsive cocaine seeking and sign (or cue) tracking. Here we assess human waiting impulsivity using a novel translational task, the 4-CSRT, and the relationship with reward cues. Methods: Healthy volunteers (n=29) performed the monetary incentive delay task as a functional MRI study where subjects observe a cue predicting reward (cue) and wait to respond for high (£5), low (£1) or no reward...
August 8, 2017: International Journal of Neuropsychopharmacology
https://www.readbyqxmd.com/read/29016431/incidence-of-congenital-spinal-abnormalities-among-pediatric-patients-and-their-association-with-scoliosis-and-systemic-anomalies
#12
Peter G Passias, Gregory W Poorman, Cyrus M Jalai, Bassel G Diebo, Shaleen Vira, Samantha R Horn, Joseph F Baker, Kartik Shenoy, Saqib Hasan, John Buza, Wesley Bronson, Justin C Paul, Ian Kaye, Norah A Foster, Ryan T Cassilly, Jonathan H Oren, Ronald Moskovich, Breton Line, Cheongeun Oh, Shay Bess, Virginie LaFage, Thomas J Errico
BACKGROUND: Congenital abnormalities when present, according to VACTERL theory, occur nonrandomly with other congenital anomalies. This study estimates the prevalence of congenital spinal anomalies, and their concurrence with other systemic anomalies. METHODS: A retrospective cohort analysis on Health care Cost and Utilization Project's Kids Inpatient Database (KID), years 2000, 2003, 2006, 2009 was performed. ICD-9 coding identified congenital anomalies of the spine and other body systems...
October 9, 2017: Journal of Pediatric Orthopedics
https://www.readbyqxmd.com/read/28982632/a-data-oriented-self-calibration-and-robust-chemical-shift-encoding-by-using-clusterization-oscar-theory-optimization-and-clinical-validation-in-neuromuscular-disorders
#13
G Siracusano, A La Corte, M Gaeta, G Finocchio
Multi-echo Chemical Shift-Encoded (CSE) methods for Fat-Water quantification are growing in clinical use due to their ability to estimate and correct some confounding effects. State of the art CSE water/fat separation approaches rely on a multi-peak fat spectrum with peak frequencies and relative amplitudes kept constant over the entire MRI dataset. However, the latter approximation introduces a systematic error in fat percentage quantification in patients where the differences in lipid chemical composition are significant (such as for neuromuscular disorders) because of the spatial dependence of the peak amplitudes...
October 2, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28981646/increased-global-interaction-across-functional-brain-modules-during-cognitive-emotion-regulation
#14
Felix Brandl, Satja Mulej Bratec, Xiyao Xie, Afra M Wohlschläger, Valentin Riedl, Chun Meng, Christian Sorg
Cognitive emotion regulation (CER) enables humans to flexibly modulate their emotions. While local theories of CER neurobiology suggest interactions between specialized local brain circuits underlying CER, e.g., in subparts of amygdala and medial prefrontal cortices (mPFC), global theories hypothesize global interaction increases among larger functional brain modules comprising local circuits. We tested the global CER hypothesis using graph-based whole-brain network analysis of functional MRI data during aversive emotional processing with and without CER...
July 13, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28975039/creative-music-therapy-to-promote-brain-structure-function-and-neurobehavioral-outcomes-in-preterm-infants-a-randomized-controlled-pilot-trial-protocol
#15
Friederike Barbara Haslbeck, Hans-Ulrich Bucher, Dirk Bassler, Cornelia Hagmann
BACKGROUND: Preterm birth is associated with increased risk of neurological impairment and deficits in cognition, motor function, and behavioral problems. Limited studies indicate that multi-sensory experiences support brain development in preterm infants. Music appears to promote neurobiological processes and neuronal learning in the human brain. Creative music therapy (CMT) is an individualized, interactive therapeutic approach based on the theory and methods of Nordoff and Robbins...
2017: Pilot and Feasibility Studies
https://www.readbyqxmd.com/read/28968754/influences-on-the-test-retest-reliability-of-functional-connectivity-mri-and-its-relationship-with-behavioral-utility
#16
Stephanie Noble, Marisa N Spann, Fuyuze Tokoglu, Xilin Shen, R Todd Constable, Dustin Scheinost
Best practices are currently being developed for the acquisition and processing of resting-state magnetic resonance imaging data used to estimate brain functional organization-or "functional connectivity." Standards have been proposed based on test-retest reliability, but open questions remain. These include how amount of data per subject influences whole-brain reliability, the influence of increasing runs versus sessions, the spatial distribution of reliability, the reliability of multivariate methods, and, crucially, how reliability maps onto prediction of behavior...
September 12, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28949286/altered-intrinsic-functional-brain-architecture-in-female-patients-with-bulimia-nervosa
#17
Li Wang, Qing-Mei Kong, Ke Li, Xue-Ni Li, Ya-Wei Zeng, Chao Chen, Ying Qian, Shi-Jie Feng, Ji-Tao Li, Yun'Ai Su, Christoph U Correll, Philip B Mitchell, Chao-Gan Yan, Da-Rong Zhang, Tian-Mei Si
BACKGROUND: Bulimia nervosa is a severe psychiatric syndrome with uncertain pathogenesis. Neural systems involved in sensorimotor and visual processing, reward and impulsive control may contribute to the binge eating and purging behaviours characterizing bulimia nervosa. However, little is known about the alterations of functional organization of whole brain networks in individuals with this disorder. METHODS: We used resting-state functional MRI and graph theory to characterize functional brain networks of unmedicated women with bulimia nervosa and healthy women...
November 2017: Journal of Psychiatry & Neuroscience: JPN
https://www.readbyqxmd.com/read/28946750/age-related-changes-in-topological-degradation-of-white-matter-networks-and-gene-expression-in-chronic-schizophrenia
#18
Fon Powell, Eve LoCastro, Diana Acosta, Mohamed Ahmed, Stefani O'Donoghue, Natalie Forde, Dara Cannon, Cathy Scanlon, Tushar Rao, Colm McDonald, Ashish Raj
Current hypotheses stipulate core symptoms of schizophrenia (SZ) result from the brain's incapacity to integrate neural processes. Converging diffusion magnetic resonance imaging and graph theory studies provide evidence of macrostructural alterations in SZ. However, age-related topological changes within and between white matter (WM) networks and its relationship to gene expression with disease progression remain incompletely understood. This cross-sectional study uses network modeling to investigate changes in WM network organization with disease progression in chronic SZ as well its relationship with gene expression in healthy brains...
November 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28944305/network-organization-is-globally-atypical-in-autism-a-graph-theory-study-of-intrinsic-functional-connectivity
#19
Christopher L Keown, Michael C Datko, Colleen P Chen, José Omar Maximo, Afrooz Jahedi, Ralph-Axel Müller
BACKGROUND: Despite abundant evidence of brain network anomalies in autism spectrum disorder (ASD), findings have varied from broad functional underconnectivity to broad overconnectivity. Rather than pursuing overly simplifying general hypotheses ('under' vs. 'over'), we tested the hypothesis of atypical network distribution in ASD (i.e., participation of unusual loci in distributed functional networks). METHODS: We used a selective high-quality data subset from the ABIDE datashare (including 111 ASD and 174 typically developing [TD] participants) and several graph theory metrics...
January 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
https://www.readbyqxmd.com/read/28932236/quantitative-evaluation-of-temporal-regularizers-in-compressed-sensing-dynamic-contrast-enhanced-mri-of-the-breast
#20
Dong Wang, Lori R Arlinghaus, Thomas E Yankeelov, Xiaoping Yang, David S Smith
PURPOSE: Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is used in cancer imaging to probe tumor vascular properties. Compressed sensing (CS) theory makes it possible to recover MR images from randomly undersampled k-space data using nonlinear recovery schemes. The purpose of this paper is to quantitatively evaluate common temporal sparsity-promoting regularizers for CS DCE-MRI of the breast. METHODS: We considered five ubiquitous temporal regularizers on 4...
2017: International Journal of Biomedical Imaging
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