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https://www.readbyqxmd.com/read/28076867/identifying-host-genetic-variants-associated-with-microbiome-composition-by-testing-multiple-beta-diversity-matrices
#1
Xing Hua, James J Goedert, Maria Teresa Landi, Jianxin Shi
OBJECTIVES: Host genetics have been recently reported to affect human microbiome composition. We previously developed a statistical framework, microbiomeGWAS, to identify host genetic variants associated with microbiome composition by testing a distance matrix. However, statistical power depends on the choice of a microbiome distance matrix. To achieve more robust statistical power, we aim to extend microbiomeGWAS to test the association with many distance matrices, which are defined based on multilevel taxa abundances and phylogenetic information...
2016: Human Heredity
https://www.readbyqxmd.com/read/28057085/3d-analysis-of-apparent-diffusion-coefficient-histograms-in-hepatocellular-carcinoma-correlation-with-histological-grade
#2
Tomohisa Moriya, Kazuhiro Saito, Yu Tajima, Taiyo L Harada, Yoichi Araki, Katsutoshi Sugimoto, Koichi Tokuuye
BACKGROUND: To evaluate the usefulness of differentiation of histological grade in hepatocellular carcinoma (HCC) using three-dimensional (3D) analysis of apparent diffusion coefficient (ADC) histograms retrospectively. METHODS: The subjects consisted of 53 patients with 56 HCCs. The subjects included 12 well-differentiated, 35 moderately differentiated, and nine poorly differentiated HCCs. Diffusion-weighted imaging (b-values of 100 and 800 s/mm(2)) were obtained within 3 months before surgery...
January 5, 2017: Cancer Imaging: the Official Publication of the International Cancer Imaging Society
https://www.readbyqxmd.com/read/28048488/su-f-t-602-central-moments-to-analyze-dose-distributions-in-planning-target-volumes
#3
Q Zhang, Y Cao, A Jamshidi, P Vigneri, L Potters, E Klein
PURPOSE: To quantify the dose distribution inside planning target volumes (PTV), the coefficient of variation, skewness (third central moment) and kurtosis (fourth central moment) were used to analyze the dose distributions of PTVs for lung and prostate cases. Those variables can be used to measure the shape of the dose distribution. METHODS: The mean dose, coefficient of variation, skewness, and kurtosis were used to analyze the dose distributions inside PTVs for 24 randomly selected patients...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048091/su-f-r-50-radiation-induced-changes-in-ct-number-histogram-during-chemoradiation-therapy-for-pancreatic-cancer
#4
X Chen, D Schott, Y Song, D Li, W Hall, B Erickson, X Li
PURPOSE: In an effort of early assessment of treatment response, we investigate radiation induced changes in CT number histogram of GTV during the delivery of chemoradiation therapy (CRT) for pancreatic cancer. METHODS: Diagnostic-quality CT data acquired daily during routine CT-guided CRT using a CT-on-rails for 20 pancreatic head cancer patients were analyzed. All patients were treated with a radiation dose of 50.4 in 28 fractions. On each daily CT set, the contours of the pancreatic head and the spinal cord were delineated...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047615/su-g-jep2-12-quantification-of-3d-geometric-distortion-for-1-5t-and-3t-mri-scanners-used-for-radiation-therapy
#5
M Stowe, N Gupta, B Raterman, L Lu
PURPOSE: To quantify the magnitude of geometric distortion for MRI scanners and provide recommendations for MRI imaging for radiation therapy METHODS: A novel phantom, QUASAR MRID3D [Modus Medical Devices Inc.], was scanned to evaluate the level of 3D geometric distortion present in five MRI scanners used for radiation therapy in our department. The phantom was scanned using the body coil with 1mm image slice thickness to acquire 3D images of the phantom body. The phantom was aligned to its geometric center for each scan, and the field of view was set to visualize the entire phantom...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047590/su-f-r-02-imaging-genomics-for-predicting-gbm-molecular-subclasses-and-survival
#6
F Mahmoudi, L Poisson, H Bagher-Ebadian, M Nazem-Zadeh, H Soltanian-Zadeh
PURPOSE: Glioblastoma (GBM) is the most common and fatal primary intracranial neoplasm. GBM is categorized into five sub-classes (classical, G-CIMP, mesenchymal, proneural and neural) that can only be determined by an invasive brain biopsy followed by RNA and DNA methylation profiling. The goal of this study is to develop imaging features extracted from conventional MRI scans and an ensemble-classification method as a potential noninvasive method to predict the five molecular sub-classes and 12-month survival status...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047418/su-f-j-195-on-the-performance-of-four-dual-energy-ct-formalisms-for-extracting-proton-stopping-powers
#7
E Baer, A Lalonde, G Royle, H Bouchard
PURPOSE: Dual energy CT can predict stopping power ratios (SPR) for ion therapy treatment planning. Several approaches have been proposed recently, however accuracy and practicability in a clinical workflow are unaddressed. The aim of this work is to provide a fair comparison of available approaches in a human-like phantom to find the optimal method for tissue characterization in a clinical situation. METHODS: The SPR determination accuracy is investigated using simulated DECT images...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046825/su-g-tep1-04-deriving-spot-shape-criteria-for-proton-pencil-beam-scanning
#8
J Wulff, A Huggins
PURPOSE: The shape of a single beam in proton PBS influences the resulting dose distribution. Spot profiles are modelled as two-dimensional Gaussian (single/ double) distributions in treatment planning systems (TPS). Impact of slight deviations from an ideal Gaussian on resulting dose distributions is typically assumed to be small due to alleviation by multiple Coulomb scattering (MCS) in tissue and superposition of many spots. Quantitative limits are however not clear per se. METHODS: A set of 1250 deliberately deformed profiles with sigma=4 mm for a Gaussian fit were constructed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046276/su-g-jep2-03-automatic-quantification-of-mlc-positional-accuracy-in-an-mri-guided-radiotherapy-system
#9
X Li, M Studenski, F Yang, N Dogan, N Lamichhane, K Padgett
PURPOSE: MRI-guided-radiotherapy (MRIGRT) systems lack many features of traditional Linac based RT systems and specialized tests need to be developed to evaluate MLC performance. This work describes automatic tools for the analysis of positional accuracy of an MLC equipped MRIGRT system. METHODS: This MLC analysis tool was developed for the MRIdian™ RT system which has three Co-60 equipped treatment heads each with a double focused MLC containing 30 leaf pairs, leaf thickness is 1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27911670/quantitative-assessment-of-metal-elements-using-moss-species-as-biomonitors-in-downwind-area-of-lead-zinc-mine
#10
Biljana Balabanova, Trajče Stafilov, Robert Šajn, Katerina Bačeva Andonovska
Distributions of a total of 21 elements were monitored in significantly lead-zinc polluted area using moss species (Hypnum cupressiforme and Camptothecium lutescens) used interchangeably, covering a denser sampling network. Interspecies comparison was conducted using Box-Cox transformed values, due to their skewed distribution. The median concentrations of trace elements in the both mosses examined decreased in the following order: Fe>Mn>Zn>Pb>Cu>Ni∼Cr∼As>Co>Cd>Hg. For almost all analyzed elements, H...
December 2, 2016: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/27873148/local-texture-descriptors-for-the-assessment-of-differences-in-diffusion-magnetic-resonance-imaging-of-the-brain
#11
Felix Sebastian Leo Thomsen, Claudio Augusto Delrieux, Rodrigo de Luis-García
PURPOSE: Descriptors extracted from magnetic resonance imaging (MRI) of the brain can be employed to locate and characterize a wide range of pathologies. Scalar measures are typically derived within a single-voxel unit, but neighborhood-based texture measures can also be applied. In this work, we propose a new set of descriptors to compute local texture characteristics from scalar measures of diffusion tensor imaging (DTI), such as mean and radial diffusivity, and fractional anisotropy...
November 21, 2016: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/27866068/an-abnormal-ocular-motor-manifestation-of-joubert-syndrome
#12
Jeanie Ling, Viraj Mehta, Anvesh Reddy, Matthew Hollar, Sean Donahue
Joubert syndrome is a congenital neurodevelopmental disorder primarily affecting the midbrain and hindbrain. It is characterized by ataxia, hypotonia, and developmental delay as well as apnea or abnormal ocular motor function. We describe and present a video of a child with Joubert syndrome with an alternating skew deviation in primary position rather than on lateral gaze, which is a more characteristic phenotype of this condition.
November 16, 2016: Journal of AAPOS: the Official Publication of the American Association for Pediatric Ophthalmology and Strabismus
https://www.readbyqxmd.com/read/27862582/whole-tumor-mri-histogram-analyses-of-hepatocellular-carcinoma-correlations-with-ki-67-labeling-index
#13
Xin-Xing Hu, Zhao-Xia Yang, He-Yue Liang, Ying Ding, Robert Grimm, Cai-Xia Fu, Hui Liu, Xu Yan, Yuan Ji, Meng-Su Zeng, Sheng-Xiang Rao
PURPOSE: To evaluate whether whole-tumor histogram-derived parameters for an apparent diffusion coefficient (ADC) map and contrast-enhanced magnetic resonance imaging (MRI) could aid in assessing Ki-67 labeling index (LI) of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: In all, 57 patients with HCC who underwent pretreatment MRI with a 3T MR scanner were included retrospectively. Histogram parameters including mean, median, standard deviation, skewness, kurtosis, and percentiles (5(th) , 25(th) , 75(th) , 95(th) ) were derived from the ADC map and MR enhancement...
November 10, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27855460/-diagnosis-and-current-therapy-of-vestibular-syndromes
#14
Michael Strupp, Thomas Brandt
Vertigo and dizziness are with an annual incidence of more than 10% and a lifetime prevalence of more than 30% among the most frequent symptoms. The keys to the diagnosis are the patient history and the bedside examination: a) for the patient history the time course, type and triggers of symptoms and accompanying symptoms, b) for the clinical examination of the vestibular system the head-impulse test (HIT), the examination for a spontaneous nystagmus, a displacement of subjective visual vertical, a positional nystagmus and the Romberg test, and c) for the differentiation between an acute peripheral and central vestibular lesion the skew deviation, central fixation nystagmus, gaze-evoked nystagmus, saccadic smooth pursuit and a normal HIT...
November 2016: Deutsche Medizinische Wochenschrift
https://www.readbyqxmd.com/read/27824897/functional-plasticity-after-unilateral-vestibular-midbrain-infarction-in-human-positron-emission-tomography
#15
Sandra Becker-Bense, Hans-Georg Buchholz, Bernhard Baier, Mathias Schreckenberger, Peter Bartenstein, Andreas Zwergal, Thomas Brandt, Marianne Dieterich
The aim of the study was to uncover mechanisms of central compensation of vestibular function at brainstem, cerebellar, and cortical levels in patients with acute unilateral midbrain infarctions presenting with an acute vestibular tone imbalance. Eight out of 17 patients with unilateral midbrain infarctions were selected on the basis of signs of a vestibular tone imbalance, e.g., graviceptive (tilts of perceived verticality) and oculomotor dysfunction (skew deviation, ocular torsion) in F18-fluordeoxyglucose (FDG)-PET at two time points: A) in the acute stage, and B) after recovery 6 months later...
2016: PloS One
https://www.readbyqxmd.com/read/27804074/mechanical-dyssynchrony-according-to-validated-cut-off-values-using-gated-spect-myocardial-perfusion-imaging
#16
Santiago Aguadé-Bruix, Guillermo Romero-Farina, Jaume Candell-Riera, María N Pizzi, David García-Dorado
BACKGROUND: The aim of this study was to establish different degrees of mechanical dyssynchrony according to validated cut-off (CO) values of myocardial perfusion gated SPECT phase analysis parameters (SD, standard deviation; B, bandwidth; S, skewness; K, kurtosis). METHODS: Using Emory Cardiac Toolbox™, we prospectively analyzed 408 patients (mean age 64.1 years, 26.7% female), divided into a control group of 150 normal subjects and a validation group of 258 patients (left bundle branch block: 17...
November 1, 2016: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/27797678/anorexia-nervosa-analysis-of-trabecular-texture-with-ct
#17
Azadeh Tabari, Martin Torriani, Karen K Miller, Anne Klibanski, Mannudeep K Kalra, Miriam A Bredella
Purpose To determine indexes of skeletal integrity by using computed tomographic (CT) trabecular texture analysis of the lumbar spine in patients with anorexia nervosa and normal-weight control subjects and to determine body composition predictors of trabecular texture. Materials and Methods This cross-sectional study was approved by the institutional review board and compliant with HIPAA. Written informed consent was obtained. The study included 30 women with anorexia nervosa (mean age ± standard deviation, 26 years ± 6) and 30 normal-weight age-matched women (control group)...
October 31, 2016: Radiology
https://www.readbyqxmd.com/read/27794314/the-bursts-of-stops-can-convey-dialectal-information
#18
Charalambos Themistocleous
This study investigates the effects of the dialect of the speaker on the spectral properties of stop bursts. Forty-five female speakers-20 Standard Modern Greek and 25 Cypriot Greek speakers-participated in this study. The spectral properties of stop bursts were calculated from the burst spectra and analyzed using spectral moments. The findings show that besides linguistic information, i.e., the place of articulation and the stress, the speech signals of bursts can encode social information, i.e., the dialects...
October 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27789191/winning-hearts-and-minds-inspiring-medical-students-into-cardiothoracic-surgery-through-highly-interactive-workshops
#19
Joseph George, Tom Combellack, Ana Lopez-Marco, Umair Aslam, Yasir Ahmed, Prakash Nanjaiah, Aprim Youhana, Pankaj Kumar
BACKGROUND: The cardiothoracic surgical (CTS) specialty has witnessed a decline in the applicant pool. Early exposure, positive experiences, inspiring role models, and career insight are key in the decision-making process for specialty choice. Our objective was to assess the effect of high tutor:student ratio interactive CTS workshops in influencing the career choice of UK undergraduate medical students. METHODS: Medical students attended a workshop comprising (1) guided dissection of fresh animal hearts, (2) surgical skills practice on models and fresh hearts, (3) operative videos (adult, congenital, transplant, and aortic) with interactive commentary, and (4) careers seminar...
October 24, 2016: Journal of Surgical Education
https://www.readbyqxmd.com/read/27782979/operationalizing-the-measurement-of-socioeconomic-position-in-our-urogynecology-study-populations-an-illustrative-review
#20
Michael Heit, Nayera Guirguis, Nadine Kassis, Michelle Takase-Sanchez, Janet Carpenter
OBJECTIVES: The purpose of this illustrative review is to provide guidance for the measurement of socioeconomic position when conducting health disparities research in urogynecology study populations. METHODS: Deidentified data were extracted from existing investigational review board-approved research databases for illustrative purposes. Attributes collected included the study participant's marital status, level of educational attainment (in number of years of school completed) and occupation as well as the study participant's last/only spouses' level of education and occupation...
October 25, 2016: Female Pelvic Medicine & Reconstructive Surgery
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