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https://www.readbyqxmd.com/read/28339422/diffusion-kurtosis-imaging-for-diagnosis-of-parkinson-s-disease-a-novel-software-tool-proposal
#1
Cruz Gloria, Sheng Dong Nie
In order to diagnose Parkinson disease (PD) at an early stage, it is important to develop a sensitive method for detecting structural changes in the substantia nigra (SN). Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) have become important tools in supporting diagnosis of PD, with findings based on increased apparent diffusion coefficients (ADCs) in basal ganglia and decreased fractional anisotropy (FA) in SN. Based on the hypothesis that a diffusion kurtosis imaging (DKI) theory is a valuable method for PD diagnosis based on the non-Gaussian diffusion of water in biologic systems, the purpose of this study is to develop an image processing scheme (software) based on Image-J for the facilitating the application of DKI to assist PD diagnosis...
March 21, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28331228/traumatic-brain-injury-results-in-acute-rarefication-of-the-vascular-network
#2
Andre Obenaus, Michelle Ng, Amanda M Orantes, Eli Kinney-Lang, Faisal Rashid, Mary Hamer, Richard A DeFazio, Jiping Tang, John H Zhang, William J Pearce
The role of the cerebrovascular network and its acute response to TBI is poorly defined and emerging evidence suggests that cerebrovascular reactivity is altered. We explored how cortical vessels are physically altered following TBI using a newly developed technique, vessel painting. We tested our hypothesis that a focal moderate TBI results in global decrements to structural aspects of the vasculature. Rats (naïve, sham-operated, TBI) underwent a moderate controlled cortical impact. Animals underwent vessel painting perfusion to label the entire cortex at 1 day post TBI followed by whole brain axial and coronal images using a wide-field fluorescence microscope...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28328072/tensor-estimation-for-double-pulsed-diffusional-kurtosis-imaging
#3
Calvin B Shaw, Edward S Hui, Joseph A Helpern, Jens H Jensen
Double-pulsed diffusional kurtosis imaging (DP-DKI) represents the double diffusion encoding (DDE) MRI signal in terms of six-dimensional (6D) diffusion and kurtosis tensors. Here a method for estimating these tensors from experimental data is described. A standard numerical algorithm for tensor estimation from conventional (i.e. single diffusion encoding) diffusional kurtosis imaging (DKI) data is generalized to DP-DKI. This algorithm is based on a weighted least squares (WLS) fit of the signal model to the data combined with constraints designed to minimize unphysical parameter estimates...
March 22, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28323371/diffusional-kurtosis-imaging-of-parotid-glands-in-sj%C3%A3-gren-s-syndrome-initial-findings
#4
Chen Chu, Huayong Zhang, Nan Zhou, Xin Dou, Ming Li, Song Liu, Yun Zhu, Chun Wang, Weibo Chen, Queenie Chan, Lingyun Sun, Jian He, Zhengyang Zhou
PURPOSE: To explore the role of diffusion kurtosis imaging (DKI) of parotid glands in diagnosing Sjögren's syndrome (SS). MATERIALS AND METHODS: A total of 40 patients with SS and 40 healthy volunteers underwent 3.0T magnetic resonance imaging (MRI) including DKI, which generated the apparent diffusion coefficient (ADC), corrected diffusion (D), and diffusional kurtosis (K) values. The MR nodular grade was determined on the basis of MR morphological findings. RESULTS: The parotid ADC, D, and K values in patients with SS were significantly higher than those of healthy volunteers (P = 0...
March 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28314916/texture-analysis-of-the-liver-at-mdct-for-assessing-hepatic-fibrosis
#5
Meghan G Lubner, Kyle Malecki, John Kloke, Balaji Ganeshan, Perry J Pickhardt
PURPOSE: To evaluate CT texture analysis (CTTA) for staging of hepatic fibrosis (stages F0-F4) METHODS: Quantitative texture analysis (QTA) of the liver was performed on abdominal MDCT scans using commercially available software (TexRAD), which uses a filtration-histogram statistic-based technique. Single-slice ROI measurements of the total liver, Couinaud segments IV-VIII, and segments I-III were obtained. CTTA parameters were correlated against fibrosis stage (F0-F4), with biopsy performed within one year for all cases with intermediate fibrosis (F1-F3)...
March 17, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28295854/diffusion-kurtosis-imaging-for-differentiating-borderline-from-malignant-epithelial-ovarian-tumors-a-correlation-with-ki-67-expression
#6
Hai Ming Li, Shu Hui Zhao, Jin Wei Qiang, Guo Fu Zhang, Feng Feng, Feng Hua Ma, Yong Ai Li, Wei Yong Gu
PURPOSE: To investigate the use of diffusion kurtosis imaging (DKI) in differentiating borderline from malignant epithelial ovarian tumors (MEOTs) and to correlate DKI parameters with Ki-67 expression. MATERIALS AND METHODS: Fifty-two consecutive patients with epithelial ovarian tumors (17 borderline epithelial ovarian tumors, BEOTs; 35 MEOTs) were prospectively evaluated using DKI with b values of 0, 500, 1000, 1500, 2000, and 2500 s/mm(2) and standard diffusion-weighted imaging (DWI) with b values of 0 and 1000 s/mm(2) using a 1...
March 10, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28282883/the-shock-pulse-index-and-its-application-in-the-fault-diagnosis-of-rolling-element-bearings
#7
Peng Sun, Yuhe Liao, Jin Lin
The properties of the time domain parameters of vibration signals have been extensively studied for the fault diagnosis of rolling element bearings (REBs). Parameters like kurtosis and Envelope Harmonic-to-Noise Ratio are the most widely applied in this field and some important progress has been made. However, since only one-sided information is contained in these parameters, problems still exist in practice when the signals collected are of complicated structure and/or contaminated by strong background noises...
March 8, 2017: Sensors
https://www.readbyqxmd.com/read/28277038/has-growth-mixture-modeling-improved-our-understanding-of-how-early-change-predicts-psychotherapy-outcome
#8
Andrew Koffmann
OBJECTIVE: Early change in psychotherapy predicts outcome. Seven studies have used growth mixture modeling [GMM; Muthén, B. (2001). Second-generation structural equation modeling with a combination of categorical and continuous latent variables: New opportunities for latent class-latent growth modeling. In L. M. Collins & A. G. Sawyers (Eds.), New methods for the analysis of change (pp. 291-322). Washington, DC: American Psychological Association] to identify patient classes based on early change but have yielded conflicting results...
March 2, 2017: Psychotherapy Research: Journal of the Society for Psychotherapy Research
https://www.readbyqxmd.com/read/28273747/histogram-analysis-of-volume-based-apparent-diffusion-coefficient-in-breast-cancer
#9
Ga Eun Park, Sung Hun Kim, Eun Jeong Kim, Bong Joo Kang, Mi Sun Park
Background Breast cancer is a heterogeneous disease. Recent studies showed that apparent diffusion coefficient (ADC) values have various association with tumor aggressiveness and prognosis. Purpose To evaluate the value of histogram analysis of ADC values obtained from the whole tumor volume in invasive ductal cancer (IDC) and ductal carcinoma in situ (DCIS). Material and Methods This retrospective study included 201 patients with confirmed DCIS (n = 37) and IDC (n = 164). The IDC group was divided into two groups based on the presence of a DCIS component: IDC-DCIS (n = 76) and pure IDC (n = 88)...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28272771/sensitivity-of-diffusion-mri-to-perilesional-reactive-astrogliosis-in-focal-ischemia
#10
Rachel A Weber, Clifford H Chan, Xingju Nie, Emily Maggioncalda, Grace Valiulis, Abigail Lauer, Edward S Hui, Jens H Jensen, DeAnna L Adkins
Reactive astrogliosis is a response to injury in the central nervous system that plays an essential role in inflammation and tissue repair. It is characterized by hypertrophy of astrocytes, alterations in astrocyte gene expression and astrocyte proliferation. Reactive astrogliosis occurs in multiple neuropathologies, including stroke, traumatic brain injury and Alzheimer's disease, and it has been proposed as a possible source of the changes in diffusion magnetic resonance imaging (dMRI) metrics observed with these diseases...
March 8, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28270649/assessment-of-kidney-function-after-allograft-transplantation-by-texture-analysis
#11
Ali Abbasian Ardakani, Afshin Mohammadi, Bahareh Khalili Najafabad, Jamileh Abolghasemi
INTRODUCTION: Ultrasonography is the preferable imaging technique for monitoring and assessing complications in kidney allograft transplants. Computer-aided diagnostic system based on texture analysis in ultrasonographic imaging is recommended to identify changes in kidney function after allograft transplantation. MATERIALS AND METHODS: A total of 61 biopsy-proven kidney allograft recipients (11 rejected and 50 unrejected) were assessed by a computer-aided diagnostic system...
March 2017: Iranian Journal of Kidney Diseases
https://www.readbyqxmd.com/read/28269088/an-analysis-of-sounds-for-lungs-with-excessive-water
#12
Kah Jun Hong, Wee Ser, David Chee-Guan Foo
Excessive lung water occurs when too much water accumulates in the lung, causing breathing difficulty. Current diagnosis methods include X-rays and CT-scans. However, because of their bulk and the need for trained professionals to operate, physicians rely on auscultation for preliminary diagnosis. Recent attempts have been made to automate the auscultation process and some degree of success has been reported. Thus, it would be useful to provide more analysis of such lung sounds. This paper attempts to study the characteristics of breathing sounds from lungs with excessive water and compare them with breathing sounds from healthy lungs...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268986/low-cost-and-efficient-kurtosis-based-deflationary-ica-method-application-to-mrs-sources-separation-problem
#13
M Saleh, A Karfoul, A Kachenoura, L Senhadji, L Albera
Improving the execution time and the numerical complexity of the well-known kurtosis-based maximization method, the RobustICA, is investigated in this paper. A Newton-based scheme is proposed and compared to the conventional RobustICA method. A new implementation using the nonlinear Conjugate Gradient one is investigated also. Regarding the Newton approach, an exact computation of the Hessian of the considered cost function is provided. The proposed approaches and the considered implementations inherit the global plane search of the initial RobustICA method for which a better convergence speed for a given direction is still guaranteed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268902/inspection-of-short-time-resting-state-electroencephalogram-functional-networks-in-alzheimer-s-disease
#14
Javier Escudero, Keith Smith, Hamed Azami, Daniel Abasolo
Functional connectivity has proven useful to characterise electroencephalogram (EEG) activity in Alzheimer's disease (AD). However, most current functional connectivity analyses have been static, disregarding any potential variability of the connectivity with time. In this pilot study, we compute short-time resting state EEG functional connectivity based on the imaginary part of coherency for 12 AD patients and 11 controls. We derive binary unweighted graphs using the cluster-span threshold, an objective binary threshold...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268479/early-warnings-of-heart-rate-deterioration
#15
Vania G Almeida, Ian T Nabney
Hospitals can experience difficulty in detecting and responding to early signs of patient deterioration leading to late intensive care referrals, excess mortality and morbidity, and increased hospital costs. Our study aims to explore potential indicators of physiological deterioration by the analysis of vital-signs. The dataset used comprises heart rate (HR) measurements from MIMIC II waveform database, taken from six patients admitted to the Intensive Care Unit (ICU) and diagnosed with severe sepsis. Different indicators were considered: 1) generic early warning indicators used in ecosystems analysis (autocorrelation at-1-lag (ACF1), standard deviation (SD), skewness, kurtosis and heteroskedasticity) and 2) entropy analysis (kernel entropy and multi scale entropy)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268379/kurtosis-as-a-statistical-approach-to-identify-the-pivot-point-of-the-rotor
#16
Shivaram P Arunachalam, Elizabeth M Annoni, Siva K Mulpuru, Paul A Friedman, Elena G Tolkacheva
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia that causes stroke affecting more than 2.3 million people in the US. Catheter ablation to terminate AF is successful for paroxysmal AF but suffers limitations with persistent AF patients as current mapping methods cannot identify AF active substrates outside of pulmonary vein region. In this work, we developed a novel Kurtosis based mapping technique that can accurately identify pivot points of the rotors that were induced in ex-vivo isolated rabbit heart...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28265814/a-comparative-study-of-the-sensitivity-of-diffusion-related-parameters-obtained-from-diffusion-tensor-imaging-diffusional-kurtosis-imaging-q-space-analysis-and-bi-exponential-modelling-in-the-early-disease-course-24%C3%A2-h-of-hyperacute-6%C3%A2-h-ischemic-stroke-patients
#17
Gaëtan Duchêne, Frank Peeters, André Peeters, Thierry Duprez
OBJECTIVES: To compare the sensitivity and early temporal changes of diffusion parameters obtained from diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), q-space analysis (QSA) and bi-exponential modelling in hyperacute stroke patients. MATERIALS AND METHODS: A single investigational acquisition allowing the four diffusion analyses was performed on seven hyperacute stroke patients with a 3T system. The percentage change between ipsi- and contralateral regions were compared at admission and 24 h later...
March 6, 2017: Magma
https://www.readbyqxmd.com/read/28264721/densitometric-and-local-histogram-based-analysis-of-computed-tomography-images-in-patients-with-idiopathic-pulmonary-fibrosis
#18
Samuel Y Ash, Rola Harmouche, Diego Lassala Lopez Vallejo, Julian A Villalba, Kris Ostridge, River Gunville, Carolyn E Come, Jorge Onieva Onieva, James C Ross, Gary M Hunninghake, Souheil Y El-Chemaly, Tracy J Doyle, Pietro Nardelli, Gonzalo V Sanchez-Ferrero, Hilary J Goldberg, Ivan O Rosas, Raul San Jose Estepar, George R Washko
BACKGROUND: Prior studies of clinical prognostication in idiopathic pulmonary fibrosis (IPF) using computed tomography (CT) have often used subjective analyses or have evaluated quantitative measures in isolation. This study examined associations between both densitometric and local histogram based quantitative CT measurements with pulmonary function test (PFT) parameters and mortality. In addition, this study sought to compare risk prediction scores that incorporate quantitative CT measures with previously described systems...
March 7, 2017: Respiratory Research
https://www.readbyqxmd.com/read/28249595/non-contact-synchronous-dynamic-measurement-of-respiratory-rate-and-heart-rate-based-on-dual-sensitive-regions
#19
Bing Wei, Xuan He, Chao Zhang, Xiaopei Wu
BACKGROUND: Currently, many imaging photoplethysmography (IPPG) researches have reported non-contact measurements of physiological parameters, such as heart rate (HR), respiratory rate (RR), etc. However, it is accepted that only HR measurement has been mature for applications, and other estimations are relatively incapable for reliable applications. Thus, it is worth keeping on persistent studies. Besides, there are some issues commonly involved in these approaches need to be explored further...
January 17, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28244188/model-based-denoising-in-diffusion-weighted-imaging-using-generalized-spherical-deconvolution
#20
Jonathan I Sperl, Tim Sprenger, Ek T Tan, Marion I Menzel, Christopher J Hardy, Luca Marinelli
PURPOSE: Diffusion MRI often suffers from low signal-to-noise ratio, especially for high b-values. This work proposes a model-based denoising technique to address this limitation. METHODS: A generalization of the multi-shell spherical deconvolution model using a Richardson-Lucy algorithm is applied to noisy data. The reconstructed coefficients are then used in the forward model to compute denoised diffusion-weighted images (DWIs). The proposed method operates in the diffusion space and thus is complementary to image-based denoising methods...
February 28, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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