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https://www.readbyqxmd.com/read/28926313/toward-a-standardized-approach-to-estimate-kurtosis-in-body-applications-of-a-non-gaussian-diffusion-kurtosis-imaging-model-of-water-diffusion
#1
Marco Giannelli, Chiara Marzi, Mario Mascalchi, Stefano Diciotti, Carlo Tessa
No abstract text is available yet for this article.
October 2017: Radiology
https://www.readbyqxmd.com/read/28924568/convolutional-neural-network-for-high-accuracy-functional-near-infrared-spectroscopy-in-a-brain-computer-interface-three-class-classification-of-rest-right-and-left-hand-motor-execution
#2
Thanawin Trakoolwilaiwan, Bahareh Behboodi, Jaeseok Lee, Kyungsoo Kim, Ji-Woong Choi
The aim of this work is to develop an effective brain-computer interface (BCI) method based on functional near-infrared spectroscopy (fNIRS). In order to improve the performance of the BCI system in terms of accuracy, the ability to discriminate features from input signals and proper classification are desired. Previous studies have mainly extracted features from the signal manually, but proper features need to be selected carefully. To avoid performance degradation caused by manual feature selection, we applied convolutional neural networks (CNNs) as the automatic feature extractor and classifier for fNIRS-based BCI...
January 2018: Neurophotonics
https://www.readbyqxmd.com/read/28923471/accurately-diagnosing-uric-acid-stones-from-conventional-ct-imaging-development-and-preliminary-assessment-of-a-pixel-mapping-software
#3
Vishnu Ganesan, Shubha De, Nicholas Shkumat, Giovanni Marchini, Manoj Monga
PURPOSE: Preoperative determination of uric acid stones from computed tomography (CT) imaging would be of tremendous clinical utility. We proposed to design a software algorithm that can utilize data from non-contrast CT to predict the presence of uric acid stones. MATERIALS AND METHODS: Patients with pure uric acid (UA) and calcium oxalate (CaOx) stones were identified from our stone registry. Only stones >4 mm and clearly traceable from initial CT to final composition were included...
September 15, 2017: Journal of Urology
https://www.readbyqxmd.com/read/28915319/an-improved-model-for-prostate-diffusion-incorporating-the-results-of-monte-carlo-simulations-of-diffusion-in-the-cellular-compartment
#4
Nima Gilani, Paul Malcolm, Glyn Johnson
The purpose of this work was to refine a previously published model of prostate diffusion by incorporating improved estimates of cellular diffusivity obtained by Monte Carlo simulation. Stromal and epithelial cell size and intracellular volume fraction in different grades of cancer were determined from histological images. Diffusion in different mixtures of cells, corresponding to different tumor grades, was simulated and cellular apparent diffusion coefficient and kurtosis values determined. These values were incorporated into the previously published model of prostate diffusion and model predictions compared with values found in the literature...
September 15, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28912727/a-hybrid-emd-kurtosis-method-for-estimating-fetal-heart-rate-from-continuous-doppler-signals
#5
Haitham M Al-Angari, Yoshitaka Kimura, Leontios J Hadjileontiadis, Ahsan H Khandoker
Monitoring of fetal heart rate (FHR) is an important measure of fetal wellbeing during the months of pregnancy. Previous works on estimating FHR variability from Doppler ultrasound (DUS) signal mainly through autocorrelation analysis showed low accuracy when compared with heart rate variability (HRV) computed from fetal electrocardiography (fECG). In this work, we proposed a method based on empirical mode decomposition (EMD) and the kurtosis statistics to estimate FHR and its variability from DUS. Comparison between estimated beat-to-beat intervals using the proposed method and the autocorrelation function (AF) with respect to RR intervals computed from fECG as the ground truth was done on DUS signals from 44 pregnant mothers in the early (20 cases) and late (24 cases) gestational weeks...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28912282/apparent-diffusion-coefficient-histograms-of-human-papillomavirus-positive-and-human-papillomavirus-negative-head-and-neck-squamous-cell-carcinoma-assessment-of-tumor-heterogeneity-and-comparison-with-histopathology
#6
T de Perrot, V Lenoir, M Domingo Ayllón, N Dulguerov, M Pusztaszeri, M Becker
BACKGROUND AND PURPOSE: Head and neck squamous cell carcinoma associated with human papillomavirus infection represents a distinct tumor entity. We hypothesized that diffusion phenotypes based on the histogram analysis of ADC values reflect distinct degrees of tumor heterogeneity in human papillomavirus-positive and human papillomavirus-negative head and neck squamous cell carcinomas. MATERIALS AND METHODS: One hundred five consecutive patients (mean age, 64 years; range, 45-87 years) with primary oropharyngeal (n = 52) and oral cavity (n = 53) head and neck squamous cell carcinoma underwent MR imaging with anatomic and diffusion-weighted sequences (b = 0, b = 1000 s/mm(2), monoexponential ADC calculation)...
September 14, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28910821/vascular-disrupting-agent-in-pancreatic-and-hepatic-tumour-allografts-observations-of-location-dependent-efficacy-by-mri-microangiography-and-histomorphology
#7
Ting Yin, Yewei Liu, Ronald Peeters, Yuanbo Feng, Jie Yu, Uwe Himmelreich, Raymond Oyen, Yicheng Ni
BACKGROUND: Tumours growing in organs of different vascular environment could exhibit diverse responses to vascular disrupting agent (VDA). This study was aimed to identify in vivo imaging biomarkers for evaluation of pancreatic and hepatic tumours and comparison of their responses to a VDA Combretastatin A4 Phosphate (CA4P) using multiparametric MRI. METHODS: Male WAG/Rij rats were used for orthotopic pancreatic head tumour and hepatic tumour implantation; tumour growth was monitored by 3D isotropic MRI using a 3...
September 14, 2017: British Journal of Cancer
https://www.readbyqxmd.com/read/28900220/diffusion-kurtosis-imaging-evaluating-epithelial-mesenchymal-transition-in-colorectal-carcinoma-xenografts-model-a-preliminary-study
#8
Huanhuan Liu, Wenbin Shen, Caiyuan Zhang, Yanfen Cui, Jinning Li, Tingting Zhang, Weibo Chen, Dengbin Wang
Epithelial-mesenchymal transition (EMT) plays an important role in aggravating invasiveness and metastatic behavior of colorectal cancer (CRC). Identification of EMT is important for structuring treatment strategy, but has not yet been studied by using noninvasive imaging modality. Diffusion kurtosis imaging (DKI) is an advanced diffusion weighted model that could reflect tissue microstructural changes in vivo. In this study, EMT was induced in CRC cells (HCT116) by overexpressing Snail1 gene. We aimed to investigate the value of DKI in identifying EMT in CRC and decipher the correlations between DKI-derived parameters and EMT biomarker E-cadherin and cell proliferative index Ki-67 expression...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28894296/test-retest-reliability-of-high-spatial-resolution-diffusion-tensor-and-diffusion-kurtosis-imaging
#9
Pashtun Shahim, Laurena Holleran, Joong H Kim, David L Brody
We assessed the test-retest reliability of high spatial resolution diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI). Diffusion MRI was acquired using a Siemens 3 Tesla Prisma scanner with 80 mT/m gradients and a 32-channel head coil from each of 3 concussive traumatic brain injury (cTBI) patients and 4 controls twice 0 to 24 days apart. Coefficients of variation (CoV) for DTI parameters were calculated in each DTI Studio parcellated white matter tract at 1.25 mm and 1.75 mm isotropic voxel resolution, as well as DKI parameters at 1...
September 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28884356/diagnostic-value-of-mri-based-3d-texture-analysis-for-tissue-characterisation-and-discrimination-of-low-grade-chondrosarcoma-from-enchondroma-a-pilot-study
#10
Catharina S Lisson, Christoph G Lisson, Kerstin Flosdorf, Regine Mayer-Steinacker, Markus Schultheiss, Alexandra von Baer, Thomas F E Barth, Ambros J Beer, Matthias Baumhauer, Reinhard Meier, Meinrad Beer, Stefan A Schmidt
OBJECTIVES: To explore the diagnostic value of MRI-based 3D texture analysis to identify texture features that can be used for discrimination of low-grade chondrosarcoma from enchondroma. METHODS: Eleven patients with low-grade chondrosarcoma and 11 patients with enchondroma were retrospectively evaluated. Texture analysis was performed using mint Lesion: Kurtosis, entropy, skewness, mean of positive pixels (MPP) and uniformity of positive pixel distribution (UPP) were obtained in four MRI sequences and correlated with histopathology...
September 7, 2017: European Radiology
https://www.readbyqxmd.com/read/28877829/major-metabolite-levels-of-preoperative-proton-magnetic-resonance-sectroscopy-and-intraoperative-fluorescence-intensity-in-glioblastoma
#11
Hai-Long Tian, Yu-Liang Zu, Chao-Chao Wang, Tao Lin, Zhen-Tao Guo, Bin Jiang, Xin Yin, Wen-Qiang Guo, Zhi-Gang Wang
Objective To compare the intraoperative major metabolite level of preoperative proton magnetic resonance spectroscopy((1)H-MRS)and fluorescence intensity marked with fluorescein sodium(FLs)in glioblastoma(GBM)and thus provide an objective basis for fluorescence surgical treatment of GBM. Methods All newly diagnosed patients by plain and enhanced magnetic resonance imaging from the April 1,2014 to December 31,2015 were enrolled in this study.All of them received (1)H-MRS and marked with FLs.The expression of Ki67 in tumor boundary were confirmed by postoperative pathology and determined by immunostaining assay...
August 20, 2017: Zhongguo Yi Xue Ke Xue Yuan Xue Bao. Acta Academiae Medicinae Sinicae
https://www.readbyqxmd.com/read/28872673/direction-of-dependence-in-measurement-error-models
#12
Wolfgang Wiedermann, Edgar C Merkle, Alexander von Eye
Methods to determine the direction of a regression line, that is, to determine the direction of dependence in reversible linear regression models (e.g., x→y vs. y→x), have experienced rapid development within the last decade. However, previous research largely rested on the assumption that the true predictor is measured without measurement error. The present paper extends the direction dependence principle to measurement error models. First, we discuss asymmetric representations of the reliability coefficient in terms of higher moments of variables and the attenuation of skewness and excess kurtosis due to measurement error...
September 5, 2017: British Journal of Mathematical and Statistical Psychology
https://www.readbyqxmd.com/read/28872186/asymptotic-confidence-intervals-for-the-pearson-correlation-via-skewness-and-kurtosis
#13
Anthony J Bishara, Jiexiang Li, Thomas Nash
When bivariate normality is violated, the default confidence interval of the Pearson correlation can be inaccurate. Two new methods were developed based on the asymptotic sampling distribution of Fisher's z' under the general case where bivariate normality need not be assumed. In Monte Carlo simulations, the most successful of these methods relied on the (Vale & Maurelli, 1983, Psychometrika, 48, 465) family to approximate a distribution via the marginal skewness and kurtosis of the sample data. In Simulation 1, this method provided more accurate confidence intervals of the correlation in non-normal data, at least as compared to no adjustment of the Fisher z' interval, or to adjustment via the sample joint moments...
September 4, 2017: British Journal of Mathematical and Statistical Psychology
https://www.readbyqxmd.com/read/28870086/histogram-analysis-of-apparent-diffusion-coefficient-maps-for-the-differentiation-between-lymphoma-and-metastatic-lymph-nodes-of-squamous-cell-carcinoma-in-head-and-neck-region
#14
Yan-Jun Wang, Xiao-Quan Xu, Hao Hu, Guo-Yi Su, Jie Shen, Hai-Bin Shi, Fei-Yun Wu
Background To clarify the nature of cervical malignant lymphadenopathy is highly important for the diagnosis and differential diagnosis of head and neck tumors. Purpose To investigate the role of first-order apparent diffusion coefficient (ADC) histogram analysis for differentiating lymphoma from metastatic lymph nodes of squamous cell carcinoma (SCC) in the head and neck region. Material and Methods Diffusion-weighted imaging (DWI) data of 67 patients (lymphoma, n = 20; SCC, n = 47) with malignant lymphadenopathy were retrospectively analyzed...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28865921/in-vivo-assessment-of-tumor-heterogeneity-in-who-2016-glioma-grades-using-diffusion-kurtosis-imaging-diagnostic-performance-and-improvement-of-feasibility-in-routine-clinical-practice
#15
J-M Hempel, J Schittenhelm, S Bisdas, C Brendle, B Bender, G Bier, M Skardelly, G Tabatabai, S Castaneda Vega, U Ernemann, U Klose
PURPOSE: To assess the diagnostic performance of normalized and non-normalized diffusion kurtosis imaging (DKI) metrics extracted from different tumor volume data for grading glioma according to the integrated approach of the revised 2016 WHO classification. MATERIALS AND METHODS: Sixty patients with histopathologically confirmed glioma, who provided written informed consent, were retrospectively assessed between 01/2013 and 08/2016 from a prospective trial approved by the local institutional review board...
September 1, 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28858222/diurnal-changes-in-distribution-characteristics-of-salivary-cortisol-and-immunoglobulin-a-concentrations
#16
Hiromitsu Kobayashi, Chorong Song, Harumi Ikei, Bum-Jin Park, Takahide Kagawa, Yoshifumi Miyazaki
Salivary cortisol and secretory immunoglobulin A (S-IgA) are important biomarkers for environmental and public health research. The present study investigated the diurnal variations of these salivary biomarkers, with a focus on the change of distribution characteristics (i.e., skewness and kurtosis) of the concentrations. The participants in this study were 113 healthy young males. Salivary samples were collected in the morning (6:30-7:30 a.m.) and afternoon (1:00-4:00 p.m.). The skewness and kurtosis of salivary cortisol concentrations in afternoon samples (skewness = 1...
August 31, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28856177/intravoxel-incoherent-motion-ivim-histogram-biomarkers-for-prediction-of-neoadjuvant-treatment-response-in-breast-cancer-patients
#17
Gene Y Cho, Lucas Gennaro, Elizabeth J Sutton, Emily C Zabor, Zhigang Zhang, Dilip Giri, Linda Moy, Daniel K Sodickson, Elizabeth A Morris, Eric E Sigmund, Sunitha B Thakur
OBJECTIVE: To examine the prognostic capabilities of intravoxel incoherent motion (IVIM) metrics and their ability to predict response to neoadjuvant treatment (NAT). Additionally, to observe changes in IVIM metrics between pre- and post-treatment MRI. METHODS: This IRB-approved, HIPAA-compliant retrospective study observed 31 breast cancer patients (32 lesions). Patients underwent standard bilateral breast MRI along with diffusion-weighted imaging before and after NAT...
2017: European Journal of Radiology Open
https://www.readbyqxmd.com/read/28845175/microstructural-abnormalities-of-basal-ganglia-and-thalamus-in-bipolar-and-unipolar-disorders-a-diffusion-kurtosis-and-perfusion-imaging-study
#18
Lianping Zhao, Ying Wang, Yanbin Jia, Shuming Zhong, Yao Sun, Zhifeng Zhou, Zhongping Zhang, Li Huang
OBJECTIVE: Bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in subcorticalgray matter regions between BD and UD. METHODS: Thirty-five BD patients, 30 UD patients and 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr) and cerebral blood flow (CBF) were measured by using regions-of-interest analysis in the caudate, putamen and thalamus of the subcortical gray matter regions...
July 2017: Psychiatry Investigation
https://www.readbyqxmd.com/read/28844845/lepidic-predominant-pulmonary-lesions-lpl-ct-based-distinction-from-more-invasive-adenocarcinomas-using-3d-volumetric-density-and-first-order-ct-texture-analysis
#19
Jeffrey B Alpert, Henry Rusinek, Jane P Ko, Bari Dane, Harvey I Pass, Bernard K Crawford, Amy Rapkiewicz, David P Naidich
RATIONALE AND OBJECTIVES: This study aimed to differentiate pathologically defined lepidic predominant lesions (LPL) from more invasive adenocarcinomas (INV) using three-dimensional (3D) volumetric density and first-order texture histogram analysis of surgically excised stage 1 lung adenocarcinomas. MATERIALS AND METHODS: This retrospective study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. Sixty-four cases of pathologically proven stage 1 lung adenocarcinoma surgically resected between September 2006 and October 2015, including LPL (n = 43) and INV (n = 21), were evaluated using high-resolution computed tomography...
August 24, 2017: Academic Radiology
https://www.readbyqxmd.com/read/28841758/precision-and-accuracy-of-diffusion-kurtosis-estimation-and-the-influence-of-b-value-selection
#20
Andrey Chuhutin, Brian Hansen, Sune Nørhøj Jespersen
Diffusion kurtosis imaging (DKI) is an extension of diffusion tensor imaging that accounts for leading non-Gaussian diffusion effects. In DKI studies, a wide range of different gradient strengths (b-values) is used, which is known to affect the estimated diffusivity and kurtosis parameters. Hence there is a need to assess the accuracy and precision of the estimated parameters as a function of b-value. This work examines the error in the estimation of mean of the kurtosis tensor (MKT) with respect to the ground truth, using simulations based on a biophysical model for both gray (GM) and white (WM) matter...
August 25, 2017: NMR in Biomedicine
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