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diffusion kurtosis

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https://www.readbyqxmd.com/read/28214960/axonal-disruption-in-white-matter-underlying-cortical-sulcus-tau-pathology-in-chronic-traumatic-encephalopathy
#1
Laurena Holleran, Joong Hee Kim, Mihika Gangolli, Thor Stein, Victor Alvarez, Ann McKee, David L Brody
Chronic traumatic encephalopathy (CTE) is a progressive degenerative disorder associated with repetitive traumatic brain injury. One of the primary defining neuropathological lesions in CTE, based on the first consensus conference, is the accumulation of hyperphosphorylated tau in gray matter sulcal depths. Post-mortem CTE studies have also reported myelin loss, axonal injury and white matter degeneration. Currently, the diagnosis of CTE is restricted to post-mortem neuropathological analysis. We hypothesized that high spatial resolution advanced diffusion MRI might be useful for detecting white matter microstructural changes directly adjacent to gray matter tau pathology...
February 18, 2017: Acta Neuropathologica
https://www.readbyqxmd.com/read/28208489/prediction-of-the-moments-in-advection-diffusion-lattice-boltzmann-method-ii-attenuation-of-the-boundary-layers-via-double-%C3%AE-bounce-back-flux-scheme
#2
Irina Ginzburg
Impact of the unphysical tangential advective-diffusion constraint of the bounce-back (BB) reflection on the impermeable solid surface is examined for the first four moments of concentration. Despite the number of recent improvements for the Neumann condition in the lattice Boltzmann method-advection-diffusion equation, the BB rule remains the only known local mass-conserving no-flux condition suitable for staircase porous geometry. We examine the closure relation of the BB rule in straight channel and cylindrical capillary analytically, and show that it excites the Knudsen-type boundary layers in the nonequilibrium solution for full-weight equilibrium stencil...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208379/prediction-of-the-moments-in-advection-diffusion-lattice-boltzmann-method-i-truncation-dispersion-skewness-and-kurtosis
#3
Irina Ginzburg
The effect of the heterogeneity in the soil structure or the nonuniformity of the velocity field on the modeled resident time distribution (RTD) and breakthrough curves is quantified by their moments. While the first moment provides the effective velocity, the second moment is related to the longitudinal dispersion coefficient (k_{T}) in the developed Taylor regime; the third and fourth moments are characterized by their normalized values skewness (Sk) and kurtosis (Ku), respectively. The purpose of this investigation is to examine the role of the truncation corrections of the numerical scheme in k_{T}, Sk, and Ku because of their interference with the second moment, in the form of the numerical dispersion, and in the higher-order moments, by their definition...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28207858/non-small-cell-lung-cancer-whole-lesion-histogram-analysis-of-the-apparent-diffusion-coefficient-for-assessment-of-tumor-grade-lymphovascular-invasion-and-pleural-invasion
#4
Naoko Tsuchiya, Mariko Doai, Katsuo Usuda, Hidetaka Uramoto, Hisao Tonami
PURPOSE: Investigating the diagnostic accuracy of histogram analyses of apparent diffusion coefficient (ADC) values for determining non-small cell lung cancer (NSCLC) tumor grades, lymphovascular invasion, and pleural invasion. MATERIALS AND METHODS: We studied 60 surgically diagnosed NSCLC patients. Diffusion-weighted imaging (DWI) was performed in the axial plane using a navigator-triggered single-shot, echo-planar imaging sequence with prospective acquisition correction...
2017: PloS One
https://www.readbyqxmd.com/read/28205277/preliminary-evaluation-of-altered-brain-microstructure-in-the-emotion-cognition-region-in-children-with-haemophilia-a-a-diffusional-kurtosis-imaging-study
#5
D Hu, H Kang, Y Lv, N Zhang, L Tang, J Zhang, K Shi, R Wu, Y Peng
AIM: Using diffusional kurtosis imaging (DKI) to assess the impact of emotional disorders on microstructural changes of the brain in children with haemophilia A. MATERIALS AND METHODS: Diffusional kurtosis imaging was acquired from haemophilia A (n = 22) and controls (n = 22) using a 3T scanner. A regression analysis of frontal, cingulate, hippocampus, insula and amygdala regions of interest (ROIs) was conducted. Clinical data and results of psychological tests were collected...
February 15, 2017: Haemophilia: the Official Journal of the World Federation of Hemophilia
https://www.readbyqxmd.com/read/28199367/evaluation-of-different-mathematical-models-and-different-b-value-ranges-of-diffusion-weighted-imaging-in-peripheral-zone-prostate-cancer-detection-using-b-value-up-to-4500-s-mm2
#6
Zhaoyan Feng, Xiangde Min, Daniel J A Margolis, Caohui Duan, Yuping Chen, Vivek Kumar Sah, Nabin Chaudhary, Basen Li, Zan Ke, Peipei Zhang, Liang Wang
OBJECTIVES: To evaluate the diagnostic performance of different mathematical models and different b-value ranges of diffusion-weighted imaging (DWI) in peripheral zone prostate cancer (PZ PCa) detection. METHODS: Fifty-six patients with histologically proven PZ PCa who underwent DWI-magnetic resonance imaging (MRI) using 21 b-values (0-4500 s/mm2) were included. The mean signal intensities of the regions of interest (ROIs) placed in benign PZs and cancerous tissues on DWI images were fitted using mono-exponential, bi-exponential, stretched-exponential, and kurtosis models...
2017: PloS One
https://www.readbyqxmd.com/read/28194415/diffusion-kurtosis-imaging-detects-microstructural-changes-in-the-brain-after-acute-alcohol-intoxication-in-rats
#7
Xi-Ran Chen, Jie-Ying Zeng, Zhi-Wei Shen, Ling-Mei Kong, Wen-Bin Zheng
The aim of this study was to test the technical feasibility of diffusion kurtosis imaging (DKI) in the brain after acute alcohol intoxication. Diffusion tensor imaging (DTI) and DKI during 7.0 T MRI were performed in the frontal lobe and thalamus before and 30 min, 2 h, and 6 h after ethyl alcohol administration. Compared with controls, mean kurtosis values of the frontal lobe and thalamus first decreased by 44% and 38% within 30 min (p < 0.01 all) and then increased by 14% and 46% at 2 h (frontal lobe, p > 0...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28176436/differential-microstructural-and-morphological-abnormalities-in-mild-cognitive-impairment-and-alzheimer-s-disease-evidence-from-cortical-and-deep-gray-matter
#8
Nan-Jie Gong, Chun-Chung Chan, Lam-Ming Leung, Chun-Sing Wong, Russell Dibb, Chunlei Liu
One aim of this study is to use non-Gaussian diffusion kurtosis imaging (DKI) for capturing microstructural abnormalities in gray matter of Alzheimer's disease (AD). The other aim is to compare DKI metrics against thickness of cortical gray matter and volume of deep gray matter, respectively. A cohort of 18 patients with AD, 18 patients with amnestic mild cognitive impairment (MCI), and 18 normal controls underwent morphological and DKI MR imaging. Images were investigated using regions-of-interest-based analyses for deep gray matter and vertex-wise analyses for cortical gray matter...
February 8, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28160039/measuring-the-apparent-diffusion-coefficient-in-primary-rectal-tumors-is-there-a-benefit-in-performing-histogram-analyses
#9
Miriam M van Heeswijk, Doenja M J Lambregts, Monique Maas, Max J Lahaye, Z Ayas, Jos M G M Slenter, Geerard L Beets, Frans C H Bakers, Regina G H Beets-Tan
PURPOSE: The apparent diffusion coefficient (ADC) is a potential prognostic imaging marker in rectal cancer. Typically, mean ADC values are used, derived from precise manual whole-volume tumor delineations by experts. The aim was first to explore whether non-precise circular delineation combined with histogram analysis can be a less cumbersome alternative to acquire similar ADC measurements and second to explore whether histogram analyses provide additional prognostic information. METHODS: Thirty-seven patients who underwent a primary staging MRI including diffusion-weighted imaging (DWI; b0, 25, 50, 100, 500, 1000; 1...
February 3, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28151889/early-white-matter-injuries-in-patients-with-acute-carbon-monoxide-intoxication-a-tract-specific-diffusion-kurtosis-imaging-study-and-strobe-compliant-article
#10
Ping-Huei Tsai, Ming-Chung Chou, Shih-Wei Chiang, Hsiao-Wen Chung, Hua-Shan Liu, Hung-Wen Kao, Cheng-Yu Chen
Evaluation of acute white matter injuries caused by carbon monoxide (CO) poisoning can be limited by conventional magnetic resonance (MR) imaging. We aim to evaluate the feasibility of diffusion kurtosis imaging (DKI) for early detection of white matter alterations in patients with acute CO intoxication.A total of 30 subjects including 15 acute CO patients and 15 age- and sex-matched healthy volunteers were enrolled in this study. MR examinations were performed on a 3T MR scanner within 8 days after CO intoxication...
February 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28139225/toward-ideal-separation-by-size-exclusion-chromatography
#11
Miloš Netopilík
In analyses of polystyrene standards by size-exclusion chromatography for polymers of molecular weight about thirty thousand and higher, the separation improved with decreasing flow-rate is in accord with Giddings observation of transversal diffusion as a factor decreasing the broadening of the band broadening function. The variance of the elution curves is larger than it corresponds to dispersity M¯w/M¯n and the shape of the elution curves depends on the experimental conditions which suggests that it reflects properties of the band broadening function...
March 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28139036/multiparametric-diffusion-weighted-imaging-in-breast-lesions-association-with-pathologic-diagnosis-and-prognostic-factors
#12
Shiteng Suo, Fang Cheng, Mengqiu Cao, Jiwen Kang, Mingyao Wang, Jia Hua, Xiaolan Hua, Lan Li, Qing Lu, Jialin Liu, Jianrong Xu
PURPOSE: To determine the utility of multiparametric diffusion-weighted imaging (DWI) including monoexponential (apparent diffusion coefficient [ADC]), biexponential (Df , Ds , and f), stretched-exponential (distributed diffusion coefficient [DDC] and α), and kurtosis (mean diffusivity [MD] and mean kurtosis [MK]) models in the differentiation and characterization of breast lesions, and assess their associations with prognostic factors in invasive breast cancer. MATERIALS AND METHODS: This study included 101 patients (44 benign and 57 malignant lesions) who underwent 3T breast multi-b-value DWI...
January 31, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28111394/comparison-of-analytical-values-in-diffusion-kurtosis-imaging-among-different-mri-units
#13
Shogo Tan, Koichi Ujita, Yasuhiro Fukushima, Takayuki Suto
Diffusion kurtosis imaging (DKI) is a method of analyzing restricted diffusion. Mean kurtosis (MK) is obtained from DKI. It is not known how different MRI scanners and coil systems will change MK when the same imaging parameters are used. The purpose of this study is to identify tendencies in MK when using various MRI scanners and coil systems. A total of 27 healthy volunteers were enrolled in this study. DKI was performed on the brain for each volunteer on five MRI scanner/coil system combinations using the same scan parameters...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28090658/analysis-of-the-effects-of-noise-dwi-sampling-and-value-of-assumed-parameters-in-diffusion-mri-models
#14
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
https://www.readbyqxmd.com/read/28057085/3d-analysis-of-apparent-diffusion-coefficient-histograms-in-hepatocellular-carcinoma-correlation-with-histological-grade
#15
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/28055267/microstructural-changes-in-the-thalamus-after-mild-traumatic-brain-injury-a-longitudinal-diffusion-and-mean-kurtosis-tensor-mri-study
#16
Erhard Trillingsgaard Næss-Schmidt, Jakob Udby Blicher, Simon Fristed Eskildsen, Anna Tietze, Brian Hansen, Peter William Stubbs, Sune Jespersen, Leif Østergaard, Jørgen Feldbæk Nielsen
PRIMARY OBJECTIVE: The primary aim of this study was to assess microstructural changes in the thalamus, hippocampus and corpus callosum with a fast mean kurtosis tensor (MKT) technique, in the acute and sub-acute phase after mTBI. It was hypothesized that MKT would differ between baseline and follow-up in patients. The secondary aim was to relate diffusion measures to symptoms of mTBI. RESEARCH DESIGN: A longitudinal case-control study. METHODS AND PROCEDURES: Twenty-seven patients with mTBI and 27 age- and gender-matched healthy controls were enrolled in the study...
2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/28054731/lung-adenocarcinoma-assessment-of-epidermal-growth-factor-receptor-mutation-status-based-on-extended-models-of-diffusion-weighted-image
#17
Mei Yuan, Xue-Hui Pu, Xiao-Quan Xu, Yu-Dong Zhang, Yan Zhong, Hai Li, Jiang-Fen Wu, Tong-Fu Yu
PURPOSE: To evaluate the diagnostic performance of extended models of diffusion-weighted (DW) imaging to help differentiate the epidermal growth factor receptor (EGFR) mutation status in stage IIIA-IV lung adenocarcinoma. MATERIALS AND METHODS: This retrospective study had institutional research board approval and was HIPAA compliant. Preoperative extended DW imaging including intravoxel incoherent motion (IVIM) and diffusional kurtosis imaging (DKI) 3 Tesla MRI were retrospectively evaluated in 53 patients with pathologically confirmed non-early stage (IIIA-IV) lung adenocarcinoma...
January 5, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28046847/su-g-iep1-05-diffusion-kurtosis-imaging-for-oropharyngeal-cancer-detection
#18
Y Ding, A Mohamed, J Ma, S Frank, J Wang, C Fuller
PURPOSE: Diffusion kurtosis imaging (DKI) is an emerging diffusion MRI technique in cancer diagnosis applications. The objective of this study is to compare DKI with conventional diffusion weighted imaging (DWI) for diagnosis of head and neck cancer. METHODS: Five male patients with histologically documented phase II/III squamous cell carcinoma of the oropharynx were included in this study. DKI (with 6 b-values of 0-2000 s/mm2) and conventional DWI data were acquired at a 3...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046728/su-f-r-29-the-influence-of-four-dimensional-diffusion-weighted-mri-4d-dwi-on-feature-analysis-of-time-resolved-apparent-diffusion-coefficient-adc-measurement-initial-evaluation
#19
Y Liu, F Yin, J Cai
PURPOSE: Diffusion-weighted imaging (DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection compared to other MRI sequences and CT. This study aims at developing and evaluating the effects of the four dimensional DWI (4D-DWI) technique on the feature analysis of time-resolved Apparent Diffusion Coefficient (ADC) measurement. METHODS: Image acquisition was performed by repeatedly imaging a volume of interest using a multi-slice single-shot 2D-DWI sequence in the axial planes...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28026061/detection-of-smoke-induced-pulmonary-lesions-by-hyperpolarized-129-xe-diffusion-kurtosis-imaging-in-rat-models
#20
Weiwei Ruan, Jianping Zhong, Yu Guan, Yi Xia, Xiuchao Zhao, Yeqing Han, Xianping Sun, Shiyuan Liu, Chaohui Ye, Xin Zhou
PURPOSE: To demonstrate that hyperpolarized (HP) xenon diffusion kurtosis imaging (DKI) is able to detect smoke-induced pulmonary lesions in rat models. METHODS: Multi-b DKI with hyperpolarized xenon was used for the first time in five smoke-exposed rats and five healthy rats. Additionally, DKI with b values of up to 80 s/cm(2) were used in two healthy rats to probe the critical b value (a limit beyond which the DKI cannot describe the non-Gaussian diffusion). RESULTS: The mean apparent diffusion coefficient (Dapp ) and diffusion kurtosis (Kapp ) extracted by the DKI model revealed significant changes in the smoke-exposed rats compared with those in the control group (P = 0...
December 27, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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