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Archie C Reyes, Tina L Amyes, John P Richard
Primary deuterium isotope effects (1°DKIE) on (kcat/KGA, M(-1)s(-1)) for dianion (X(2-)) activated hydride transfer from NADL to glycolaldehyde (GA) catalyzed by glycerol 3-phosphate dehydrogenase are reported: (X(2-), 1°DKIE); FPO3(2-), 2.8 ± 0.1; HPO3(2-), 2.5 ± 0.1; SO4(2-), 2.8 ± 0.2; HOPO3(2-), 2.5 ± 0.1; S2O3(2-), 2.9 ± 0.1; unactivated; 2.4 ± 0.2. The 1°DKIEs on kcat are similar, consistent with fast and reversible ligand binding, and the conclusion that the observed 1°DKIEs are equal to the intrinsic 1°DKIE...
October 21, 2016: Journal of the American Chemical Society
Jing Xuan Jiang, Zuo Hua Tang, Yu Feng Zhong, Jin Wei Qiang
PURPOSE: The study aimed to evaluate diffusion kurtosis imaging (DKI) in the differentiation between benign and malignant sinonasal lesions, and to compare the diagnostic performance of DKI with diffusion weighted imaging (DWI). MATERIALS AND METHODS: Eight-one patients with solid sinonasal lesions confirmed by surgery and pathology (46 malignant and 35 benign) underwent conventional MRI, DWI, and DKI. DKI was performed employing a 13 extended b-value ranging from 0 to 2500 s/mm(2) ...
October 19, 2016: Journal of Magnetic Resonance Imaging: JMRI
B F Kjølby, A R Khan, A Chuhutin, L Pedersen, J B Jensen, S Jakobsen, D Zeidler, R Sangill, J R Nyengaard, S N Jespersen, B Hansen
Diffusion kurtosis imaging (DKI) is sensitive to tissue microstructure and may therefore be useful in the diagnosis and monitoring of disease in brain and body organs. Generally, diffusion magnetic resonance imaging (dMRI) in the body is challenging because of the heterogeneous body composition, which can cause image artefacts as a result of chemical shifts and susceptibility differences. In addition, the abdomen possesses physiological factors (e.g. breathing, heartbeat, blood flow) which may severely reduce image quality, especially when echo planar imaging is employed, as is typical in dMRI...
October 12, 2016: NMR in Biomedicine
Iris Yuwen Zhou, Yingkun Guo, Takahiro Igarashi, Yu Wang, Emiri Mandeville, Suk-Tak Chan, Lingyi Wen, Mark Vangel, Eng H Lo, Xunming Ji, Phillip Zhe Sun
Diffusion kurtosis imaging (DKI) has been shown to augment diffusion-weighted imaging (DWI) for the definition of irreversible ischemic injury. However, the complexity of cerebral structure/composition makes the kurtosis map heterogeneous, limiting the specificity of kurtosis hyperintensity to acute ischemia. We propose an Inherent COrrelation-based Normalization (ICON) analysis to suppress the intrinsic kurtosis heterogeneity for improved characterization of heterogeneous ischemic tissue injury. Fast DKI and relaxation measurements were performed on normal (n = 10) and stroke rats following middle cerebral artery occlusion (MCAO) (n = 20)...
October 3, 2016: NMR in Biomedicine
Xiao-Xue Zhang, Le-Kang Yin, Xiao-Zhu Hao, Jia-Qi Tian, Chan-Chan Li, Xiao-Yuan Feng, Yan-Mei Yang
BACKGROUND: The purpose of our study is to explore the relationship between recovery of neural function and transformation of the internal capsule (IC) after transient middle cerebral artery occlusion (MCAO) by using diffusion kurtosis imaging (DKI). METHODS: Six male adult Sprague-Dawley rats implemented with transient MCAO were used in this study. Sensorimotor function was assessed according to repetitive behavioral testing on day 1, 3, 7, 14, and 28 after cerebral ischemia...
September 29, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
Farida Grinberg, Ivan I Maximov, Ezequiel Farrher, Irene Neuner, Laura Amort, Heike Thönneßen, Eileen Oberwelland, Kerstin Konrad, N Jon Shah
The most common modality of diffusion MRI used in the ageing and development studies is diffusion tensor imaging (DTI) providing two key measures, fractional anisotropy and mean diffusivity. Here, we investigated diffusional changes occurring between childhood (average age 10.3 years) and mitddle adult age (average age 54.3 years) with the help of diffusion kurtosis imaging (DKI), a recent novel extension of DTI that provides additional metrics quantifying non-Gaussianity of water diffusion in brain tissue...
September 14, 2016: NeuroImage
Jing Yu, Qing Xu, Jia-Cheng Song, Yan Li, Xin Dai, Dong-Ya Huang, Ling Zhang, Yang Li, Hai-Bin Shi
OBJECTIVES: To evaluate the feasibility and value of diffusion kurtosis (DK) imaging in assessing treatment response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC). METHODS: Forty-one patients were included. All patients underwent pre- and post-CRT DCE-MRI on a 3.0-Tesla MRI scanner. Imaging indices (D app , K app and ADC values) were measured. Change value (∆X) and change ratio (r∆X) were calculated. Pathological tumour regression grade scores (Mandard) were the standard reference (good responders: pTRG 1-2; poor responders: pTRG 3-5)...
September 8, 2016: European Radiology
Johann-Martin Hempel, Sotirios Bisdas, Jens Schittenhelm, Cornelia Brendle, Benjamin Bender, Henk Wassmann, Marco Skardelly, Ghazaleh Tabatabai, Salvador Castaneda Vega, Ulrike Ernemann, Uwe Klose
The purpose of this study is to assess the diagnostic performance of diffusion kurtosis imaging (DKI) for in vivo molecular profiling of human glioma. Normalized mean kurtosis (MKn) and mean diffusivity (MDn) metrics from DKI were assessed in 50 patients with histopathologically confirmed glioma. The results were compared in regard to the WHO-based histological findings and molecular characteristics leading to integrated diagnosis (Haarlem Consensus): isocitrate-dehydrogenase (IDH1/2) mutation status, alpha-thalassemia/mental retardation syndrome X-linked (ATRX) expression, chromosome 1p/19q loss of heterozygosity (LOH), and O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status...
September 7, 2016: Journal of Neuro-oncology
Brian Hansen, Sune Nørhøj Jespersen
Here we describe and provide diffusion magnetic resonance imaging (dMRI) data that was acquired in neural tissue and a physical phantom. Data acquired in biological tissue includes: fixed rat brain (acquired at 9.4 T) and spinal cord (acquired at 16.4 T) and in normal human brain (acquired at 3 T). This data was recently used for evaluation of diffusion kurtosis imaging (DKI) contrasts and for comparison to diffusion tensor imaging (DTI) parameter contrast. The data has also been used to optimize b-values for ex vivo and in vivo fast kurtosis imaging...
2016: Scientific Data
Ying Yu, Qian Sun, Lin-Feng Yan, Yu-Chuan Hu, Hai-Yan Nan, Yang Yang, Zhi-Cheng Liu, Wen Wang, Guang-Bin Cui
BACKGROUND: Type 2 diabetes mellitus (T2DM) is a risk factor for dementia. Mild cognitive impairment (MCI), an intermediary state between normal cognition and dementia, often occurs during the prodromal diabetic stage, making early diagnosis and intervention of MCI very important. Latest neuroimaging techniques revealed some underlying microstructure alterations for diabetic MCI, from certain aspects. But there still lacks an integrated multimodal MRI system to detect early neuroimaging changes in diabetic MCI patients...
2016: BMC Medical Imaging
Brian Hansen, Noam Shemesh, Sune Nørhøj Jespersen
Diffusion kurtosis imaging (DKI) is being increasingly reported to provide sensitive biomarkers of subtle changes in tissue microstructure. However, DKI also imposes larger data requirements than diffusion tensor imaging (DTI), hence, the widespread adaptation and exploration of DKI would benefit from more efficient acquisition and computational methods. To meet this demand, we recently developed a method capable of estimating mean kurtosis with only 13 diffusion weighted images. This approach was later shown to provide very accurate mean kurtosis estimates and to be more efficient in terms of contrast to noise per unit time...
August 15, 2016: NeuroImage
Alberto De Luca, Alessandra Bertoldo, Martijn Froeling
PURPOSE: In this study, we evaluated the effects of perfusion of the skeletal muscle on diffusion tensor imaging (DTI) and diffusional kurtosis imaging (DKI) parameters and their reproducibility. METHODS: Diffusion tensor imaging and DKI models, with and without intravoxel incoherent motion (IVIM) correction, were applied to simulated data at different physiological conditions and signal-to-noise ratio levels. Next, the same models were applied to data of the right calf of five healthy volunteers, acquired twice at 3 telsa...
August 19, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Dan Wang, Yue-Hua Li, Jie Fu, He Wang
PURPOSE: Diffusion kurtosis imaging (DKI) is a MRI technique which can measure alterations in the diffusion of water molecules to reflect tissue changes in both white and grey matter. This study evaluated the potential of DKI for the early diagnosis of radiation-induced temporal lobe changes in the grey and white matter of the temporal lobe in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Sixty patients with NPC who had normal MRI brain scans were enrolled and underwent DKI at 1 week (n=20), 6 months (n=20) or 1 year (n=20) after radiotherapy; 20 normal control individuals were also evaluated...
October 1, 2016: Brain Research
Guohua Zhang, Yuhu Zhang, Chengguo Zhang, Yukai Wang, Guixian Ma, Kun Nie, Haiqun Xie, Jianping Liu, Lijuan Wang
A recent study has shown that striatal silent infarction may occur secondary to the degeneration of dopaminergic neurons in the substantia nigra (SN) of mice. However, it is uncertain whether this phenomenon occurs in patients with early-stage Parkinson's disease (PD) and can be detected by diffusion kurtosis imaging (DKI). A total of 72 untreated patients with early-stage PD underwent conventional MRI and DKI. Participants were divided into control and striatal silent lacunar infarction (SSLI) groups. The differences in mean kurtosis (MK) values of the SN, Hoehn-Yahr (H-Y) staging, and Unified Parkinson's Disease Rating Scale (UPDRS) III score between groups, were analyzed...
November 2016: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Vijayakumar Chinnadurai, C M Sreedhar, Subash Khushu
OBJECTIVE: The use of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) was evaluated in assessing cochlear nerve deficiency (CND) and its effect on normal maturation of auditory tract. METHODS: 25 CND patients and 25 controls (age matched: 2months to 17years, gender matched) were evaluated by mean kurtosis (MK), axial kurtosis, and radial kurtosis and compared against fractional anisotropy (FA), axial and radial diffusivities in internal auditory canal (IAC), lateral lemniscus (LL) and inferior colliculus (IC)...
November 2016: Magnetic Resonance Imaging
Yue-Lin Guo, Su-Juan Li, Zhong-Ping Zhang, Zhi-Wei Shen, Gui-Shan Zhang, Gen Yan, Yan-Ting Wang, Hai-Bing Rao, Wen-Bin Zheng, Ren-Hua Wu
Diffusional kurtosis imaging (DKI) is a new type diffusion-weighted sequence which measures the non-Gaussianity of water diffusion. The present study aimed to investigate whether the parameters of DKI could distinguish between differences in water molecule diffusion in various brain regions under the conditions of acute infarction and to identify the optimal DKI parameter for locating ischemic lesions in each brain region. A total of 28 patients with acute ischemic stroke in different brain regions were recruited for the present study...
August 2016: Experimental and Therapeutic Medicine
Calvin B Shaw, Jens H Jensen, Rachael L Deardorff, Maria Vittoria Spampinato, Joseph A Helpern
PURPOSE: To quantitatively compare diffusion metrics for human brain estimated with diffusional kurtosis imaging (DKI) at applied field strengths of 1.5 and 3T. MATERIALS AND METHODS: DKI data for brain were acquired at both 1.5 and 3T from each of six healthy volunteers using a twice-refocused diffusion-weighted imaging sequence. From these data, parametric maps of mean diffusivity (MD), axial diffusivity (D‖ ), radial diffusivity (D⊥ ), fractional anisotropy (FA), mean diffusional kurtosis (MK), axial kurtosis (K‖ ), radial kurtosis (K⊥ ), and kurtosis fractional anisotropy (KFA) were estimated...
July 12, 2016: Journal of Magnetic Resonance Imaging: JMRI
Ahmad Raza Khan, Andrey Chuhutin, Ove Wiborg, Christopher D Kroenke, Jens R Nyengaard, Brian Hansen, Sune Nørhøj Jespersen
Depression is one of the leading causes of disability worldwide. Immense heterogeneity in symptoms of depression causes difficulty in diagnosis, and to date, there are no established biomarkers or imaging methods to examine depression. Unpredictable chronic mild stress (CMS) induced anhedonia is considered to be a realistic model of depression in studies of animal subjects. Stereological and neuronal tracing techniques have demonstrated persistent remodeling of microstructure in hippocampus, prefrontal cortex and amygdala of CMS brains...
July 4, 2016: NeuroImage
Yulia Surova, Björn Lampinen, Markus Nilsson, Jimmy Lätt, Sara Hall, Håkan Widner, Danielle van Westen, Oskar Hansson
In Parkinson's disease (PD), pathological microstructural changes occur and such changes might be detected using diffusion magnetic resonance imaging (dMRI). However, it is unclear whether dMRI improves PD diagnosis or helps differentiating between phenotypes, such as postural instability gait difficulty (PIGD) and tremor dominant (TD) PD. We included 105 patients with PD and 44 healthy controls (HC), all of whom underwent dMRI as part of the prospective Swedish BioFINDER study. Diffusion kurtosis imaging (DKI) and neurite density imaging (NDI) analyses were performed using regions of interest in the basal ganglia, the thalamus, the pons and the midbrain as well as tractography of selected white matter tracts...
2016: PloS One
Feng Wang, Cheng Peng, Guangyuan Zhang, Qing Zhao, Changyou Xuan, Meng Wei, Niansong Wang
It is occasionally observed that patients without contrast-induced nephropathy (CIN) develop kidney injury within 1-6 months after coronary angiography (CAG), termed delayed CIN or delayed kidney injury (DKI) following CAG. The present study aimed to investigate the associated risk factors of delayed CIN and its possible pathogenesis. Subjects with CAG or coronary stenting from January 2008 to December 2009 were studied. A retrospective survey on DKI after CAG was conducted and the risk factors were analyzed...
July 2016: Experimental and Therapeutic Medicine
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