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Apparent diffusion coefficient

Cailei Zhao, Yongxin Li, Weiguo Cao, Kui Xiang, Heye Zhang, Jian Yang, Yungen Gan
To explore the use of diffusion tensor imaging (DTI) parameters in the quantitative assessment of early brain microstructure changes before and after ventriculoperitoneal shunt in children with high intracranial pressure hydrocephalus.Ten patients with communicating hydrocephalus (age: 2-36 months) and 14 age-/gender-matched controls (age: 2-36 months) were enrolled in this study. All patients underwent the ventriculoperitoneal shunt procedure. The imaging data were collected before and 3 months after the operation...
October 2016: Medicine (Baltimore)
Pietro Valerio Foti, Antonio Longo, Michele Reibaldi, Andrea Russo, Giuseppe Privitera, Corrado Spatola, Luigi Raffaele, Vincenzo Salamone, Renato Farina, Stefano Palmucci, Andrea Musumeci, Rosario Caltabiano, Marco Ragusa, Cesare Mariotti, Teresio Avitabile, Pietro Milone, Giovanni Carlo Ettorre
PURPOSE: The purpose of this prospective study was to investigate the proton-beam-induced changes in apparent diffusion coefficient (ADC) values of ocular melanoma treated with proton-beam therapy (PBT) in patients undergoing long-term magnetic resonance imaging (MRI) follow-up and to assess whether variations in ADC constitute a reliable biomarker for predicting and detecting the response of ocular melanoma to PBT. METHODS: Seventeen patients with ocular melanoma treated with PBT were enrolled...
October 17, 2016: La Radiologia Medica
Lipeng Ning, Evren Özarslan, Carl-Fredrik Westin, Yogesh Rathi
Inferring the microstructure of complex media from the diffusive motion of molecules is a challenging problem in diffusion physics. In this paper, we introduce a novel representation of diffusion MRI (dMRI) signal from tissue with spatially-varying diffusivity using a diffusion disturbance function. This disturbance function contains information about the (intra-voxel) spatial fluctuations in diffusivity due to restrictions, hindrances and tissue heterogeneity of the underlying tissue substrate. We derive the short- and long-range disturbance coefficients from this disturbance function to characterize the tissue structure and organization...
October 14, 2016: NeuroImage
Hidehito Kimura, Masaaki Taniguchi, Tatsuya Mori, Kohkichi Hosoda, Eiji Kohmura
We present a rare case of a patient suffering temporary aphasia after an extracranial-to-intracranial (EC-IC) bypass surgery, which was shown as a transient hypointense lesion on diffusion-weighted imaging (DWI) with increased apparent diffusion coefficient (ADC) value, evidence of postoperative hyperperfusion. Postoperative hyperperfusion syndrome after EC-IC bypass causing temporary neurological deterioration has been reported rarely as isosignal intensity on DWI with hyperintense lesion on T2-weighted image and fluid-attenuated inversion recovery (FLAIR) image as an expression of vasogenic edema...
October 14, 2016: World Neurosurgery
Cristian Picioreanu, Julio Pérez, Mark C M van Loosdrecht
A three-dimensional (3-D) diffusion-reaction model was used to assess the effects of nitrifiers growing in cell clusters on the apparent oxygen half-saturation coefficients in activated sludge flocs. The model allows conciliation of seemingly contradictory reports by several research groups. Although intrinsic half-saturation coefficients (i.e., not affected by diffusion) show a better affinity for oxygen for ammonia oxidizing (AOB) than for nitrite oxidizing bacteria (NOB) (KO,AOB < KO,NOB), measurements in flocs often produced reversed apparent values (KO,AOB,app > KO,NOB,app), which can now be explained by the 3-D model with AOB and NOB microcolonies...
October 8, 2016: Water Research
Weifei Wu, Jie Liang, Ying Chen, Aihua Chen, Bin Wu, Zong Yang
To investigate the microstructural changes in compressed nerves using diffusion tensor imaging (DTI) of herniated disc treated with percutaneous transforaminal endoscopic discectomy.Diffusion tensor imaging has been widely used to visualize peripheral nerves, and the microstructure of compressed nerve roots can be assessed using DTI. However, the microstructural changes after surgery are not well-understood in patients with lumbar disc herniation.Thirty-four consecutive patients with foraminal disc herniation affecting unilateral sacral 1 (S1) nerve roots were enrolled in this study...
October 2016: Medicine (Baltimore)
Nicole S Glaser, Sandra L Wootton-Gorges, Isaac Kim, Daniel J Tancredi, James P Marcin, Andrew Muir, Nathan Kuppermann
OBJECTIVE: To characterize regional differences in brain water distribution and content during diabetic ketoacidosis (DKA) in children and determine whether these differences correlate with regional vascular supply. STUDY DESIGN: We compared changes in brain water distribution and water content in different brain regions during DKA by analyzing magnetic resonance diffusion weighted imaging data collected during DKA and after recovery in 45 children (<18 years of age)...
October 13, 2016: Journal of Pediatrics
Samata Kakkad, Jiangyang Zhang, Alireza Akhbardeh, Desmond Jacob, Balaji Krishnamachary, Meiyappan Solaiyappan, Michael A Jacobs, Venu Raman, Dieter Leibfritz, Kristine Glunde, Zaver M Bhujwalla
Collagen 1 (Col1) fibers play an important role in tumor interstitial macromolecular transport and cancer cell dissemination. Our goal was to understand the influence of Col1 fibers on water diffusion, and to examine the potential of using noninvasive diffusion tensor imaging (DTI) to indirectly detect Col1 fibers in breast lesions. We previously observed, in human MDA-MB-231 breast cancer xenografts engineered to fluoresce under hypoxia, relatively low amounts of Col1 fibers in fluorescent hypoxic regions...
October 2016: Neoplasia: An International Journal for Oncology Research
Martin T Freitag, Klaus H Maier-Hein, Francisczek Binczyk, Frederik B Laun, Christian Weber, David Bonekamp, Rafal Tarnawski, Barbara Bobek-Billewicz, Joanna Polanska, Henryk Majchrzak, Bram Stieltjes
OBJECTIVE: Here, we retrospectively investigate the value of voxel-wisely plotted diffusion tensor-derived (DTI) axial, radial and mean diffusivity for the early detection of malignant transformation (MT) in WHO II glioma compared to contrast-enhanced images. MATERIALS AND METHODS: Forty-seven patients underwent brain magnetic resonance imaging follow-up between 2006-2014 after gross-tumor resection of intra-axial WHO II glioma. Axial/Mean/Radial diffusivity maps (AD/MD/RD) were generated from DTI data...
2016: PloS One
Claudia Joseph, Jens Mibus, Paul Trepte, Christa Müller, Vinzenz Brendler, Dan M Park, Yongqin Jiao, Annie B Kersting, Mavrik Zavarin
As a contribution to the safety assessment of nuclear waste repositories, U(VI) diffusion through the potential buffer material MX-80 bentonite was investigated at three clay dry densities over six years. Synthetic MX-80 model pore water was used as background electrolyte. Speciation calculations showed that Ca2UO2(CO3)3(aq) was the main U(VI) species. The in- and out-diffusion of U(VI) was investigated separately. U(VI) diffused about 3mm, 1.5mm, and 1mm into the clay plug at ρ=1.3, 1.6, and 1.9g/cm(3), respectively...
October 11, 2016: Science of the Total Environment
Xin Mao, Ling-Fang Wu, Hai-Juan Zhao, Wen-Yi Liang, Wen-Jing Chen, Shu-Xian Han, Qi Qi, Ya-Ping Cui, Shi Li, Guang-Hui Yang, Yan-Yan Shao, Dan Zhu, Ru-Feng Wang, Yun You, Lan-Zhen Zhang
Objective. To investigate the absorption property of the representative hydrolyzable tannin, namely corilagin, and its hydrolysates gallic acid (GA) and ellagic acid (EA) from the Fructus Phyllanthi tannin fraction (PTF) in vitro. Methods. Caco-2 cells monolayer model was established. Influences of PTF on Caco-2 cells viability were detected with MTT assay. The transport across monolayers was examined for different time points, concentrations, and secretory directions. The inhibitors of P-glycoprotein (P-gp), multidrug resistance proteins (MRPs), organic anion transporting polypeptide (OATP) and sodium/glucose cotransporter 1 (SGLT1), and tight junction modulators were used to study the transport mechanism...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
Jeremy W Gordon, Eugene Milshteyn, Irene Marco-Rius, Michael Ohliger, Daniel B Vigneron, Peder E Z Larson
PURPOSE: The purpose of this work was to explore the impact of slice profile effects on apparent diffusion coefficient (ADC) mapping of hyperpolarized (HP) substrates. METHODS: Slice profile effects were simulated using a Gaussian radiofrequency (RF) pulse with a variety of flip angle schedules and b-value ordering schemes. A long T1 water phantom was used to validate the simulation results, and ADC mapping of HP [(13) C,(15) N2 ]urea was performed on the murine liver to assess these effects in vivo...
October 13, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Hooman Hamedani, Stephen Kadlecek, Yi Xin, Sarmad Siddiqui, Heather Gatens, Joseph Naji, Masaru Ishii, Maurizio Cereda, Milton Rossman, Rahim Rizi
PURPOSE: To present a method for simultaneous acquisition of alveolar oxygen tension (PA O2 ), specific ventilation (SV), and apparent diffusion coefficient (ADC) of hyperpolarized (HP) gas in the human lung, allowing reinterpretation of the PA O2 and SV maps to produce a map of oxygen uptake (R). METHOD: An imaging scheme was designed with a series of identical normoxic HP gas wash-in breaths to measure ADC, SV, PA O2 , and R in less than 2 min. Signal dynamics were fit to an iterative recursive model that regionally solved for these parameters...
October 13, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Benita Tamrazi, Melike Pekmezci, Mariam Aboian, Tarik Tihan, Christine M Glastonbury
RATIONALE AND OBJECTIVES: Pituitary macroadenomas are predominantly benign intracranial neoplasms that can be locally aggressive with invasion of adjacent structures. Biomarkers of aggressive behavior have been identified in the pathology literature, including the proliferative marker MIB-1. In the radiology literature, diffusion weighted imaging and low ADC values provide similar markers of aggressive behavior in brain tumors. The purpose of this study was to determine if there is a correlation between ADC and MIB-1 in pituitary macroadenomas...
October 12, 2016: Pituitary
Prateek Katiyar, Mathew R Divine, Ursula Kohlhofer, Leticia Quintanilla-Martinez, Bernhard Schölkopf, Bernd J Pichler, Jonathan A Disselhorst
PURPOSE: We aimed to precisely estimate intra-tumoral heterogeneity using spatially regularized spectral clustering (SRSC) on multiparametric MRI data and compare the efficacy of SRSC with the previously reported segmentation techniques in MRI studies. PROCEDURES: Six NMRI nu/nu mice bearing subcutaneous human glioblastoma U87 MG tumors were scanned using a dedicated small animal 7T magnetic resonance imaging (MRI) scanner. The data consisted of T2 weighted images, apparent diffusion coefficient maps, and pre- and post-contrast T2 and T2* maps...
October 12, 2016: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
Da-Zhen Jiang, Ding-Yi Zhou, Wei-Qing Wu, Guang-Yao Wu, Hong Quan
BACKGROUND: Magnetic resonance imaging (MRI) and functional MRI techniques have been widely used in the diagnosis of human immunodeficiency virus (HIV) infection related diseases. PURPOSE: To explore whether magnetic resonance diffusion-weighted imaging (DWI) can track water molecular diffusion changes in the brain of asymptomatic HIV-positive adolescents. MATERIAL AND METHODS: Multi-b value DWI was performed in 23 adolescents, including 15 HIV-positive participants and eight HIV-negative healthy participants...
October 12, 2016: Acta Radiologica
Tahreema N Matin, Najib Rahman, Annabel H Nickol, Mitchell Chen, Xiaojun Xu, Neil J Stewart, Tom Doel, Vicente Grau, James M Wild, Fergus V Gleeson
Purpose To compare lobar ventilation and apparent diffusion coefficient (ADC) values obtained with hyperpolarized xenon 129 ((129)Xe) magnetic resonance (MR) imaging to quantitative computed tomography (CT) metrics on a lobar basis and pulmonary function test (PFT) results on a whole-lung basis in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods The study was approved by the National Research Ethics Service Committee; written informed consent was obtained from all patients. Twenty-two patients with COPD (Global Initiative for Chronic Obstructive Lung Disease stage II-IV) underwent hyperpolarized (129)Xe MR imaging at 1...
October 12, 2016: Radiology
Ursula I Tuor, Min Qiao, Manasi Sule, Melissa Morgunov, Tadeusz Foniok
Stroke is a major cause of disability in adults and children. Recently, we have developed an adult rat model of minor stroke containing a peri-infarct region with a modest T2 increase and mild ischemic damage. We hypothesized that a neonatal minor stroke with mild peri-ischemic changes could also be produced, but with potential ontogenic differences. Using our minor photothrombosis method, we produced a range of severities of ischemic lesions (mini, minor, moderate and severe) within magnetic resonance imaging (MRI) slices of adult and neonatal rats...
October 12, 2016: NMR in Biomedicine
Shuji Nagata, Hiroshi Nishimura, Kimberly K Amrami, Jun Akiba, Tatsuyuki Tonan, Kiminori Fujimoto, Toshi Abe
OBJECTIVE: The purpose of this study is to evaluate the usefulness of MRI in differentiating between fibrous and cellular solitary fibrous tumors (SFTs). MATERIALS AND METHODS: This retrospective study included 17 patients with histopathologically confirmed SFTs, including 10 patients with fibrous SFTs and seven patients with cellular SFTs. We evaluated the differences between fibrous and cellular SFTs with regard to clinical data and MRI findings, such as tumor margin definition, signal intensity, heterogeneity on T1- and T2-weighted images, presence of capsules, intratumoral cystic changes, flow signal void, perilesional edema, enhancement pattern on dynamic contrast-enhanced MRI (DCE-MRI), and mean apparent diffusion coefficient (ADC) values...
October 11, 2016: AJR. American Journal of Roentgenology
Peter D Chang, Daniel S Chow, Peter H Yang, Christopher G Filippi, Angela Lignelli
OBJECTIVE: Recurrence of glioblastoma multiforme (GBM) arises from areas of microscopic tumor infiltration that have yet to disrupt the blood-brain barrier. We hypothesize that these microscopic foci of invasion cause subtle variations in the apparent diffusion coefficient (ADC) and FLAIR signal detectable with the use of computational big-data modeling. MATERIALS AND METHODS: Twenty-six patients with native GBM were studied immediately after undergoing gross total tumor resection...
October 11, 2016: AJR. American Journal of Roentgenology
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