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Relaxometry

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https://www.readbyqxmd.com/read/29777389/iron-based-metal-organic-frameworks-as-a-theranostic-carrier-for-local-tuberculosis-therapy
#1
Gabriela Wyszogrodzka, Przemysław Dorożyński, Barbara Gil, Wieslaw J Roth, Maciej Strzempek, Bartosz Marszałek, Władysław P Węglarz, Elżbieta Menaszek, Weronika Strzempek, Piotr Kulinowski
PURPOSE: The purpose of the study was initial evaluation of applicability of metal organic framework (MOF) Fe-MIL-101-NH2 as a theranostic carrier of antituberculous drug in terms of its functionality, i.e. drug loading, drug dissolution, magnetic resonance imaging (MRI) contrast and cytotoxic safety. METHODS: Fe-MIL-101-NH2 was characterized using X-ray powder diffraction, FTIR spectrometry and scanning electron microscopy. The particle size analysis was determined using laser diffraction...
May 18, 2018: Pharmaceutical Research
https://www.readbyqxmd.com/read/29770484/inter-method-reproducibility-of-biexponential-r-2-mr-relaxometry-for-estimation-of-liver-iron-concentration
#2
Ali Pirasteh, Qing Yuan, Diego Hernando, Scott B Reeder, Ivan Pedrosa, Takeshi Yokoo
PURPOSE: To assess the reproducibility of biexponential R2 -relaxometry MRI for estimation of liver iron concentration (LIC) between proprietary and nonproprietary analysis methods. METHODS: This single-center retrospective study, approved by investigational review board and compliant with the Health Insurance Portability and Accountability Act, included 40 liver MRI exams in 38 subjects with suspected or known iron overload. From spin-echo images of the liver, acquired at 5 different echo times (TE = 6-18 ms), biexponential R2 maps were calculated using 1 proprietary (FerriScan, Resonance Health Ltd...
May 16, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29763672/using-3d-spatial-correlations-to-improve-the-noise-robustness-of-multi-component-analysis-of-3d-multi-echo-quantitative-t2-relaxometry-data
#3
Dushyant Kumar, Hari Hariharan, Tobias D Faizy, Patrick Borchert, Susanne Siemonsen, Jens Fiehler, Ravinder Reddy, Jan Sedlacik
PURPOSE: We present a computationally feasible and iterative multi-voxel spatially regularized algorithm for myelin water fraction (MWF) reconstruction. This method utilizes 3D spatial correlations present in anatomical/pathological tissues and underlying B1+ -inhomogeneity or flip angle inhomogeneity to enhance the noise robustness of the reconstruction while intrinsically accounting for stimulated echo contributions using T2-distribution data alone. METHODS: Simulated data and in vivo data acquired using 3D non-selective multi-echo spin echo (3DNS-MESE) were used to compare the reconstruction quality of the proposed approach against those of the popular algorithm (the method by Prasloski et al...
May 12, 2018: NeuroImage
https://www.readbyqxmd.com/read/29758451/diffusion-effect-on-t2-relaxometry-in-triple-echo-steady-state-free-precession-sequence
#4
Yangzi Qiao, Chao Zou, Chuanli Cheng, Qian Wan, Changjun Tie, Dong Liang, Hairong Zheng, Xin Liu, Yiu-Cho Chung
PURPOSE: The purpose of this study is to evaluate the effect of diffusion on SSFP (Steady-state Free Precession) signals in triple-echo steady state (TESS) sequence and ultimately on the accuracy of T2 relaxometry. METHODS: The extended phase graph (EPG) algorithm was used to study the effect of diffusion on SSFP signals and T2 relaxometry. The simulation results were verified by a commercial phantom and in vivo studies. Based on the simulation results, a correction scheme was proposed to correct the estimated T2 values...
May 2, 2018: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29751058/imaging-brain-tumour-microstructure
#5
Markus Nilsson, Elisabet Englund, Filip Szczepankiewicz, Danielle van Westen, Pia C Sundgren
Imaging is an indispensable tool for brain tumour diagnosis, surgical planning, and follow-up. Definite diagnosis, however, often demands histopathological analysis of microscopic features of tissue samples, which have to be obtained by invasive means. A non-invasive alternative may be to probe corresponding microscopic tissue characteristics by MRI, or so called 'microstructure imaging'. The promise of microstructure imaging is one of 'virtual biopsy' with the goal to offset the need for invasive procedures in favour of imaging that can guide pre-surgical planning and can be repeated longitudinally to monitor and predict treatment response...
May 8, 2018: NeuroImage
https://www.readbyqxmd.com/read/29717787/isotropic-morphometry-and-multicomponent-t-1-%C3%AF-mapping-of-human-knee-articular-cartilage-in-vivo-at-3t
#6
Rahman Baboli, Azadeh Sharafi, Gregory Chang, Ravinder R Regatte
BACKGROUND: The progressive loss of hyaline articular cartilage due to osteoarthritis (OA) changes the functional and biochemical properties of cartilage. Measuring the T1 ρ along with the morphological assessment can potentially be used as noninvasive biomarkers in detecting early-stage OA. To correlate the biochemical and morphological data, submillimeter isotropic resolution for both studies is required. PURPOSE: To implement a high spatial resolution 3D-isotropic-MRI sequence for simultaneous assessment of morphological and biexponential T1 ρ relaxometry of human knee cartilage in vivo...
May 2, 2018: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29689381/on-the-use-of-superparamagnetic-hydroxyapatite-nanoparticles-as-an-agent-for-magnetic-and-nuclear-in-vivo-imaging
#7
Alessio Adamiano, Michele Iafisco, Monica Sandri, Martina Basini, Paolo Arosio, Tamara Canu, Giovanni Sitia, Antonio Esposito, Vincenzo Iannotti, Giovanni Ausanio, Eirini Fragogeorgi, Maritina Rouchota, George Loudos, Alessandro Lascialfari, Anna Tampieri
The identification of alternative biocompatible magnetic NPs for advanced clinical application is becoming an important need due to raising concerns about iron accumulation in soft issues associated to the administration of superparamagnetic iron oxide nanoparticles (NPs). Here, we report on the performance of previously synthetized iron-doped hydroxyapatite (FeHA) NPs as contrast agent for magnetic resonance imaging (MRI). The MRI contrast abilities of FeHA and Endorem® (dextran coated iron oxide NPs) were assessed by 1 H nuclear magnetic resonance relaxometry and their performance in healthy mice was monitored by a 7 Tesla scanner...
April 21, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29681528/local-associations-between-knee-cartilage-t-1%C3%AF-and-t-2-relaxation-times-and-patellofemoral-joint-stress-during-walking-a-voxel-based-relaxometry-analysis
#8
Hsiang-Ling Teng, Valentina Pedoia, Thomas M Link, Sharmila Majumdar, Richard B Souza
BACKGROUND: This study aimed to utilize voxel-based relaxometry (VBR) to examine local correlations between patellofemoral joint (PFJ) stress during gait and PFJ cartilage relaxation times. METHODS: Eighty-three subjects with and without PFJ osteoarthritis (OA) underwent knee magnetic resonance (MR) images using fast spin-echo, T1ρ and T2 relaxation time sequences. Patellar and trochlear cartilage relaxation times were computed for each voxel. Peak PFJ stress was computed during the stance phase from three-dimensional gait analysis...
April 19, 2018: Knee
https://www.readbyqxmd.com/read/29668721/ultra-high-field-mri-of-human-hippocampi-morphological-and-multiparametric-differentiation-of-hippocampal-sclerosis-subtypes
#9
Clarissa Gillmann, Roland Coras, Karl Rössler, Arnd Doerfler, Michael Uder, Ingmar Blümcke, Tobias Bäuerle
The aim of the present study is to differentiate subtypes of hippocampal sclerosis (HS) using ex vivo ultra-high field magnetic resonance imaging (MRI). Included were 14 surgically resected hippocampi of patients with medically intractable temporal lobe epilepsy. The resected hippocampi were histologically categorized into subtypes of hippocampal sclerosis (HS type 1 (n = 10), HS type 2 (n = 2) and no-HS (n = 2)) and subsequently scanned on a preclinical 7T MRI acquiring T2-weighted morphology, relaxometry and diffusion tensor imaging...
2018: PloS One
https://www.readbyqxmd.com/read/29657915/macromolecular-crowding-may-significantly-affect-the-performance-of-an-mri-contrast-agent-a-1-h-nmr-spectroscopy-microimaging-and-fast-field-cycling-nmr-relaxometry-study
#10
Ren-Hao Cheng, Jie-Min Chen, Yu-Wen Chen, Honghao Cai, Xiaohong Cui, Dennis W Hwang, Zhong Chen, Shangwu Ding
Contrast enhancement agents are often employed in magnetic resonance imaging (MRI) for clinical diagnosis and biomedical research. However, the current theory on MRI contrast generation does not consider the ubiquitous presence of macromolecular crowders in biological systems, which poses the risk of inaccurate data interpretation and misdiagnosis. To address this issue, herein the macromolecular crowding effects on MRI contrast agent are investigated with the 1 H relaxation rate of water in aqueous solutions of Dotarem with different concentrations of macromolecules...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29655938/delineation-of-early-brain-development-from-fetuses-to-infants-with-diffusion-mri-and-beyond
#11
REVIEW
Minhui Ouyang, Jessica Dubois, Qinlin Yu, Pratik Mukherjee, Hao Huang
Dynamic macrostructural and microstructural changes take place from the mid-fetal stage to 2 years after birth. Delineating brain structural changes during this early developmental period provides new insights into the complicated processes of both typical brain development and the pathological mechanisms underlying various psychiatric and neurological disorders including autism, attention deficit hyperactivity disorder and schizophrenia. Decades of histological studies have identified strong spatial and functional gradients of maturation in human brain gray and white matter...
April 12, 2018: NeuroImage
https://www.readbyqxmd.com/read/29652481/amplified-sensitivity-of-nitrogen-vacancy-spins-in-nanodiamonds-using-all-optical-charge-readout
#12
David A Hopper, Richard R Grote, Samuel M Parks, Lee C Bassett
Nanodiamonds containing nitrogen-vacancy (NV) centers offer a versatile platform for sensing applications spanning from nanomagnetism to in-vivo monitoring of cellular processes. In many cases, however, weak optical signals and poor contrast demand long acquisition times that prevent the measurement of environmental dynamics. Here, we demonstrate the ability to perform fast, high-contrast optical measurements of charge distributions in ensembles of NV centers in nanodiamonds and use the technique to improve the spin readout signal-to-noise ratio through spin-to-charge conversion...
April 13, 2018: ACS Nano
https://www.readbyqxmd.com/read/29626891/dynamic-signatures-of-the-transition-from-stacking-disordered-to-hexagonal-ice-dielectric-and-nuclear-magnetic-resonance-studies
#13
C Gainaru, E Vynokur, K W Köster, V Fuentes-Landete, N Spettel, J Zollner, T Loerting, R Böhmer
Using various temperature-cycling protocols, the dynamics of ice I were studied via dielectric spectroscopy and nuclear magnetic resonance relaxometry on protonated and deuterated samples obtained by heating high-density amorphous ices as well as crystalline ice XII. Previous structural studies of ice I established that at temperatures of about 230 K, the stacking disorder of the cubic/hexagonal oxygen lattice vanishes. The present dielectric and nuclear magnetic resonance investigations of spectral changes disclose that the memory of the existence of a precursor phase is preserved in the hydrogen matrix up to 270 K...
April 7, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29584598/use-of-2d-u-net-convolutional-neural-networks-for-automated-cartilage-and-meniscus-segmentation-of-knee-mr-imaging-data-to-determine-relaxometry-and-morphometry
#14
Berk Norman, Valentina Pedoia, Sharmila Majumdar
Purpose To analyze how automatic segmentation translates in accuracy and precision to morphology and relaxometry compared with manual segmentation and increases the speed and accuracy of the work flow that uses quantitative magnetic resonance (MR) imaging to study knee degenerative diseases such as osteoarthritis (OA). Materials and Methods This retrospective study involved the analysis of 638 MR imaging volumes from two data cohorts acquired at 3.0 T: (a) spoiled gradient-recalled acquisition in the steady state T1ρ -weighted images and (b) three-dimensional (3D) double-echo steady-state (DESS) images...
March 27, 2018: Radiology
https://www.readbyqxmd.com/read/29577976/effects-of-iron-oxide-contrast-agent-in-combination-with-various-transfection-agents-during-mesenchymal-stem-cells-labelling-an-in-vitro-toxicological-evaluation
#15
Sushanta Kumar Mishra, Subash Khushu, Gurudutta Gangenahalli
The use of iron oxide nanoparticles for different biomedical applications, hold immense promise to develop negative tissue contrast in magnetic resonance imaging (MRI). Previously, we have optimized the labelling of mesenchymal stem cells (MSCs) with iron oxide nanoparticles complexed to different transfection agents like poly-l-lysine (IO-PLL) and protamine sulfate (Fe-Pro) on the basis of relaxation behaviour and its biological expressions. However, there is a distinct need to investigate the biocompatibility and biosafety concerns coupled with its cytotoxicity and genotoxicity...
March 22, 2018: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/29575414/evidence-for-the-role-of-intracellular-water-lifetime-as-a-tumour-biomarker-by-in-vivo-field-cycling-relaxometry
#16
Maria Rosaria Ruggiero, Simona Baroni, Stefania Pezzana, Gianni Ferrante, Simonetta Geninatti Crich, Silvio Aime
Through access to in vivo T1 measurements at low magnetic fields it was established that tumour cells display proton T1 values that are markedly longer than the those shown by healthy tissue. Moreover, it has been found that the elongation of T1 parallels the aggressiveness of the investigated tumour. The T1-lengthening is associated with an enhanced water exchange rate across the transcytolemmal membrane through an overexpression/upregulation of GLUT1 and Na+/K+ATPase transporters. It follows that the intracellular (IN) water lifetime represents a hallmark of tumour cells that can be easily monitored by measuring T1 at different magnetic field strengths ranging from 0...
March 25, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29574318/r-1-dispersion-contrast-at-high-field-with-fast-field-cycling-mri
#17
Markus Bödenler, Martina Basini, Maria Francesca Casula, Evrim Umut, Christian Gösweiner, Andreas Petrovic, Danuta Kruk, Hermann Scharfetter
Contrast agents with a strong R1 dispersion have been shown to be effective in generating target-specific contrast in MRI. The utilization of this R1 field dependence requires the adaptation of an MRI scanner for fast field-cycling (FFC). Here, we present the first implementation and validation of FFC-MRI at a clinical field strength of 3 T. A field-cycling range of ±100 mT around the nominal B0 field was realized by inserting an additional insert coil into an otherwise conventional MRI system. System validation was successfully performed with selected iron oxide magnetic nanoparticles and comparison to FFC-NMR relaxometry measurements...
March 17, 2018: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29573009/a-diffusion-model-free-framework-with-echo-time-dependence-for-free-water-elimination-and-brain-tissue-microstructure-characterization
#18
Miguel Molina-Romero, Pedro A Gómez, Jonathan I Sperl, Michael Czisch, Philipp G Sämann, Derek K Jones, Marion I Menzel, Bjoern H Menze
PURPOSE: The compartmental nature of brain tissue microstructure is typically studied by diffusion MRI, MR relaxometry or their correlation. Diffusion MRI relies on signal representations or biophysical models, while MR relaxometry and correlation studies are based on regularized inverse Laplace transforms (ILTs). Here we introduce a general framework for characterizing microstructure that does not depend on diffusion modeling and replaces ill-posed ILTs with blind source separation (BSS)...
March 23, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29559776/targeting-experimental-orthotopic-glioblastoma-with-chitosan-based-superparamagnetic-iron-oxide-nanoparticles-cs-dx-spions
#19
Maxim Shevtsov, Boris Nikolaev, Yaroslav Marchenko, Ludmila Yakovleva, Nikita Skvortsov, Anton Mazur, Peter Tolstoy, Vyacheslav Ryzhov, Gabriele Multhoff
Background: Glioblastoma is the most devastating primary brain tumor of the central nervous system in adults. Magnetic nanocarriers may help not only for a targeted delivery of chemotherapeutic agents into the tumor site but also provide contrast enhancing properties for diagnostics using magnetic resonance imaging (MRI). Methods: Synthesized hybrid chitosan-dextran superparamagnetic nanoparticles (CS-DX-SPIONs) were characterized using transmission electron microscopy (TEM) and relaxometry studies...
2018: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/29550400/systematic-review-and-meta-analysis-of-the-reliability-and-discriminative-validity-of-cartilage-compositional-mri-in-knee-osteoarthritis
#20
REVIEW
James W MacKay, Samantha B L Low, Toby O Smith, Andoni P Toms, Andrew M McCaskie, Fiona J Gilbert
OBJECTIVE: To assess reliability and discriminative validity of cartilage compositional magnetic resonance imaging (MRI) in knee osteoarthritis (OA). DESIGN: The study was carried out per PRISMA recommendations. We searched MEDLINE and EMBASE (1974 - present) for eligible studies. We performed qualitative synthesis of reliability data. Where data from at least 2 discrimination studies were available, we estimated pooled standardized mean difference (SMD) between subjects with and without OA...
March 14, 2018: Osteoarthritis and Cartilage
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