keyword
MENU ▼
Read by QxMD icon Read
search

Low field MRI

keyword
https://www.readbyqxmd.com/read/28543921/correlations-of-low-field-nmr-and-variable-field-nmr-parameters-with-osteoarthritis-in-human-articular-cartilage-under-load
#1
Erik Rössler, Carlos Mattea, Simo Saarakkala, Petri Lehenkari, Mikko Finnilä, Lassi Rieppo, Sakari Karhula, Miika T Nieminen, Siegfried Stapf
NMR experiments carried out at magnetic fields below 1 T provide new relaxation parameters unavailable with conventional clinical scanners. Contrast of T1 generally becomes larger towards low fields, as slow molecular reorientation processes dominate relaxation at the corresponding Larmor frequencies. This advantage has to be considered in the context of lower sensitivity and frequently reduced spatial resolution. The layered structure of cartilage is one example where a particularly strong variation of T1 across the tissue occurs, being affected by degenerative diseases such as osteoarthritis (OA)...
May 24, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28531809/multifocal-visual-evoked-potentials-in-optic-neuritis-and-multiple-sclerosis-a-review
#2
REVIEW
Gorm Pihl-Jensen, Mathias Falck Schmidt, Jette Lautrup Frederiksen
Multifocal visual evoked potential (mf-VEP) represents a new approach to the classical full field (ff-)VEP with separate responses from up to 60 sectors of the visual field. A thorough literature survey of the use of mf-VEP in optic neuritis (ON) and multiple sclerosis (MS) is presented (38 published studies were retrieved). Mf-VEP provides direct topographical information of specific lesions and facilitates investigations on structural-functional correlations thus providing new methods for exploring the interplay between demyelination, atrophy and remyelination in MS...
April 11, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28528845/comparison-of-3-and-7-t-asl-techniques-for-concurrent-functional-perfusion-and-bold-studies
#3
Dimo Ivanov, Anna Gardumi, Roy Am Haast, Josef Pfeuffer, Benedikt A Poser, Kâmil Uludağ
Arterial spin labeling (ASL) is the primary non-invasive MRI approach to measure baseline cerebral blood flow (CBF) in healthy subjects and patients. ASL also allows concurrent functional BOLD signal and CBF measurements, but the latter typically suffers from low contrast-to-noise (CNR) ratio. Ultra-high-field imaging significantly boosts BOLD signal CNR. However, it is contested whether also CBF CNR benefits from increasing magnetic field strength, especially given that technical challenges related to field inhomogeneities and power deposition constraints exist...
May 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/28528099/investigation-on-water-status-and-distribution-in-broccoli-and-the-effects-of-drying-on-water-status-using-nmr-and-mri-methods
#4
Fangfang Xu, Xin Jin, Lu Zhang, Xiao Dong Chen
Many quality attributes of food products are influenced by the water status and the microstructure. Low-field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methods are applied to non-destructively monitor the water status and structure of food. The aim of this study is to investigate the water status and distribution inside broccoli tissues and the effects of hot-air drying on the water status by using NMR and MRI methods. Transverse relaxation times (T2) provide the information of water status and water distribution...
June 2017: Food Research International
https://www.readbyqxmd.com/read/28516447/metacarpophalangeal-joint-injury-patterns-on-magnetic-resonance-imaging-a-comparison-in-racing-standardbreds-and-thoroughbreds
#5
Julien Olive, Nicolas Serraud, Thibault Vila, Jean-Philippe Germain
The metacarpal condyle has received extensive attention as a predominant site of overload arthropathy in racehorses. However, detailed descriptions of MRI lesion patterns for the metacarpophalangeal joint and comparisons between types of racing horses are currently lacking. Aims of this retrospective, cross-sectional study were to describe and compare standing low-field magnetic resonance findings in the metacarpophalangeal joints for groups of Standardbreds and Thoroughbreds using systematic semiquantitative scores...
May 17, 2017: Veterinary Radiology & Ultrasound
https://www.readbyqxmd.com/read/28516042/sensitivity-enhancement-of-traveling-wave-mri-using-free-local-resonators-an-experimental-demonstration
#6
Xiaoliang Zhang
BACKGROUND: Traveling wave MR uses the far fields in signal excitation and reception, therefore its acquisition efficiency is low in contrast to the conventional near field magnetic resonance (MR). Here we show a simple and efficient method based on the local resonator to improving sensitivity of traveling wave MR technique. The proposed method utilizes a standalone or free local resonator to amplify the radio frequency magnetic fields in the interested target. The resonators have no wire connections to the MR system and thus can be conveniently placed to any place around imaging simples...
April 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28507682/sabre-hyperpolarisation-of-vitamin-b3-as-a-function-of-ph
#7
A M Olaru, M J Burns, G G R Green, S B Duckett
In this work we describe how the signal enhancements obtained through the SABRE process in methanol-d4 solution are significantly affected by pH. Nicotinic acid (vitamin B3, NA) is used as the agent, and changing pH is shown to modify the level of polarisation transfer by over an order of magnitude, with significant improvements being seen in terms of the signal amplitude and relaxation rate at high pH values. These observations reveal that manipulating pH to improve SABRE enhancements levels may improve the potential of this method to quantify low concentrations of analytes in mixtures...
March 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28506802/stealth-magnetic-nanocarriers-of-sirna-as-platform-for-breast-cancer-theranostics
#8
J Bruniaux, S Ben Djemaa, K Hervé-Aubert, H Marchais, I Chourpa, S David
The endogenous mechanism of RNA interference is more and more used in research to obtain specific down-regulation of gene expression in diseases such as breast cancer. Currently, despite the new fields of study open up by RNA interference, the rapid degradation of siRNA by nucleases and their negative charges prevent them from crossing cell membranes. To overcome these limitations, superparamagnetic iron oxide nanoparticles (SPIONs) represent a promising alternative for nucleic acid delivery. Previously, we reported the magnetic siRNA nanovectors (MSN) formulation using electrostatic assembly of (1) SPIONs, also able to act as contrast agents for magnetic resonance imaging (MRI), (2) siRNA and (3) chitosan aiming at their protection and enhancing their transfection efficacy...
May 12, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28477400/mixed-model-phase-evolution-for-correction-of-magnetic-field-inhomogeneity-effects-in-3d-quantitative-gradient-echo-based-mri
#9
Chemseddine Fatnassi, Rachid Boucenna, Habib Zaidi
PURPOSE: In 3D gradient echo magnetic resonance imaging (MRI), strong field gradients (B0macro ) are visually observed at air/tissue interfaces. At low spatial resolution in particular, the respective field gradients lead to an apparent increase in intravoxel dephasing and, subsequently, to signal loss or inaccurate R2 * estimates. If the strong field gradients are measured, their influence can be removed by post processing. METHODS: Conventional corrections usually assume a linear phase evolution with time...
May 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28463165/novel-super-resolution-approach-to-time-resolved-volumetric-4-dimensional-magnetic-resonance-imaging-with-high-spatiotemporal-resolution-for-multi-breathing-cycle-motion-assessment
#10
Guang Li, Jie Wei, Mo Kadbi, Jason Moody, August Sun, Shirong Zhang, Svetlana Markova, Kristen Zakian, Margie Hunt, Joseph O Deasy
PURPOSE: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. METHODS AND MATERIALS: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration...
June 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28461279/metabolic-in-vivo-visualization-of-pituitary-adenomas-a-systematic-review-of-imaging-modalities
#11
REVIEW
Amy Yao, Priti Balchandani, Raj K Shrivastava
INTRODUCTION: Pituitary adenomas are the most common intrasellar mass. Functional pituitary adenomas (PAs) constitute the majority of pituitary tumors and can produce symptoms related to hormonal overproduction. Timely and accurate detection is therefore of vital importance to prevent potentially irreversible sequelae. Magnetic resonance imaging (MRI) is the gold standard for detecting PAs, but is limited by poor sensitivity for microadenomas and an inability to differentiate scar tissue from tumor residual or predict treatment response...
April 28, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28453748/incidence-of-pseudoprogression-in-low-grade-gliomas-treated-with-radiotherapy
#12
Sophie E van West, Hein G de Bruin, Bart van de Langerijt, Annemarie T Swaak-Kragten, Martin J van den Bent, Walter Taal
Background.: As the incidence of pseudo-progressive disease (psPD), or pseudoprogression, in low-grade glioma (LGG) is unknown, we retrospectively investigated this phenomenon in a cohort of LGG patients given radiotherapy (RT). Methods.: All MRI scans and clinical data from patients with histologically proven LGG treated with radiation between 2000 and 2011 were reviewed. PsPD was scored when a new enhancing lesion occurred after RT and subsequently disappeared or remained stable for at least a year without therapy, including dexamethasone...
May 1, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/28448428/therapeutic-ultrasound-in-navicular-stress-injuries-in-elite-track-and-field-athletes
#13
Nikolaos Malliaropoulos, Dimosthenis Alaseirlis, George Konstantinidis, Agapi Papalada, Ioannis Tsifountoudis, Kosmas Petras, Nicola Maffulli
OBJECTIVE: To ascertain whether therapeutic ultrasound (TUS) can be used to assess the progression of conservative management in navicular stress injuries. DESIGN: This is a prospective, clinical case series. Level of evidence IV. SETTING: All participants were examined and followed up in a private Sports Injury Clinic. PARTICIPANTS: Ten elite track and field athletes with severe dorsal midfoot pain over the navicular bone participated in this study...
May 2017: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
https://www.readbyqxmd.com/read/28443626/nanodiamond-enhanced-mri-via-in-situ-hyperpolarization
#14
David E J Waddington, Mathieu Sarracanie, Huiliang Zhang, Najat Salameh, David R Glenn, Ewa Rej, Torsten Gaebel, Thomas Boele, Ronald L Walsworth, David J Reilly, Matthew S Rosen
Nanodiamonds are of interest as nontoxic substrates for targeted drug delivery and as highly biostable fluorescent markers for cellular tracking. Beyond optical techniques, however, options for noninvasive imaging of nanodiamonds in vivo are severely limited. Here, we demonstrate that the Overhauser effect, a proton-electron polarization transfer technique, can enable high-contrast magnetic resonance imaging (MRI) of nanodiamonds in water at room temperature and ultra-low magnetic field. The technique transfers spin polarization from paramagnetic impurities at nanodiamond surfaces to (1)H spins in the surrounding water solution, creating MRI contrast on-demand...
April 26, 2017: Nature Communications
https://www.readbyqxmd.com/read/28441282/magnetic-field-reference-levels-for-arbitrary-periodic-waveforms-for-prevention-of-peripheral-nerve-stimulation
#15
Gregory B Gajda, Stephen H Bly
Guidelines for prevention of peripheral nerve stimulation from exposure to low frequency magnetic fields have been developed by standard-setting bodies. Exposure limits or reference levels (RLs) are typically set in terms of the maximum root-mean-square amplitude of a sinusoidal waveform; however, environmental flux densities are often periodic, non-sinusoidal waveforms. This work presents a procedure for deriving RLs for any generalized periodic waveform using the empirical nerve-stimulation threshold data obtained from human volunteer MRI experiments...
June 2017: Health Physics
https://www.readbyqxmd.com/read/28420375/silent-progression-in-patients-with-rheumatoid-arthritis-is-das28-remission-an-insufficient-goal-in-ra-results-from-the-german-remission-plus-cohort
#16
Philipp Sewerin, Stefan Vordenbaeumen, Annika Hoyer, Ralph Brinks, Christian Buchbender, Falk Miese, Christoph Schleich, Sabine Klein, Matthias Schneider, Benedikt Ostendorf
BACKGROUND: Remission is arguably the ultimate therapeutic goal in rheumatoid arthritis (RA). Applying modern strategies, clinical remission can be achieved in a substantial number of patients with early RA (ERA). Even in those patients, the number and scope of erosions can increase. We, therefore, investigated the value of MRI for the detection of radiological progression in patients with DAS28 improvement and/or clinical remission of the German Remission-plus cohort. METHODS: Data-sets of 80 RA patients (according to 2010 ACR/EULAR criteria) from the Remission-plus study cohort, who fulfilled the following criteria, were retrospectively analysed: availability of two consecutive MRI scans (low-field MRI, follow-up interval 1 year) of the clinically dominant hand and wrist, and the presence of DAS28 (CRP) scores at both time points, which was used to assess disease activity...
April 19, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28410055/olfactory-recognition-based-on-eeg-gamma-band-activity
#17
Onder Aydemir
There are various kinds of brain monitoring techniques, including local field potential, near-infrared spectroscopy, magnetic resonance imaging (MRI), positron emission tomography, functional MRI, electroencephalography (EEG), and magnetoencephalography. Among those techniques, EEG is the most widely used one due to its portability, low setup cost, and noninvasiveness. Apart from other advantages, EEG signals also help to evaluate the ability of the smelling organ. In such studies, EEG signals, which are recorded during smelling, are analyzed to determine the subject lacks any smelling ability or to measure the response of the brain...
April 14, 2017: Neural Computation
https://www.readbyqxmd.com/read/28394083/bone-volume-to-total-volume-ratio-measured-in-trabecular-bone-by-single-sided-nmr-devices
#18
Leonardo Brizi, Marco Barbieri, Fabio Baruffaldi, Villiam Bortolotti, Chiara Fersini, Huabing Liu, Marcel Nogueira d'Eurydice, Sergei Obruchkov, Fangrong Zong, Petrik Galvosas, Paola Fantazzini
PURPOSE: Reduced bone strength is associated with a loss of bone mass, usually evaluated by dual-energy X-ray absorptiometry, although it is known that the bone microstructure also affects the bone strength. Here, a method is proposed to measure (in laboratory) the bone volume-to-total volume ratio by single-sided NMR scanners, which is related to the microstructure of the trabecular bone. METHODS: Three single-sided scanners were used on animal bone samples. These low-field, mobile, low-cost devices are able to detect the NMR signal, regardless of the sample sizes, without the use of ionizing radiations, with the further advantage of signal localization offered by their intrinsic magnetic field gradients...
April 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28391424/optimal-radiation-therapy-for-small-cell-lung-cancer
#19
REVIEW
Michael F Gensheimer, Billy W Loo
Radiation therapy plays an important role in the management of both limited stage and extensive stage small cell lung cancer. For limited stage disease, there has been a trend toward reduced size of thoracic radiation fields, which has the potential to reduce toxicity. FDG-PET staging helps make this possible by more accurately identifying areas of nodal and metastatic involvement. Trials have demonstrated similar outcomes using a range of radiation fractionation schedules, allowing flexibility in individualizing treatment...
April 2017: Current Treatment Options in Oncology
https://www.readbyqxmd.com/read/28390805/from-transmandibular-to-transoral-robotic-approach-for-parapharyngeal-space-tumors
#20
Francesco Chu, Marta Tagliabue, Gioacchino Giugliano, Luca Calabrese, Lorenzo Preda, Mohssen Ansarin
PURPOSE: Parapharyngeal space (PPS) tumors are rare, accounting for 0.5% of all head-and-neck masses. Surgery remains the standard treatment for most cases, including different approaches (cervical approach, parotidectomy, mandibulotomy, transoral/robotic). We report our experience in the management of PPS tumors, aiming to create a surgical algorithm on the base of tumor's radiological and clinical characteristics. MATERIALS AND METHODS: Critical retrospective analysis of patients with PPS neoplasms who underwent surgery at our Institute...
March 31, 2017: American Journal of Otolaryngology
keyword
keyword
113472
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"