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Low field MRI

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https://www.readbyqxmd.com/read/28922355/image-identification-from-brain-activity-using-the-population-receptive-field-model
#1
Wietske Zuiderbaan, Ben M Harvey, Serge O Dumoulin
A goal of computational models is not only to explain experimental data but also to make new predictions. A current focus of computational neuroimaging is to predict features of the presented stimulus from measured brain signals. These computational neuroimaging approaches may be agnostic about the underlying neural processes or may be biologically inspired. Here, we use the biologically inspired population receptive field (pRF) approach to identify presented images from fMRI recordings of the visual cortex, using an explicit model of the underlying neural response selectivity...
2017: PloS One
https://www.readbyqxmd.com/read/28919265/pretherapeutic-staging-of-locally-advanced-cervical-cancer-inframesenteric-paraaortic-lymphadenectomy-accuracy-to-detect-paraaortic-metastases-in-comparison-with-infrarenal-paraaortic-lymphadenectomy
#2
Henri Azaïs, Louise Ghesquière, Clothilde Petitnicolas, Yves Borghesi, Emmanuelle Tresch-Bruneel, Abel Cordoba, Fabrice Narducci, Lucie Bresson, Eric Leblanc
BACKGROUND: Extended-field chemoradiation therapy is usually performed in patients with locally advanced cervical cancer (LACC) and paraaortic (PA) node metastases. Considering the very low rate of skip metastases above inferior mesenteric artery, ilio-inframesenteric paraaortic lymph node dissection (IM-PALND) seems to be an adequate pattern of PALND. Our objective was to assess the accuracy of this management to determine PA nodal status in comparison with infrarenal paraaortic lymphadenectomy (IR-PALND) in case of squamous or glandular cervical cancer...
September 14, 2017: Gynecologic Oncology
https://www.readbyqxmd.com/read/28912147/performance-of-a-pet-insert-for-high-resolution-small-animal-pet-mr-imaging-at-7t
#3
Greg Stortz, Jonathan D Thiessen, Daryl Bishop, Muhammad S Khan, Piotr Kozlowski, Fabrice Retière, Graham Schellenberg, Ehsan Shams, Xuezhu Zhang, Christopher J Thompson, Andrew Goertzen, Vesna Sossi
We present the characterization of a compact magnetic resonance (MR) compatible positron emission tomography (PET) insert for simultaneous pre-clinical PET/MR imaging. While specifically designed with the strict size constraint to fit inside the 114 mm inner diameter of the BGA-12S gradient coil used in the Bruker 70/20 and 94/20 series of small animal MR imaging (MRI) systems, the insert can be easily installed in any appropriate MRI scanner or used as a stand-alone PET system. Methods: The insert is made from a ring of 16 detector-blocks each made from depth-of-interaction capable dual-layer-offset arrays of cerium-doped lutetium-yttrium oxyorthosilicate crystals read out by silicon photomultiplier (SiPM) arrays...
September 14, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28910997/paediatric-nuclear-medicine-imaging
#4
Lorenzo Biassoni, Marina Easty
Background: Nuclear medicine imaging explores tissue viability and function by using radiotracers that are taken up at cellular level with different mechanism. This imaging technique can also be used to assess blood flow and transit through tubular organs. Nuclear medicine imaging has been used in paediatrics for decades and this field is continuously evolving. Sources of data: The data presented comes from clinical experience and some milestone papers on the subject...
September 1, 2017: British Medical Bulletin
https://www.readbyqxmd.com/read/28904988/neurite-dispersion-a-new-marker-of-multiple-sclerosis-spinal-cord-pathology
#5
Francesco Grussu, Torben Schneider, Carmen Tur, Richard L Yates, Mohamed Tachrount, Andrada Ianuş, Marios C Yiannakas, Jia Newcombe, Hui Zhang, Daniel C Alexander, Gabriele C DeLuca, Claudia A M Gandini Wheeler-Kingshott
OBJECTIVE: Conventional magnetic resonance imaging (MRI) of the multiple sclerosis spinal cord is limited by low specificity regarding the underlying pathological processes, and new MRI metrics assessing microscopic damage are required. We aim to show for the first time that neurite orientation dispersion (i.e., variability in axon/dendrite orientations) is a new biomarker that uncovers previously undetected layers of complexity of multiple sclerosis spinal cord pathology. Also, we validate against histology a clinically viable MRI technique for dispersion measurement (neurite orientation dispersion and density imaging, NODDI), to demonstrate the strong potential of the new marker...
September 2017: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/28901137/a-metamaterial-combining-electric-and-magnetic-dipole-based-configurations-for-unique-dual-band-signal-enhancement-in-ultra-high-field-magnetic-resonance-imaging
#6
Rita Schmidt, Andrew Webb
Magnetic resonance imaging and spectroscopy (MRI and MRS) are both widely used techniques in medical diagnostics and research. One of the major thrusts in recent years has been the introduction of ultra-high field magnets in order to boost the sensitivity. Several MRI studies have examined further potential improvements in sensitivity using metamaterials, focusing on single frequency applications. However, metamaterials have yet to reach a level which is practical for routine MRI use. In this work, we explore a new metamaterial implementation for MRI, a dual-nuclei resonant structure, which can be used for both proton and heteronuclear magnetic resonance...
September 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28894763/adaptive-anatomical-preservation-optimal-denoising-for-radiation-therapy-daily-mri
#7
Rapeepan Maitree, Gloria J Guzman Perez-Carrillo, Joshua S Shimony, H Michael Gach, Anupama Chundury, Michael Roach, H Harold Li, Deshan Yang
Low-field magnetic resonance imaging (MRI) has recently been integrated with radiation therapy systems to provide image guidance for daily cancer radiation treatments. The main benefit of the low-field strength is minimal electron return effects. The main disadvantage of low-field strength is increased image noise compared to diagnostic MRIs conducted at 1.5 T or higher. The increased image noise affects both the discernibility of soft tissues and the accuracy of further image processing tasks for both clinical and research applications, such as tumor tracking, feature analysis, image segmentation, and image registration...
July 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28867033/-recommendations-for-imaging-neonatal-ischemic-stroke
#8
B Husson, C Durand, L Hertz-Pannier
Neuroimaging is critical for the diagnosis of neonatal arterial ischemic stroke (NAIS) and for prognosis estimation. The purpose of this work is to define guidelines of clinical neuroimaging for the diagnosis of NAIS, for the optimization of the imaging timing and for the assessment of the prognostic value of each imaging technique. A systematic search of electronic databases (Medline via Pubmed) for studies whose title and abstract were focused on NAIS has been conducted. One hundred and ten articles were selected and their results were analyzed by three Senior Practitioners of pediatric radiology using common methodology for guidelines elaboration within the group of experts gathered by Scientific Societies in the field...
September 2017: Archives de Pédiatrie: Organe Officiel de la Sociéte Française de Pédiatrie
https://www.readbyqxmd.com/read/28865227/pathological-findings-in-low-field-magnetic-resonance-imaging-of-the-canine-spine-a-study-of-112-patients
#9
P Holak, J Głodek, M Mieszkowska, M Jałyński, Y Zhalniarovich, Z Adamiak
Magnetic resonance imaging (MRI) is a method of choice in diagnosing nervous system disorders. This paper presents the results of a study where selected segments of the canine spine were examined by low-field MRI in 112 patients. Images of pathological changes were obtained in spin echo (SE), fast spin echo (FSE) and hybrid contrast enhancement (3D HYCE) sequences. The cervical region of the spinal cord (C1-C5) was examined in 32 patients, the cervicothoracic region (C6-Th2)- in 14 patients, the thoracolumbar region (Th3-L3) - in 23 patients, and the lumbosacral region (L4-S3) - in 43 patients...
March 1, 2017: Polish Journal of Veterinary Sciences
https://www.readbyqxmd.com/read/28858871/unilateral-upper-lung-field-pulmonary-fibrosis-radiologically-consistent-with-pleuroparenchymal-fibroelastosis-after-thoracotomy-a-new-disease-entity-related-to-thoracotomy
#10
Akimasa Sekine, Hiroaki Satoh, Tae Iwasawa, Kentaro Matsui, Eriko Ikeya, Satoshi Ikeda, Hideaki Yamakawa, Ryo Okuda, Hideya Kitamura, Takeshi Shinohara, Tomohisa Baba, Shigeru Komatsu, Terufumi Kato, Eri Hagiwara, Takashi Ogura
BACKGROUND: Pleuroparenchymal fibroelastosis (PPFE) is a rare bilateral idiopathic interstitial pneumonia defined by pleural-parenchymal involvement. In clinical practice, we encountered patients with upper lung field pulmonary fibrosis (Upper-PF), which was radiologically consistent with PPFE, but apparently limited to the unilateral lung. OBJECTIVES: The purpose of the study was to clarify the clinical characteristics in those patients. METHODS: We examined the medical records of all the consecutive patients from 2012 to 2016 to see whether there were patients having unilateral Upper-PF...
September 1, 2017: Respiration; International Review of Thoracic Diseases
https://www.readbyqxmd.com/read/28858475/dysprosium-modified-tobacco-mosaic-virus-nanoparticles-for-ultra-high-field-magnetic-resonance-and-near-infrared-fluorescence-imaging-of-prostate-cancer
#11
He Hu, Yifan Zhang, Sourabh Shukla, Yuning Gu, Xin Yu, Nicole F Steinmetz
The increasing prevalence of ultra-high-field magnetic resonance imaging (UHFMRI) in biomedical research and clinical settings will improve the resolution and diagnostic accuracy of MRI scans. However, better contrast agents are needed to achieve a satisfactory signal-to-noise ratio. Here, we report the synthesis of a bimodal contrast agent prepared by loading the internal cavity of tobacco mosaic virus (TMV) nanoparticles with a dysprosium (Dy(3+)) complex and the near-infrared fluorescence (NIRF) dye Cy7...
September 6, 2017: ACS Nano
https://www.readbyqxmd.com/read/28855113/fpga-implementation-of-real-time-sense-reconstruction-using-pre-scan-and-emaps-sensitivities
#12
Muhammad Faisal Siddiqui, Ahmed Wasif Reza, Abubakr Shafique, Hammad Omer, Jeevan Kanesan
Sensitivity Encoding (SENSE) is a widely used technique in Parallel Magnetic Resonance Imaging (MRI) to reduce scan time. Reconfigurable hardware based architecture for SENSE can potentially provide image reconstruction with much less computation time. Application specific hardware platform for SENSE may dramatically increase the power efficiency of the system and can decrease the execution time to obtain MR images. A new implementation of SENSE on Field Programmable Gate Array (FPGA) is presented in this study, which provides real-time SENSE reconstruction right on the receiver coil data acquisition system with no need to transfer the raw data to the MRI server, thereby minimizing the transmission noise and memory usage...
August 30, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28853316/effect-of-electromagnetic-field-accompanying-the-magnetic-resonance-imaging-on-human-heart-rate-variability%C3%A2-%C3%A2-a-pilot-study
#13
Arkadiusz Derkacz, Jakub Gawrys, Karolina Gawrys, Maciej Podgorski, Agnieszka Magott-Derkacz, Rafał Poreba, Adrian Doroszko
The effect of electromagnetic field on cardiovascular system in the literature is defined in ambiguous way. The aim of this study was to evaluate the effect of electromagnetic field on the heart rate variability (HRV) during the examination with magnetic resonance. Forty-two patients underwent Holter ECG heart monitoring for 30 minutes twice: immediately before and after the examination with magnetic resonance imaging (MRI). HRV was analysed by assessing a few selected time and spectral parameters. Is has been shown that standard deviation of NN intervals (SDNN) and very low frequency rates increased, whereas the low frequency:high frequency parameter significantly decreased following the MRI examination...
August 30, 2017: International Journal of Injury Control and Safety Promotion
https://www.readbyqxmd.com/read/28844780/5-aminolevulinic-acid-fluorescence-guided-resection-of-malignant-glioma-hong-kong-experience
#14
Danny Tat Ming Chan, Hsieh Yi-Pin Sonia, Wai Sang Poon
BACKGROUND: 5-Aminolevulinic Acid (5-ALA) induced fluorescence is useful in guiding glioma resection. The extent of 5-ALA accumulation is beyond gadolinium contrast enhancement.(1,2) Supratotal resection may be achieved, potentially granting patients with better survival. We present our experience on 5-ALA guided glioma resection in Chinese ethnics. METHOD: Sixteen Patients ingested 5-ALA (Gliolan, Medas Germany) 20 mg/kg·m(2) 4 h before surgery. The tumor resection was guided by fluorescence with neurosurgical microscope...
August 24, 2017: Asian Journal of Surgery
https://www.readbyqxmd.com/read/28841762/comparison-of-different-compressed-sensing-algorithms-for-low-snr-19-f-mri-applications-imaging-of-transplanted-pancreatic-islets-and-cells-labeled-with-perfluorocarbons
#15
Sayuan Liang, Tom Dresselaers, Karim Louchami, Ce Zhu, Yipeng Liu, Uwe Himmelreich
Transplantation of pancreatic islets is a possible treatment option for patients suffering from Type I diabetes. In vivo imaging of transplanted islets is important for assessment of the transplantation site and islet distribution. Thanks to its high specificity, the absence of intrinsic background signal in tissue and its potential for quantification, (19) F MRI is a promising technique for monitoring the fate of transplanted islets in vivo. In order to overcome the inherent low sensitivity of (19) F MRI, leading to long acquisition times with low signal-to-noise ratio (SNR), compressed sensing (CS) techniques are a valuable option...
August 25, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28841293/heading-toward-macromolecular-and-nanosized-bioresponsive-mri-probes-for-successful-functional-imaging
#16
Goran Angelovski
The quest for bioresponsive or smart contrast agents (SCAs) in molecular imaging, in particular magnetic resonance imaging (MRI), is progressively increasing since they allow for the monitoring of essential biological processes on molecular and cellular levels in a dynamic fashion. These are offshoot molecules of common contrast agents that are sensitive to biochemical changes in their environment, capable of reporting on such changes by inducing MRI signal alteration. Various mechanistic approaches and different types of SCAs have been developed in order to visualize desired processes, using diverse imaging protocols and methods...
August 25, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28837234/a-precision-3d-conformal-treatment-technique-in-rats-application-to-whole-brain-radiotherapy-with-hippocampal-avoidance
#17
Suk W Yoon, Christina K Cramer, Devin A Miles, Michael H Reinsvold, Kyeung M Joo, David G Kirsch, Mark Oldham
PURPOSE: To develop and validate 3D conformal hippocampal sparing whole-brain radiation therapy (HA-WBRT) for Wistar rats utilizing precision 3D printed immobilization and micro-blocks. This technique paves the way for future pre-clinical studies investigating brain treatments that reduce neurotoxicity. METHODS AND MATERIALS: A novel pre-clinical treatment planning and delivery process was developed to enable precision 3D conformal treatment and hippocampal avoidance capability for the Xrad 225cx small animal irradiator...
August 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28827975/architecture-and-transport-properties-of-multifilamentary-mgb2-strands-for-mri-and-low-ac-loss-applications
#18
F Wan, M D Sumption, M A Rindfleisch, M J Tomsic, E W Collings
Standard in-situ type MgB2 strands manufactured by Hyper Tech Inc have 19 - 36 subelements, a monel outer sheath, and a Cu interfilamentary matrix. Typical transport Jc s of the strands are 2×10(5) A/cm(2) with n-values of 20 - 30 at 4.2 K and 5 T. This work introduces two new MgB2 conductor designs. First, a new class of MgB2 strand is designed for magnetic resonance imaging applications. This type has a higher Cu content designed to enhance protection of a magnet wound with it, and a larger diameter to increase the critical current...
June 2017: IEEE Transactions on Applied Superconductivity: a Publication of the IEEE Superconductivity Committee
https://www.readbyqxmd.com/read/28827099/4d-cardiac-imaging-at-clinical-3-0t-provides-accurate-assessment-of-murine-myocardial-function-and-viability
#19
Lindsey A Crowe, Fabrizio Montecucco, Federico Carbone, Iris Friedli, Anne-Lise Hachulla, Vincent Braunersreuther, François Mach, Jean-Paul Vallée
OBJECTIVES: We validate a 4D strategy tailored for 3T clinical systems to simultaneously quantify function and infarct size in wild type mice after ischemia/reperfusion, with improved spatial and temporal resolution by comparison to previous published protocols using clinical field MRI systems. METHODS: C57BL/6J mice underwent 60min ischemia/reperfusion (n=14) or were controls without surgery (n=6). Twenty-four hours after surgery mice were imaged with gadolinium injection and sacrificed for post-mortem MRI and histology with serum also taken for Troponin I levels...
August 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28822153/-analyze-moisture-transformation-and-transport-rules-during-processing-of-paeoniae-radix-alba-by-using-low-field-nmr
#20
Wen-Juan Duan, Yue Li, Li Cui, Feng Liu, Guo-Hong Yang, Lan-Ping Guo, Xiao Wang
Moisture status and content during the processing of Paeoniae Radix Alba were studied by nuclear magnetic resonance (NMR) and nuclear magnetic resonance imaging (MRI) to investigate the changes of transverse relaxation time (T ₂) and MRI images during boiling and drying processes of Paeoniae Radix Alba. The results showed that water in Paeoniae Radix Alba fresh products was major of free water, and in the boiling process, the content of free water increased whereas the content of bound water declined. At the end of boiling, content of free water reached over 90%...
June 2017: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
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