2,672 Hits in 5.1 sec

Multiple Coils for Reduction of Flow Artefacts in MR Images [chapter]

David Atkinson, David J. Larkman, Philipp G. Batchelor, Derek L. G. Hill, Joseph V. Hajnal
2004 Lecture Notes in Computer Science  
Flowing blood can cause streak or blob artefacts in MR images and these may degrade subsequent image analysis.  ...  Multiple MRI receiver coils enable the reconstruction of images using data from different combinations of coils.  ...  Odd and even echos in EPI images have been used for flow artefact reduction [3] . Here we apply a new, more general, technique to the problem of artefacts from flowing blood.  ... 
doi:10.1007/978-3-540-30136-3_154 fatcat:g4gylfsgdzbt3nnct7ngy56dc4

A short overview of MRI artefacts

L.J. Erasmus, D. Hurter, M. Naude, H.G. Kritzinger, S. Acho
2004 South African Journal of Radiology  
An artefact is a feature appearing in an image that is not present in the original object.  ...  Artefacts can be classified as patient related, signal processing-dependent and hardware (machine)-related.This article presents an overview of MRI artefacts and possible rectifying methods.  ...  Patient-related MR artefacts Motion artefacts Motion is one of the most common artefacts in MR imaging, causing either ghost images or diffuse image noise in the phase-encoding direction.  ... 
doi:10.4102/sajr.v8i2.127 fatcat:6szbx63fivee5dqdlt7vpsgh6e

Motion correction in MRI of the brain

F Godenschweger, U Kägebein, D Stucht, U Yarach, A Sciarra, R Yakupov, F Lüsebrink, P Schulze, O Speck
2016 Physics in Medicine and Biology  
Retrospective motion correction modifies the MR image data during the reconstruction, while prospective motion correction performs an adaptive update of the data acquisition.  ...  It explains the sources and types of motion and related artefacts, classifies and describes existing techniques for motion detection, compensation and correction and lists established and experimental  ...  Acknowledgments The work of this paper is partly funded by the Federal Ministry of Education and Research within the Forschungscampus STIMULATE under grant number '13GW0095A', the FP7 Marie Curie Actions  ... 
doi:10.1088/0031-9155/61/5/r32 pmid:26864183 pmcid:PMC4930872 fatcat:lqh4phs4bnfmrjpddrf7sbmimm

Magnetic resonance angiography

M J Graves
1997 British Journal of Radiology  
MRA techniques can be divided into two main classifications depending upon the primary effect responsible for contrast in the image.  ...  Magnetic resonance angiography (MRA) permits the non-invasive visualization of blood flow through the effects of moving spins on the magnetic resonance signal.  ...  Sandra Powell, Erica Scurr and Sue Cleminson are thanked for their assistance in collecting the data for Figures 3, 4, 6, 7, 9, 11 and 14 all of which were acquired using a 1.5 T IGE Signa Advantage  ... 
doi:10.1259/bjr.70.829.9059290 pmid:9059290 fatcat:siso5ubmt5bwzb2ocgbw5wyj4y

Magnetic resonance imaging methodology

Ewald Moser, Andreas Stadlbauer, Christian Windischberger, Harald H. Quick, Mark E. Ladd
2009 European Journal of Nuclear Medicine and Molecular Imaging  
Multiple coil elements form a multi-channel RF array coil.  ...  The differences in occurrence and magnitude of the signal changes are evaluated via an arterial input function (AIF). T2*-based PWI allows for imaging of flow at the capillary level.  ... 
doi:10.1007/s00259-009-1079-z fatcat:ek3odbsnbngrxa6vv5eg2sbm3q

Magnetic resonance imaging methodology

Ewald Moser, Andreas Stadlbauer, Christian Windischberger, Harald H. Quick, Mark E. Ladd
2008 European Journal of Nuclear Medicine and Molecular Imaging  
Multiple coil elements form a multi-channel RF array coil.  ...  The differences in occurrence and magnitude of the signal changes are evaluated via an arterial input function (AIF). T2*-based PWI allows for imaging of flow at the capillary level.  ... 
doi:10.1007/s00259-008-0938-3 pmid:19104805 fatcat:gznvl4b4dvh2dbqh6l2xwii5xy

Feasibility of Non-contrast-enhanced Magnetic Resonance Angiography for Imaging Upper Extremity Vasculature Prior to Vascular Access Creation

A.S. Bode, R.N. Planken, M.A.G. Merkx, F.M. van der Sande, L. Geerts, J.H.M. Tordoir, T. Leiner
2012 European Journal of Vascular and Endovascular Surgery  
Non-contrast-enhanced MRA is a feasible diagnostic modality in patients with end-stage renal disease who need imaging of the upper extremity vasculature prior to dialysis access creation  ...  WHAT THIS PAPER ADDS The present study is the first to investigate the potential of non-contrast-enhanced balanced turbo field echo (bTFE) magnetic resonance angiography (MRA) for depiction of upper extremity  ...  Acknowledgements The authors acknowledge the European Commission for their funding of the ARCH project (ICT 224390), in the context of which this study has been performed.  ... 
doi:10.1016/j.ejvs.2011.09.012 pmid:22070856 fatcat:hg43fijenbgujoanxt7gutlkem

Reducing acquisition time in clinical MRI by data undersampling and compressed sensing reconstruction

Kieren Grant Hollingsworth
2015 Physics in Medicine and Biology  
Recently, there has been research interest in using the theory of compressed sensing (CS) in MR imaging to reduce scan acquisition times.  ...  The theory argues that if our target MR image is sparse, having signal information in only a small proportion of pixels (like an angiogram), or if the image can be mathematically transformed to be sparse  ...  The author would like to acknowledge the reviewers of this manuscript for their thoughtful criticism and useful suggestions.  ... 
doi:10.1088/0031-9155/60/21/r297 pmid:26448064 fatcat:dz6la4j7ejapdntfmo75mdokme

MR-guided endovascular interventions: a comprehensive review on techniques and applications

Sebastian Kos, Rolf Huegli, Georg M. Bongartz, Augustinus L. Jacob, Deniz Bilecen
2007 European Radiology  
The development of interventional devices, both applicable and safe for MR imaging (MRI), was also mandatory.  ...  MR angiography is not only an imaging tool for the vasculature but can also simultaneously depict high tissue contrast, including the differentiation of the vascular wall and perivascular tissues, as well  ...  Multiple coils along the device axis allow separate visualization of the different coils, which can be encoded in different colours on the roadmap image, but again increase the technical effort significantly  ... 
doi:10.1007/s00330-007-0818-4 pmid:18071710 fatcat:t7cjykmb7vad3fcszibabm2gv4

Reducing ghosting due to k-space discontinuities in fast spin echo (FSE) imaging by a new combination of k-space ordering and parallel imaging

David W. Carmichael, David L. Thomas, Roger J. Ordidge
2009 Journal of magnetic resonance (San Diego, Calif. 1997 : Print)  
Recently, utilising multiple coils for signal reception has become the standard configuration for MR systems due to the additional flexibility that parallel imaging (PI) methods can provide.  ...  This moves the resulting ghost artefacts to the edges of the field of view. This property of the ghost then makes them amenable to removal using PI methods.  ...  Acknowledgment The Wellcome Trust provided funding for D.T. the 4.7 T scanner and R.J.O., the MRC provided financial support for D.W.C.  ... 
doi:10.1016/j.jmr.2009.06.013 pmid:19608444 pmcid:PMC2728202 fatcat:7mxszfpjvrfelkvsbhe3fcigmu

Endovascular interventional magnetic resonance imaging

L W Bartels, C J G Bakker
2003 Physics in Medicine and Biology  
The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion  ...  Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering  ...  Acknowledgments The authors wish to thank Drs Bos, Glowinski and Ladd for kindly providing figures for this article and would like to acknowledge financial support for the endovascular interventional MRI  ... 
doi:10.1088/0031-9155/48/14/201 pmid:12894968 fatcat:36uqja67mnexdl4ysiubjp2pdm

Fast TWIST with iterative reconstruction improves diagnostic accuracy of AVM of the hand

Veronika I. Huf, Claudia Fellner, Walter A. Wohlgemuth, Christian Stroszczynski, Michaela Schmidt, Christoph Forman, Jens Wetzl, Wibke Uller
2020 Scientific Reports  
Very high temporal and spatial resolution is mandatory for the diagnosis of arteriovenous malformations (AVM) of the hand.  ...  Depending on the regularization factors, SNR, delineation of arterial feeders and non-involved hand and interdigital arteries, as well as artefact levels varied.  ...  For the imaging of high-flow vessels, a high acquisition speed is mandatory.  ... 
doi:10.1038/s41598-020-73331-6 pmid:33004952 fatcat:aqdituvlkngivan64r5envhgvy

Parallel magnetic resonance imaging

David J Larkman, Rita G Nunes
2007 Physics in Medicine and Biology  
The use of multiple receiver coils to augment the time consuming Fourier encoding has reduced acquisition times significantly.  ...  Theoretical (the g-factor) and practical (coil design) limits to acquisition speed are reviewed. The practical implementation of parallel imaging is also discussed, in particular coil calibration.  ...  So for a given imaging experiment multiple full images, one for each coil element, can be reconstructed. We are then left with the problem of how to combine these images for optimal SNR.  ... 
doi:10.1088/0031-9155/52/7/r01 pmid:17374908 fatcat:5akpijhwgfdovkfe4wykbj6lqa

Thin-film micro-coil detectors: Application in MR-thermometry

Evdokia M. Kardoulaki, Richard R.A. Syms, Ian R. Young, Marc Rea, Wladyslaw M.W. Gedroyc
2015 Sensors and Actuators A-Physical  
Thin-film micro-coils are integrated with commercially available ablation catheters, for MR-thermometry during laser interstitial thermal therapies (LITTs).  ...  Thin-film micro-coil detectors In this Section, we describe the integration of a micro-coil with an ablation catheter. We outline the resonator design, the http://dx.  ...  Munir Ahmad for help with the gel preparation, to Mr. Phil Jones for machining the experimental rig and to Dr. Kaushal Choonee for assistance with the experiments.  ... 
doi:10.1016/j.sna.2015.02.030 fatcat:d75lj33s5fdc7g357v3syhpgdq

Motion artifacts in MRI: A complex problem with many partial solutions

Maxim Zaitsev, Julian Maclaren, Michael Herbst
2015 Journal of Magnetic Resonance Imaging  
For the appreciation of the effect of motion on MR images it is important to realize that the data acquisition Zaitsev et al.  ...  Over 30 years of research have produced numerous methods to mitigate or correct for motion artefacts, but no single method can be applied in all imaging situations.  ...  Therefore, for the sake of completeness, we review the current artefact reduction strategies below.  ... 
doi:10.1002/jmri.24850 pmid:25630632 pmcid:PMC4517972 fatcat:zzzzofenlra7bnly2omhamd75q
« Previous Showing results 1 — 15 out of 2,672 results