Selection of Optimal Pulse Sequences for fMRI

2016 ◽  
pp. 69-111
Author(s):  
Mark J. Lowe ◽  
Erik B. Beall
Keyword(s):  
Pulse Sequences ◽  
Selection Of

scholarly journals Radiation diagnostics of cerebral cavernous malformations

2021 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
Elena N. Girya ◽  
Valentin E. Sinitsyn ◽  
Alexey S. Tokarev
Keyword(s):  
Pulse Sequences ◽  
Vascular Pathology ◽  
Cerebral Cavernous Malformations ◽  
Cavernous Malformations ◽  
Imaging Sequence ◽  
Magnetic Resonance Imaging Mri ◽  
The Moment ◽  
Ct And Mri ◽  
Selection Of

Cerebral cavernous malformations are a fairly common vascular pathology at the moment, with the number of detected cases increasing dramatically in recent years. This is because modern neuroimaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI) have been introduced into clinical practice and are widely available. Prior to the advent of CT and MRI technologies, it was extremely difficult to diagnose this pathology, and the diagnosis was usually made intraoperatively or based on autopsy data. Further, the literature review is devoted to the radiological diagnosis of cerebral cavernous malformations (CM). The role of neuroimaging methods in the diagnosis of cavernous malformations, as well as the use of MRI for CM visualization, was analyzed. The advantages of MRI over other neuroimaging methods for this pathology have been demonstrated. Pulse sequences of MRI and signaling characteristics of various foci were characterized, depending on the morphological substrate. The significance of the susceptibility-weighted imaging sequence was also evaluated for the detection of multifocal lesions in cases of familial CM. The study of the main pulse sequences of MRI for visualization of CM will improve the protocol algorithm for the timely diagnosis of this pathology and the selection of therapeutic approach.

scholarly journals Two-Field Transverse Relaxation-Optimized Spectroscopy for the Study of Large Biomolecules – an in Silico Investigation

2020 ◽  
Author(s):  
Nicolas Bolik-Coulon ◽  
Philippe Pelupessy ◽  
Guillaume Bouvignies ◽  
Fabien Ferrage
Keyword(s):  
Pulse Sequence ◽  
Chemical Shifts ◽  
Chemical Shift Anisotropy ◽  
Pulse Sequences ◽  
Transverse Relaxation ◽  
Order Of Magnitude ◽  
Spin Pairs ◽  
Single Field ◽  
Selection Of ◽  
Higher Sensitivity

<div> <div> <div> <p>Biomolecular NMR spectroscopy has greatly benefited from the development of TROSY-type pulse sequences, in pair with specific labeling. The selection of spin operators with favorable relaxation properties has led to an increase in the resolution and sensitivity of spectra of large biomolecules. However, nuclei with a large chemical shift anisotropy (CSA) contribution to relaxation can still suffer from large linewidths at conventional magnetic fields (higher than 9 T). Here, we introduce the concept of two-field TROSY (2F-TROSY) where the chemical shifts of nuclei with large CSA is labeled at low fields (ca. 2 T) dramatically reducing the contribution of CSA to relaxation. Signal detection is performed at high field (> 9 T) on a nucleus with efficient TROSY interference to yield high-resolution and sensitivity. We use comprehensive numerical simulations to demonstrate the power of this approach on aromatic 13C-19F spin pairs for which a TROSY pulse sequence has recently been published. We predict that the 2F- TROSY experiment shall yield good quality spectra for large proteins (global tumbling correlation times as high as 100 ns) with one order of magnitude higher sensitivity than the single-field experiment. </p> </div> </div> </div>

scholarly journals Two-Field Transverse Relaxation-Optimized Spectroscopy for the Study of Large Biomolecules – an in Silico Investigation

2020 ◽  
Author(s):  
Nicolas Bolik-Coulon ◽  
Philippe Pelupessy ◽  
Guillaume Bouvignies ◽  
Fabien Ferrage
Keyword(s):  
Pulse Sequence ◽  
Chemical Shifts ◽  
Chemical Shift Anisotropy ◽  
Pulse Sequences ◽  
Transverse Relaxation ◽  
Order Of Magnitude ◽  
Spin Pairs ◽  
Single Field ◽  
Selection Of ◽  
Higher Sensitivity

<div> <div> <div> <p>Biomolecular NMR spectroscopy has greatly benefited from the development of TROSY-type pulse sequences, in pair with specific labeling. The selection of spin operators with favorable relaxation properties has led to an increase in the resolution and sensitivity of spectra of large biomolecules. However, nuclei with a large chemical shift anisotropy (CSA) contribution to relaxation can still suffer from large linewidths at conventional magnetic fields (higher than 9 T). Here, we introduce the concept of two-field TROSY (2F-TROSY) where the chemical shifts of nuclei with large CSA is labeled at low fields (ca. 2 T) dramatically reducing the contribution of CSA to relaxation. Signal detection is performed at high field (> 9 T) on a nucleus with efficient TROSY interference to yield high-resolution and sensitivity. We use comprehensive numerical simulations to demonstrate the power of this approach on aromatic 13C-19F spin pairs for which a TROSY pulse sequence has recently been published. We predict that the 2F- TROSY experiment shall yield good quality spectra for large proteins (global tumbling correlation times as high as 100 ns) with one order of magnitude higher sensitivity than the single-field experiment. </p> </div> </div> </div>

Selection of Optimal Pulse Sequences for fMRI

2009 ◽  
pp. 69-108
Author(s):  
Mark J. Lowe ◽  
Erik B. Beall
Keyword(s):  
Pulse Sequences ◽  
Selection Of

scholarly journals Two-Field Transverse Relaxation-Optimized Spectroscopy for the Study of Large Biomolecules – an in Silico Investigation

2020 ◽  
Author(s):  
Nicolas Bolik-Coulon ◽  
Philippe Pelupessy ◽  
Guillaume Bouvignies ◽  
Fabien Ferrage
Keyword(s):  
Pulse Sequence ◽  
Chemical Shifts ◽  
Chemical Shift Anisotropy ◽  
Pulse Sequences ◽  
Transverse Relaxation ◽  
Order Of Magnitude ◽  
Spin Pairs ◽  
Single Field ◽  
Selection Of ◽  
Higher Sensitivity

<div> <div> <div> <p>Biomolecular NMR spectroscopy has greatly benefited from the development of TROSY-type pulse sequences, in pair with specific labeling. The selection of spin operators with favorable relaxation properties has led to an increase in the resolution and sensitivity of spectra of large biomolecules. However, nuclei with a large chemical shift anisotropy (CSA) contribution to relaxation can still suffer from large linewidths at conventional magnetic fields (higher than 9 T). Here, we introduce the concept of two-field TROSY (2F-TROSY) where the chemical shifts of nuclei with large CSA is labeled at low fields (ca. 2 T) dramatically reducing the contribution of CSA to relaxation. Signal detection is performed at high field (> 9 T) on a nucleus with efficient TROSY interference to yield high-resolution and sensitivity. We use comprehensive numerical simulations to demonstrate the power of this approach on aromatic 13C-19F spin pairs for which a TROSY pulse sequence has recently been published. We predict that the 2F- TROSY experiment shall yield good quality spectra for large proteins (global tumbling correlation times as high as 100 ns) with one order of magnitude higher sensitivity than the single-field experiment. </p> </div> </div> </div>

Cognitive gadgets and cognitive priors

2019 ◽  
Vol 42 ◽  
Author(s):  
Gian Domenico Iannetti ◽  
Giorgio Vallortigara
Keyword(s):  
Cognitive Neuroscience ◽  
Selection Of

Abstract Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

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