scholarly journals In vivo super-resolution track-density imaging for thalamic nuclei identification

2021 ◽  
Author(s):  
Gianpaolo Antonio Basile ◽  
Salvatore Bertino ◽  
Alessia Bramanti ◽  
Giuseppe Pio Anastasi ◽  
Demetrio Milardi ◽  
...  
Keyword(s):  
High Reliability ◽  
Intraclass Correlation ◽  
Super Resolution ◽  
Track Density ◽  
High Angular Resolution ◽  
Thalamic Nuclei ◽  
Brain Physiology ◽  
Human Connectome Project ◽  
Neuropsychiatric Diseases

AbstractThe development of novel techniques for the in vivo, non-invasive visualization and identification of thalamic nuclei has represented a major challenge for human neuroimaging research in the last decades. Thalamic nuclei have important implications in various key aspects of brain physiology and many of them show selective alterations in various neurologic and psychiatric disorders. In addition, both surgical stimulation and ablation of specific thalamic nuclei have been proven to be useful for the treatment of different neuropsychiatric diseases. The present work aimed at describing a novel protocol for histologically-guided delineation of thalamic nuclei based on short-tracks track-density imaging (stTDI), which is an advanced imaging technique that exploits high angular resolution diffusion tractography to obtain super-resolved white matter maps with high anatomical information. We tested this protocol on i) six healthy individual 3T MRI scans from the Human Connectome Project database, and on ii) a group population template reconstructed by averaging 100 unrelated healthy subjects scans from the same repository. We demonstrated that this approach can identify up to 13 distinct thalamic nuclei bilaterally with very high reliability (intraclass correlation coefficient: 0.996, 95% CI: 0.993-0.998; total accumulated overlap: 0.43) and that both subject-based and group-level thalamic parcellation show a fair share of similarity to a recent standard-space histological thalamic atlas. Finally, we showed that stTDI-derived thalamic maps can be successfully employed to study thalamic structural and functional connectivity, and may have potential implications both for basic and translational research, as well as for pre-surgical planning purposes.

scholarly journals Quantification of [11C]PIB PET for Imaging Myelin in the Human Brain: A Test—Retest Reproducibility Study in High-Resolution Research Tomography

2015 ◽  
Vol 35 (11) ◽  
pp. 1771-1782 ◽  
Author(s):  
Mattia Veronese ◽  
Benedetta Bodini ◽  
Daniel García-Lorenzo ◽  
Marco Battaglini ◽  
Salvatore Bongarzone ◽  
...  
Keyword(s):  
High Resolution ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Volume Ratio ◽  
Reference Region ◽  
Brain White Matter ◽  
Reproducibility Study ◽  
Pet Tracer ◽  
Positron Emission

An accurate in vivo measure of myelin content is essential to deepen our insight into the mechanisms underlying demyelinating and dysmyelinating neurological disorders, and to evaluate the effects of emerging remyelinating treatments. Recently [11C]PIB, a positron emission tomography (PET) tracer originally conceived as a beta-amyloid marker, has been shown to be sensitive to myelin changes in preclinical models and humans. In this work, we propose a reference-region methodology for the voxelwise quantification of brain white-matter (WM) binding for [11C]PIB. This methodology consists of a supervised procedure for the automatic extraction of a reference region and the application of the Logan graphical method to generate distribution volume ratio (DVR) maps. This approach was assessed on a test–retest group of 10 healthy volunteers using a high-resolution PET tomograph. The [11C]PIB PET tracer binding was shown to be up to 23% higher in WM compared with gray matter, depending on the image reconstruction. The DVR estimates were characterized by high reliability (outliers < 1%) and reproducibility (intraclass correlation coefficient (ICC) > 0.95). [11C]PIB parametric maps were also found to be significantly correlated ( R2 > 0.50) to mRNA expressions of the most represented proteins in the myelin sheath. On the contrary, no correlation was found between [11C]PIB imaging and nonmyelin-associated proteins.

scholarly journals FOD-Net: A Deep Learning Method for Fiber Orientation Distribution Angular Super Resolution

2021 ◽  
Author(s):  
Rui Zeng ◽  
Jinglei Lv ◽  
He Wang ◽  
Luping Zhou ◽  
Michael Barnett ◽  
...  
Keyword(s):  
Deep Learning ◽  
Angular Resolution ◽  
Super Resolution ◽  
Orientation Distribution ◽  
Quality Data ◽  
High Angular Resolution ◽  
Clinical Protocols ◽  
High Quality ◽  
Human Connectome Project ◽  
Fiber Orientation Distribution

ABSTRACTMapping the human connectome using fibre-tracking permits the study of brain connectivity and yields new insights into neuroscience. However, reliable connectome reconstruction using diffusion magnetic resonance imaging (dMRI) data acquired by widely available clinical protocols remains challenging, thus limiting the connectome/tractography clinical applications. Here we develop fibre orientation distribution (FOD) network (FOD-Net), a deep-learning-based framework for FOD angular super-resolution. Our method enhances the angular resolution of FOD images computed from common clinical-quality dMRI data, to obtain FODs with quality comparable to those produced from advanced research scanners. Super-resolved FOD images enable superior tractography and structural connectome reconstruction from clinical protocols. The method was trained and tested with high-quality data from the Human Connectome Project (HCP) and further validated with a local clinical 3.0T scanner. Using this method, we improve the angular resolution of FOD images acquired with typical single-shell low-angular-resolution dMRI data (e.g., 32 directions, b=1000 s/mm2) to approximate the quality of FODs derived from time-consuming, multi-shell high-angular-resolution dMRI research protocols. We also demonstrate tractography improvement, removing spurious connections and bridging missing connections. We further demonstrate that connectomes reconstructed by super-resolved FOD achieve comparable results to those obtained with more advanced dMRI acquisition protocols, on both HCP and clinical 3T data. Advances in deep-learning approaches used in FOD-Net facilitate the generation of high quality tractography/connectome analysis from existing clinical MRI environments.

scholarly journals Ventralis intermedius nucleus anatomical variability assessment by MRI structural connectivity

2020 ◽  
Author(s):  
Francisca Ferreira ◽  
Harith Akram ◽  
John Ashburner ◽  
Ludvic Zrinzo ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Structural Connectivity ◽  
List Type ◽  
Superior Cerebellar Peduncle ◽  
Probabilistic Tractography ◽  
Thalamic Nuclei ◽  
Individual Subject ◽  
Neurosurgical Planning ◽  
Human Connectome Project ◽  
The Right

AbstractThe ventralis intermedius nucleus (Vim) is centrally placed in the dentato-thalamo-cortical pathway (DTCp) and is a key surgical target in the treatment of severe medically refractory tremor. It is not visible on conventional MRI sequences; consequently, stereotactic targeting currently relies on atlas-based coordinates. This fails to capture individual anatomical variability, which may lead to poor long-term clinical efficacy. Probabilistic tractography, combined with known anatomical connectivity, enables localisation of thalamic nuclei at an individual subject level. There are, however, a number of confounds associated with this technique that may influence results.Here we focused on an established method, using probabilistic tractography to reconstruct the DTCp, to identify the connectivity-defined Vim (cd-Vim) in vivo. Using 100 healthy individuals from the Human Connectome Project, our aim was to quantify cd-Vim variability across this population, measure the discrepancy with atlas-defined Vim (ad-Vim), and assess the influence of potential methodological confounds.We found no significant effect of any of the confounds. The mean cd-Vim coordinate was located within 1.9 mm (left) and 2.1 mm (right) of the average midpoint and 4.9 mm (left) and 5.4 mm (right) from the ad-Vim coordinates. cd-Vim location was more variable on the right, which reflects hemispheric asymmetries in the probabilistic DTCp reconstructed. The superior cerebellar peduncle was identified as a potential source of artificial variance.This work demonstrates significant individual anatomical variability of the cd-Vim that atlas-based approaches fail to capture. This variability was not related to any methodological confound tested. Lateralisation of cerebellar functions, such as speech, may contribute to the observed asymmetry. Tractography-based methods seem sensitive to individual anatomical variability that is missed by conventional neurosurgical targeting; These findings may form the basis for translational tools to improve efficacy and reduce side-effects of thalamic surgery for tremor.HighlightsConnectivity-based Vim position varied markedly between subjects and from atlas-defined coordinates.This positional variability was not related to any methodological confound tested.Hemispheric asymmetry was observed in connectivity-based Vim position.We hypothesise lateralization of cerebellar functions, such as language, may contribute to asymmetry.Knowledge of Vim position variability could help inform neurosurgical planning in the management of tremor.

Reliability and Precision of in Vivo Scapular Kinematic Measurements Using an Electromagnetic Tracking Device

2006 ◽  
Vol 15 (2) ◽  
pp. 125-143 ◽  
Author(s):  
Joseph Myers ◽  
John Jolly ◽  
Takashi Nagai ◽  
Scott Lephart
Keyword(s):  
Outcome Measures ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Human Movement ◽  
Published Data ◽  
Electromagnetic Tracking ◽  
Scapular Kinematics ◽  
The Mean ◽  
Tracking Device

Context:In vivo scapular kinematics during humeral movements are commonly assessed with electromagnetic tracking devices despite few published data related to reliability and precision of these measurements.Objective:To determine the intrasession reliability and precision of assessing scapular kinematics using an electromagnetic tracking device.Design:Scapular position and orientation were measured with an electromagnetic tracking device during humeral elevation/depression in several planes. Intrasession reliability and precision were established by comparing 2 trials performed in succession.Setting:A human-movement research laboratory.Participants:15 healthy individuals.Main Outcome Measures:Intrasession intraclass correlation coefficients and standard error of measurement of all scapular variables were established.Results:The mean intrasession reliability for all variables was ICC = .97 ± .03. The mean intrasession precision was .99° ± .36°.Conclusions:In vivo scapular kinematics can be measured with high reliability and precision during intrasession research designs.

scholarly journals Exploring sex differences in the adult zebra finch brain: In vivo diffusion tensor imaging and ex vivo super-resolution track density imaging

NeuroImage ◽  
2017 ◽  
Vol 146 ◽  
pp. 789-803 ◽  
Author(s):  
Julie Hamaide ◽  
Geert De Groof ◽  
Gwendolyn Van Steenkiste ◽  
Ben Jeurissen ◽  
Johan Van Audekerke ◽  
...  
Keyword(s):  
Sex Differences ◽  
Diffusion Tensor Imaging ◽  
Zebra Finch ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Super Resolution ◽  
Track Density

scholarly journals In vivo 3D Reconstruction of the Human Pallidothalamic and Nigrothalamic Pathways With Super-Resolution 7T MR Track Density Imaging and Fiber Tractography

2021 ◽  
Vol 15 ◽  
Author(s):  
Dae-Hyuk Kwon ◽  
Sun Ha Paek ◽  
Young-Bo Kim ◽  
Haigun Lee ◽  
Zang-Hee Cho
Keyword(s):  
Basal Ganglia ◽  
3D Reconstruction ◽  
Human Brain ◽  
Super Resolution ◽  
Track Density ◽  
7 Tesla ◽  
Fiber Tractography ◽  
Resolution Limit ◽  
Magnetic Resonance Imaging Mri

The output network of the basal ganglia plays an important role in motor, associative, and limbic processing and is generally characterized by the pallidothalamic and nigrothalamic pathways. However, these connections in the human brain remain difficult to elucidate because of the resolution limit of current neuroimaging techniques. The present study aimed to investigate the mesoscopic nature of these connections between the thalamus, substantia nigra pars reticulata, and globus pallidus internal segment using 7 Tesla (7T) magnetic resonance imaging (MRI). In this study, track-density imaging (TDI) of the whole human brain was employed to overcome the limitations of observing the pallidothalamic and nigrothalamic tracts. Owing to the super-resolution of the TD images, the substructures of the SN, as well as the associated tracts, were identified. This study demonstrates that 7T MRI and MR tractography can be used to visualize anatomical details, as well as 3D reconstruction, of the output projections of the basal ganglia.

scholarly journals The reliability and heritability of cortical folds and their genetic correlations across hemispheres

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Fabrizio Pizzagalli ◽  
Guillaume Auzias ◽  
Qifan Yang ◽  
Samuel R. Mathias ◽  
Joshua Faskowitz ◽  
...  
Keyword(s):  
High Reliability ◽  
Large Population ◽  
Intraclass Correlation ◽  
Genetic Correlations ◽  
Complex Trait ◽  
Total N ◽  
Human Cortex ◽  
Variance Components Analysis ◽  
Family Based

AbstractCortical folds help drive the parcellation of the human cortex into functionally specific regions. Variations in the length, depth, width, and surface area of these sulcal landmarks have been associated with disease, and may be genetically mediated. Before estimating the heritability of sulcal variation, the extent to which these metrics can be reliably extracted from in-vivo MRI must be established. Using four independent test-retest datasets, we found high reliability across the brain (intraclass correlation interquartile range: 0.65–0.85). Heritability estimates were derived for three family-based cohorts using variance components analysis and pooled (total N > 3000); the overall sulcal heritability pattern was correlated to that derived for a large population cohort (N > 9000) calculated using genomic complex trait analysis. Overall, sulcal width was the most heritable metric, and earlier forming sulci showed higher heritability. The inter-hemispheric genetic correlations were high, yet select sulci showed incomplete pleiotropy, suggesting hemisphere-specific genetic influences.

Programmable in vitro Co-Encapsidation of Guest Proteins Inside Protein Nanocages

2018 ◽  
Author(s):  
Noor H. Dashti ◽  
Rufika S. Abidin ◽  
Frank Sainsbury
Keyword(s):  
Self Assembly ◽  
Mammalian Cells ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Super Resolution ◽  
Cell Engineering ◽  
Particle Analysis ◽  
Protein Cages

Bioinspired self-sorting and self-assembling systems using engineered versions of natural protein cages have been developed for biocatalysis and therapeutic delivery. The packaging and intracellular delivery of guest proteins is of particular interest for both <i>in vitro</i> and <i>in vivo</i> cell engineering. However, there is a lack of platforms in bionanotechnology that combine programmable guest protein encapsidation with efficient intracellular uptake. We report a minimal peptide anchor for <i>in vivo</i> self-sorting of cargo-linked capsomeres of the Murine polyomavirus (MPyV) major coat protein that enables controlled encapsidation of guest proteins by <i>in vitro</i> self-assembly. Using Förster resonance energy transfer (FRET) we demonstrate the flexibility in this system to support co-encapsidation of multiple proteins. Complementing these ensemble measurements with single particle analysis by super-resolution microscopy shows that the stochastic nature of co-encapsidation is an overriding principle. This has implications for the design and deployment of both native and engineered self-sorting encapsulation systems and for the assembly of infectious virions. Taking advantage of the encoded affinity for sialic acids ubiquitously displayed on the surface of mammalian cells, we demonstrate the ability of self-assembled MPyV virus-like particles to mediate efficient delivery of guest proteins to the cytosol of primary human cells. This platform for programmable co-encapsidation and efficient cytosolic delivery of complementary biomolecules therefore has enormous potential in cell engineering.

scholarly journals Is there a relationship between the overhead press and split jerk maximum performance? Influence of sex

2021 ◽  
pp. 174795412110204
Author(s):  
Marcos A Soriano ◽  
G Gregory Haff ◽  
Paul Comfort ◽  
Francisco J Amaro-Gahete ◽  
Antonio Torres-González ◽  
...  
Keyword(s):  
Confidence Intervals ◽  
Body Mass ◽  
Upper Limb ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Training Experience ◽  
Maximum Performance ◽  
Repetition Maximum ◽  
Intraclass Correlation Coefficients

The aims of this study were to (I) determine the differences and relationship between the overhead press and split jerk performance in athletes involved in weightlifting training, and (II) explore the magnitude of these differences in one-repetition maximum (1RM) performances between sexes. Sixty-one men (age: 30.4 ± 6.7 years; height: 1.8 ± 0.5 m; body mass 82.5 ± 8.5 kg; weightlifting training experience: 3.7 ± 3.5 yrs) and 21 women (age: 29.5 ± 5.2 yrs; height: 1.7 ± 0.5 m; body mass: 62.6 ± 5.7 kg; weightlifting training experience: 3.0 ± 1.5 yrs) participated. The 1RM performance of the overhead press and split jerk were assessed for all participants, with the overhead press assessed on two occasions to determine between-session reliability. The intraclass correlation coefficients (ICC) and 95% confidence intervals showed a high reliability for the overhead press ICC = 0.98 (0.97 – 0.99). A very strong correlation and significant differences were found between the overhead press and split jerk 1RM performances for all participants (r = 0.90 [0.93 – 0.85], 60.2 ± 18.3 kg, 95.7 ± 29.3 kg, p ≤ 0.001). Men demonstrated stronger correlations between the overhead press and split jerk 1RM performances (r = 0.83 [0.73-0.90], p ≤ 0.001) compared with women (r = 0.56 [0.17-0.80], p = 0.008). These results provide evidence that 1RM performance of the overhead press and split jerk performance are highly related, highlighting the importance of upper-limb strength in the split jerk maximum performance.

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