scholarly journals Resolution and b value dependent Structural Connectome in ex vivo Mouse Brain

2022 ◽  
Author(s):  
Stephanie Crater ◽  
Surendra Maharjan ◽  
Yi Qi ◽  
Qi Zhao ◽  
Gary Cofer ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Mouse Brain ◽  
Diffusion Mri ◽  
Angular Resolution ◽  
Ex Vivo ◽  
B Value ◽  
High Angular Resolution ◽  
Preclinical Studies ◽  
High Quality ◽  
Structural Connectome

Diffusion magnetic resonance imaging has been widely used in both clinical and preclinical studies to characterize tissue microstructure and structural connectivity. The diffusion MRI protocol for the Human Connectome Project (HCP) has been developed and optimized to obtain high-quality, high-resolution diffusion MRI (dMRI) datasets. However, such efforts have not been fully explored in preclinical studies, especially for rodents. In this study, high quality dMRI datasets of mouse brains were acquired at 9.4T system from two vendors. In particular, we acquired a high-spatial resolution dMRI dataset (25 um isotropic with 126 diffusion encoding directions), which we believe to be the highest spatial resolution yet obtained; and a high-angular resolution dMRI dataset (50 um isotropic with 384 diffusion encoding directions), which we believe to be the highest angular resolution compared to the dMRI datasets at the microscopic resolution. We systematically investigated the effects of three important parameters that affect the final outcome of the connectome: b value (1000 s/mm2 to 8000 s/mm2), angular resolution (10 to 126), and spatial resolution (25 um to 200 um). The stability of tractography and connectome increase with the angular resolution, where more than 50 angles are necessary to achieve consistent results. The connectome and quantitative parameters derived from graph theory exhibit a linear relationship to the b value (R2 > 0.99); a single-shell acquisition with b value of 3000 s/mm2 shows comparable results to the multi-shell high angular resolution dataset. The dice coefficient decreases and both false positive rate and false negative rate gradually increase with coarser spatial resolution. Our study provides guidelines and foundations for exploration of tradeoffs among acquisition parameters for the structural connectome in ex vivo mouse brain.

scholarly journals Spatial versus angular resolution for tractography-assisted planning of deep brain stimulation

2019 ◽  
Author(s):  
Luka C. Liebrand ◽  
Guido A. van Wingen ◽  
Frans M. Vos ◽  
Damiaan Denys ◽  
Matthan W.A. Caan
Keyword(s):  
Deep Brain Stimulation ◽  
Spatial Resolution ◽  
Brain Stimulation ◽  
Diffusion Mri ◽  
Angular Resolution ◽  
Internal Capsule ◽  
High Angular Resolution ◽  
Scanning Time ◽  
Mri Protocol ◽  
Deep Brain

AbstractGiven the restricted total scanning time for clinical neuroimaging, it is unclear whether clinical diffusion MRI protocols would benefit more from higher spatial resolution or higher angular resolution. In this work, we investigated the relative benefit of improving spatial or angular resolution in diffusion MRI to separate two parallel running white matter tracts that are targets for deep brain stimulation: the anterior thalamic radiation and the supero-lateral branch of the medial forebrain bundle. Both these tracts are situated in the ventral anterior limb of the internal capsule, and recent studies suggest that targeting a specific tract could improve treatment efficacy. Therefore, we scanned 19 healthy volunteers at 3T and 7T according to three diffusion MRI protocols with respectively standard clinical settings, increased spatial resolution of 1.4 mm, and increased angular resolution (64 additional gradient directions at b=2200s/mm2). We performed probabilistic tractography for all protocols and quantified the separability of both tracts. The higher spatial resolution protocol improved separability by 41% with respect to the clinical standard, presumably due to decreased partial voluming. The higher angular resolution protocol resulted in increased apparent tract volumes and overlap, which is disadvantageous for application in precise treatment planning. We thus recommend to increase the spatial resolution for deep brain stimulation planning to 1.4 mm while maintaining angular resolution. This recommendation complements the general advice to aim for high angular resolution to resolve crossing fibers, confirming that the specific application and anatomical considerations are leading in clinical diffusion MRI protocol optimization.

scholarly journals High Quality Imaging for Space VLBI Observations with Ultra High Angular Resolution

2001 ◽  
Vol 205 ◽  
pp. 430-431
Author(s):  
Sergey Likhachev
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
High Quality ◽  
Vlbi Observations ◽  
Quality Imaging

This presentation focuses on the problems associated with obtaining high quality images from a high orbiting space VLBI (SVLBI) mission. SVLBI intensifies and magnifies all imaging problems, making these problems clearer to understand, though much harder to solve.

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 Structural core of the executive control network: A high angular resolution diffusion MRI study

2019 ◽  
Vol 41 (5) ◽  
pp. 1226-1236 ◽  
Author(s):  
Kai‐kai Shen ◽  
Thomas Welton ◽  
Matthew Lyon ◽  
Andrew N. McCorkindale ◽  
Greg T. Sutherland ◽  
...  
Keyword(s):  
Executive Control ◽  
Diffusion Mri ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
Control Network ◽  
Executive Control Network ◽  
Mri Study

scholarly journals High spatial resolution multiwavelength observations of star and planet formation

2001 ◽  
Vol 205 ◽  
pp. 236-243
Author(s):  
Mark J. McCaughrean
Keyword(s):  
Spatial Resolution ◽  
Planet Formation ◽  
Angular Resolution ◽  
High Spatial Resolution ◽  
High Angular Resolution ◽  
Multiwavelength Observations

We discuss the importance of multiwavelength (optical, infrared, millimetre, and radio), high angular resolution (arcsec to subarcsec) observations in studying star and planet formation. We provide a few illustrative examples, and briefly discuss how future observational facilities will allow a yet more detailed view of the important processes at work.

scholarly journals Prospects for High Angular Resolution Instrumentation at Millimeter and Submillimeter Wavelengths

2001 ◽  
Vol 205 ◽  
pp. 432-437
Author(s):  
Karl M. Menten
Keyword(s):  
Spatial Resolution ◽  
Angular Resolution ◽  
Diffraction Limit ◽  
High Angular Resolution ◽  
Submillimeter Wavelength ◽  
Millimeter Astronomy ◽  
Short Summary ◽  
Submillimeter Wavelengths ◽  
Millimeter And Submillimeter Wavelengths ◽  
Infrared Telescopes

Millimeter- and submillimeter wavelength interferometry is a powerful technique allowing imaging of dust and molecules in a multitude of astronomical environments. With the arrival of the Atacama Large Millimeter Array (ALMA), such studies will be possible with unprecedented sensitivity and a spatial resolution similar to the diffraction limit of large optical/infrared telescopes. In this paper, we mention a few aspects of (sub) millimeter astronomy and provide a short summary of ALMA's capabilities.

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