scholarly journals The Connectivity of the Human Pulvinar: A Diffusion Tensor Imaging Tractography Study

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Sandra E. Leh ◽  
M. Mallar Chakravarty ◽  
Alain Ptito
Keyword(s):  
Diffusion Tensor Imaging ◽  
Visual Processing ◽  
Animal Studies ◽  
Diffusion Tensor ◽  
Human Vision ◽  
Subcortical Structures ◽  
Fiber Tracts ◽  
Visual Spatial ◽  
Visual Areas

Previous studies in nonhuman primates and cats have shown that the pulvinar receives input from various cortical and subcortical areas involved in vision. Although the contribution of the pulvinar to human vision remains to be established, anatomical tracer and electrophysiological animal studies on cortico-pulvinar circuits suggest an important role of this structure in visual spatial attention, visual integration, and higher-order visual processing. Because methodological constraints limit investigations of the human pulvinar's function, its role could, up to now, only be inferred from animal studies. In the present study, we used an innovative imaging technique, Diffusion Tensor Imaging (DTI) tractography, to determine cortical and subcortical connections of the human pulvinar. We were able to reconstruct pulvinar fiber tracts and compare variability across subjects in vivo. Here we demonstrate that the human pulvinar is interconnected with subcortical structures (superior colliculus, thalamus, and caudate nucleus) as well as with cortical regions (primary visual areas (area 17), secondary visual areas (area 18, 19), visual inferotemporal areas (area 20), posterior parietal association areas (area 7), frontal eye fields and prefrontal areas). These results are consistent with the connectivity reported in animal anatomical studies.

Diffusion tensor imaging analysis of long association bundles in the presence of an arteriovenous malformation

2007 ◽  
Vol 107 (3) ◽  
pp. 509-514 ◽  
Author(s):  
Josée Bérubé ◽  
Nancy Mclaughlin ◽  
Pierre Bourgouin ◽  
Gilles Beaudoin ◽  
Michel W. Bojanowski
Keyword(s):  
Diffusion Tensor Imaging ◽  
Arteriovenous Malformation ◽  
Diffusion Tensor ◽  
Clinical Manifestations ◽  
Cerebral White Matter ◽  
Visual Deficits ◽  
Fiber Tracts ◽  
Inferior Longitudinal Fasciculus ◽  
Association Fibers

Object Conventional imaging demonstrates intertwined fibers of the cerebral white matter as a homogeneous substrate. Recently, diffusion tensor imaging has allowed 3D reconstruction of these fiber bundles. The goal of this study was to analyze the modifications of the association fibers induced by an arteriovenous malformation (AVM) in the parietotemporooccipital (PTO) associative area and their clinical significance. Methods The authors analyzed the long association fibers in seven patients harboring an AVM in or near the PTO region in relation with the fibers' clinical manifestation. The fibers include the arcuate fasciculus (AF), the occipitofrontal fasciculus (OFF), and the inferior longitudinal fasciculus (ILF). These structures were compared with the contra-lateral bundles. Results The modification of the tracts could establish a pattern signature depending on the specific location of the vascular malformation. There was a positive correlation between the degree of modifications of OFF and ILF fiber tracts and visual deficits. Alteration of the AF correlated with a speech disorder and the risk of postoperative deficits. Conclusions Diffusion tensor imaging enables in vivo dissection of fiber tracts coursing through the PTO area. Depending on the location of the AVMs, long association fibers are variously modified. These findings correlate with clinical manifestations and may predict outcome after surgery.

Diffusion Tensor Imaging in Preclinical and Human Studies of Huntington’s Disease: What Have we Learned so Far?

2019 ◽  
Vol 15 (6) ◽  
pp. 521-542 ◽  
Author(s):  
Rodolfo Gabriel Gatto ◽  
Carina Weissmann
Keyword(s):  
Diffusion Tensor Imaging ◽  
Animal Models ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Clinical Studies ◽  
Animal Studies ◽  
Grey Matter ◽  
Diffusion Tensor ◽  
Ultrastructural Changes

Background:Huntington’s Disease is an irreversible neurodegenerative disease characterized by the progressive deterioration of specific brain nerve cells. The current evaluation of cellular and physiological events in patients with HD relies on the development of transgenic animal models. To explore such events in vivo, diffusion tensor imaging has been developed to examine the early macro and microstructural changes in brain tissue. However, the gap in diffusion tensor imaging findings between animal models and clinical studies and the lack of microstructural confirmation by histological methods has questioned the validity of this method.Objective:This review explores white and grey matter ultrastructural changes associated to diffusion tensor imaging, as well as similarities and differences between preclinical and clinical Huntington’s Disease studies.Methods:A comprehensive review of the literature using online-resources was performed (Pub- Med search).Results:Similar changes in fractional anisotropy as well as axial, radial and mean diffusivities were observed in white matter tracts across clinical and animal studies. However, comparative diffusion alterations in different grey matter structures were inconsistent between clinical and animal studies.Conclusion:Diffusion tensor imaging can be related to specific structural anomalies in specific cellular populations. However, some differences between animal and clinical studies could derive from the contrasting neuroanatomy or connectivity across species. Such differences should be considered before generalizing preclinical results into the clinical practice. Moreover, current limitations of this technique to accurately represent complex multicellular events at the single micro scale are real. Future work applying complex diffusion models should be considered.

In vivo diffusion tensor imaging of the neonatal rat brain development

2013 ◽  
Vol 44 (S 01) ◽  
Author(s):  
M Breu ◽  
D Reisinger ◽  
D Wu ◽  
Y Zhang ◽  
A Fatemi ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Brain Development ◽  
Rat Brain ◽  
Diffusion Tensor ◽  
Neonatal Rat ◽  
Neonatal Rat Brain

scholarly journals Meyer’s Loop Anatomy Demonstrated Using Diffusion Tensor MR Imaging and Fiber Tractography at 3T

2014 ◽  
Vol 60 (5) ◽  
pp. 215-222 ◽  
Author(s):  
Cristina Goga ◽  
Zeynep Firat ◽  
Klara Brinzaniuc ◽  
Is Florian
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Region Of Interest ◽  
Fiber Tractography ◽  
Brain Images ◽  
3 Dimensional ◽  
Software Release ◽  
Magnetic Resonance Imaging Mri ◽  
Meyer’S Loop

Abstract Objective: The ultimate anatomy of the Meyer’s loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer’s loop and the optic radiations. This study aims at exploring the anatomy of the Meyer’s loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer’s loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer’s loop. Two patterns of angulation of the Meyer’s loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer’s loop.

scholarly journals Integrative Structural Brain Network Analysis In Diffusion Tensor Imaging

2017 ◽  
Author(s):  
Moo K. Chung ◽  
Jamie L. Hanson ◽  
Nagesh Adluru ◽  
Andrew L. Alexander ◽  
Richard J. Davidson ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Brain Regions ◽  
Brain Network ◽  
Node Degree ◽  
Fiber Tracts ◽  
White Matter Fiber Tracts ◽  
Structural Brain Network ◽  
Structural Networks

AbstractIn diffusion tensor imaging, structural connectivity between brain regions is often measured by the number of white matter fiber tracts connecting them. Other features such as the length of tracts or fractional anisotropy (FA) are also used in measuring the strength of connectivity. In this study, we investigated the effects of incorporating the number of tracts, the tract length and FA-values into the connectivity model. Using various node-degree based graph theory features, the three connectivity models are compared. The methods are applied in characterizing structural networks between normal controls and maltreated children, who experienced maltreatment while living in post-institutional settings before being adopted by families in the US.

Diffusion Tensor Imaging and Fiber Tractography

2009 ◽  
pp. 229-246
Author(s):  
Evanthia E. Tripoliti ◽  
Dimitrios I. Fotiadis ◽  
Konstantia Veliou
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Cerebral White Matter ◽  
Tissue Microstructure ◽  
Diffusion Weighted Images ◽  
Fiber Tracts ◽  
Diffusion Weighted ◽  
Magnetic Resonance Imaging Mri

Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) modality which can significantly improve our understanding of the brain structures and neural connectivity. DTI measures are thought to be representative of brain tissue microstructure and are particularly useful for examining organized brain regions, such as white matter tract areas. DTI measures the water diffusion tensor using diffusion weighted pulse sequences which are sensitive to microscopic random water motion. The resulting diffusion weighted images (DWI) display and allow quantification of how water diffuses along axes or diffusion encoding directions. This can help to measure and quantify the tissue’s orientation and structure, making it an ideal tool for examining cerebral white matter and neural fiber tracts. In this chapter the authors discuss the theoretical aspects of DTI, the information that can be extracted from DTI data, and the use of the extracted information for the reconstruction of fiber tracts and the diagnosis of a disease. In addition, a review of known fiber tracking algorithms is presented.

In Vivo Diffusion Tensor Imaging and Tractography of Human Thigh Muscles in Healthy Subjects

2010 ◽  
Vol 195 (5) ◽  
pp. W352-W356 ◽  
Author(s):  
Erwan Kermarrec ◽  
Jean-François Budzik ◽  
Chadi Khalil ◽  
Vianney Le Thuc ◽  
Caroline Hancart-Destee ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Healthy Subjects ◽  
Diffusion Tensor ◽  
Thigh Muscles
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