High-Definition Fiber Tractography of the Human Brain

Neurosurgery ◽  
2012 ◽  
Vol 71 (2) ◽  
pp. 430-453 ◽  
Author(s):  
Juan C. Fernandez-Miranda ◽  
Sudhir Pathak ◽  
Johnathan Engh ◽  
Kevin Jarbo ◽  
Timothy Verstynen ◽  
...  
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Structural Connectivity ◽  
Low Grade ◽  
Superior Cerebellar Peduncle ◽  
Fiber Tractography ◽  
Imaging Data ◽  
Thalamic Nuclei ◽  
High Definition ◽  
Diffusion Spectrum Imaging

Abstract BACKGROUND: High-definition fiber tracking (HDFT) is a novel combination of processing, reconstruction, and tractography methods that can track white matter fibers from cortex, through complex fiber crossings, to cortical and subcortical targets with subvoxel resolution. OBJECTIVE: To perform neuroanatomical validation of HDFT and to investigate its neurosurgical applications. METHODS: Six neurologically healthy adults and 36 patients with brain lesions were studied. Diffusion spectrum imaging data were reconstructed with a Generalized Q-Ball Imaging approach. Fiber dissection studies were performed in 20 human brains, and selected dissection results were compared with tractography. RESULTS: HDFT provides accurate replication of known neuroanatomical features such as the gyral and sulcal folding patterns, the characteristic shape of the claustrum, the segmentation of the thalamic nuclei, the decussation of the superior cerebellar peduncle, the multiple fiber crossing at the centrum semiovale, the complex angulation of the optic radiations, the terminal arborization of the arcuate tract, and the cortical segmentation of the dorsal Broca area. From a clinical perspective, we show that HDFT provides accurate structural connectivity studies in patients with intracerebral lesions, allowing qualitative and quantitative white matter damage assessment, aiding in understanding lesional patterns of white matter structural injury, and facilitating innovative neurosurgical applications. High-grade gliomas produce significant disruption of fibers, and low-grade gliomas cause fiber displacement. Cavernomas cause both displacement and disruption of fibers. CONCLUSION: Our HDFT approach provides an accurate reconstruction of white matter fiber tracts with unprecedented detail in both the normal and pathological human brain. Further studies to validate the clinical findings are needed.

Left Pan-Hippocampal Low Grade Glioma—2-Stage Transsylvian Transventricular and Paramedian Supracerebellar Transtentorial Approaches: 2-Dimensional Operative Video

2018 ◽  
Vol 16 (3) ◽  
pp. E82-E82
Author(s):  
Juan C Fernandez-Miranda
Keyword(s):  
Tumor Resection ◽  
Spatial Relationship ◽  
Low Grade Glioma ◽  
Parahippocampal Gyrus ◽  
Surgical Approaches ◽  
Low Grade ◽  
Fiber Tractography ◽  
High Definition ◽  
Posterior Portion ◽  
Fiber Tracts

Abstract The surgical goal for low-grade gliomas (LGGs) is to maximize resection while minimizing morbidity. Pan-hippocampal LGGs extend from the hippocampal head to the hippocampal tail, and involve the parahippocampal gyrus and uncus. Given their anteroposterior extension, they cannot be completely removed with 1 single approach, requiring a 2-stage front-to-back operation.  In this video, we present the case of a 52-yr-old man with new onset of generalized seizures and a dominant-side, nonenhancing, pan-hippocampal infiltrative lesion compatible with a low-grade glioma. Preoperative high-definition fiber tractography (HDFT) showed the spatial relationship of the tumor with surrounding fiber tracts, such as the arcuate, inferior fronto-occipital, and middle longitudinal fascicles, and optic radiations.  Surgical resection was planned in 2 separate stages. The first stage consisted of a transsylvian transinferior insular sulcus approach to the extra- and intraventricular aspects of the uncohippocampal region. The entire anterior and middle portions of the tumor were successfully removed with minimal morbidity, including transient naming difficulties and permanent superior quadrantanopia. Postoperative HDFT showed preservation of all fiber tracts, except for a portion of Meyer's loop and the inferior-most aspect of the inferior fronto-occipital fascicle. The second stage was completed 8 wk later and consisted of a paramedian supracerebellar-transtentorial approach on sitting position. The posterior portion of the tumor was entirely removed to achieve a complete macroscopic tumor resection. The final diagnosis was IDH1-positive LGG.  Pan-hippocampal tumors remain a surgical challenge but accurate knowledge of surgical neuroanatomy and surgical approaches facilitates their safe and effective treatment.  The patient signed an informed consent including the use of photographic and video material for educational or academic purposes.

scholarly journals Group-Level Ranking-Based Hubness Analysis of Human Brain Connectome Reveals Significant Interhemispheric Asymmetry and Intraparcel Heterogeneities

2021 ◽  
Vol 15 ◽  
Author(s):  
Sahin Hanalioglu ◽  
Siyar Bahadir ◽  
Ilkay Isikay ◽  
Pinar Celtikci ◽  
Emrah Celtikci ◽  
...  
Keyword(s):  
Human Brain ◽  
Diffusion Imaging ◽  
Structural Connectivity ◽  
Population Level ◽  
Similar Distribution ◽  
Group Level ◽  
Imaging Data ◽  
Brain Connectome ◽  
Human Connectome Project ◽  
Intuitive Method

Objective: Graph theory applications are commonly used in connectomics research to better understand connectivity architecture and characterize its role in cognition, behavior and disease conditions. One of the numerous open questions in the field is how to represent inter-individual differences with graph theoretical methods to make inferences for the population. Here, we proposed and tested a simple intuitive method that is based on finding the correlation between the rank-ordering of nodes within each connectome with respect to a given metric to quantify the differences/similarities between different connectomes.Methods: We used the diffusion imaging data of the entire HCP-1065 dataset of the Human Connectome Project (HCP) (n = 1,065 subjects). A customized cortical subparcellation of HCP-MMP atlas (360 parcels) (yielding a total of 1,598 ROIs) was used to generate connectivity matrices. Six graph measures including degree, strength, coreness, betweenness, closeness, and an overall “hubness” measure combining all five were studied. Group-level ranking-based aggregation method (“measure-then-aggregate”) was used to investigate network properties on population level.Results: Measure-then-aggregate technique was shown to represent population better than commonly used aggregate-then-measure technique (overall rs: 0.7 vs 0.5). Hubness measure was shown to highly correlate with all five graph measures (rs: 0.88–0.99). Minimum sample size required for optimal representation of population was found to be 50 to 100 subjects. Network analysis revealed a widely distributed set of cortical hubs on both hemispheres. Although highly-connected hub clusters had similar distribution between two hemispheres, average ranking values of homologous parcels of two hemispheres were significantly different in 71% of all cortical parcels on group-level.Conclusion: In this study, we provided experimental evidence for the robustness, limits and applicability of a novel group-level ranking-based hubness analysis technique. Graph-based analysis of large HCP dataset using this new technique revealed striking hemispheric asymmetry and intraparcel heterogeneities in the structural connectivity of the human brain.

scholarly journals High-definition fiber tractography for the evaluation of perilesional white matter tracts in high-grade glioma surgery

2015 ◽  
pp. nov113 ◽  
Author(s):  
Kumar Abhinav ◽  
Fang-Cheng Yeh ◽  
Alireza Mansouri ◽  
Gelareh Zadeh ◽  
Juan C. Fernandez-Miranda
Keyword(s):  
White Matter ◽  
High Grade Glioma ◽  
High Grade ◽  
Fiber Tractography ◽  
High Definition ◽  
Glioma Surgery ◽  
White Matter Tracts

scholarly journals White matter microstructure of the extended limbic system in male and female youth with conduct disorder

2019 ◽  
Vol 50 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Karen González-Madruga ◽  
Jack Rogers ◽  
Nicola Toschi ◽  
Roberta Riccelli ◽  
Areti Smaragdi ◽  
...  
Keyword(s):  
Sex Differences ◽  
White Matter ◽  
Conduct Disorder ◽  
Limbic System ◽  
Structural Connectivity ◽  
Imaging Data ◽  
Spherical Deconvolution ◽  
Weighted Magnetic Resonance Imaging ◽  
The Right ◽  
And Control

AbstractBackgroundPrevious studies of conduct disorder (CD) have reported structural and functional alterations in the limbic system. However, the white matter tracts that connect limbic regions have not been comprehensively studied. The uncinate fasciculus (UF), a tract connecting limbic to prefrontal regions, has been implicated in CD. However, CD-related alterations in other limbic tracts, such as the cingulum and the fornix, have not been investigated. Furthermore, few studies have examined the influence of sex and none have been adequately powered to test whether the relationship between CD and structural connectivity differs by sex. We examined whether adolescent males and females with CD exhibit differences in structural connectivity compared with typically developing controls.MethodsWe acquired diffusion-weighted magnetic resonance imaging data from 101 adolescents with CD (52 females) and 99 controls (50 females). Data were processed for deterministic spherical deconvolution tractography. Virtual dissections of the UF, the three subdivisions of the cingulum [retrosplenial cingulum (RSC), parahippocampal and subgenual cingulum], and the fornix were performed and measures of fractional anisotropy (FA) and hindrance-modulated orientational anisotropy (HMOA) were analysed.ResultsThe CD group had lower FA and HMOA in the right RSC tract relative to controls. Importantly, these effects were moderated by sex – males with CD significantly lower FA compared to male controls, whereas CD and control females did not differ.ConclusionsOur results highlight the importance of considering sex when studying the neurobiological basis of CD. Sex differences in RSC connectivity may contribute to sex differences in the clinical presentation of CD.

scholarly journals Prevalence of white matter pathways coming into a single diffusion MRI voxel orientation: the bottleneck issue in tractography

2021 ◽  
Author(s):  
Kurt Schilling ◽  
Chantal M.W. Tax ◽  
Francois M.W. Rheault ◽  
Bennett A Landman ◽  
Adam W Anderson ◽  
...  
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Diffusion Mri ◽  
Brain Connectivity ◽  
False Negative ◽  
Fiber Tractography ◽  
Single Voxel ◽  
Ill Posed ◽  
Pass Through

Characterizing and understanding the limitations of diffusion MRI fiber tractography is a prerequisite for methodological advances and innovations which will allow these techniques to accurately map the connections of the human brain. The so-called "crossing fiber problem" has received tremendous attention and has continuously triggered the community to develop novel approaches for disentangling distinctly oriented fiber populations. Perhaps an even greater challenge occurs when multiple white matter bundles converge within a single voxel, or throughout a single brain region, and share the same parallel orientation, before diverging and continuing towards their final cortical or sub-cortical terminations. These so-called "bottleneck" regions contribute to the ill-posed nature of the tractography process, and lead to both false positive and false negative estimated connections. Yet, as opposed to the extent of crossing fibers, a thorough characterization of bottleneck regions has not been performed. The aim of this study is to quantify the prevalence of bottleneck regions. To do this, we use diffusion tractography to segment known white matter bundles of the brain, and assign each bundle to voxels they pass through and to specific orientations within those voxels (i.e. fixels). We demonstrate that bottlenecks occur in greater than 50-70% of fixels in the white matter of the human brain. We find that all projection, association, and commissural fibers contribute to, and are affected by, this phenomenon, and show that even regions traditionally considered "single fiber voxels" often contain multiple fiber populations. Together, this study shows that a majority of white matter presents bottlenecks for tractography which may lead to incorrect or erroneous estimates of brain connectivity or quantitative tractography (i.e., tractometry), and underscores the need for a paradigm shift in the process of tractography and bundle segmentation for studying the fiber pathways of the human brain.

scholarly journals Euclidean distance as a measure to distinguish ventral and dorsal white matter connectivity in the human brain

2016 ◽  
Author(s):  
Philipp Kellmeyer ◽  
Magnus-Sebastian Vry
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Cognitive Processing ◽  
Euclidean Distance ◽  
Large Scale ◽  
Diffusion Tensor ◽  
Large Body ◽  
Coordinate Space ◽  
Fiber Tractography

AbstractFiber tractography based on diffusion tensor imaging (DTI) has become an important research tool for investigating the anatomical connectivity between brain regions in vivo. Combining DTI with functional magnetic resonance imaging (fMRI) allows for the mapping of structural and functional architecture of large-scale networks for cognitive processing. This line of research has shown that ventral and dorsal fiber pathways subserve different aspects of bottom-up- and top-down processing in the human brain.Here, we investigate the feasibility and applicability of Euclidean distance as a simple geometric measure to differentiate ventral and dorsal long-range white matter fiber pathways tween parietal and inferior frontal cortical regions, employing a body of studies that used probabilistic tractography.We show that ventral pathways between parietal and inferior frontal cortex have on average a significantly longer Euclidean distance in 3D-coordinate space than dorsal pathways. We argue that Euclidean distance could provide a simple measure and potentially a boundary value to assess patterns of connectivity in fMRI studies. This would allow for a much broader assessment of general patterns of ventral and dorsal large-scale fiber connectivity for different cognitive operations in the large body of existing fMRI studies lacking additional DTI data.

scholarly journals White matter maturation reshapes structural connectivity in the late developing human brain

2010 ◽  
Vol 107 (44) ◽  
pp. 19067-19072 ◽  
Author(s):  
P. Hagmann ◽  
O. Sporns ◽  
N. Madan ◽  
L. Cammoun ◽  
R. Pienaar ◽  
...  
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Structural Connectivity ◽  
White Matter Maturation

scholarly journals White Matter Abnormalities in Body Integrity Dysphoria

2021 ◽  
Author(s):  
Gianluca Saetta ◽  
Kathy Ruddy ◽  
Laura Zapparoli ◽  
Martina Gandola ◽  
Gerardo Salvato ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Structural Connectivity ◽  
The Body ◽  
Limb Amputation ◽  
Middle Temporal Gyrus ◽  
Imaging Data ◽  
Severe Condition ◽  
The Right

Body integrity dysphoria (BID) is a severe condition affecting non-psychotic individuals where a limb may be experienced as non-belonging, despite normal anatomical development and intact sensorimotor functions. Limb amputation is desired for restoring their own identity. We previously demonstrated altered brain structural (gray matter) and functional connectivity in 16 men with a long-lasting and exclusive desire for left leg amputation. Here we aimed to identify in the same sample altered patterns of white matter structural connectivity. Fractional anisotropy (FA), derived from Diffusion Tensor Imaging data, was considered as a measure of structural connectivity. Results showed reduced structural connectivity of: i) the right superior parietal lobule (rSPL) with the right cuneus, superior occipital and posterior cingulate gyri, and cuneus, ii) the pars orbitalis of the right middle frontal gyrus (rMFGOrb) with the putamen iii) the left middle temporal gyrus (lMTG) with the pars triangularis of the left inferior frontal gyrus. Increased connectivity was observed between the right paracentral lobule (rPLC) and the right caudate nucleus. By using a complementary method of investigation, we confirmed and extended previous results showing alterations in areas tuned to the processing of the sensorimotor representations of the affected leg (rPCL), and to higher-order components of bodily representation such as the body image (rSPL). Alongside this network for bodily awareness, other networks such as the limbic (rMFGOrb) and the mirror (lMTG) systems showed structural alterations as well. These findings consolidate current understanding of the neural correlates of BID, which might in turn guide diagnostics and rehabilitative treatments.

scholarly journals Controllability of structural brain networks and the waxing and waning of negative affect in daily life

2021 ◽  
Author(s):  
Amanda Lee McGowan ◽  
Linden Parkes ◽  
Xiaosong He ◽  
Ovidia Stanoi ◽  
Yoona Kang ◽  
...  
Keyword(s):  
Negative Affect ◽  
Brain Structure ◽  
Daily Life ◽  
Structural Connectivity ◽  
Network Control ◽  
Imaging Data ◽  
Daily Lives ◽  
Diffusion Spectrum Imaging ◽  
Cortical Regions ◽  
Structural Networks

The waxing and waning of negative affect in daily life is normative, reflecting an adaptive capacity to respond flexibly to changing circumstances. Here, we provide insight into facets of brain structure that may enable negative affect variability in daily life. We use diffusion spectrum imaging data from 95 young adults (Mage = 20.19 years, SDage = 1.80; 56 women) to construct structural connectivity networks that map white matter fiber connections between 200 cortical and 14 sub-cortical regions. We apply network control theory to these structural networks to estimate the degree to which each brain region’s pattern of structural connectivity facilitates the spread of activity to other brain systems (i.e., the region’s average controllability). We examine how the average controllability of functional brain systems relates to negative affect variability, computed by taking the standard deviation of negative affect self-reports collected via smartphone-based experience-sampling twice per day over 28 days as participants went about their daily lives. We find that high average controllability of the cingulo-insular system is associated with increased negative affect variability. Our results highlight the role brain structure plays in affective dynamics as observed in the context of daily life.

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