Tractometer: Towards validation of tractography pipelines

Côté, Marc-Alexandre; Girard, Gabriel; Boré, Arnaud; Garyfallidis, Eleftherios; Houde, Jean‐Christophe; Descoteaux, Maxime

doi:10.1016/j.media.2013.03.009

Cited by 194 publications

(219 citation statements)

References 54 publications

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“…According to the fiber tracing algorithm, we employed the method of deterministic tractography that could effectively avoid invalid fibers in the reconstruction step (Côté et al. 2013). Lastly, significant correlations between cognitive measurements and functional and fiber parameters were not detected.…”

Section: Discussionmentioning

confidence: 99%

Long‐term acclimatization to high‐altitude hypoxia modifies interhemispheric functional and structural connectivity in the adult brain

Chen

Li²,

Han³

et al. 2016

Brain and Behavior

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BackgroundStructural and functional networks can be reorganized to adjust to environmental pressures and physiologic changes in the adult brain, but such processes remain unclear in prolonged adaptation to high‐altitude (HA) hypoxia. This study aimed to characterize the interhemispheric functionally and structurally coupled modifications in the brains of adult HA immigrants.MethodsWe performed resting‐state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) in 16 adults who had immigrated to the Qinghai‐Tibet Plateau (2300–4400 m) for 2 years and in 16 age‐matched sea‐level (SL) controls. A recently validated approach of voxel‐mirrored homotopic connectivity (VMHC) was employed to examine the interhemispheric resting‐state functional connectivity. Areas showing changed VMHC in HA immigrants were selected as regions of interest for follow‐up DTI tractography analysis. The fiber parameters of fractional anisotropy and fiber length were obtained. Cognitive and physiological assessments were made and correlated with the resulting image metrics.ResultsCompared with SL controls, VMHC in the bilateral visual cortex was significantly increased in HA immigrants. The mean VMHC value extracted within the visual cortex was positively correlated with hemoglobin concentration. Moreover, the path length of the commissural fibers connecting homotopic visual areas was increased in HA immigrants, covarying positively with VMHC.ConclusionsThese observations are the first to demonstrate interhemispheric functional and structural connectivity resilience in the adult brain after prolonged HA acclimatization independent of inherited and developmental effects, and the coupled modifications in the bilateral visual cortex indicate important neural compensatory mechanisms underlying visual dysfunction in physiologically well‐acclimatized HA immigrants. The study of human central adaptation to extreme environments promotes the understanding of our brain's capacity for survival.

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Section: Discussionmentioning

confidence: 99%

Long‐term acclimatization to high‐altitude hypoxia modifies interhemispheric functional and structural connectivity in the adult brain

Chen

Li²,

Han³

et al. 2016

Brain and Behavior

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“…Table I reports the scores computed using the Tractometer methodology proposed in [38], which is an evaluation system for tractography pipelines with a particular emphasis on global connectivity. Results are reported both for the tracking algorithms alone, i.e.…”

Section: A Quantitative Evaluation On Realistic Phantommentioning

confidence: 99%

COMMIT: Convex Optimization Modeling for Microstructure Informed Tractography

Daducci

Palù

Lemkaddem

et al. 2015

IEEE Trans. Med. Imaging

213

259

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Abstract-Tractography is a class of algorithms aiming at invivo mapping the major neuronal pathways in the white matter from diffusion MRI data. These techniques offer a powerful tool to noninvasively investigate at the macroscopic scale the architecture of the neuronal connections of the brain. However, unfortunately, the reconstructions recovered with existing tractography algorithms are not really quantitative even though diffusion MRI is a quantitative modality by nature. As a matter of fact, several techniques have been proposed in recent years to estimate, at the voxel level, intrinsic microstructural features of the tissue, such as axonal density and diameter, by using multicompartment models. In this article, we present a novel framework to reestablish the link between tractography and tissue microstructure. Starting from an input set of candidate fiber-tracts, which are estimated from the data using standard fiber-tracking techniques, we model the diffusion MRI signal in each voxel of the image as a linear combination of the restricted and hindered contributions generated in every location of the brain by these candidate tracts. Then, we seek for the global weight of each of them, i.e. the effective contribution or volume, such that they globally fit the measured signal at best. We demonstrate that these weights can be easily recovered by solving a global convex optimization problem and using efficient algorithms. The effectiveness of our approach has been evaluated both on a realistic phantom with known ground-truth and in-vivo brain data. Results clearly demonstrate the benefits of the proposed formulation, opening new perspectives for a more quantitative and biologically-plausible assessment of the structural connectivity of the brain.

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“…Similarly to Diffantom, the organizers used an HCP subject as source of structural information. While this phantom is designed for the bundle-wise evaluation of tractography (with the scores defined in the Tractometer (Côté et al, 2013), such as geometrical coverage, valid connections, invalid connections, missed connections, etc. ), Diffantom is intended for the connectome-wise evaluation of results, yielding a tractography with a large number of bundles.…”

Section: Discussionmentioning

confidence: 99%

“…Côté et al (2013) conducted a thorough review of tractography methodologies using the so-called FiberCup phantom (Poupon et al, 2008;Fillard et al, 2011). These phantoms are appropriate to evaluate the angular resolution in fiber crossings and accuracy of direction-independent scalar parameters in very simplistic geometries.…”

Section: Introductionmentioning

confidence: 99%