ORCID Profile
0000-0003-2499-5367
Current Organisations
Brazilian Corporation of Agricultural Research (Embrapa Vegetables)
,
CNRS
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Publisher: Springer Science and Business Media LLC
Date: 07-11-2017
DOI: 10.1038/S41467-017-01285-X
Abstract: Tractography based on non-invasive diffusion imaging is central to the study of human brain connectivity. To date, the approach has not been systematically validated in ground truth studies. Based on a simulated human brain data set with ground truth tracts, we organized an open international tractography challenge, which resulted in 96 distinct submissions from 20 research groups. Here, we report the encouraging finding that most state-of-the-art algorithms produce tractograms containing 90% of the ground truth bundles (to at least some extent). However, the same tractograms contain many more invalid than valid bundles, and half of these invalid bundles occur systematically across research groups. Taken together, our results demonstrate and confirm fundamental ambiguities inherent in tract reconstruction based on orientation information alone, which need to be considered when interpreting tractography and connectivity results. Our approach provides a novel framework for estimating reliability of tractography and encourages innovation to address its current limitations.
Publisher: Cold Spring Harbor Laboratory
Date: 08-10-2020
DOI: 10.1101/2020.10.07.321083
Abstract: White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same intended white matter pathways, which directly affects tractography results, quantification, and interpretation. In this study, we aim to evaluate and quantify the variability that arises from different protocols for bundle segmentation. Through an open call to users of fiber tractography, including anatomists, clinicians, and algorithm developers, 42 independent teams were given processed sets of human whole-brain streamlines and asked to segment 14 white matter fascicles on six subjects. In total, we received 57 different bundle segmentation protocols, which enabled detailed volume-based and streamline-based analyses of agreement and disagreement among protocols for each fiber pathway. Results show that even when given the exact same sets of underlying streamlines, the variability across protocols for bundle segmentation is greater than all other sources of variability in the virtual dissection process, including variability within protocols and variability across subjects. In order to foster the use of tractography bundle dissection in routine clinical settings, and as a fundamental analytical tool, future endeavors must aim to resolve and reduce this heterogeneity. Although external validation is needed to verify the anatomical accuracy of bundle dissections, reducing heterogeneity is a step towards reproducible research and may be achieved through the use of standard nomenclature and definitions of white matter bundles and well-chosen constraints and decisions in the dissection process.
Publisher: MDPI AG
Date: 19-06-2022
DOI: 10.3390/NU14122547
Abstract: Mauritia flexuosa (Buriti) pulp oil contains bioactive substances and lipids that are protective against cardiovascular and inflammatory diseases. We performed physical and chemical analyses to verify its quality and stability. Buriti oil was stable according to the Rancimat test, presenting an induction period of 6.6 h. We evaluated the effect of supplementation with crude buriti oil and olive oil on metabolic parameters in 108 Swiss mice for 90 days. We investigated six groups: extra virgin olive oil (EVOO) 1 and 2 (1000 and 2000 mg/kg), buriti oil (BO) 1 and 2 (1000 and 2000 mg/kg), synergic (S) (BO1 + EVOO1), and control (water dose 1000 mg/kg). The animals were euthanized to examine their blood, livers, and fats. The supplementation did not interfere with food consumption, weight gain, and histological alterations in the liver. Group S showed the strongest relationship with the fractions HDL-c and non-HDL-c, indicating a possible cardioprotective effect. Moreover, we observed significantly higher IL-6 levels in the control, EVOO2, and BO1 groups than in the EVOO1 group. Resistin was also significantly higher for the synergic treatment than for the control. We conclude that BO combined with EVOO could be an excellent food supplement for human consumption.
Location: Brazil
No related grants have been discovered for Laurent Petit.