Optic radiation structure and anatomy in the normally developing brain determined using diffusion MRI and tractography

Dayan, Michael; Muñoz, Mónica; Jentschke, Sebastian; Chadwick, Martin J.; Cooper, Janine M.; Riney, Kate; Vargha‐Khadem, Faraneh; Clark, Chris A.

doi:10.1007/s00429-013-0655-y

Cited by 41 publications

(41 citation statements)

References 93 publications

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“…Our findings are consistent with a prior study of children and youth that found left lateralization of FA values due to a higher first eigenvalue, suggesting a lower axon density in the left hemisphere (Dayan et al, 2015). As myelination of the optic radiation is mature by three years of age (Brown et al, 2014), a two- to three-year longitudinal follow-up of our cohort is needed to investigate changes in diffusion measures over the latter phase of maturation.…”

Section: Discussionsupporting

confidence: 93%

Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants

et al. 2016

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Diffusion tensor imaging (DTI) has been widely used to investigate the development of the neonatal and infant brain, and deviations related to various diseases or medical conditions like preterm birth. In this study, we created a probabilistic map of fiber pathways with known associated functions, on a published neonatal multimodal atlas. The pathways-of-interest include the superficial white matter (SWM) fibers just beneath the specific cytoarchitectonically defined cortical areas, which were difficult to evaluate with existing DTI analysis methods. The Jülich cytoarchitectonic atlas was applied to define cortical areas related to specific brain functions, and the Dynamic Programming (DP) method was applied to delineate the white matter pathways traversing through the SWM. Probabilistic maps were created for pathways related to motor, somatosensory, auditory, visual, and limbic functions, as well as major white matter tracts, such as the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle, by delineating these structures in eleven healthy term-born neonates. In order to characterize maturation-related changes in diffusivity measures of these pathways, the probabilistic maps were then applied to DTIs of 49 healthy infants who were longitudinally scanned at three time-points, approximately five weeks apart. First, we investigated the normal developmental pattern based on 19 term-born infants. Next, we analyzed 30 preterm-born infants to identify developmental patterns related to preterm birth. Last, we investigated the difference in diffusion measures between these groups to evaluate the effects of preterm birth on the development of these functional pathways. Term-born and preterm-born infants both demonstrated a time-dependent decrease in diffusivity, indicating postnatal maturation in these pathways, with laterality seen in the corticospinal tract and the optic radiation. The comparison between term- and preterm-born infants indicated higher diffusivity in the preterm-born infants than in the term-born infants in three of these pathways: the body of the corpus callosum; the left inferior longitudinal fasciculus; and the pathway connecting the left primary/ secondary visual cortices and the motion-sensitive area in the occipitotemporal visual cortex (V5/MT+). Probabilistic maps provided an opportunity to investigate developmental changes of each white matter pathway. Whether alterations in white matter pathways can predict functional outcomes will be further investigated in a follow-up study.

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Section: Discussionsupporting

confidence: 93%

Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants

et al. 2016

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“…This may be the result of a number of differences in the microstructural characteristics, including smaller axon diameter, denser axonal packing, or higher myelination [Le Bihan, ; Pierpaoli and Basser, ]. There is evidence for left‐ and/or rightward asymmetries in varying combinations of FA, AD, MD, and RD in the optic radiations of healthy participants, yet to our knowledge, previous research has not accounted for any differences dependent on eye dominance [Dayan et al, ; de Schotten et al, ; Sherbondy et al, ]. Ocular dominance is shown to influence functional activity in V1 such that the proportion of activation is considerably greater when the dominant eye is stimulated compared to the nondominant eye [Menon et al, ; Rombouts et al, ].…”

Section: Discussionmentioning

confidence: 99%

Altered white matter structure in the visual system following early monocular enucleation

Wong

Rafique

Kelly

et al. 2017

Human Brain Mapping

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Partial visual deprivation from early monocular enucleation (the surgical removal of one eye within the first few years of life) results in a number of long-term morphological adaptations in adult cortical and subcortical visual, auditory, and multisensory brain regions. In this study, we investigated whether early monocular enucleation also results in the altered development of white matter structure. Diffusion tensor imaging and probabilistic tractography were performed to assess potential differences in visual system white matter in adult participants who had undergone early monocular enucleation compared to binocularly intact controls. To examine the microstructural properties of these tracts, mean diffusion parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were extracted bilaterally. Asymmetries opposite to those observed in controls were found for FA, MD, and RD in the optic radiations, the projections from primary visual cortex (V1) to the lateral geniculate nucleus (LGN), and the interhemispheric V1 projections of early monocular enucleation participants. Early monocular enucleation was also associated with significantly lower FA bidirectionally in the interhemispheric V1 projections. These differences were consistently greater for the tracts contralateral to the enucleated eye, and are consistent with the asymmetric LGN volumes and optic tract diameters previously demonstrated in this group of participants. Overall, these results indicate that early monocular enucleation has long-term effects on white matter structure in the visual pathway that results in reduced fiber organization in tracts contralateral to the enucleated eye. Hum Brain Mapp 39:133-144, 2018.V C 2017 Wiley Periodicals, Inc.

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“…The position of the most anterior voxel belonging to the OR was chosen as the location of the tip of ML. The location of the temporal pole (TP) was evaluated on the color‐coded FA maps and chosen as the coronal slice coinciding with the most anterior extent of the temporal lobe – including the TP – and the beginning of the frontal lobe . In cases where several coronal plane positions along the anterior–posterior axis fit this criterion, the most anterior position was systematically selected.…”

Section: Methodsmentioning

confidence: 99%

Tractography of the optic radiation: a repeatability and reproducibility study

Dayan¹,

Kreutzer

Clark³

2015

NMR Biomed.

Self Cite

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Our main objective was to evaluate the repeatability and reproducibility of optic radiation (OR) reconstruction from diffusion MRI (dMRI) data. 14 adults were scanned twice with the same 60-direction dMRI sequence. Peaks in the diffusion profile were estimated with the single tensor (ST), Q-ball (QSH) and persistent angular structure (PAS) methods. Segmentation of the OR was performed by two experimenters with probabilistic tractography based on a manually drawn region-of-interest (ROI) protocol typically employed for OR segmentation, with both standard and extended sets of ROIs. The repeatability and reproducibility were assessed by calculating the intra-class correlation coefficient (ICC) of intra- and inter-rater experiments, respectively. ICCs were calculated for commonly used dMRI metrics (FA, MD, AD, RD) and anatomical dimensions of the optic radiation (distance from Meyer's loop to the temporal pole, ML-TP), as well as the Dice similarity coefficient (DSC) between the raters' OR segmentation. Bland-Altman plots were also calculated to investigate bias and variability in the reproducibility measurements. The OR was successfully reconstructed in all subjects by both raters. The ICC was found to be in the good to excellent range for both repeatability and reproducibility of the dMRI metrics, DSC and ML-TP distance. The Bland-Altman plots did not show any apparent systematic bias for any quantities. Overall, higher ICC values were found for the multi-fiber methods, QSH and PAS, and for the standard set of ROIs. Considering the good to excellent repeatability and reproducibility of all the quantities investigated, these findings support the use of multi-fiber OR reconstruction with a limited number of manually drawn ROIs in clinical applications utilizing either OR microstructure characterization or OR dimensions, as is the case in neurosurgical planning for temporal lobectomy.

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Optic radiation structure and anatomy in the normally developing brain determined using diffusion MRI and tractography

Cited by 41 publications

References 93 publications

Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants

Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants

Altered white matter structure in the visual system following early monocular enucleation

Tractography of the optic radiation: a repeatability and reproducibility study

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