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Arijit Chakraborty, Ben Thompson, Marlee Vandewouw, Brenda L Gallie, Daphne L McCulloch, Margot J Taylor, Benjamin Dunkley; Altered white matter structure within the visual pathway of children with early unilateral enucleation. Invest. Ophthalmol. Vis. Sci. 2018;59(9):4142. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Following unilateral enucleation in infancy, adults have altered white matter microstructure in subcortical and cortical projections of visual pathway. Within a prospective, observational study, we used diffusion tensor imaging (DTI) to investigate whether these white matter alterations are present at an earlier stage of visual development.
DTI data (30/40/60 directions, b value = 1000/1600/2600 s/mm2) were acquired from seven children (age: 8-12 years) enucleated for retinoblastoma between 6 and 36 months of age and seven age and sex-matched controls using a Siemens 3T MAGNETOM MRI with a 12-channel head coil. Reconstruction of the optic radiations, V1 to LGN, interhemispheric V1 to V1, and V1 to MT projections was performed using the Probabilistic Tracking with Crossing Fibers (PROBTRACKX) tool, from the FMRIB3s Software Library. Values for fractional anisotropy (FA), radial diffusivity (RD), mean diffusivity, axial diffusivity (AD), and mean diffusivity (MD) were extracted from each tract of interest within each hemisphere.
Uniocular children had significantly lower FA within the optic radiations (U = 4, p = 0.026), the V1-LGN (U = 6, p = 0.045) and V1-MT (U = 3, p = 0.015) projections. There was also a trend for lower FA within the interhemispheric V1-V1 (U = 7, p = 0.065) projection. RD and MD were significantly higher for uniocular children within the V1-LGN, interhemispheric V1-V1, and V1-MT projections (all U < 5 and p < 0.02).
Uniocular enucleation in infancy results in abnormal subcortical and cortical white matter development that is evident in mid-childhood. The functional implications of these changes for visual function are currently unknown. Overall, our results highlight the importance of binocular input for normal structural development of the visual pathway and extrastriate cortex.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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