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3.
Neuroimage ; 101: 555-68, 2014 Nov 01.
Article in English | MEDLINE | ID: mdl-25008959

ABSTRACT

There is growing interest in exploring fetal functional brain development, particularly with Resting State fMRI. However, during a typical fMRI acquisition, the womb moves due to maternal respiration and the fetus may perform large-scale and unpredictable movements. Conventional fMRI processing pipelines, which assume that brain movements are infrequent or at least small, are not suitable. Previous published studies have tackled this problem by adopting conventional methods and discarding as much as 40% or more of the acquired data. In this work, we developed and tested a processing framework for fetal Resting State fMRI, capable of correcting gross motion. The method comprises bias field and spin history corrections in the scanner frame of reference, combined with slice to volume registration and scattered data interpolation to place all data into a consistent anatomical space. The aim is to recover an ordered set of samples suitable for further analysis using standard tools such as Group Independent Component Analysis (Group ICA). We have tested the approach using simulations and in vivo data acquired at 1.5 T. After full motion correction, Group ICA performed on a population of 8 fetuses extracted 20 networks, 6 of which were identified as matching those previously observed in preterm babies.


Subject(s)
Brain Mapping/methods , Brain/embryology , Fetus/physiology , Magnetic Resonance Imaging/methods , Nerve Net/physiology , Brain Mapping/standards , Female , Gestational Age , Humans , Magnetic Resonance Imaging/standards , Motion , Pregnancy , Pregnancy Trimester, Third , Prenatal Diagnosis
4.
J Acad Nutr Diet ; 114(4): 533-6, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24656502
5.
Cortex ; 56: 30-7, 2014 Jul.
Article in English | MEDLINE | ID: mdl-22482694

ABSTRACT

INTRODUCTION: Visual impairment in preterm infants at term equivalent age (TEA) is associated with impaired microstructural development in the optic radiation, measured as reduced fractional anisotropy (FA) by Diffusion Tensor Imaging (DTI). We tested the hypothesis that these abnormalities develop during the late preterm period. METHODS: DTI was performed in 53 infants born at a median (range) of 30(+1) (25(+4)-34(+6)) weeks post-menstrual age (PMA), 22 of whom were imaged twice. RESULTS: FA in the optic radiation at TEA was related to: visual function (p = .003); PMA at birth (p = .015); and PMA at scan (p = .008); while a significant interaction between PMA at birth and scan (p = .019) revealed an effect of the period of premature extra-uterine life additional to the degree of prematurity. We explored this further in a sub-group of 22 infants who were studied twice. FA increased from mean (95% CI) .174 (.164-.176) on the first image at 32(+5) (29(+5)-36) weeks PMA, to .198 (.190-.206) on the second image at 40(+6) (39(+2)-46) weeks PMA. Visual function was not predicted by FA on the images obtained in the early neonatal period, but was significantly related to the rate of increase in FA between scans (p = .027) and to FA on the second image (p = .015). CONCLUSION: Microstructural maturation during the late preterm period is thus required for normal visual function, suggesting that interventions applied after 30 weeks PMA might reduce impairment in preterm infants.


Subject(s)
Brain/physiopathology , Nerve Fibers, Myelinated/physiology , Vision Disorders/physiopathology , Vision, Ocular/physiology , Anisotropy , Brain/growth & development , Diffusion Tensor Imaging , Female , Humans , Infant , Infant, Newborn , Infant, Premature , Infant, Very Low Birth Weight , Male
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