Automatic quantification of normal cortical folding patterns from fetal brain MRI

Abstract

We automatically quantify patterns of normal cortical folding in the developing fetus from in utero MR images (N=80) over a wide gestational age (GA) range (21.7 to 38.9weeks). This work on data from healthy subjects represents a first step towards characterising abnormal folding that may be related to pathology, facilitating earlier diagnosis and intervention. The cortical boundary was delineated by automatically segmenting the brain MR image into a number of key structures. This utilised a spatio-temporal atlas as tissue priors in an expectation-maximization approach with second order Markov random field (MRF) regularization to improve the accuracy of the cortical boundary estimate. An implicit high resolution surface was then used to compute cortical folding measures. We validated the automated segmentations with manual delineations and the average surface discrepancy was of the order of 1mm. Eight curvature-based folding measures were computed for each fetal cortex and used to give summary shape descriptors. These were strongly correlated with GA (R(2)=0.99) confirming the close link between neurological development and cortical convolution. This allowed an age-dependent non-linear model to be accurately fitted to the folding measures. The model supports visual observations that, after a slow initial start, cortical folding increases rapidly between 25 and 30weeks and subsequently slows near birth. The model allows the accurate prediction of fetal age from an observed folding measure with a smaller error where growth is fastest. We also analysed regional patterns in folding by parcellating each fetal cortex using a nine-region anatomical atlas and found that Gompertz models fitted the change in lobar regions. Regional differences in growth rate were detected, with the parietal and posterior temporal lobes exhibiting the fastest growth, while the cingulate, frontal and medial temporal lobes developed more slowly.

Relation between clinical risk factors, early cortical changes, and neurodevelopmental outcome in preterm infants

“…29 disturbances related to preterm birth and severity of illness will have a larger impact on these early developing sulci compared with the later developing sulci whose active folding will occur during a more stable period for most of extremely preterm infants (Wright et al 2014), especially in the absence of severe white matter injury.…”

NEOCIVET: Extraction of Cortical Surface and Analysis of Neonatal Gyrification Using a Modified CIVET Pipeline

“…Another weakness is the lack of point-wise correspondence between subjects, which challenges group-wise analysis of regional changes [1][2]. We overcame these weaknesses using a segmentation method with a local tissue contrast model without prior information as well as a surface registration technique that re-arranges mesh triangulation based on cortical folding similarity between subjects, thus optimizing point correspondence.…”

“…To quantify such early morphological development, it is necessary to extract cortical surface, especially the interface of the gray matter (GM) and white matter (WM). Only a few packages [1,2] have been proposed to perform this task. To enable regional analysis, they co-register an individual lobar atlas to each subject's cortical surface.…”

Pharyngeal mucosal wall folds in subjects with obstructive sleep apnea

“…In the geological literature, a topographical fold is defined in terms of curvature, with a fold defined by measuring a curvature "crest" subtended by two curvature "inflection points" (38), similar to our definition of folds. Very recently, a similar analysis has been used to characterize cortical folding patterns in fetal brains, also based on surface curvature measurements (49).…”