Multi-atlas multi-shape segmentation of fetal brain MRI for volumetric and morphometric analysis of ventriculomegaly

Abstract

The recent development of motion robust super-resolution fetal brain MRI holds out the potential for dramatic new advances in volumetric and morphometric analysis. Volumetric analysis based on volumetric and morphometric biomarkers of the developing fetal brain must include segmentation. Automatic segmentation of fetal brain MRI is challenging, however, due to the highly variable size and shape of the developing brain; possible structural abnormalities; and the relatively poor resolution of fetal MRI scans. To overcome these limitations, we present a novel, constrained, multi-atlas, multi-shape automatic segmentation method that specifically addresses the challenge of segmenting multiple structures with similar intensity values in subjects with strong anatomic variability. Accordingly, we have applied this method to shape segmentation of normal, dilated, or fused lateral ventricles for quantitative analysis of ventriculomegaly (VM), which is a pivotal finding in the earliest stages of fetal brain development, and warrants further investigation. Utilizing these innovative techniques, we introduce novel volumetric and morphometric biomarkers of VM comparing these values to those that are generated by standard methods of VM analysis, i.e., by measuring the ventricular atrial diameter (AD) on manually selected sections of 2D ultrasound or 2D MRI. To this end, we studied 25 normal and abnormal fetuses in the gestation age (GA) range of 19 to 39 weeks (mean=28.26, stdev=6.56). This heterogenous dataset was essentially used to 1) validate our segmentation method for normal and abnormal ventricles; and 2) show that the proposed biomarkers may provide improved detection of VM as compared to the AD measurement.

3D MR ventricle segmentation in pre-term infants with post-hemorrhagic ventricle dilatation (PHVD) using multi-phase geodesic level-sets

“…The mean DSC obtained by the proposed method is lower than a DSC of 87.0% reported in Anbeek et al (2005), a median DSC of 95.9% reported in Coupé et al (2011), and a mean DSC of 88.0 ± 6.7% reported in Gholipour et al (2012). However, both Anbeek et al (2005) and Coupé et al (2011) used images from adult populations, which had better image quality and much less anatomic variation.…”

“…Moreover, these methods were only validated on high-quality healthy neonate images generated for research purposes only while patients were sedated. Gholipour et al (2012) developed a ventricle segmentation method of fetal brain MRIs using 13 normal brains and 12 fetuses with mild VM, which is the most similar study to ours. However, unlike the healthy brains and the brains with mild VM, the MR images of neonatal patients with IVH and hydrocephalus used in this study provide greater challenges for segmentation.…”

Automatic Measurement of Fetal Brain Development from Magnetic Resonance Imaging: New Reference Data

“…Earlier studies used manual segmentation, which is a time-consuming method that limits its applicability to large datasets and is largely sensitive to inter-rater variability [22,23]. More recent studies proposed automatic and semi-automatic methods for volume reconstruction [24,25] or registration of the MRI scans to an appropriate atlas [26][27][28]. Yet, to date, these methods have neither been applied on large datasets nor implemented clinically.…”

Cerebrospinal Fluid and Parenchymal Brain Development and Growth in the Healthy Fetus

“…Such studies may combine 3D volumetric and surface analysis of the lateral ventricles, as well as the relationship of lateral ventricle development with surrounding cerebral tissue. In support of this approach are previous reports of differences in surface measures of ventricular curvature and cortical folding in subjects with isolated mild ventriculomegaly compared to controls [41] , as well as studies showing significant variation in 3D morphometry of the lateral ventricles [42] , which might explain the limitations of standard 2D measures. Though previous 3D MRI reports have not reported a gender difference in the fetal ventricular system [16] , we report a modest difference between male and female fetuses, which corroborates previous large sonographic studies [43] .…”