Normative volume measurements of the fetal intra-cranial compartments using 3D volume in utero MR imaging

Abstract

Purpose To describe the normal linear measurements of the skull (bi-parietal diameter and occipito-frontal diameter) and intracranial volumes (ventricular volume, brain parenchymal volume, extra-axial volume and total intra-cranial volume) in normal fetuses. Materials and methods We recruited pregnant women from low-risk pregnancies whose fetuses had normal ultrasound and in utero MR studies. All volunteers had in utero MR imaging on the same 1.5T MR scanner with a protocol consisting of routine and 3D steady-state volume imaging of the fetal brain. Linear measurements of the skull were made using the volume imaging. The 3D volume imaging also was manually segmented to delineate the intracranial compartments described above to determine quantitative values for each. Results Two hundred normal fetuses were studied with gestational ages between 18 and 37 weeks. The linear skull measurements made on in utero MR imaging closely correlate with published data from ultrasonography. The intracranial volume data is presented as graphs and as tabular summaries of 3rd, 10th, 50th, 90th and 97th centiles. Conclusion It is now possible to measure the volumes of the intracranial compartments in individual fetuses using ultrafast in utero MR techniques. Key Points • There are limitations in using the skull size of the fetus to comment on the state of the fetal brain. • Volumes for the intracranial compartments are presented, based on in utero MR imaging of the fetal brain between 18 and 37 weeks gestational age. • Those normative values can be used to assess fetuses with known or suspected structural brain abnormalities and may assist the differential diagnosis provided by visual assessment of routine iuMR studies. Electronic supplementary material The online version of this article (10.1007/s00330-018-5938-5) contains supplementary material, which is available to authorized users.

Ontogenetic and in silico models of spatial‐packing in the hypermuscular mouse skull

“…For example, consider the fetus suspended in amniotic fluid, nourished via the umbilical cord and with a flexible, membranous, calvarium. Recent in‐utero MR images have also shown a comfortable margin of cerebrospinal fluid surrounding the brain, which could be displaced via arachnoid granulations to lessen the physical effects of encephalisation on the surrounding skull (see figures in Jarvis et al, 2019; Kyriakopoulou et al, 2017). In other words, the head is not yet spatially optimised at this stage and retains capacity to accommodate expanding tissues.…”

Reference biometry of foetal brain by prenatal MRI and the distribution of measurements in foetuses with ventricular septal defect

“…So far, not much study of prenatal brain MRI measurements with large cohort represented by multiple statistical methods has been reported. Some of them were based on the measurement of the skull in comparison with ultrasound, not for the brain itself [ 26 ]. Some of them were based on volume measurement which was time-consuming [ 26 , 27 ].…”

An automatic multi-tissue human fetal brain segmentation benchmark using the Fetal Tissue Annotation Dataset

“…It is clinically relevant to analyse information such as shape or volume of the developing cortex, cerebellum, brainstem, white matter and cerebrospinal fluid spaces, as many congenital disorders cause subtle changes to these tissue compartments 6,15,16 . Existing growth data is mainly based on normally developing brains [17][18][19] , and we lack growth data for many pathologies and congenital disorders. The automatic segmentation of the developing human brain would be a first step in being able to perform such an analysis, as manual segmentation is both time-consuming and prone to human error.…”