To determine long-term efficacy and safety of epilepsy surgery in children and adolescents with malformations of cortical development (MCD) and to identify differences in seizure outcome of the various MCD subgroups. Special focus was set on the newly introduced International League Against Epilepsy (ILAE) classification of focal cortical dysplasia (FCD).
Magnetic resonance imaging (MRI) is a powerful, noninvasive tool to study fetal lung volumes after 18 weeks of gestation in vivo. In neonates with congenital heart disease (CHD), proper lung function is essential for postnatal survival. Antenatal detection of abnormal pulmonary development may help to optimize prenatal and perinatal management of at-risk fetuses. We aimed to investigate lung volumes in fetuses with prenatally diagnosed heart disease.
In cases of "spina bifida," a detailed prenatal imaging assessment of the exact morphology of neural tube defects (NTD) is often limited. Due to the diverse clinical prognosis and prenatal treatment options, imaging parameters that support the prenatal differentiation between open and closed neural tube defects (ONTDs and CNTDs) are required. This fetal MR study aims to evaluate the clivus-supraocciput angle (CSA) and the maximum transverse diameter of the posterior fossa (TDPF) as morphometric parameters to aid in the reliable diagnosis of either ONTDs or CNTDs.
The functional connectivity architecture of the adult human brain enables complex cognitive processes, and exhibits a remarkably complex structure shared across individuals. We are only beginning to understand its heterogeneous structure, ranging from a strongly hierarchical organization in sensorimotor areas to widely distributed networks in areas such as the parieto-frontal cortex. Our study relied on the functional magnetic resonance imaging (fMRI) data of 32 fetuses with no detectable morphological abnormalities. After adapting functional magnetic resonance acquisition, motion correction, and nuisance signal reduction procedures of resting-state functional data analysis to fetuses, we extracted neural activity information for major cortical and subcortical structures. Resting fMRI networks were observed for increasing regional functional connectivity from 21st to 38th gestational weeks (GWs) with a network-based statistical inference approach. The overall connectivity network, short range, and interhemispheric connections showed sigmoid expansion curve peaking at the 26-29 GW. In contrast, long-range connections exhibited linear increase with no periods of peaking development. Region-specific increase of functional signal synchrony followed a sequence of occipital (peak: 24.8 GW), temporal (peak: 26 GW), frontal (peak: 26.4 GW), and parietal expansion (peak: 27.5 GW). We successfully adapted functional neuroimaging and image post-processing approaches to correlate macroscopical scale activations in the fetal brain with gestational age. This in vivo study reflects the fact that the mid-fetal period hosts events that cause the architecture of the brain circuitry to mature, which presumably manifests in increasing strength of intra- and interhemispheric functional macro connectivity.
While the visuomotor system is known to develop rapidly after birth, studies have observed spontaneous activity in vertebrates in visually excitable cortical areas already before extrinsic stimuli are present. Resting state networks and fetal eye movements were observed independently in utero, but no functional brain activity coupled with visual stimuli could be detected using fetal fMRI. This study closes this gap and links in utero eye movement with corresponding functional networks. BOLD resting-state fMRI data were acquired from seven singleton fetuses between gestational weeks 30-36 with normal brain development. During the scan time, fetal eye movements were detected and tracked in the functional MRI data. We show that already in utero spontaneous fetal eye movements are linked to simultaneous networks in visual- and frontal cerebral areas. In our small but in terms of gestational age homogenous sample, evidence across the population suggests that the preparation of the human visuomotor system links visual and motor areas already prior to birth.
Prenatal neuroimaging requires reference models that reflect the normal spectrum of fetal brain development, and summarize observations from a representative sample of individuals. Collecting a sufficiently large data set of manually annotated data to construct a comprehensive in vivo atlas of rapidly developing structures is challenging but necessary for large population studies and clinical application. We propose a method for the semi-supervised learning of a spatio-temporal latent atlas of fetal brain development, and corresponding segmentations of emerging cerebral structures, such as the ventricles or cortex. The atlas is based on the annotation of a few examples, and a large number of imaging data without annotation. It models the morphological and developmental variability across the population. Furthermore, it serves as basis for the estimation of a structures morphological age, and its deviation from the nominal gestational age during the assessment of pathologies. Experimental results covering the gestational period of 20-30 gestational weeks demonstrate segmentation accuracy achievable with minimal annotation, and precision of morphological age estimation. Age estimation results on fetuses suffering from lissencephaly demonstrate that they detect significant differences in the age offset compared to a control group.
Complete or partial agenesis of the corpus callosum are rather common developmental abnormalities, resulting in a wide spectrum of clinical neurodevelopmental deficits. Currently, a significant number of these cases are detected by prenatal sonography during second trimester screening examinations. However, major uncertainties about a detailed morphological diagnosis and the clinical significance do not allow accurate prenatal counselling. Here, we were able to demonstrate the 3D connectivity of aberrant commissural tracts in 16 cases with complete and four cases with partial callosal agenesis using the foetal magnetic resonance imaging techniques of diffusion tensor imaging and tractography in utero and in vivo between gestational weeks 20 and 37. The misguided pre-myelinated callosal axons that represent the bundle of Probst were non-invasively visualized, and they showed a degree of structural integrity similar to that of the callosal pathways of age-matched foetuses without cerebral pathologies. In two foetuses, we were able to prove, by post-mortem histology, that diffusion tensor imaging allows the depiction of the bundle of Probst, even during early stages of pre-myelination at 20 and 22 gestational weeks. In cases with partial callosal agenesis, an aberrant sigmoid-shaped bundle was prenatally depicted, confirming the findings of heterotopic interhemispheric connectivity in adults with partial callosal agenesis. In addition to the corpus callosum, other white matter pathways were also involved, including somatosensory and motor pathways that showed significantly higher fractional anisotropy values in cases with callosal agenesis compared with control subjects. A detailed prenatal assessment of abnormal white matter connectivity in cases of midline anomalies will help to explain and understand the clinical heterogeneity in these cases, taking future foetal neurological counselling strategies to a new level.
Eye movements are the physical expression of upper fetal brainstem function. Our aim was to identify and differentiate specific types of fetal eye movement patterns using dynamic MRI sequences. Their occurrence as well as the presence of conjugated eyeball motion and consistently parallel eyeball position was systematically analyzed.
This review focuses on the application of magnetic resonance imaging methods in utero studying functional brain development of spontaneous brain activity generated under resting conditions and of task-evoked activity using stimulation. These imaging approaches have been useful to explore the brains functional organization during development, as already shown in different substantial resting-state studies in preterms. We also discuss emerging future directions regarding analyzing methods and combination of functional and structural connectivity approaches.
Magnetic resonance imaging has become an important noninvasive technique to gain insight into fetal brain development. Its capabilities go beyond ultrasound when diagnosing high-risk pregnancies. To summarize observations across a population in magnetic resonance imaging studies, reference systems such as atlases that establish correspondences across a cohort are key. In this article, we review the evolution of atlas-building methods in light of their relevance, limitations, and benefits for the modeling of human brain development. Starting with single anatomical templates to which brain scans where mapped to such as Talairach and Montreal Neurological Institute space, we explore the uses of atlases as a means to establish correspondences across a cohort and as a model that captures the population characteristics of the cases the atlas is built from. We discuss methods that capture features of increasingly heterogeneous populations and approaches that are able to generalize with only minimal annotation. The main focus of this review are methods that explicitly model the variability in the population with regard to time, such as in the modeling of disease progression and brain development. We highlight the applicability and limitations of state-of-the art approaches, how insights from the study of disease progression are helpful in developmental studies, and point to the directions of future research that is still necessary.
Situs anomalies refer to an abnormal organ arrangement, which may be associated with severe errors of development. Due regard being given to prenatal magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US), this study sought to demonstrate the in utero visualization of situs anomalies on MRI, compared to US.
Magnetic resonance (MR) neurography comprises an evolving group of techniques with the potential to allow optimal noninvasive evaluation of many abnormalities of the brachial plexus. MR neurography is clinically useful in the evaluation of suspected brachial plexus traumatic injuries, intrinsic and extrinsic tumors, and post-radiogenic inflammation, and can be particularly beneficial in pediatric patients with obstetric trauma to the brachial plexus. The most common MR neurographic techniques for displaying the brachial plexus can be divided into two categories: structural MR neurography; and microstructural MR neurography. Structural MR neurography uses mainly the STIR sequence to image the nerves of the brachial plexus, can be performed in 2D or 3D mode, and the 2D sequence can be repeated in different planes. Microstructural MR neurography depends on the diffusion tensor imaging that provides quantitative information about the degree and direction of water diffusion within the nerves of the brachial plexus, as well as on tractography to visualize the white matter tracts and to characterize their integrity. The successful evaluation of the brachial plexus requires the implementation of appropriate techniques and familiarity with the pathologies that might involve the brachial plexus.
Fetal tumors can have a devastating effect on the fetus, and may occur in association with congenital malformations. In view of the increasing role of fetal magnetic resonance imaging (MRI) as an adjunct to prenatal ultrasonography (US), we sought to demonstrate the visualization of fetal tumors, with regard to congenital abnormalities, on MRI.
Hypothalamic hamartomas are rare lesions for which different classification schemes have been proposed. The authors report on an exceptionally large solid-cystic hamartoma that led to hydrocephalus, precocious puberty, and intractable gelastic seizures. They discuss potential mechanisms of the development of hypothalamic hamartomas.
In view of the increasing role of magnetic resonance imaging (MRI) as an adjunct to prenatal ultrasonography (US), this study sought to demonstrate the visualization of fetal akinesia and associated abnormalities on MRI.
Anatomical and functional hemispheric lateralization originates from differential gene expression and leads to asymmetric structural brain development, which initially appears in the perisylvian regions by 26 gestational weeks (GWs). In this in vivo neuroimaging study, we demonstrated a predominant pattern of temporal lobe (TL) asymmetry in a large cohort of human fetuses between 18 and 37 GWs. Over two-thirds of fetuses showed a larger, left-sided TL, combined with the earlier appearance of the right superior temporal sulcus by 23 GWs (vs. 25 GWs on the left side), which was also deeper than its left counterpart in the majority of cases (94.2%). Shape analysis detected highly significant differences in the contour of the right and left TLs by 20 GWs. Thus, fetal hemispheric asymmetry can be detected in utero, opening new diagnostic possibilities for the assessment of diseases that are believed to be linked to atypical hemispheric lateralization.
Recently, diffusion-weighted (DWI) magnetic resonance imaging of the fetus has evolved from a basic research application to an important diagnostic imaging tool in fetal magnetic resonance imaging. Although technically challenging and still plagued with several sources of artifacts, DWI can add clinically important information, which cannot be provided by any other prenatal imaging modality. Its potential to noninvasively probe tissue structures on the basis of Brownian molecular motion enables the detection of early changes associated with acute fetal diseases, as well as structural alterations of functionally diverse compartments of different fetal organs. In this article, the current clinical applications of fetal brain and body DWI are outlined, as well as its current limitations.
Forebrain malformations include some of the most severe developmental anomalies and require early diagnosis. The proof of normal or abnormal prosencephalic development may have an influence on further management in the event of a suspected fetal malformation. The purpose of this retrospective study was to evaluate the detectability of anatomical landmarks of forebrain development using in vivo fetal magnetic resonance imaging (MRI) before gestational week (gw) 27.
Diabetes type 1 seems to be more prevalent in epilepsy, and low-carbohydrate diets improve glycemic control in diabetes type 2, but data on the use of the classic ketogenic diet (KD) in epilepsy and diabetes are scarce. We present 15 months of follow-up of a 3 years and 6 months old girl with diabetes type 1 (on the KD), right-sided hemiparesis, and focal epilepsy due to a malformation of cortical development. Although epileptiform activity on electroencephalography (EEG) persisted (especially during sleep), clinically overt seizures have not been reported since the KD. An improved activity level and significant developmental achievements were noticed. Glycosylated hemoglobin (HbA1c) levels improved, and glycemic control was excellent, without severe side effects. Our experience indicates that diabetes does not preclude the use of the KD.
Fetal magnetic resonance imaging (MRI) may add important diagnostic information to prenatal sonography and has the power to confirm or change decisions at critical points in clinical care. Recent studies have shown MRI to be a critical clinical adjunct in the evaluation of the developing central nervous system (CNS), especially at early gestational ages, and MRI has been used in three significant ways: (1) for the quantification of brain growth and structural abnormalities using biometry, (2) for the qualitative evaluation of CNS microstructure, and (3) for the qualitative assessment of dynamic fetal movements in utero.
Recent technological advances in fetal magnetic resonance imaging (MRI) and increased reliability of MRI in depicting abnormalities and lesions, especially in the central nervous system, are increasingly bringing up challenging issues with regard to accurate diagnosis. There are also pitfalls not only attributable to image acquisition but also in clinical interpretation. The misinterpretation of findings because of insufficient knowledge about fetal brain development as visualized by MRI may also be regarded as an important limitation of fetal MRI. We provide an overview of the most common pitfalls experienced in fetal MRI in routine practice, demonstrate how to identify some of the factors that lead to imaging misinterpretation, and suggest ways to tackle these problems, with an emphasis on MR techniques and image calibration.
While ultrasound is still the gold standard method of placental investigation, magnetic resonance imaging (MRI) has certain benefits. In advanced gestational age, obese women, and posterior placental location, MRI is advantageous due to the larger field of view and its multiplanar capabilities. Some pathologies are seen more clearly in MRI, such as infarctions and placental invasive disorders. The future development is towards functional placental MRI. Placental MRI has become an important complementary method for evaluation of placental anatomy and pathologies contributing to fetal problems such as intrauterine growth restriction.
Clubfoot, or talipes equinovarus (TEV), is commonly diagnosed on prenatal ultrasound. This study sought to visualize TEV and associated abnormalities on fetal magnetic resonance imaging (MRI) compared with ultrasound.
To investigate whether fetal lung signals and fetal lung signal progression over gestation observed on magnetic resonance imaging are different in mothers who reported smoking during pregnancy compared with nonsmoking controls.
Abstract Objectives: Inferior vena cava compression syndrome (VCCS) is a serious complication of supine fetal magnetic resonance imaging (MRI) examinations, particularly during late gestation. This morphologic study correlated the occurrence of VCCS with the grade of inferior vena cava (IVC) compression. Materials and methods: There were 56 fetal MRI in the supine position [median gestational weeks (GW) 27+4] and 16 fetal MRI in the lateral position (median GW 30+6) retrospectively analyzed. The grade of maternal IVC compression was determined by the maximal anterior-posterior diameter (DAP) at the level of L4/L5. Fetal head position and right-sided uterus volume were analyzed. Clinical VCCS-related symptoms during fetal MRI were assessed. Results: A noncompressed IVC was present in 1.8% (n=1) and a DAP of 5 to <10 mm in 33.3% (n=19) and 1 to <5 mm in 64.9% (n=36). The DAP was independent of fetal head position (P=0.99) and showed no significant correlation with gestational age (r=0.33). IVC compression increased with right-sided uterus volume (r=-0.328; P=0.014). There was a significant difference in DAP in the lateral position compared with the supine position (P<0.001). Clinical assessment revealed no symptoms of VCCS in any woman. Conclusions: The presented data support the concept of physiologic compensation for significantly reduced venous backflow in the supine position during the second and third trimesters of pregnancy.
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