Normal Brain Anatomy Research Articles

Generative adversarial network-based reconstruction of healthy anatomy for anomaly detection in brain CT scans.

To help radiologists examine the growing number of computed tomography (CT) scans, automatic anomaly detection is an ongoing focus of medical imaging research. Radiologists must analyze a CT scan by searching for any deviation from normal healthy anatomy. We propose an approach to detecting abnormalities in axial 2D CT slice images of the brain. Although much research has been done on detecting abnormalities in magnetic resonance images of the brain, there is little work on CT scans, where abnormalities are more difficult to detect due to the low image contrast that must be represented by the model used. We use a generative adversarial network (GAN) to learn normal brain anatomy in the first step and compare two approaches to image reconstruction: training an encoder in the second step and using iterative optimization during inference. Then, we analyze the differences from the original scan to detect and localize anomalies in the brain. Our approach can reconstruct healthy anatomy with good image contrast for brain CT scans. We obtain median Dice scores of 0.71 on our hemorrhage test data and 0.43 on our test set with additional tumor images from publicly available data sources. We also compare our models to a state-of-the-art autoencoder and a diffusion model and obtain qualitatively more accurate reconstructions. Without defining anomalies during training, a GAN-based network was used to learn healthy anatomy for brain CT scans. Notably, our approach is not limited to the localization of hemorrhages and tumors and could thus be used to detect structural anatomical changes and other lesions.

Effect of magnet strength on fetal brain biometry - a single-center retrospective MRI-based cohort study.

Abnormal fetal brain measurements might affect clinical management and parental counseling. The effect of between-field-strength differences was not evaluated in quantitative fetal brain imaging until now. Our study aimed to compare fetal brain biometry measurements in 3.0T with 1.5T scanners. A retrospective cohort of 1150 low-risk fetuses scanned between 2012 and 2021, with apparently normal brain anatomy, were retrospectively evaluated for biometric measurements. The cohort included 1.5T (442 fetuses) and 3.0T scans (708 fetuses) of populations with comparable characteristics in the same tertiary medical center. Manually measured biometry included bi-parietal, fronto-occipital and trans-cerebellar diameters, length of the corpus-callosum, vermis height, and width. Measurements were then converted to centiles based on previously reported biometric reference charts. The 1.5T centiles were compared with the 3.0T centiles. No significant differences between centiles of bi-parietal diameter, trans-cerebellar diameter, or length of the corpus callosum between 1.5T and 3.0T scanners were found. Small absolute differences were found in the vermis height, with higher centiles in the 3.0T, compared to the 1.5T scanner (54.6th-centile, vs. 39.0th-centile, p < 0.001); less significant differences were found in vermis width centiles (46.9th-centile vs. 37.5th-centile, p = 0.03). Fronto-occipital diameter was higher in 1.5T than in the 3.0T scanner (66.0th-centile vs. 61.8th-centile, p = 0.02). The increasing use of 3.0T MRI for fetal imaging poses a potential bias when using 1.5T-based charts. We elucidate those biometric measurements are comparable, with relatively small between-field-strength differences, when using manual biometric measurements. Small inter-magnet differences can be related to higher spatial resolution with 3T scanners and may be substantial when evaluating small brain structures, such as the vermis.

Development and Characterization of Inducible Astrocyte-Specific Aromatase Knockout Mice.

17β-estradiol (E2) is produced in the brain as a neurosteroid, in addition to being an endocrine signal in the periphery. The current animal models for studying brain-derived E2 include global and conditional non-inducible knockout mouse models. The aim of this study was to develop a tamoxifen (TMX)-inducible astrocyte-specific aromatase knockout mouse line (GFAP-ARO-iKO mice) to specifically deplete the E2 synthesis enzymes and aromatase in astrocytes after their development in adult mice. The characterization of the GFAP-ARO-iKO mice revealed a specific and robust depletion in the aromatase expressions of their astrocytes and a significant decrease in their hippocampal E2 levels after a GCI. The GFAP-ARO-iKO animals were alive and fertile and had a normal general brain anatomy, with a normal astrocyte shape, intensity, and distribution. In the hippocampus, after a GCI, the GFAP-ARO-iKO animals showed a major deficiency in their reactive astrogliosis, a dramatically increased neuronal loss, and increased microglial activation. These findings indicate that astrocyte-derived E2 (ADE2) regulates the ischemic induction of reactive astrogliosis and microglial activation and is neuroprotective in the ischemic brain. The GFAP-ARO-iKO mouse models thus provide an important new model to help elucidate the roles and functions of ADE2 in the brain.

Assessment of role of cranial ultrasound (CUS) in the evaluation of high-risk preterm and term neonates

BackgroundCranial ultrasonography (CUS) has become an important tool to depict normal brain anatomy and to detect the ischemic and hemorrhagic brain injury patterns in high-risk neonates. The present study aimed to assess the utility of CUS to diagnose the spectrum of brain injury patterns in high-risk preterm and term neonates admitted to the neonatal intensive care unit (NICU) and to find the association of CUS findings in various adverse antenatal and perinatal feto-maternal factors.ResultsOut of the 200 neonates, 76 (38%) neonates had abnormal CUS findings and 124 (62%) had a normal CUS. Germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) (28/76; 36.8 %) was the commonest abnormality with GMH (grade 1) in 14/76 (18.4%), grade 2 in 7 (9.2%), grade 3 in 5 (6.5%), and grade 4 in 2 (2.63%). The other findings observed were cerebral edema (14/76; 18.4%), thalamic hyperechogenicity (10/76; 13.1%), periventricular leukomalacia (PVL) (4/76; 5.2%), and congenital anomalies (8; 10.5%). Abnormal CUS findings had a statistically significant association with birth weight <2000 g, prematurity, Apgar score <7, and adverse peri-natal fetal and maternal factors (all p-values <0.05). Abnormal CUS findings had a statistically significant association with poor cry, poor activity, abnormal tone, and presence of cyanosis (all p-values <0.05).ConclusionIn this cohort study of high-risk preterm and term infants GMH-IVH, cerebral edema, thalamic hyperechogenicity, PVL, and congenital malformations were the commonest lesions detected on CUS. Abnormal CUS findings were found to have a statistically significant association with various adverse peri-natal fetal and maternal factors.

Fetal Brain Anatomy.

"Fetal brain development has been well studied, allowing for an ample knowledge of the normal changes that occur during gestation. Imaging modalities used to evaluate the fetal central nervous system (CNS) include ultrasound and MRI. MRI is the most accurate imaging modality for parenchymal evaluation and depiction of developmental CNS anomalies. The depiction of CNS abnormalities in a fetus can only be accurately made when there is an understanding of its normal development. This article reviews the expected normal fetal brain anatomy and development during gestation. Additional anatomic structures seen on brain imaging sequences are also reviewed."

Sonography of fetal holoprosencephaly: a guide to recognize the lesser varieties

Background Alobar holoprosencephaly (HPE) is easily detected during a first-trimester screening examination, conversely, recognizing the lesser varieties may be difficult even in the second trimester. Objectives To describe the imaging findings of a cohort of fetuses with holoprosencephaly (HPE) and to elucidate the appearances of the different anatomical varieties. Materials and methods We reviewed medical records and stored images of pregnant women referred to our clinic because of a diagnosis or the suspicion of various forms of HPE. We reported the imaging characteristics, the presence of other associated anomalies, magnetic resonance findings, karyotype and autoptic examinations when available. Results Alobar forms show great distortion of normal brain anatomy, with a single ventricle detectable during the first trimester of pregnancy. Extracerebral, face and karyotype abnormalities are often associated. In semilobar and lobar forms the septum pellucidum is typically absent in axial planes, with fused frontal horns, while posterior fossa is often normal. At multiplanar neurosonogram, anomalies involving corpus callosum and cortex development can be detected. Face abnormalities are mild in lobar forms: receding forehead, various degrees of hypotelorism and the presence of a single central maxillary incisor are reported. Conclusions The alobar forms are detectable since the first trimester, with a peculiar single ventricle and extremely frequent extracerebral and karyotype abnormalities. The semilobar and lobar forms are more challenging and the diagnosis is easily missed in a mid-trimester screening exam unless a careful evaluation of both cavum septi pellucidi and frontal horns as well is conducted.

Structural asymmetries in normal brain anatomy: A brief overview

PurposeA fundamental feature in interpreting gross or neuroimaging brain anatomy is reliance on an assumed high degree of morphologic symmetry in bilateral hemispheres. However, the normal brain is not perfectly symmetrical, and subtle inherent structural asymmetries could potentially confound appreciation of pathology-induced asymmetry or how a given brain asymmetry can relate to its function. Material and MethodsWe review the literature and provide a brief overview of structural asymmetries in normal brain anatomy. ResultsBrain structural asymmetries are either rotational or pure right-left asymmetries, and many are a consequence of unique features linked to the use of human language. Yakovlevian torque is the tendency of the right hemisphere to rotate slightly forward relative to the left, which may make the right frontal lobe bigger and wider, and the left occipital lobe wider and protrude rightward. This makes the left Sylvian fissure longer and flatter, resulting in a larger planum temporale. We also discuss right-left asymmetries in the cortex, white matter structures, deep gray nuclei, and lateral ventricles. Brain asymmetries are not random but result from distinct patterns in structural design that confer evolutionary functional advantages. ConclusionMinor brain asymmetries are important and should be accounted for as they can be connected to function, and like individual variability, are essential for evolution. This overview will help understand structural brain asymmetries for improved diagnostic neuroimaging interpretation, constructing symmetry-based paradigms for automatic localization, segmentation of brain lesions, and as a reference for studies on possible implications of excessive asymmetry and altered laterality in cognitive, neurological, and psychiatric disorders.

Modeling Healthy Anatomy with Artificial Intelligence for Unsupervised Anomaly Detection in Brain MRI.

To develop an unsupervised deep learning model on MR images of normal brain anatomy to automatically detect deviations indicative of pathologic states on abnormal MR images. In this retrospective study, spatial autoencoders with skip-connections (which can learn to compress and reconstruct data) were leveraged to learn the normal variability of the brain from MR scans of healthy individuals. A total of 100 normal, in-house MR scans were used for training. Subsequently, as the model was unable to reconstruct anomalies well, this characteristic was exploited for detecting and delineating various diseases by computing the difference between the input data and their reconstruction. The unsupervised model was compared with a supervised U-Net- and threshold-based classifier trained on data from 50 patients with multiple sclerosis (in-house dataset) and 50 patients from The Cancer Imaging Archive. Both the unsupervised and supervised U-Net models were tested on five different datasets containing MR images of microangiopathy, glioblastoma, and multiple sclerosis. Precision-recall statistics and derivations thereof (mean area under the precision-recall curve, Dice score) were used to quantify lesion detection and segmentation performance. The unsupervised approach outperformed the naive thresholding approach in lesion detection (mean F1 scores ranging from 17% to 62% vs 6.4% to 15% across the five different datasets) and performed similarly to the supervised U-Net (20%-64%) across a variety of pathologic conditions. This outperformance was mostly driven by improved precision compared with the thresholding approach (mean precisions, 15%-59% vs 3.4%-10%). The model was also developed to create an anomaly heatmap display. The unsupervised deep learning model was able to automatically detect anomalies on brain MR images with high performance. Supplemental material is available for this article. Keywords: Brain/Brain Stem Computer Aided Diagnosis (CAD), Convolutional Neural Network (CNN), Experimental Investigations, Head/Neck, MR-Imaging, Quantification, Segmentation, Stacked Auto-Encoders, Technology Assessment, Tissue Characterization © RSNA, 2021.

Brain folding shapes the branching pattern of the middle cerebral artery.

The folds of the brain offer a particular challenge for the subarachnoid vascular grid. The primitive blood vessels that occupy this space, when the brain is flat, have to adapt to an everchanging geometry while constructing an efficient network. Surprisingly, the result is a non-redundant arterial system easily challenged by acute occlusions. Here, we generalize the optimal network building principles of a flat surface growing into a folded configuration and generate an ideal middle cerebral artery (MCA) configuration that can be directly compared with the normal brain anatomy. We then describe how the Sylvian fissure (the fold in which the MCA is buried) is formed during development and use our findings to account for the differences between the ideal and the actual shaping pattern of the MCA. Our results reveal that folding dynamics condition the development of arterial anastomosis yielding a network without loops and poor response to acute occlusions.

Brain views that benefit from three-dimensional ultrasound.

Fetal central nervous system malformations are among the most common congenital anomalies. Whereas simple axial views are sufficient for basic fetal brain examination, other important views are essential for a more detailed examination, which are sometimes challenging to obtain. Three-dimensional ultrasound can be helpful in obtaining standardized and reproducible images of many difficult fetal brain views. The aim of the present review is to explore the most recent evidence on the utility and technique of three-dimensional ultrasound in the examination of the fetal brain, with particular emphasis on the brain views that benefit from three-dimensional ultrasound. The article describes the various techniques of acquisition and analyses of three-dimensional ultrasound volumes of the fetal brain and their usefulness in the assessment of normal and abnormal fetal brain anatomy. Three-dimensional ultrasound has also permitted the application of many new technologies, such as artificial intelligence and deep machine learning. Recently, thanks to high-quality three-dimensional ultrasound, fetal cortical development can be assessed quantitatively and reliably. Three dimensional ultrasound can help as a complementary tool to two-dimensional ultrasound in the assessment of the fetal brain development and malformations. In addition, it paves the way for the application of promising technologies in the evaluation of fetal brain. A video summarizing the findings of the article. The video illustrates the various approaches and techniques applied for the examination of the fetal brain using three-dimensional ultrasound. Furthermore, the advantages and future perspectives of the application of three-dimensional ultrasound in the examination of the fetal brain are discussed, http://links.lww.com/COOG/A74.

Efficient T2 brain region extraction algorithm using morphological operation and overlapping test from 2D and 3D MRI images

The main purpose of segmentation in MRI images is to diagnose the problems in the normal brain anatomy and to find the location of tumour. Many of the algorithms have been found in recent years which aid to segment the medical images and identify the diseases. This paper proposes a novel 3D brain extraction algorithm (3D-BEA) for segmentation of MRI images to extract the exact brain region. Transverse relaxation time (T2) weighted images are used as an input for the development of algorithm as these images provide bright compartments and dark fat tissues in the MRI brain region. The images are first denoised and smoothed for further processing. The final brain volume has been generated using this 3D-BEA process. The result of this developed proposed algorithm is validated by comparing proposed algorithm with the results of the existing segmentation algorithm.

Absent Cavum Septi Pellucidi

Absent Cavum Septi Pellucidi

Optimizing accuracy of freehand cannulation of the ipsilateral ventricle for intracranial pressure monitoring in patients with brain trauma.

Intracranial pressure (ICP) monitoring in traumatic brain injury (TBI) usually requires the placement of a catheter into the ipsilateral ventricle. This surgical procedure is commonly performed via a freehand method using surface anatomical landmarks as guides. The current accuracy of the catheter placement remains relatively low and even lower among TBI patients. This study was undertaken to optimize the freehand ventricular cannulation to increase the accuracy for TBI. The authors hypothesized that an optimal surgical plan of cannulation should give an operator the greatest degrees of freedom, which could be measured as the range of operation angle, range of catheter placement depth, and size of the target area. An imaging simulation was first performed using the computed tomography (CT) images of 47 adult patients with normal brain anatomy. On the reconstructed 3D head model, four different coronal planes of ventricular cannulation were identified: a 4-cm anterior, a 2-cm anterior, a standard (central), and a 2-cm posterior plane. The degrees of freedom during the cannulation procedure were determined, including the relevant angles, lengths of cannulation, cross-sectional area, and bounding rectangle of the lateral ventricle. Next, a retrospective assessment was performed on the CT scans of another 111 patients with TBI who underwent freehand ventricular cannulation for ICP monitoring. Postoperative measurements were also performed based on CT images to calculate the accuracy and safety of catheter placement between coronal planes in practice. Our simulation results showed that the 2-cm anterior plane had more extensive degrees of freedom for ventricular cannulation, in terms of length of catheter trajectory (7% longer, P<0.001), cross-sectional area of the lateral ventricle (14% larger, P=0.046), and length of the lateral ventricle (17% wider, P<0.001) than that of the standard plane, while both the 4-cm anterior and 2-cm posterior planes did not offer advantages over the standard plane in these ways. The mean length range of catheter trajectory in the 2-cm anterior plane was 41 to 58 mm. Retrospective assessment of TBI patients with ICP monitor placement also confirmed our simulation data. It showed that the accuracy of ipsilateral ventricle cannulation in the 2-cm anterior plane was 70.6%, which was a significant increase from 42.9% in the standard plane (P=0.007). Our imaging simulation and retrospective study demonstrate that different coronal planes could provide different degrees of freedom for cannulation, the 2-cm anterior plane has the greatest degrees of freedom in terms of larger target area and greater length range of the trajectory. The optimized surgical plan in this manner could improve cannulation accuracy and benefit a significant number of TBI patients.

Intellectual Disability in KATP Channel Neonatal Diabetes.

Neonatal diabetes has been shown to be associated with high neuropsychiatric morbidity in a genotype-phenotype-dependent manner. However, the specific impact of different mutations on intellectual functioning is still insufficiently characterized. Specifically, only a small number of subjects with developmental delay have been comprehensively assessed, creating a knowledge gap about patients carrying the heaviest burden. We assessed the intellectual functioning and mental health of the complete Norwegian population with KATP channel neonatal diabetes. Eight sulfonylurea-treated children (five with the p.V59M genotype [KCNJ11]) were assessed using age-matched control subjects with type 1 diabetes. The investigations included a physical and motor developmental examination, cerebral MRI, psychometrical examination, and questionnaires assessing intellectual capabilities and psychiatric morbidity. A strong genotype-phenotype correlation was found, revealing the p.V59M genotype as highly associated with substantial intellectual disability, with no significant correlation with the time of sulfonylurea initiation. Consistent with previous studies, other genotypes were associated with minor cognitive impairment. Cerebral MRI verified normal brain anatomy in all but one child. We here presented a comprehensive assessment of intellectual functioning in the largest cohort of p.V59M subjects to date. The level of intellectual disability revealed not only changes the interpretation of other psychological measures but downplays a strong protective effect of sulfonylurea. Within the scope of this study, we could not find evidence supporting an early treatment start to be beneficial, although a weaker effect cannot be ruled out.

Apparent diffusion coefficient of different areas of brain in foetuses with intrauterine growth restriction.

PurposeThis study aimed to compare the apparent diffusion coefficient (ADC) values of different brain areas between two groups of intrauterine growth restricted (IUGR) foetuses and control cases.Material and methodsA total of 38 foetuses with IUGR and 18 normal control foetuses with similar gestational age were compared using a 3T magnetic resonance scanner. IUGR cases included 23 foetuses with clinical severity signs (group A) and 15 foetuses without clinical severity signs (group B). ADC values were measured in different brain regions and compared among groups. Foetuses with structural brain abnormalities were excluded from the study.ResultsAll foetuses had normal foetal structural brain anatomy. Head circumference (HC) < 5% was more common in IUGR group A compared to IUGR group B (56.5% vs. 13.3%, p < 0.0001). In comparison to the normal group, the ADC values in IUGR foetuses were significantly lower in cerebellar hemispheres (CH) (1.239 vs. 1.280.5 × 10–3 mm2/s, p = 0.045), thalami (1.205 vs. 1.285 × 10–3 mm2/s, p = 0.031) and caudate nucleus (CN) (1.319 vs. 1.394 × 10–3 mm2/s, p = 0.04). However, there were no significant differences in ADC values between IUGR subtypes. Among all brain regions, pons had the lowest ADC values.ConclusionsADC values of thalami, CN, and CH were significantly lower in IUGR than control foetuses, while there was no significant difference among IUGR groups. Further studies are needed to evaluate the prognostic value of ADC changes in IUGR foetuses.

Prospective detection and differential diagnosis of cystic posterior fossa anomalies by assessing posterior brain at 11–14 weeks

The role of the first-trimester scan has expanded from aneuploidy screening to the diagnosis of fetal malformations. Abnormal appearance of the posterior brain at 11-14 weeks gestation is a marker of cerebral anomalies; in fact an increased amount of fluid, particularly when the choroid plexus of the fourth ventricle is not visible and only 2 brain spaces instead of 3 are seen, may indicate the presence of cystic or cyst-like posterior fossa anomalies, such as Blake's pouch cyst or Dandy-Walker malformation. The purpose of this study was to assess the role of ultrasound scanning in the identification of cystic posterior fossa anomalies at 11-14 weeks gestation. A prospective cohort study of fetuses with cystic appearance of the posterior fossa at 11-14 weeks gestation was performed. In all cases and in a control group of 40 normal fetuses, the brainstem-tentorium angle was also measured. The presence or absence of cystic posterior anomalies was determined at birth or at postmortem evaluation. In the period 2014-2018, 32 fetuses with an increased brainstem-occipital bone distance and/or failure to visualize the choroid plexus of fourth ventricle (2 brain spaces) were seen. Of these, 18 fetuses were terminated in the first trimester because of associated anomalies and were excluded from the study because of unavailable autoptic findings. The remaining 14 fetuses eventually were found to have a Dandy-Walker malformation in 4 cases, a Blake's pouch cyst in 8 cases, and normal brain anatomy in 2 cases. Two brain spaces were seen in all cases with Dandy-Walker malformation and in 2 of 8 cases with Blake's pouch cyst. Both brainstem-occipital bone measurement and brainstem-tentorium angle were significantly different in fetuses with Dandy-Walker malformation, Blake's pouch cyst, and control subjects (P<.0001). The brainstem-occipital bone z-scores of fetuses with Dandy-Walker malformation and Blake's pouch cyst were always+3 or more and+1.7 or more, respectively. The brainstem-tentorium angle z-scores were always -5 or less and -0.1 or less, respectively. Our study confirms that sonography of the posterior brain at 11-14 weeks gestation allows the identification of cystic posterior fossa anomalies. A large brainstem-occipital bone predicts Dandy-Walker malformation or Blake's pouch cyst. The presence of 2 brain spaces and a small brainstem-tentorium angle are correlated significantly with the presence of Dandy-Walker malformation.

Virtual reality objects improve learning efficiency and retention of diagnostic ability in fetal ultrasound.

Virtual reality (VR) objects of fetal ultrasound volumes have been proposed for teaching and learning diagnostic ultrasound. The aim of this study was to determine if VR objects improve learning efficiency and retention of diagnostic ability in fetal ultrasound. Medical students and junior doctors were taught normal and abnormal sonographic fetal brain anatomy using conventional means (video lectures and review articles; control group) or additionally with selected VR objects from a novel fetal brain atlas (Pocket Brain, http://pb.fetal.ch; study group). Knowledge, speed of recognition and retention of diagnostic ability were tested in multiple-choice questionnaires 1 and 4 months after teaching, and the results were compared between those taught using conventional means only and those taught using VR objects. Participants taught using VR objects answered significantly more questions correctly and solved the tests quicker than those taught using conventional methods only, both 1 and 4 months after teaching. The use of VR objects in teaching fetal ultrasound significantly improves learning efficiency and knowledge retention. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Microsurgical Angioarchitectonics of Deep Brain Structures and Deep Arterial Anastomoses

Surgeries for deep and eloquent cerebral lesions require a detailed knowledge of normal brain anatomy and accurate planning. Important parts of brain anatomy are the cerebral blood supply and collateral circulation system. In addition to well-known cortical and basal (circle of Willis) anastomoses, there is also a deep interarterial anastomotic circle that is not described in the literature. Twenty brain specimens were studied for deep arterial anastomotic connections between branches of the anterior and posterior choroidal arteries. We have marked 3 symmetric zones of deep arterial anastomoses that form an epithalamic circle. Epithalamic anastomoses provide an additional mechanism of blood distribution that may play a role during surgical interventions or stroke.

Increased Functional MEG Connectivity as a Hallmark of MRI-Negative Focal and Generalized Epilepsy.

Epilepsy is one of the most prevalent neurological diseases with a high morbidity. Accumulating evidence has shown that epilepsy is an archetypical neural network disorder. Here we developed a non-invasive cortical functional connectivity analysis based on magnetoencephalography (MEG) to assess commonalities and differences in the network phenotype in different epilepsy syndromes (non-lesional/cryptogenic focal and idiopathic/genetic generalized epilepsy). Thirty-seven epilepsy patients with normal structural brain anatomy underwent a 30-min resting state MEG measurement with eyes closed. We only analyzed interictal epochs without epileptiform discharges. The imaginary part of coherency was calculated as an indicator of cortical functional connectivity in five classical frequency bands. This connectivity measure was computed between all sources on individually reconstructed cortical surfaces that were surface-aligned to a common template. In comparison to healthy controls, both focal and generalized epilepsy patients showed widespread increased functional connectivity in several frequency bands, demonstrating the potential of elevated functional connectivity as a common pathophysiological hallmark in different epilepsy types. Furthermore, the comparison between focal and generalized epilepsies revealed increased network connectivity in bilateral mesio-frontal and motor regions specifically for the generalized epilepsy patients. Our study indicated that the surface-based normalization of MEG sources of individual brains enables the comparison of imaging findings across subjects and groups on a united platform, which leads to a straightforward and effective disclosure of pathological network characteristics in epilepsy. This approach may allow for the definition of more specific markers of different epilepsy syndromes, and increased MEG-based resting-state functional connectivity seems to be a common feature in MRI-negative epilepsy syndromes.

Prenatal Brain MR Imaging: Reference Linear Biometric Centiles between 20 and 24 Gestational Weeks.

Evaluation of biometry is a fundamental step in prenatal brain MR imaging. While different studies have reported reference centiles for MR imaging biometric data of fetuses in the late second and third trimesters of gestation, no one has reported them in fetuses in the early second trimester. We report centiles of normal MR imaging linear biometric data of a large cohort of fetal brains within 24 weeks of gestation. From the data bases of 2 referral centers of fetal medicine, accounting for 3850 examinations, we retrospectively collected 169 prenatal brain MR imaging examinations of singleton pregnancies, between 20 and 24 weeks of gestational age, with normal brain anatomy at MR imaging and normal postnatal neurologic development. To trace the reference centiles, we used the CG-LMS method. Reference biometric centiles for the developing structures of the cerebrum, cerebellum, brain stem, and theca were obtained. The overall interassessor agreement was adequate for all measurements. Reference biometric centiles of the brain structures in fetuses between 20 and 24 weeks of gestational age may be a reliable tool in assessing fetal brain development.