Interhemispheric Fissure Research Articles

Characteristics of Stratum Structure and Fracture Evolution in Stratified Mining of Shallow Buried High-Gas-Thick Coal Seam by Similarity Simulation

The stratified mining of super thick coal seam is a process of repeated disturbance of the top roof, especially in the lower stratification, the upper complex rock layer has a greater settlement space, resulting in great changes in the strata structure and fissure distribution. The main coal seam thickness of Rujigou Coal Mine exceeds 20 m, due to the high gas content of the coal seam, it is prone to spontaneous combustion, and the stratified mining method is adopted. When a small-size section coal pillar (less than 10 m) is used, the complex rock structure evolution and fissure development characteristics during the stratified mining of shallow buried thick coal seam will directly affect the movement of gas transportation between the working face and the goaf and will directly affect the safety of the working face. Taking Rujigou coal mine as engineering background, this paper analyzes the breaking structure, fracture development, and evolution law of overlying strata in different layers and different sections of coal seam when the buried depth is shallow, and the extra-thick coal seam is stratified mining. The results show that in the process of stratified mining, the overlying strata break, in addition to the whole trapezoidal failure structure, will also form a local F type fracture structure, and with the stratified downward mining, the F type fracture structure will continue to move up and disappear until it is compacted. The “V” type and “U” type subsidence characteristics of different strata overburden are presented after mining in stratified working face of extra-thick coal seam, and the subsidence amount is approximately symmetrical distribution along the middle line of goaf. In the mining process of the lower part of the layer, the end broken rock block is easy to slip along the hinge point by the hinged rock beam structure, and the sliding instability occurs. In the process of stratified mining of ultrathick coal seam, the main fissure of overburden is mainly longitudinal fissure, and it is very easy to form through with the upper layer and will finally connect with the surface under the condition of shallow buried depth. The inclined cracks connected with the adjacent goaf are formed above the coal pillar of the section, which becomes the passage of gas migration in the goaf. The research conclusion shows that for the stratified mining of high gas thick coal seam, special attention should be paid to the treatment of the gas on the stratified working face. In addition to the conventional gas treatment measures such as coal seam prepumping, the buried pipe pumping in the mining area can also be adopted, which can effectively reduce the gas concentration of the working surface.

Interhemispheric Contralateral Transfalcine Approach for Subparacentral Arteriovenous Malformation: 3-Dimensional Operative Video.

Neurovascular procedures along the interhemispheric fissure harbor unique features differentiating them from those arteriovenous malformations (AVMs) located at the lateral surface of the brain.1-4 The aim of this 3-dimensional operative video is to present a microsurgical resection of an AVM in a subparacentral location, operated through an interhemispheric contralateral transfalcine approach.1,3,5 This is a case of a 29-yr-old female, with headaches and history of seizures. The patient presented an interhemispheric bleeding 6 mo before the surgery. The magnetic resonance imaging (MRI) showed a vascular lesion located on the medial surface of the right hemisphere at the confluence between the cingulate sulcus and its ascending sulcus. In the cerebral angiography, a right medial AVM was observed, receiving afference from the right anterior cerebral artery and draining to the superior longitudinal sinus. The patient signed an informed consent for the procedure and agreed with the use of her images and surgical video for research and academic purposes. The patient was in a supine position, and a left interhemispheric contralateral transfalcine approach was performed,1-3 a circumferential dissection of the nidus, and, finally, the AVM was resected in one piece. The patient evolved without neurological deficits after the surgery. The postoperative MRI and angiography showed a complete resection of the AVM. In the case presented, to avoid exposing the drainage vein first and to use the gravity of the exposure, the contralateral transfalcine interhemispheric approach was used,1,2 which finally accomplished the proposed objectives.

Hybrid Fluoroscopic and Neurophysiological Targeting of Responsive Neurostimulation of the Rolandic Cortex.

Precise targeting of cortical surface electrodes to epileptogenic regions defined by anatomic and electrophysiological guideposts remains a surgical challenge during implantation of responsive neurostimulation (RNS) devices. To describe a hybrid fluoroscopic and neurophysiological technique for targeting of subdural cortical surface electrodes to anatomic regions with limited direct visualization, such as the interhemispheric fissure. Intraoperative two-dimensional (2D) fluoroscopy was used to colocalize and align an electrode for permanent device implantation with a temporary in Situ electrode placed for extraoperative seizure mapping. Intraoperative phase reversal mapping technique was performed to distinguish primary somatosensory and motor cortex. We applied these techniques to optimize placement of an interhemispheric strip electrode connected to a responsive neurostimulator system for detection and treatment of seizures arising from a large perirolandic cortical malformation. Intraoperative neuromonitoring (IONM) phase reversal technique facilitated neuroanatomic mapping and electrode placement. In challenging-to-access anatomic regions, fluoroscopy and intraoperative neurophysiology can be employed to augment targeting of neuromodulation electrodes to the site of seizure onset zone or specific neurophysiological biomarkers of clinical interest while minimizing brain retraction.

Impaired cerebrospinal fluid transport due to idiopathic subdural hematoma in pig: an unusual case

BackgroundWe report the effects of the presentation of an idiopathic subdural hematoma (SDH) in an adult domestic pig on the glymphatic system, a brain-wide solute clearance system. This accidental finding is based on our recently published study that described this system for the first time in large mammals. Our current results define the need to investigate cerebrovascular pathologies that could compromise glymphatic function in gyrencephalic animal models as a tool to bridge rodent and human glymphatic studies.Case presentationThe pig underwent intracisternal infusion of a fluorescent tracer under general anesthesia to delineate cerebrospinal fluid (CSF) pathways, and was euthanized at the end of 3 h of tracer circulation. During brain isolation, a hematoma measuring approximately 15 × 35 mm in size beneath the dura was evident overlying fronto-parietal brain surface. Interestingly, CSF tracer distribution was markedly reduced on dorsal, lateral and ventral surfaces of the brain when compared with a control pig that was infused with the same tracer. Furthermore, regional distribution of tracer along the interhemispheric fissure, lateral fissure and hippocampus was 4–5-fold reduced in comparison with a control pig. Microscopically, glial-fibrillary acidic protein and aquaporin-4 water channel immunoreactivities were altered in the SDH pig brain.ConclusionsThis is the first case of impaired glymphatic pathway due to an idiopathic SDH in a pig. Potential etiology could involve an acceleration-deceleration injury inflicted prior to arrival at our housing facility (e.g., during animal transportation) leading to disruption of bridging veins along the superior sagittal sinus and impairing CSF pathways in the whole brain. This accidental finding of globally impaired glymphatic function sheds light on a novel consequence of SDH, which may play a role in the enhanced cognitive decline seen in elderly presenting with chronic SDH.

Utility of a novel exoscope, ORBEYE, in gravity-assisted brain retraction surgery for midline lesions of the brain.

Background: Midline brain lesions, such as falx meningioma, arteriovenous malformations, and cavernous malformations, are usually approached from the ipsilateral interhemispheric fissure. To this end, patients are positioned laterally with the ipsilateral side up. However, some studies have reported the usefulness of gravity-assisted brain retraction surgery, in which patients are placed laterally with the ipsilateral side down or up, enabling surgeons to approach the lesions through the ipsilateral side or through a contralateral interhemispheric fissure, respectively. This surgery requires less brain retraction. However, when using an operative microscope, performing this surgery requires the surgeon to operate in an awkward position. A recently developed high-definition (4K-HD) 3-D exoscope system, ORBEYE, can improve the surgeon’s posture while performing gravity-assisted brain retraction surgery.Methods: We report five cases with midline brain tumors managed by resectioning with gravity-assisted brain retraction surgery using ORBEYE. We also performed an ergonomic analysis of gravity-assisted brain retraction surgery with a craniotomy model and a neuronavigation system.Results: Gravity-assisted brain retraction surgery to the midline brain tumors was successfully performed for all five patients, using ORBEYE, without any postoperative neurological deficit.Conclusion: Gravity-assisted brain retraction surgery to the midline brain lesions using ORBEYE is feasible, and ORBEYE is ergonomically more favorable than a microscope. ORBEYE has the potential to generalize neurosurgical approaches considered difficult due to the surgeon’s awkward position, such as gravity-assisted brain retraction surgery.

Resection of a recurrent pineal region teratoma via a posterior interhemispheric transcallosal approach.

The authors describe the unusual case of a 6-year-old boy presenting with decorticate posturing, diminished hearing, and an inability to open his eyes, despite being verbally responsive. He underwent a posterior interhemispheric transcallosal intervenous approach for resection of a pineal region mature teratoma, which recurred 2 years postoperatively. This video demonstrates his initial surgery and reresection, illustrating the value of this approach for more complex lesions that involve the internal cerebral veins (ICVs). At the time of recurrence, microsurgical dissection of the scarred interhemispheric fissure was required to facilitate removal of the multifocal recurrent teratoma, resulting in gross-total resection.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2134.

Transection of the Superior Sagittal Sinus Enables Bilateral Access to the Rodent Midline Brain Structures.

Stereotaxic access to brain areas underneath the superior sagittal sinus (SSS) is notoriously challenging. As a major drainage vessel, covering the whole extension of the sagittal fissure, the SSS impedes direct bilateral access to underlying regions for recording and stimulation probes, drug-delivery cannulas, and injection devices. We now describe a new method for transection and retraction of the SSS in rats, that allows the accurate placement of microinjection devices, or chronic electrode probes, while avoiding hemorrhage and the ensuing deleterious consequences for local structures, animal health, and behavior. To demonstrate the feasibility of this approach we evaluated its consequences acutely during surgery, and thereafter during surgical survival, recovery, behavioral testing, as well as postmortem analysis of histologic impact in the related brain structures of male rats. This method provides a new approach enabling direct access for manipulation and recording of activity in brain areas previously obstructed by the SSS.

Morphology and Morphometry of Foetal Corpus Callosum Using MRI – A Retrospective Study

Introduction: Corpus callosum (CC) is the largest commissural white fibres interconnecting cerebral hemispheres. The corpus callosum is responsible for interhemispheric transfer of information which is essential for cognitive function. The foetal corpus callosum serves as sensitive indicator for normal brain development and maturation. As the corpus callosum is a part of the highest order latest maturing mental network of the brain, its measurements are important to assess normal brain development and to locate structural changes. A comprehensive evaluation of normal human foetal corpus callosal development is essential to detect and understand the congenital anomalies of the brain. Thus, the prenatal diagnosis of partial or complete agenesis of the corpus callosum is important for predicting the normal development of the foetus. Foetal neural anomalies that are suspected on prenatal ultrasonography (USG) can be detected in early stage using foetal MRI. This imaging technique is highly useful for detailed visualization of normal neural development. Certain conditions like colpocephaly and widening of interhemispheric fissure can be clearly visualized using foetal MRI when compared to prenatal ultrasonography. Aim and objective: Was to establish the normal reference values for the measurement of foetal corpus callosum. The length and thickness of the foetal CC was measured corresponding to gestational age (GA) between 18-36weeks. Materials and methods: A retrospective MRI study was carried out in Radiology department of Sri Ramachandra Hospital. The study was conducted on 50 pregnant women with GA of 18-32 weeks and morphology of foetal corpus callosum was measured using MRI. The corpus callosum was visualized in a mid-sagittal plane as an anechoic structure, delimited by two echogenic lines superiorly by sulcus of the corpus callosum and inferiorly by the septum pellucidum. The length of corpus callosum was measured from the anterior most aspect of genu to the posterior most aspect of the splenium and the width of individual parts were measured and correlated with gestational age. The values obtained from the study were statistically calculated using regression coefficient method. Results: In the present study following parameters were observed such as length and width of diverse parts of Corpus callosum. The length of foetal CC ranged from 25.96 to 47.2 mm in 18 to 32 weeks of gestational age. The range of width of rostrum, genu, body and splenium were 1.2 to 2.2 mm, 1.2-2.8mm, 1.3-3.1mm and 1.36-3.2mm respectively. Conclusion: The periodic development of nervous system can be calculated more effectively with the morphometric measurement of foetal CC and its correlation with BPD. It is considered to be accurate than using BPD measurement of head circumference in USG. Hence, with the normative data of foetal CC measurements correlated with gestational age would give us accurate details of neuronal growth rather than measuring biparietal diameter (BPD) alone using USG. This knowledge will be highly helpful for the gynaecologists to predict the abnormal development of the foetus and it is advised to include foetal CC parameters as a one of the tools for early detection of CNS anomalies.

Mouse closed head traumatic brain injury replicates the histological tau pathology pattern of human disease: characterization of a novel model and systematic review of the literature

Traumatic brain injury (TBI) constitutes one of the strongest environmental risk factors for several progressive neurodegenerative disorders of cognitive impairment and dementia that are characterized by the pathological accumulation of hyperphosphorylated tau (p-Tau). It has been questioned whether mouse closed-head TBI models can replicate human TBI-associated tauopathy. We conducted longitudinal histopathological characterization of a mouse closed head TBI model, with a focus on pathological features reported in human TBI-associated tauopathy. Male C57BL/6 J mice were subjected to once daily TBI for 5 consecutive days using a weight drop paradigm. Histological analyses (AT8, TDP-43, pTDP-43, NeuN, GFAP, Iba-1, MBP, SMI-312, Prussian blue, IgG, βAPP, alpha-synuclein) were conducted at 1 week, 4 weeks, and 24 weeks after rTBI and compared to sham operated controls. We conducted a systematic review of the literature for mouse models of closed-head injury focusing on studies referencing tau protein assessment. At 1-week post rTBI, p-Tau accumulation was restricted to the corpus callosum and perivascular spaces adjacent to the superior longitudinal fissure. Progressive p-Tau accumulation was observed in the superficial layers of the cerebral cortex, as well as in mammillary bodies and cortical perivascular, subpial, and periventricular locations at 4 to 24 weeks after rTBI. Associated cortical histopathologies included microvascular injury, neuroaxonal rarefaction, astroglial and microglial activation, and cytoplasmatic localization of TDP-43 and pTDP-43. In our systematic review, less than 1% of mouse studies (25/3756) reported p-Tau using immunostaining, of which only 3 (0.08%) reported perivascular p-Tau, which is considered a defining feature of chronic traumatic encephalopathy. Commonly reported associated pathologies included neuronal loss (23%), axonal loss (43%), microglial activation and astrogliosis (50%, each), and beta amyloid deposition (29%). Our novel model, supported by systematic review of the literature, indicates progressive tau pathology after closed head murine TBI, highlighting the suitability of mouse models to replicate pertinent human histopathology.

Cranial imaging in children with malnutrition aged 6 to 60 months

Background: India has 57 million or more than a third of the world's 146 million undernourished children. Protein energy malnutrition is associated with cerebral atrophy 2 which may be detrimental to intellectual development. The aim and objective of this stusy was to study the changes in the brain by cranial imaging in children with malnutrition aged 6 months to 5 years and to correlate these changes with severity of malnutrition.Methods: It was a hospital based prospective study done in Bal Chikitsalay, Maharana Bhupal government hospital, Udaipur during the study period July 2015 to July 2016. Total 120 children were enrolled, out of which 80 were severely malnourished, 20 were moderately malnourished and 20 normally nourished children undergoing neuroimaging for some other reason taken as controls. All the cases were subjected to CT scan and the following parameters were noted. Central atrophy was evaluated by bifrontal index (BFR) and bicaudate index (BCR). Cortical atrophy was evaluated by width of sylvian fissure (SFW) and widening of interhemispheric fissure (IHD). These parameters were then compared with the severity of malnutrition and among controls. Data was analysed with standard software of biostatics using parametric tests, Pearson’s correlation analysis, ANOVA test and student’s t test.Results: On an average 80% of SAM and 10% of MAM had various degree of cerebral atrophy while none of the controls showed significant degree of cerebral atrophy.Conclusions: Effect of malnutrition on brain can be objectively assessed by CT indices, BFR, BCR, SFW and IHD to define the degree of cerebral atrophy in the malnourished population.

Correlating functional near-infrared spectroscopy with underlying cortical regions of 0-, 1-, and 2-year-olds using theoretical light propagation analysis.

.Significance: The establishment of a light propagation analysis-based scalp-cortex correlation (SCC) between the scalp location of the source–detector (SD) pair and brain regions is essential for measuring functional brain development in the first 2 years of life using functional near-infrared spectroscopy (fNIRS).Aim: We aimed to reveal the optics-based SCC of 0-, 1-, and 2-year-olds (yo) and the suitable SD distance for this age period.Approach: Light propagation analyses using age-appropriate head models were conducted on SD pairs at 10-10 fiducial points on the scalp to obtain optics-based SCC and its metrics: the number of corresponding brain regions (), selectivity and sensitivity of the most likely corresponding brain region (MLCBR), and consistency of the MLCBR across developmental ages. Moreover, we assessed the suitable SD distances for 0-, 1-, and 2-yo by simultaneously considering the selectivity and sensitivity of the MLCBR.Results: Age-related changes in the SCC metrics were observed. For instance, the of 0-yo was larger than that of 1- and 2-yo. Conversely, the selectivity of 0-yo was lower than that of 1- and 2-yo. The sensitivity of 1-yo was higher than that of 0-yo at 15- to 30-mm SD distances and higher than that of 2-yo at 10-mm SD distance. Notably, the MLCBR of the fiducial points around the longitudinal fissure was inconsistent across age groups. An SD distance between 15 and 25 mm was found to be appropriate for satisfying both sensitivity and selectivity requirements. In addition, this work provides reference tables of optics-based SCC for 0-, 1-, and 2-yo.Conclusions: Optics-based SCC will be informative in designing and explaining child developmental studies using fNIRS. The suitable SD distances were between 15 and 25 mm for the first 2 years of life.

Building bridges in the brain

Neurodevelopment Some 200 million axons connect the right hemisphere to the left through the brain's corpus callosum. A malformed or absent corpus callosum causes neurological or cognitive deficits. During development, astroglia build a substrate for axons to use in crossing the interhemispheric fissure. Signaling by Netrin 1 (NTN1) and its receptor, Deleted in Colorectal Carcinoma (DCC), guides axons to the midline. Morcom et al. show that NTN1 and DCC function even earlier to clear the path by regulating astroglial morphology and function. Without NTN1 and DCC function, astroglia that would normally build bridges across the interhemispheric fissure are unable to do so, and thus axons, no matter how well guided, struggle to build the corpus callosum. eLife 10 , e61769 (2021)

DRAXIN regulates interhemispheric fissure remodelling to influence the extent of corpus callosum formation.

Corpus callosum dysgenesis (CCD) is a congenital disorder that incorporates either partial or complete absence of the largest cerebral commissure. Remodelling of the interhemispheric fissure (IHF) provides a substrate for callosal axons to cross between hemispheres, and its failure is the main cause of complete CCD. However, it is unclear whether defects in this process could give rise to the heterogeneity of expressivity and phenotypes seen in human cases of CCD. We identify incomplete IHF remodelling as the key structural correlate for the range of callosal abnormalities in inbred and outcrossed BTBR mouse strains, as well as in humans with partial CCD. We identify an eight base-pair deletion in Draxin and misregulated astroglial and leptomeningeal proliferation as genetic and cellular factors for variable IHF remodelling and CCD in BTBR strains. These findings support a model where genetic events determine corpus callosum structure by influencing leptomeningeal-astroglial interactions at the IHF.

Automated Midline Estimation for Symmetry Analysis of Cerebral Hemispheres in FLAIR MRI.

To perform brain asymmetry studies in large neuroimaging archives, reliable and automatic detection of the interhemispheric fissure (IF) is needed to first extract the cerebral hemispheres. The detection of the IF is often referred to as mid-sagittal plane estimation, as this plane separates the two cerebral hemispheres. However, traditional planar estimation techniques fail when the IF presents a curvature caused by existing pathology or a natural phenomenon known as brain torque. As a result, midline estimates can be inaccurate. In this study, a fully unsupervised midline estimation technique is proposed that is comprised of three main stages: head angle correction, control point estimation and midline generation. The control points are estimated using a combination of intensity, texture, gradient, and symmetry-based features. As shown, the proposed method automatically adapts to IF curvature, is applied on a slice-to-slice basis for more accurate results and also provides accurate delineation of the midline in the septum pellucidum, which is a source of failure for traditional approaches. The method is compared to two state-of-the-art methods for midline estimation and is validated using 75 imaging volumes (~3,000 imaging slices) acquired from 38 centers of subjects with dementia and vascular disease. The proposed method yields the lowest average error across all metrics: Hausdorff distance (HD) was 0.32 ± 0.23, mean absolute difference (MAD) was 1.10 ± 0.38 mm and volume difference was 7.52 ± 5.40 and 5.35 ± 3.97 ml, for left and right hemispheres, respectively. Using the proposed method, the midline was extracted for 5,360 volumes (~275K images) from 83 centers worldwide, acquired by GE, Siemens and Philips scanners. An asymmetry index was proposed that automatically detected outlier segmentations (which were <1% of the total dataset). Using the extracted hemispheres, hemispheric asymmetry texture biomarkers of the normal-appearing brain matter (NABM) were analyzed in a dementia cohort, and significant differences in biomarker means were found across SCI and MCI and SCI and AD.

Neocortical Anatomy in the South American Plains Vizcacha, Lagostomus maximus, Reveals Different Strategies in Encephalic Development among Hystricomorpha and Myomorpha Rodents

Depending on the presence or absence of sulci and convolutions, the brains of mammals are classified as gyrencephalic or lissencephalic. We analyzed the encephalic anatomy of the hystricomorph rodent Lagostomus maximus in comparison with other evolutionarily related species. The encephalization quotient (EQ), gyrencephaly index (GI), and minimum cortical thickness (MCT) were calculated for the plains vizcacha as well as for other myomorph and hystricomorph rodents. The vizcacha showed a gyrencephalic brain with a sagittal longitudinal fissure that divides both hemispheres, and 3 pairs of sulci with bilateral symmetry; that is, lateral-rostral, intraparietal, and transverse sulci. The EQ had one of the lowest values among Hystricomorpha, while GI was one of the highest. Besides, the MCT was close to the mean value for the suborder. The comparison of EQ, GI, and MCT values between hystricomorph and myomorph species allowed the detection of significant variations. Both EQ and GI showed a significant increase in Hystricomorpha compared to Myomorpha, whereas a Pearson’s analysis between EQ and GI depicted an inverse correlation pattern for Hystricomorpha. Furthermore, the ratio between MCT and GI also showed a negative correlation for Hystricomorpha and Myomorpha. Our phylogenetic analyses showed that Hystricomorpha and Myomorpha do not differ in their allometric patterning between the brain and body mass, GI and brain mass, and MCT and GI. In conclusion, gyrencephalic neuroanatomy in the vizcacha could have developed from the balance between the brain size, the presence of invaginations, and the cortical thickness, which resulted in a mixed encephalization strategy for the species. Gyrencephaly in the vizcacha, as well as in other Hystricomorpha, advocates in favor of the proposal that in the more recently evolved Myomorpha lissencephaly would have arisen from a phenotype reversal process.

DCC regulates astroglial development essential for telencephalic morphogenesis and corpus callosum formation.

The forebrain hemispheres are predominantly separated during embryogenesis by the interhemispheric fissure (IHF). Radial astroglia remodel the IHF to form a continuous substrate between the hemispheres for midline crossing of the corpus callosum (CC) and hippocampal commissure (HC). Deleted in colorectal carcinoma (DCC) and netrin 1 (NTN1) are molecules that have an evolutionarily conserved function in commissural axon guidance. The CC and HC are absent in Dcc and Ntn1 knockout mice, while other commissures are only partially affected, suggesting an additional aetiology in forebrain commissure formation. Here, we find that these molecules play a critical role in regulating astroglial development and IHF remodelling during CC and HC formation. Human subjects with DCC mutations display disrupted IHF remodelling associated with CC and HC malformations. Thus, axon guidance molecules such as DCC and NTN1 first regulate the formation of a midline substrate for dorsal commissures prior to their role in regulating axonal growth and guidance across it.

Surgical revascularization of frontal areas in pediatric Moyamoya vasculopathy: a systematic review.

The aim of this study is to systematically review the literature on surgical revascularization techniques for flow-augmentation of the frontal areas and/or anterior cerebral artery (ACA) territory in children with Moyamoya vasculopathy (MMV), to elucidate the current surgical practice and describe the outcome associated to the different techniques. The systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. MEDLINE, Web of Science and EMBASE were searched up to April 2020. Published techniques were systematically analyzed according to level of evidence, revascularization technique, opening of the interhemispheric fissure (IF), uni- or bilateral revascularization, clinical, neurocognitive, angiographic, perfusion and hemodynamic outcome. Twenty-five studies were enrolled, including 829 patients: among these, 13 patients underwent direct revascularization of ACA territories, 570 indirect revascularization and 246 patients combined revascularization. One study reached a level of evidence II (grade of recommendation B), 8 studies were level III (grade B) and 16 studies were level IV (grade C). The surgical techniques proposed in the enrolled papers were systematically described. Combined techniques (grade of recommendation B) and indirect techniques (grade of recommendation C) are considered effective for revascularizing the frontal areas and/or anterior cerebral artery (ACA) territory in children with MMV. While performing the revascularization, surgical risks can be reduced by avoiding the exposure of the superior sagittal sinus and opening of IF (recommendation grade C). There is not sufficient evidence to define which type of surgical technique should be preferred. Future studies are needed for a longitudinal assessment of comparable outcomes and to determine which revascularization technique for the frontal areas and/or ACA territory is optimal for this highly specific pediatric population.

Birth-related subdural hemorrhage: prevalence and imaging morphology.

Birth trauma accounts for 1-2% of the mortality in newborns with significant intracranial injuries presenting in the immediate postnatal period. However, a significant number of asymptomatic neonates harbor birth-related intracranial hemorrhage (ICH), with birth-related subdural hemorrhage (SDH) being a common occurrence on infant brain CT and MRI studies performed as a standard of care for a variety of reasons. Although clinically insignificant, birth-related SDH is frequently brought up in courts as an alternative explanation for SDH in suspected abusive head trauma. The aim of this study was to determine prevalence, imaging morphology and distribution of birth-related SDHs on brain CT and MRI studies obtained as a standard of care in infants up to 1month old. We further tried to ascertain the relationship of birth-related SDHs with mode of delivery and birth weight. Infants up to the age of 1month who had CT or MRI of the brain performed between Jan. 1, 2018, and March 29, 2020, were included in this retrospective observational study. In addition to the imaging data, we reviewed clinical history, birth history including birth weight and mode of delivery, and final diagnoses. Two hundred six infants younger than 30days (range 0-29days, mean 11.9days, median 11days and standard deviation [SD] 8.4days) had a CT or MRI study during the study period. Among these, 58 infants were excluded as per the exclusion criteria. Among the included 148 infants, 88 (59.5%) had no imaging evidence of SDH. An additional 56 (37.8%) infants were assessed as having birth-related SDH based on review of clinical data. Within the birth-related SDH cohort (56 infants), only supratentorial SDH was identified in 5 (8.9%), only infratentorial SDH was identified in 14 (25%), while SDHs within both compartments were identified in 37 (66.1%) infants. The most common location for supratentorial birth-related SDH was along the occipital lobes (31/42, 73.8%), with other common locations being along the posterior interhemispheric fissure (30/42, 71.4%) and fronto-parietal convexity (9/42, 21.4%). The distribution of posterior fossa SDH was along the tentorium (38/51, 74.5%), along the cerebellum (38/51, 74.5%) and in both the locations (25/51, 49.0%). The rate of SDH was significantly higher in vaginal delivery group (46/84, 54.7%) as compared to caesarean section group (10/57, 17.5%) (P<0.05). We did not find any statistically significant difference between the birth weights of normal and birth-related SDH cohorts (P>0.05). Birth-related SDH is a common occurrence, with our study suggesting a prevalence of 37.8%. The most common distribution of birth-related SDH is within both the supra- and infratentorial compartments (66.1%) followed by infratentorial compartment (25%). The rate of birth-related SDH was significantly higher in vaginal delivery group as compared to caesarean section group.

A longitudinal observation of brain structure between AD and FTLD

IntroductionAlzheimer’s disease (AD) and frontotemporal lobar degeneration (FTLD) are the leading causes of dementia. To better understand the disease development of cognitive function and anatomical structure in AD and FTLD, we analyzed the changes in brain volume by MRI and the psychological test results. Here, we report a dynamic observation of brain structure. MethodsThirteen patients diagnosed with probable AD by the 2011 NIA-AA criteria and eight FTLD patients diagnosed by the FTLD criteria underwent MRI at baseline. All subjects were rescanned after 5 months to 3 years of follow-up. The anatomic changes on T1-weighted imaging of each subject were measured, and the separate changes in the two groups and the differences in the changes between AD and FTLD were analyzed. ResultsIn AD patients, the anterior and posterior horns of the lateral ventricle and lateral fissure enlarged progressively (p < 0.001). The volume of the regions, including the medial and lateral temporal lobe, especially the parahippocampal gyrus, and the frontal lobe decreased significantly as the disease progressed (p < 0.001). Additionally, the volume of white matter in the frontal, parietal, temporal lobe and cerebellum decreased in a relatively symmetric pattern (p < 0.001). In FTLD patients, the anterior horn of the lateral ventricle, lateral fissure, cerebral longitudinal fissure, external space of the orbitofrontal cortex, and mesencephalon surrounding the cisterna were enlarged (p < 0.005), while regions including the left frontal lobe, anterior cingulate cortex, basal ganglia (especially the left basal ganglia), left lateral temporal lobe and inferior cerebellar vermis decreased as the disease progressed (p < 0.005). Regarding the differences between AD and FTLD, atrophy of the frontal lobe and bilateral basal ganglia was more significant in FTLD than in AD (p < 0.01). In addition, enlargements of the anterior horn of the lateral ventricle, left lateral fissure and interpeduncular cistern were more significant in FTLD patients than in AD patients (p < 0.01). ConclusionsThese findings suggest that AD and FTLD have distinctly different atrophy patterns: AD patients show diffuse atrophy while FTLD patients show an asymmetrical focal atrophy pattern, which might explain the relatively better and longer preservation of daily living function in FTLD patients.

ISUOG Practice Guidelines (updated): sonographic examination of the fetal central nervous system. Part 2: performance of targeted neurosonography.

ISUOG Practice Guidelines (updated): sonographic examination of the fetal central nervous system. Part 2: performance of targeted neurosonography.