The infant skull: a vault of information

Fetal macrocephaly: Pathophysiology, prenatal diagnosis and management

Macrocephaly means a large head and is defined as a head circumference (HC) above the 98th percentile or greater than +2SD above the mean for gestational age. Macrocephaly can be primary and due to increased brain tissue (megalocephaly), which in most cases is familial and benign or secondary. The latter may be due to various causes, including but not limited to communicating or non-communicating hydrocephalus, cerebral edema, focal and pericerebral increased fluid collections, thickened calvarium and brain tumors. Megalocephaly can be syndromic or non-syndromic. In the former, gyral and structural CNS anomalies are common. It is important to exercise caution when considering a diagnosis of megalocephaly due to limitations in the accuracy of HC measurement, lack of nomograms for specific populations, inconsistencies between prenatal and postnatal HC growth curves and progression over time. The degree of macrocephaly is important, with mild macrocephaly ≤2.5SD carrying a good prognosis, especially when one of the parents has macrocephaly and normal development. Cases in which the patient history and/or physical exam are positive or when parental HC are normal are more worrisome and warrant a neurosonogram, fetal MRI and genetic testing to better delineate the underlying etiology and provide appropriate counseling.

An algorithmic clinicoradiological approach to paediatric cranial vault lesions: distinguishing normal variants from pathologies

Lesions of the paediatric cranial vault are diverse both in their presentation and aetiology. As such, they pose a diagnostic challenge to the paediatric neurosurgeon and neuroradiologist. In this article, we delineate the spectrum of paediatric calvarial pathology into four distinct groups: (1) lytic lesion(s); (2) focal sclerotic lesion(s); (3) diffuse cranial vault sclerosis; and (4) abnormal shape of the cranial vault. It is our aim that this more pragmatic, algorithmic approach may mitigate diagnostic uncertainty and aid the more accurate diagnosis of paediatric calvarial lesions.

Developing Disposable EEG Cap for Infant Recordings at the Neonatal Intensive Care Unit

Long-term EEG monitoring in neonatal intensive care units (NICU) is challenged with finding solutions for setting up and maintaining a sufficient recording quality with limited technical experience. The current study evaluates different solutions for the skin-electrode interface and develops a disposable EEG cap for newborn infants. Several alternative materials for the skin-electrode interface were compared to the conventional gel and paste: conductive textiles (textured and woven), conductive Velcro, sponge, super absorbent hydrogel (SAH), and hydro fiber sheets (HF). The comparisons included the assessment of dehydration and recordings of signal quality (skin interphase impedance and powerline (50 Hz) noise) for selected materials. The test recordings were performed using snap electrodes integrated into a forearm sleeve or a forehead band along with skin-electrode interfaces to mimic an EEG cap with the aim of long-term biosignal recording on unprepared skin. In the hydration test, conductive textiles and Velcro performed poorly. While the SAH and HF remained sufficiently hydrated for over 24 h in an incubator-mimicking environment, the sponge material was dehydrated during the first 12 h. Additionally, the SAH was found to have a fragile structure and was electrically prone to artifacts after 12 h. In the electrical impedance and recording comparisons of muscle activity, the results for thick-layer HF were comparable to the conventional gel on unprepared skin. Moreover, the mechanical instability measured by 1-2 Hz and 1-20 Hz normalized relative power spectrum density was comparable with clinical EEG recordings using subdermal electrodes. The results together suggest that thick-layer HF at the skin-electrode interface is an effective candidate for a preparation-free, long-term recording, with many advantages, such as long-lasting recording quality, easy use, and compatibility with sensitive infant skin contact.

Anatomy of the Calvaria and Skull Base

A thorough understanding of the skull anatomy is of key importance to radiologists as well as specialist physicians and surgeons. We describe the anatomy of the neurocranium comprising calvaria (the skull vault) and the skull base and discuss the most common and clinically relevant anatomic variants.

Pitfalls in the interpretation of pediatric head CTs: what the emergency radiologist needs to know

Pediatric radiology studies can be some of the most anxiety-inducing imaging examinations encountered in practice. This can be in part due to the wide range of normal anatomic appearances inherent to the pediatric population that create potential interpretive pitfalls for radiologists. The pediatric head is no exception; for instance, the inherent greater water content within the neonatal brain compared to older patients could easily be mistaken for cerebral edema, and anatomic variant calvarial sutures can be mistaken for skull fractures. This article reviews potential pitfalls emergency radiologists may encounter in practice when interpreting pediatric head CTs, including trauma, extra-axial fluid collections, intra-axial hemorrhage, and ventriculoperitoneal shunt complications.

New Association between Idiopathic Scoliosis and Luckenschadel Skull (Lacunar Skull)

OBJECTIVE

Luckenschadel skull is a skull that is radiologically characterized by lacunae in the cranial vault. To date, although the association between neurological abnormalities and scoliosis is well recognized, no relationship between idiopathic scoliosis and a lacunar skull has been defined. We explored the incidence and time courses of lacunar skulls in patients with idiopathic scoliosis.

MATERIALS AND METHODS

Spinal X-rays of 3,170 children aged 6-16 years with idiopathic scoliosis evaluated from October 2010 to August 2020 were examined for the presence of an irregular inner calvarial table indicative of a Luckenschadel skull. A total of 1,760 (55.5%) of the 3,170 images included the skull. We also explored the frequency of intraspinal abnormalities in children with lacunar skull images who underwent spinal magnetic resonance imaging.

RESULTS

The study population consisted of 1,760 children, 1,203 girls (68.4%) and 557 (31.6%) boys. A total of 268 (15.2%) clearly evidenced lacunar skulls in their radiographs; 186 (69.4%) girls (11.3 ± 4.3 years) and 82 (30.6%) boys (12.6 ± 3.3 years). Two of the 56 patients (3.6%) who underwent spinal MRI had intraspinal abnormalities (isolated Chiari malformation-I). No additional neurological problems were detected in children with lacunar skulls.

CONCLUSION

We conclude that the lacunar skull is very common in children with idiopathic scoliosis who lack any other neurological pathology. The lacunar skull does not disappear even in adolescence. Although previous publications have stated that lacunar skull disappears over time in radiographic images, we observed that it became more noticeable over time in children with scoliosis.

Calvarial tuberculosis in a paediatric patient: a diagnosis not to forget

We report the case of a 10-year-old boy that presented with a palpable, painless, frontal lesion. Laboratory assessments were unremarkable and the patient was asymptomatic. Initial investigation, with a skull radiograph and unenhanced CT scan, showed a lytic midline frontal lesion involving the inner and outer tables of the skull and a large subgaleal hypodense component. MRI further depicted communication with the epidural space and contact with the superior sagittal sinus (SSS). Subsequent evaluation by Doppler ultrasound and MR angiography excluded a sinus pericranii and showed normal patency of the SSS. Surgical biopsy revealed chronic granulomatous inflammation; PCR was positive for Mycobacterium sp. One year after surgical resection and antitubercular therapy, there are no signs of recurrence. Primary calvarial involvement by tuberculosis is rare, even in developing countries. Familiarity with the expected clinical and imaging features is required to avoid diagnostic delay.

Point-of-care Ultrasound to Distinguish Subgaleal and Cephalohematoma: Case Report

Introduction

Cephalohematomas generally do not pose a significant risk to the patient and resolve spontaneously. Conversely, a subgaleal hematoma is a rare but more serious condition. While it may be challenging to make this diagnostic distinction based on a physical examination alone, the findings that differentiate these two conditions can be appreciated on point-of-care ultrasound (POCUS). We describe two pediatric patient cases where POCUS was used to distinguish between a subgaleal hematoma and a cephalohematoma.

Case Reports

We describe one case of a 14-month-old male brought to the pediatric emergency department (PED) with concern for head injury. A POCUS examination revealed a large fluid collection that did not cross the sagittal suture. Thus, the hematoma was more consistent with a cephalohematoma and less compatible with a subgaleal hematoma. Given these findings, further emergent imaging was deferred in the PED and the patient was kept for observation. In the second case an 8-week-old male presented with suspected swelling over the right parietal region. A POCUS examination was performed, which demonstrated an extensive, simple fluid collection that extended across the suture line, making it more concerning for a subgaleal hematoma. Given the heightened suspicion for a subgaleal hematoma, the patient was admitted for further imaging and evaluation.

Conclusion

Point-of-care ultrasound can be used to help differentiate between a subgaleal hematoma and a cephalohematoma to risk-stratify patients and determine the need for further imaging.

Imaging Spectrum of Calvarial Abnormalities

Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. ^©RSNA, 2021.

Cranial Vault Remodeling in Children With Ventricular Shunts

INTRODUCTION

Cranial vault surgery in children with ventricular shunts is more complex due to the possible interference of shunt location with surgical planning and increased risk of shunt related complications. The study evaluated the management of ventricular shunts during cranial vault remodeling (CVR) and subsequent outcomes and complications following CVR.

METHODS

An IRB-approved retrospective chart review was performed including patients who underwent CVR in presence of a ventricular shunt. Measured outcomes were number of shunt revisions following CVR, 30-day complication rate, 3-month complication rate, and post-CVR Whitaker classification. Finally, a review of the literature was performed, and our results were compared to previous reports.

RESULTS

Eleven patients met the inclusion criteria. Ventricular shunt was not exposed in 18%; exposed and not revised in 54%; exposed and left on a bone peninsula in 18% and simultaneously exposed and revised in 18%. Two patients experienced complications within 30-days. Three additional patients experienced complications within 3-months. An average of 2.2 shunt revisions per patient were performed following CVR. Whitaker classification was I in 7 patients, II in 1 patient and III in 2 patients. Shunt revision rate for patients undergoing CVR for hydrocephalic macrocephaly was on average of 1.2 and 1.9 for shunt-induced craniosynostosis in literature.

CONCLUSIONS

Cranial vault abnormalities in the presence of a ventricular shunt can be effectively treated with CVR. The presence of a shunt does not seem to interfere with final head shape. While leaving the shunt unexposed may appear less morbid, shunt related complications can still occur with this approach.

The Use of Virtual Surgical Planning for Reduction Cranioplasty

Hydrocephalic macrocephaly may occur as a result of untreated hydrocephalus. Reduction cranioplasty is the treatment of choice for these patients when the weight of their head interferes with normal development and negatively impacts quality of life. However, this procedure has several associated risks, including prolonged anesthesia, significant blood loss, and death. Virtual surgical planning (VSP) has been shown to be a useful adjunct for orthognathic and craniofacial surgery. The following report details the application and advantages of this technology in the setting of a reduction cranioplasty. We report the case of a 2-year-old girl with severe hydrocephalic macrocephaly who underwent a reduction cranioplasty guided by VSP with computer-aided design and manufacturing (CAD/CAM). Prefabricated cutting guides and a concave assembly bowl were used for precise fixation of bony segments. Our patient underwent a successful reduction cranioplasty using VSP and CAD/CAM. This technology allowed precise remodeling of the cranial vault with minimal bony gaps in the final construct. Head circumference and intracranial volume were reduced from 70 cm and 4,575 cm³ to 62 cm and 2,645 cm³, respectively. VSP with CAD/CAM can serve as a useful adjunct in complex cases of cranioplasty allowing for an increase in the precision, the efficacy, and the esthetic result.

Association of abnormal metopic suture causing hypertelorism, interfrontal encephalocele with craniofacial cosmetic deformity associated with myelomeningocele: management literature review

Myelomeningocele may be associated with other neural and extraneural anomalies. Authors present association of metopic suture abnormality, an interfrontal encephalocele with widening of metopic suture and abnormal shape frontal bones in the forehead in those associated with hydrocephalus. Authors describes two neonates with interfrontal encephalocele, representing first series reporting in neonate. Management and pertinent literature is briefly discussed.

Craniometaphyseal dysplasia in a 14-month old: a case report and review of imaging differential diagnosis

We report a 14-month-old male with craniometaphyseal dysplasia (CMD). The patient presented with a history of diminishing vision and hearing loss. Cranial computed tomography scan showed diffuse calvarial and skull base hyperostosis with excessive bone narrowing the internal auditory canals and skull base foramina. A subsequent skeletal survey revealed other skeletal abnormalities, which led to the diagnosis of CMD. This was later confirmed by ANKH mutation. CMD is a rare genetic disorder that belongs to the group of craniotubular bone dysplasias. It is important to recognize this condition from other causes of craniotubular bone dysplasias to institute early treatment and explain prognosis.

Zika Fetal Neuropathogenesis: Etiology of a Viral Syndrome

The ongoing Zika virus epidemic in the Americas and the observed association with both fetal abnormalities (primary microcephaly) and adult autoimmune pathology (Guillain-Barré syndrome) has brought attention to this neglected pathogen. While initial case studies generated significant interest in the Zika virus outbreak, larger prospective epidemiology and basic virology studies examining the mechanisms of Zika viral infection and associated pathophysiology are only now starting to be published. In this review, we analyze Zika fetal neuropathogenesis from a comparative pathology perspective, using the historic metaphor of "TORCH" viral pathogenesis to provide context. By drawing parallels to other viral infections of the fetus, we identify common themes and mechanisms that may illuminate the observed pathology. The existing data on the susceptibility of various cells to both Zika and other flavivirus infections are summarized. Finally, we highlight relevant aspects of the known molecular mechanisms of flavivirus replication.

Hypophosphatasia: an overview of the disease and its treatment

This review presents the current knowledge on hypophosphatasia, a rare genetic disease of very variable severity (from lethal to mild) and clinical presentation, caused by defective production of tissue-non-specific alkaline phosphatase (TNSALP). Hypophosphatasia can affect babies in utero as well as infants, children, and adults. The article first presents the genetics of TNSALP and its many known mutations underlying the disease. Then, it presents the epidemiology, classification, and clinical presentation of the six different forms of the disease (perinatal lethal, prenatal benign, infantile, childhood, adult, and odontohypophosphatasia) as well as the essential diagnostic clues. The last section on treatment presents a survey of the therapeutic approaches, up to the ongoing phase 2 studies of enzyme replacement therapy.

Chiari malformation type III: Case report and review of the literature

Chiari malformation type III is an extremely rare anomaly characterized by a small posterior fossa and a low occipital/high cervical encephalocele with herniation of the posterior fossa contents (that is, the cerebellum and/or the brainstem, occipital lobe, and fourth ventricle). We report a case of Chiari malformation type III in a neonate, discuss the etiopathogenetic and radiological features, and review the pertinent literature.

Brain Structure in Neuropsychologically Defined Subgroups of Schizophrenia and Psychotic Bipolar Disorder

BACKGROUND

Neuropsychological impairment is heterogeneous in psychosis. The association of intracranial volume (ICV) and total brain volume (TBV) with cognition suggests brain structure abnormalities in psychosis will covary with the severity of cognitive impairment. We tested the following hypotheses: (1) brain structure abnormalities will be more extensive in neuropsychologically impaired psychosis patients; (2) psychosis patients with premorbid cognitive limitations will show evidence of hypoplasia (ie, smaller ICV); and (3) psychosis patients with evidence of cognitive decline will demonstrate atrophy (ie, smaller TBV, but normal ICV).

METHODS

One hundred thirty-one individuals with psychosis and 97 healthy subjects underwent structural magnetic resonance imaging and neuropsychological testing. Patients were divided into neuropsychologically normal and impaired groups. Impaired patients were further subdivided into deteriorated and compromised groups if estimated premorbid intellect was average or below average, respectively. ICV and TBV were compared across groups. Localized brain volumes were qualitatively examined using voxel-based morphometry.

RESULTS

Compared to healthy subjects, neuropsychologically impaired patients exhibited smaller TBV, reduced grey matter volume in frontal, temporal, and subcortical brain regions, and widespread white matter volume loss. Neuropsychologically compromised patients had smaller ICV relative to healthy subjects, and neuropsychologically normal and deteriorated patient groups, but relatively normal TBV. Deteriorated patients exhibited smaller TBV compared to healthy subjects, but relatively normal ICV. Unexpectedly, TBV, adjusted for ICV, was reduced in neuropsychologically normal patients.

CONCLUSIONS

Patients with long-standing cognitive limitations exhibit evidence of early cerebral hypoplasia, whereas neuropsychologically normal and deteriorated patients show evidence of brain tissue loss consistent with progression or later cerebral dysmaturation.

Multiple occipital, parietal, temporal, and frontal foramina: a variant of enlarged parietal foramina in an infant

BACKGROUND

Calvarial lesions are often detected incidentally in routine radiology. Most lytic lesions of the skull are benign. Enlarged parietal foramina are benign lesions caused by deficient intramembranous ossification.

CASE REPORT

An 11 month-old female patient was admitted with a mass on the right of the back of the head. Physical examination showed a soft 5 cm mass area with no palpable bone in the right occipital. The family history revealed a similar mass in a maternal cousin that resolved over time. Craniography showed lytic lesions, and there were no other pathologies on a complete skeletal X-ray. Computed tomography (CT) showed regular-shaped defects in the bilateral temporal bones, right parietal bone, bilateral frontal bones in the upper-medial orbital wall, and particularly in the occipital bone. The well-defined contours, absence of a soft tissue component, and normal structure and density of the adjacent calvarial bones all pointed to a congenital defect. No change in the lesions was observed during a three-year ultrasound follow-up period.

CONCLUSION

To the best of our knowledge, this is the first described case of multiple occipital, parietal, temporal, and frontal foramina in the cranium. A diagnosis of enlarged parietal foramina variant should be considered after ruling out the differential diagnosis in patients with multiple calvarial lesions. CT may provide valuable findings for the differential diagnosis, and sonography may be used for follow-up.

Unusual diastatic separation of the sagittal suture: Avoiding confusion with inflicted head trauma

Certain artifacts presenting on a fetus due to maceration or birth trauma, mimic inflicted head trauma (IHT) occurring post partum. In such cases, absent a thorough history and examination of the circumstances, the distinction may be impossible. This case report presents an unusual artifact occurring in a stillbirth delivered after the mother had complained of not feeling fetal movements for at least 24 hours. At autopsy, the macerated fetus presented with unusual widening of the sagittal suture and galeal/subgaleal hematomas. There were no other injuries. Review of the mothers antenatal, personal and social history combined with the absence of other injuries to the mother and fetus, helped distinguish the unusual birth-related diastatic separation from IHT. Consequently, in a case where the pathologist is presented with limited information for instance an abandoned fetus, a cautious approach to the determination of the cause and manner of death is strongly recommended.

Copper Beaten Skull! Can It be a Usual Appearance?

‘Copper beaten’ skull refers to the prominent convolutional markings seen in multiple bones of the skull. Underlying cause is thought to be related to increased intracranial pressure resulting from such processes as craniosynostosis, obstructive hydrocephalus and/or intracranial masses. However, the copper beaten appearance of the skull has poor sensitivity in detecting increased intracranial pressure as such an appearance can also be seen in normal patients. In this article, we have reported a case of a 5 years old child with classical features of beaten silver skull.

How to cite this article: Desai V, Priyadarshini SR, Sharma R. Copper Beaten Skull! Can It be a Usual Appearance? Int J Clin Pediatr Dent 2014;7(1):47-49.

Isolated primary craniosynostosis in an adult: Imaging findings of a case

Craniosynostosis means premature closure of calvarial sutures. It may be primary or secondary. The patient presents with unexplained neuropsychological impairment and radiological imaging clinches the diagnosis. We present a case of 31-year-old female having primary isolated craniosynostosis who survived into adulthood without any surgical intervention. The imaging findings of such a case are rarely described in the literature.

Skeletal survey normal variants, artefacts and commonly misinterpreted findings not to be confused with non-accidental injury

Radiology plays a key part in the investigation of non-accidental injury. Many normal variants and artefacts can simulate an abnormality associated with non-accidental injury. It is essential that radiologists reporting skeletal surveys in cases of suspected child abuse are aware of these. We present a pictorial essay to aid the reporting radiologist in the differentiation between normal variants or artefacts and true traumatic injury. We show plain film examples of potential pitfalls throughout the body.

Infantile osteopetrosis, craniosynostosis, and Chiari malformation type I with novel OSTEM1 mutation

We report a case of a 9-month-old Arab infant, with novel OSTEM mutation and unpublished triad of osteopetrosis (OP), craniosynostosis (CS), and Chiari malformation type I (CM1). The index presented with progressive irritability, abnormal movements, following an accidental fall. The history revealed early onset of irritability, progressive visual loss, and global developmental delay, more prominent at the gross motor level and a suspected congenital cytomegalovirus infection. The pregnancy was uneventful with subsequent unremarkable delivery. The parents are Arabs′first cousins with no apparent symptoms or signs of bone disease. Three dimensional brain computed tomography (CT) showed ventriculomegaly, thick calvaria, and CS of the coronal and sagittal sutures. Patient had signs of left lower motor neuron facial palsy, and CT of petrous bones confirms the presence of osteopetrotic petrous with slim mastoid portions of the facial nerve canals both sides. Brain magnetic resonance imaging showed CM1. Skeletal survey showed sclerotic skeleton. He needed ventriculoperitoneal shunt and died at 18 months of age. Molecular testing for OSTEM1 gene revealed novel homozygous mutation that segregated from his parents. This novel OSTEM1 gene novel mutation and the combination of OP, infantile CS, and CM1 is to our knowledge never been reported.

Craniospinal abnormalities and neurologic complications of osteogenesis imperfecta: imaging overview

Osteogenesis imperfecta is a rare genetic disorder that leads to progressive skeletal deformities due to deficits in type I collagen, the main pathophysiologic effect of the disease. In addition, it may lead to a wide range of associated neurologic abnormalities: The central nervous system is usually involved because of softening of bone at the base of the skull, with resultant upward migration of the upper cervical spine and odontoid process into the skull base. Upward migration of the spine may cause compression of the brainstem, mechanical impingement of the spinal canal with restriction of cerebrospinal fluid circulation, and impingement of the cranial nerves. Osteogenesis imperfecta also may directly involve neurovascular structures, leading to cavernous fistulas of the carotid artery, dissection of the cervical arteries, and cerebral aneurysms. The brain parenchyma is frequently affected by the disease, with manifestations including cerebral atrophy, communicating hydrocephalus, and cerebellar hypoplasia. The imaging features of the disorder vary as widely as its clinical manifestations, depending on the severity of disease. Severe forms accompanied by debilitating skeletal fractures and progressive neurologic impairments may lead to perinatal death, whereas milder asymptomatic forms might cause only a modest reduction in life span. The most important advance in medical therapy for osteogenesis imperfecta has been the introduction of bisphosphonate therapy to slow the resorption of bone in patients with moderate to severe forms of the disease (ie, type III or IV). In some patients, neurosurgery may be necessary to correct the effects of severe basilar invagination by the odontoid process.

Absence of the sagittal suture does not result in scaphocephaly

PURPOSE

Premature fusion or craniosynostosis of suture(s) of the calvaria is known to result in skull deformation. However, absence of sutures may be interpreted as premature closure of a suture of the calvaria. In the study, the authors investigated skull configuration in skulls found to have isolated absence of the sagittal suture.

METHODS

For this study, 400 adult and child skulls from all of the authors' osteological collections were analyzed.

RESULTS

Of these 400 skulls, three specimens were found to have isolated absence of the sagittal suture (one child and two adults). None of these three skulls were found to have scaphocephaly as a result of the suture absence. No other malformations were found on any specimen. One clinical case is also presented with radiologic findings on the absence of the sagittal suture that also did not have resultant skull malformation.

CONCLUSIONS

The authors found that the isolated absence of the sagittal suture does not produce a scaphocephalic skull shape.

Neuronal networks in west syndrome as revealed by source analysis and renormalized partial directed coherence

West syndrome is a severe epileptic encephalopathy of infancy with a poor developmental outcome. This syndrome is associated with the pathognomonic EEG feature of hypsarrhythmia. The aim of the study was to describe neuronal networks underlying hypsarrhythmia using the source analysis method (dynamic imaging of coherent sources or DICS) which represents an inverse solution algorithm in the frequency domain. In order to investigate the interaction within the detected network, a renormalized partial directed coherence (RPDC) method was also applied as a measure of the directionality of information flow between the source signals. Both DICS and RPDC were performed for EEG delta activity (1-4 Hz) in eight patients with West syndrome and in eight patients with partial epilepsies (control group). The brain area with the strongest power in the given frequency range was defined as the reference region. The coherence between this reference region and the entire brain was computed using DICS. After that, the RPDC was applied to the source signals estimated by DICS. The results of electrical source imaging were compared to results of a previous EEG-fMRI study which had been carried out using the same cohort of patients. As revealed by DICS, delta activity in hypsarrhythmia was associated with coherent sources in the occipital cortex (main source) as well as the parietal cortex, putamen, caudate nucleus and brainstem. In patients with partial epilepsies, delta activity could be attributed to sources in the occipital, parietal and sensory-motor cortex. In West syndrome, RPDC showed the strongest and most significant direction of ascending information flow from the brainstem towards the putamen and cerebral cortex. The neuronal network underlying hypsarrhythmia in this study resembles the network which was described in previous EEG-fMRI and PET studies with involvement of the brainstem, putamen and cortical regions in the generation of hypsarrhythmia. The RPDC suggests that brainstem could have a key role in the pathogenesis of West syndrome. This study supports the theory that hypsarrhythmia results from ascending brainstem pathways that project widely to basal ganglia and cerebral cortex.

The human calvaria: a review of embryology, anatomy, pathology, and molecular development

INTRODUCTION

The human skull is a complex structure that deserves continued study. Few studies have directed their attention to the development, pathology, and molecular formation of the human calvaria.

MATERIALS AND METHODS

A review of the medical literature using standard search engines was performed to locate studies regarding the human calvaria.

RESULTS

The formation of the human calvaria is a complex interaction between bony and meningeal elements. Derailment of these interactions may result in deformation of this part of the skull.

CONCLUSIONS

Knowledge of the anatomy, formation, and pathology of the human calvaria will be of use to the clinician that treats skull diseases. With an increased understanding of genetic and molecular biology, treatment paradigms for calvarial issues may change.

Twenty classic signs in neuroradiology: A pictorial essay

In this article we describe 20 classic signs in neuroradiology and provide illustrations of each; we also discuss the causes for their appearance, their reliability and sensitivity, and the differential diagnoses to be considered when they are encountered on imaging.

The skeleton and musculature on foetal MRI

BACKGROUND: Magnetic resonance imaging (MRI) is used as an adjunct to ultrasound in prenatal imaging, the latter being the standard technique in obstetrical medicine. METHODS: Initial results demonstrate the ability to visualise the foetal skeleton and muscles on MRI, and highlight the potentially useful applications for foetal MRI, which has significantly profited from innovations in sequence technology. Echoplanar imaging, thick-slab T2-weighted (w) imaging, and dynamic sequences are techniques complementary to classical T2-w imaging. RESULTS: Recent study data indicate that foetal MRI may be useful in the imaging of spinal dysraphism and in differentiating between isolated and complex skeletal deformities with associated congenital malformations, which might have an impact on pre- and postnatal management. CONCLUSION: More research and technical refinement will be necessary to investigate normal human skeletal development and to identify MR imaging characteristics of skeletal abnormalities.

Imaging of the calvarium

The skull vault consists of a multitude of flat bones held together by the cranial sutures. Radiologists encounter a vast array of calvarial pathologies that tend to cause abnormalities in thickness, abnormalities in density, focal defects, or an excess of soft tissue or bone tissue. Further anomalies related to the cranial sutures and fontanelles occur in the dynamic pediatric skull. The imaging features of the host of conditions resulting in these commonly detected calvarial abnormalities are reviewed and illustrated.

Occipital sutures and its variations: the value of 3D-CT and how to differentiate it from fractures using 3D-CT?

The anatomy and embryology of occipital bone are complex and may present with a varied ossification pattern and masquerade as fractures. There are only a few articles in the literature and none on CT appearance of occiput ossification and sutures. Awareness of the normal and variant anatomy, appearance and position along with age of fusion of sutures will be helpful in confidently differentiating variant suture from fracture. This will be particularly important in children in the field of non-accidental injury with its attendant medicolegal complications. We describe the normal anatomy, embryology, normal and variant sutures of occipital bone as published in the literature so far and present a pictorial review of 15 cases of variant sutures. With CT as the primary modality in assessing for head injury now, it is important to know the CT features of these sutures, their appearance, position and variants and be able to utilize 3D-CT to be able to give a more definitive diagnosis.

Recognizing craniosynostosis

Craniosynostosis is characterized by the fusion of sutures. It presents with an abnormal head shape. This article examines this defect and discusses its embryologic origin. A systemic physical assessment guide serves as a tool to enhance early recognition of this defect. Pictorial examples increase understanding of the defect. A discussion of treatment and nursing implications, with an emphasis on family support, is provided.

Correction of hydrocephalic macrocephaly with total cranial vault remodeling and molding helmet therapy

BACKGROUND

Hydrocephalic macrocephaly is a rare problem that may result in cranial vault instability, difficulties with posture and movement, and hindrance in neurological development. The authors studied the outcomes of hydrocephalic macrocephalic cases in which patients underwent single-stage total cranial vault remodeling and postoperative helmet therapy.

METHODS

Consecutive patients with hydrocephalic macrocephaly treated at University of California, Los Angeles from 2000 to 2007 were studied (n = 8). Perioperative examinations (head circumference), lateral cranial radiographs (anteroposterior, lateral, and cranial height measurements) and three-dimensional computed tomography scans (cranial volume) were used to access cranial reduction. Developmental testing, physician evaluations (Whitaker score), and parental surveys were used.

RESULTS

Improvements in mean head circumference (from 58.8 cm to 48.9 cm, or 17 percent reduction), and cranial volume measurements (from 1924 cc to 1212 cc, or 35 percent reduction) were seen in patients after the procedure. In addition, developmental testing scores improved in half, or four of eight patients. Whitaker score was 1.9 with only one case requiring revision but five needing subsequent shunts. Surveys showed a high satisfaction rate with final appearance and ease of childcare.

CONCLUSION

For the rare patient with hydrocephalic macrocephaly, treatment with total cranial vault remodeling with postoperative helmet therapy may be successful, but follow-up monitoring and subsequent ventriculoperitoneal shunting may be necessary.

Craniosynostosis : correlation with cranial vault shape and osseous defects

This study assessed the value of three-dimensional CT (3D CT) in the diagnosis of craniosynostosis, and correlated the cranial deformity with the presence of osseous defects in cranial vault's bones. One hundred and two children (55♀ and 47♂) with a clinical suspicion of craniosynostosis, underwent spiral computed tomography with 3D reconstruction using the shaded surface display (SSD) and volume rendering (VR) algorithms. We evaluated the presence of osseous defects in cranial bones in correlation with the type of craniosynostosis and the shape of the cranial vault. 3D CT allowed the evaluation of craniosynostosis in all patients. All patients had combined forms of craniosynostosis. Osseous defects in the bones of cranial vault were found in 56 patients of whom nine had scaphocephaly, eight plagiocephaly and one trigonocephaly. CT of the skull with three-dimensional reconstruction can safely and reliably identify craniosynostoses in children and could be used for the identification of osseous defects in the cranial vault.

Osteogenesis imperfecta in the neonate

Osteogenesis imperfecta is a rare heterozygous disorder of collagen production. It is characterized by osteopenia, blue sclera, bone deformities, and progressive hearing loss. Some infants are diagnosed prenatally, whereas others are diagnosed much later in life. This article provides an overview of the disorder and discusses the etiologic origins of the syndrome. A guide for a systematic physical assessment is presented to enhance the early recognition of the disorder. Pictorial examples are provided to enhance the understanding of the wide spectrum of osteogenesis imperfecta. A discussion on treatment and clinical implications, with an emphasis on family support, is provided.

Radiographic Evaluation of Children with Growth Disorders

Short stature as well as tall stature can have a wide variety of causes. Tall stature is usually experienced as a less important problem than short stature, but for both clinical presentations it is important to make a correct diagnosis as to etiology. The identification of the diagnosis frequently relies on radiological criteria. However, no international uniformity exists with respect to the radiographic evaluation of children with growth problems. We recommend that in patients with a possible diagnosis of a skeletal dysplasia a skeletal survey must be performed. In patients with a proportionate stature, radiographic analysis of the hand and wrist will be sufficient in most cases. However, whenever there are clinical abnormalities with a possible underlying bone anomaly, a modified skeletal survey is appropriate. The combination of clinical and biochemical features and an appropriate skeletal survey can often lead to the correct diagnosis and/or guide the subsequent molecular analysis.

Geometric morphometric analysis of shape outlines of the normal and abnormal fetal skull using three-dimensional sonographic multiplanar display

OBJECTIVES

Geometric morphometric analysis has been used to quantify differences in biological shapes. Cranial irregularities are described in anomalous fetuses but are qualitative and ill-defined. Our goal was to apply geometric morphometric statistical analysis using three-dimensional (3D) multiplanar display to quantify shape differences in normal and abnormal fetal skulls.

METHODS

This was a retrospective pilot study of mid-trimester patients undergoing ultrasonography. 3D multiplanar display using spatial rotation was used to identify landmarks in coronal and transverse planes to establish a consistent fetal facial profile. Outline coordinates of the brow were determined by blinded examiners using computer software. Elliptical Fourier analysis (EFA) was used to obtain sets of functional coefficients. An atypicality index (AI) was determined from retained principal component (PC) scores. An AI > 95(th) percentile of the expected distribution defined outliers.

RESULTS

Outlines were successfully identified in 38 patients (six abnormal). Using the AI, there were three outliers, all from abnormal fetuses (trisomy 18, trisomy 21, and campomelic dysplasia). Two fetuses with trisomy 21 and one with an unbalanced translocation had normal atypicality indices.

CONCLUSIONS

3D multiplanar display and geometric morphometric analysis enable quantification of fetal skull shape. An abnormal skull shape was identified in two of four aneuploid fetuses and no normal ones. Geometric morphometric analysis represents a promising new quantitative modality which, when applied with 3D sonographic multiplanar display, may be used to more objectively analyze fetal malformation. Larger prospective trials are needed to refine the technique and improve reproducibility.