Primary craniosynostosis: imaging features

MR Protocols for Paediatric Neurosurgical Common Conditions: An Update Guide for Neurosurgeons

The biggest challenge for clinicians and surgeons when it comes to radiological examinations is the ability to request the right modalities and to understand the strengths and limitations of each modality. This is particularly important in paediatric neurosciences where despite magnetic resonance imaging (MRI) being the main imaging modality, there are several protocols, technical limitations of specific scanners and issues related to sedation that need to be taken into account. In this chapter, we describe a simple approach for six common neurosurgical conditions to guide the paediatric neurosurgeons in requesting the right MR protocol and understanding the rationale of it.Paediatric neuro-oncology, epilepsy and neck/skull base protocols are discussed elsewhere in this book and therefore will not be a focus in this chapter (Bernasconi et al., Epilepsia 60:1054-68, 2019; D'Arco et al., Neuroradiology 64:1081-100; 2022; Avula et al., Childs Nerv Syst 37:2497-508; 2021).

Orbital volume, ophthalmic sequelae and severity in unilateral coronal synostosis

PURPOSE

Unilateral coronal synostosis (UCS) results in an asymmetrical skull, including shallow and asymmetrical orbits, associated with reduced orbital volume and high prevalences of ophthalmic sequelae. Aim is to link orbital volumes in patients with UCS to severity according to UCSQ (Utrecht Cranial Shape Quantifier) and presence of ophthalmic sequelae.

METHODS

We included preoperative patients with UCS (≤ 18 months). Orbital volume was measured on CT scans by manual segmentation (Mimics software (Materialise, Leuven, Belgium)), and severity of UCS was determined by UCSQ. Orbital volume of affected side was compared to unaffected side using Wilcoxon signed rank test. Orbital volume ratio was calculated (affected/unaffected volume) and compared to the category of UCSQ by Kruskal-Wallis test. Opthalmic sequelae were noted.

RESULTS

We included 19 patients (mean age 7 months). Orbital volume on affected side was significantly lower (p = 0.001), mean orbital volume ratio was 0.93 (SD 0.03). No significant differences in group means of orbital volume ratio between different levels of severity of UCSQ were found (Kruskal-Wallis H (2) = 0.873; p > 0.05). Ophthalmic sequelae were found in 3 patients; one had adduction impairment and strabismus (mild UCS), one had astigmatism (moderate UCS), and one had abduction impairment (on both ipsi- and contralateral side) and vertical strabismus (severe UCS).

CONCLUSION

No association between orbital volume ratio and severity of UCS was found. Side-to-side asymmetry in orbital volume was noted. No association between either preoperative orbital volume ratio or severity of UCS and the presence of preoperative ophthalmic sequelae was found.

Imaging in craniosynostosis: when and what?

PURPOSE

Currently, the interest on craniosynostosis in the clinical practice is raised by their increased frequency and their genetic implications other than by the still existing search of less invasive surgical techniques. These reasons, together with the problem of legal issues, make the need of a definite diagnosis for a crucial problem, even in single-suture craniosynostosis (SSC). Although the diagnosis of craniosynostosis is primarily the result of physical examination, craniometrics measuring, and observation of the skull deformity, the radiological assessment currently plays an important role in the confirmation of the diagnosis, the surgical planning, and even the postoperative follow-up. On the other hand, in infants, the use of radiation or the need of sedation/anesthesia raises the problem to reduce them to minimum to preserve such a delicate category of patient from their adverse effects.

METHODS, RESULTS AND CONCLUSIONS

This review aims at summarizing the state of the art of the role of radiology in craniosynostosis, mainly focusing on indications and techniques, to provide an update not only to pediatric neurosurgeons or maxillofacial surgeons but also to all the other specialists involved in their management, like neonatologists, pediatricians, clinical geneticists, and pediatric neurologists.

Signs in Neuroradiology: A Pictorial Review

One of the major problems radiologists face in everyday practice is to decide the correct diagnosis, or at least narrow down the list of possibilities. In this context, indicative evidences (signs) are useful to recognize pathologies, and also to narrow the list of differential diagnoses. Despite classically being described for a single disease, or a closely related family of disorders, most indications are not restricted exclusively to their traditional definition. Therefore, using signs for prognosis requires knowledge of the mechanism of their appearance, and which pathologies they are observed in. In this study, we demonstrate some of the more common and useful neuroradiologic signs with relevant images, and discuss their use in differential diagnosis.

Effectiveness of screening for craniosynostosis with ultrasound: a retrospective review

BACKGROUND

Minimizing the ionizing radiation dose to children is fundamental to pediatric radiology. The most widely accepted imaging examination for evaluating craniosynostosis is computed tomography (CT) of the head, an examination that involves ionizing radiation.

OBJECTIVE

To determine if sonography of the cranial sutures is an adequate screening examination for the diagnosis of craniosynostosis in patients with abnormal skull shape.

MATERIALS AND METHODS

A retrospective review of all cranial suture ultrasound (US) examinations performed during the course of a 3-year period (July 2012 - September 2015) was undertaken. Results were compared with clinical follow-up and/or head CT to evaluate the accuracy of this modality as a screening tool to determine the presence or absence of craniosynostosis. Fifty-two sonographic exams were adequate for inclusion.

RESULTS

Forty-five of the examinations did not reveal synostosis. In each of these instances, follow-up physical exam findings and/or CT imaging confirmed that no abnormal premature suture closure was present. US findings demonstrated synostosis in seven cases. CT exam or operative reports of these cases confirmed all seven findings of premature suture closure. Statistical analysis demonstrated a sensitivity of 100% (95% confidence interval [CI]: 56.1-100.0%), a specificity of 100% (95% CI: 90.2-100.0%), and a negative predictive value of 100% (95% CI: 90.2-100.0%).

CONCLUSION

Cranial US is a reliable screening tool to rule out craniosynostosis in patients with abnormal head shape.

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.

Craniosynostosis: imaging review and primer on computed tomography

Craniosynostosis is encountered in the pediatric population in isolated or syndromic forms. The resulting deformity depends on the number and type of sutures involved and, in multi-sutural synostosis, the order of suture fusion. Primary craniosynostosis needs to be differentiated from the secondary variety and positional or deformational mimics. Syndromic craniosynostoses are associated with other craniofacial deformities. Evaluation with 3-D CT plays an important role in accurate diagnosis and management; however, implementation of appropriate CT techniques is essential to limit the radiation burden in these children. In this article, the authors briefly review the classification, embryopathogenesis and epidemiology and describe in detail the radiologic appearance and differential diagnoses of craniosynostosis.

Craniosynostosis

Craniosynostosis is a complex condition, characterized by the premature fusion of one of more of the cranial sutures. They can be seen individually or as part of multisystem syndromes. This review uses computed tomography (CT) with three-dimensional reconstructions to help describe some of the types and classifications of craniosynostosis, as well as describing some of the associations and the management of craniosynostosis.

Pictorial essay: The many faces of craniosynostosis

Craniosynostosis is a common condition in the pediatric age group, which may either be isolated or may present as part of a craniofacial syndrome. This pictorial review illustrates the underlying mechanisms and pathophysiology of craniosynostosis, the various types of craniosynostoses, common craniofacial syndromes and the role of imaging in their diagnosis and management.

Holoprosencephaly and craniosynostosis: A report of two siblings and review of the literature

Holoprosencephaly (HPE) and craniosynostosis are separate conditions that have occasionally been observed to occur simultaneously in the same patient. Here, we compile patients with both conditions who have been documented in the literature thus far; moreover, we report on two additional siblings who have not been previously described. We also compare the clinical features of these patients and discuss the previously hypothesized possibility of an independent association including both HPE and craniosynostosis.

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.

Validation of a simple method for measuring cranial deformities (plagiocephalometry)

Craniofacial measuring is essential for diagnosis or evaluation of growth and therapies. Skull deformities in children are mainly caused by craniosynostosis or by external pressure in positional skull deformations. Traditional anthropometry does not sufficiently analyze craniofacial shape. In computed tomography (CT) scanning, radiation loads are considerable. Both CT and magnetic resonance imaging (MRI) scanning require anaesthesia in children for accurate imaging, due to their long acquisition time. This makes CT and MRI unsuitable for long term follow-up of pediatric patients unless there is a compelling reason. Other noninvasive three-dimensional (3D) surface scanners still have limited practical use. van Vlimmeren et al presented plagiocephalometry (PCM) as a simple and versatile instrument to quantify skull deformities with high intrarater and interrater reliability, but no comparison was made with the actual skull shape. At the Erasmus University Medical Center Rotterdam, Sophia Children's Hospital PCM was compared to 3D-CT scanning in 21 children with craniosynostosis early in life. The PCM ring proved to fit closely to the skin with mean differences less than 1 mm (P < 0.05). The shape of the PCM ring was not significantly changed when taken off the head (P > 0.05). Finally, no significant differences are shown between measurements on the skull (CT-scan) and PCM ring off the head (P > 0.05). This study proves that PCM is a reliable method for analysis of skull deformities. The measurements are in agreement with 3D-CT scanning as golden standard. Although only 2-dimensional measurements are performed by PCM, the combination of simplicity, reliability, and validity make it a promising tool for daily practice.

Diagnostic imaging in the management of craniosynostoses

Craniosynostoses are the most frequent craniofacial malformations. However, with a prevalence of 3-6 cases per 10,000 live births they are amongst the rarely seen diseases and their definite diagnosis thus poses a challenge to the physician. When an abnormal calvarial configuration is detected, a radiological evaluation is necessary to characterize the deformity and to guide the corrective surgical procedure. The demand for clear diagnostic criteria is justified by the severity of the disease and the possible consequences of delayed diagnosis. In addition to the clinical signs (deformation of the head), conventional skull X-rays show typical radiological alterations and are used for basic diagnostics. Diagnostic tests that may be performed to confirm the diagnosis and assess the extent of the problem, include computed tomography (CT), 3D-CT, magnetic resonance imaging (MRI) scans, and ultrasonography. In the present review we will describe the most important clinical and radiological characteristics of craniosynostosis by means of clinical, radiological and operative situs examples.

Pitfalls for the pediatrician: positional molding or craniosynostosis?

Abnormal head morphology is common among infants and often leads parents to ask their pediatricians for guidance. While the vast majority of such children development and prevent adverse neurobehavioral sequelae secondary to increased intracranial pressure or impaired cerebral growth. The coordination of a multidisciplinary team in the setting of a center experienced in the management of craniosynostosis will assure the best possible results for each patient.

Craniosynostosis

Craniosynostosis, caused by premature fusion of the sutures, may be syndromic or non-syndromic. Radiology has an important role to play in the assessment, management and follow-up of these patients. Initial investigations may often be undertaken within general radiology departments. An understanding of the terminology and recognition of the predictable patterns of presentation are essential to enable appropriate referral to a craniofacial unit where further investigation and management are undertaken. We present the radiological features of several craniosynostoses with an emphasis on the role of plain radiography. We demonstrate the complementary role of computed tomography in their evaluation within the setting of a specialist centre.

Ultrasound diagnosis of craniosynostosis

OBJECTIVE

To retrospectively study prenatal ultrasound images of patients with craniosynostosis to determine the extent to which prenatal diagnosis is possible.

METHOD

Prenatal ultrasound images of 19 patients with postnatally diagnosed metopic or coronal suture craniosynostosis were retrospectively reviewed. The 26 ultrasound examinations obtained were compared with normal images and tables of gestation.

RESULTS

It was not possible to diagnose craniosynostosis in the first trimester. In the second trimester, Kleeblattschädel was diagnosed at 20.5 weeks. A multilobular shape to the skull and diastasis of the frontotemporal suture was identified. In a second child with Kleeblattschädel, the cephalic index was above normal 86.4 (normal range 70 to 86), and the head circumference to abdominal circumference was increased. In the third trimester, the head shape deformation was more obvious. Brachycephaly diagnosis was made in the second trimester. In Crouzon syndrome the hypertelorism was identified at 19.9 weeks. Plagiocephaly was diagnosed at 21.4 weeks. In trigonocephaly the reduced cephalic index was noted at 18.8 weeks. In the third trimester, the deformity was diagnosed in all cases.

CONCLUSION

No diagnosis of craniosynostosis was made in the first trimester. In the second trimester, it was possible to diagnose Kleeblattschädel, trigonocephaly, brachycephaly (bilateral coronal suture craniosynostosis), and plagiocephaly (unilateral coronal suture craniosynostosis) in nine of the examinations. In the third trimester and at term, it was possible to diagnose previously listed conditions from six of the seven examinations obtained. Kleeblattschädel was suspected during original examination. A total of 15 examinations of 26 were correctly diagnosed during this investigation.

Cranioestenose da sutura metópica: efeito teratogênico do valproato de sódio. Relato de caso

OBJETIVO: alertar que o uso de valproato de sódio durante a gravidez pode determinar cranioestenose no recém-nascido, em especial a trigonocefalia. MÉTODO: relato de um caso de trigonocefalia em menina de 6 meses, filha de pais jovens, não fumantes e cuja mãe fez uso de fenobarbital 100 mg/dia e valproato de sódio 500 mg duas vezes/dia durante toda a gravidez. Foi realizada revisão bibliográfica sobre o assunto. RESULTADO: no ato cirúrgico pôde-se confirmar a presença de esclerose óssea sobre a sutura metópica. A revisão bibliográfica permitiu o encontro de relatos prévios sobre a teratogenicidade do valproato de sódio, que determina principalmente cranioestenose da sutura metópica. CONCLUSÃO: o uso de valproato de sódio durante a gravidez pode determinar como ação teratogênica a cranioestenose, especialmente a trigonocefalia (fechamento precoce da sutura metópica).