Craniosynostosis and 3-dimensional computed tomography

Can Craniosynostosis be Diagnosed on Physical Examination? A Retrospective Review

Craniosynostosis is a developmental craniofacial defect in which one or more sutures of the skull fuse together prematurely. Uncorrected craniosynostosis may have serious complications including elevated intracranial pressure, developmental delay, and blindness. Proper diagnosis of craniosynostosis requires a physical examination of the head with assessment for symmetry and palpation of sutures for prominence. Often, if craniosynostosis is suspected, computed tomography (CT) imaging will be obtained. Recent literature has posited that this is unnecessary. This study aims to address whether physical examination alone is sufficient for the diagnosis and treatment planning of single suture craniosynostosis. Between 2015 and 2022, the Divisions of Pediatric Neurosurgery and Pediatric Plastic Surgery at UTHealth Houston evaluated 140 children under 36 months of age with suspected craniosynostosis by physical examination and subsequently ordered CT imaging for preoperative planning. Twenty-three patients received a clinical diagnosis of multi-sutural or syndromic craniosynostosis that was confirmed by CT. One hundred seventeen patients were diagnosed with single suture craniosynostosis on clinical examination and follow-up CT confirmed suture fusion in 109 (93.2%) patients and identified intracranial anomalies in 7 (6.0%) patients. These patients underwent surgical correction. Eight (6.8%) patients showed no evidence of craniosynostosis on CT imaging. Treatment for patients without fused sutures included molding helmets and observation alone. This evidence suggests that physical examination alone may be inadequate to accurately diagnose single suture synostosis, and surgery without preoperative CT evaluation could lead to unindicated procedures.

Pediatric craniosynostosis computed tomography: an institutional experience in reducing radiation dose while maintaining diagnostic image quality

BACKGROUND

Children with craniosynostosis may undergo multiple computed tomography (CT) examinations for diagnosis and post-treatment follow-up, resulting in cumulative radiation exposure.

OBJECTIVE

To reduce the risks associated with radiation exposure, we evaluated the compliance, radiation dose reduction and clinical image quality of a lower-dose CT protocol for pediatric craniosynostosis implemented at our institution.

MATERIALS AND METHODS

The standard of care at our institution was modified to replace pediatric head CT protocols with a lower-dose CT protocol utilizing 100 kV, 5 mAs and iterative reconstruction. Study-ordered, protocol-utilized and radiation-dose indices were collected for studies performed with routine pediatric brain protocols (n=22) and with the lower-dose CT protocol (n=135). Two pediatric neuroradiologists evaluated image quality in a subset (n=50) of the lower-dose CT studies by scoring visualization of cranial structures, confidence of diagnosis and the need for more radiation dose.

RESULTS

During the 30-month period, the lower-dose CT protocol had high compliance, with 2/137 studies performed with routine brain protocols. With the lower-dose CT protocol, volume CT dose index (CTDI_vol) was 1.1 mGy for all patients (0-9 years old) and effective dose ranged from 0.06 to 0.22 mSv, comparable to a 4-view skull radiography examination. CTDI_vol was reduced by 98% and effective dose was reduced up to 67-fold. Confidence in diagnosing craniosynostosis was high and more radiation dose was considered unnecessary in all studies (n=50) by both radiologists.

CONCLUSION

Replacing the routine pediatric brain CT protocol with a lower-dose CT craniosynostosis protocol substantially reduced radiation exposure without compromising image quality or diagnostic confidence.

Appropriateness of Computed Tomography Scanning in the Diagnosis of Craniosynostosis

INTRODUCTION

Although physicians from a variety of specialties encounter infants with possible craniosynostosis, judicious use of computed tomography (CT) imaging is important to avoid unnecessary radiation exposure and healthcare expense. The present study seeks to determine whether differences in specialty of ordering physician affects frequency of resulting diagnostic confirmations requiring operative intervention.

METHODS

Radiology databases from 2 institutions were queried for CT reports or indications that included "craniosynostosis" or "plagiocephaly." Patient demographics, specialty of ordering physician, confirmed diagnosis, and operative interventions were recorded. Cost analysis was performed using the fixed unit cost for a head CT to calculate the expense before 1 study led to operative intervention.

RESULTS

Three hundred eighty-two patients were included. 184 (48.2%) CT scans were ordered by craniofacial surgeons, 71 (18.6%) were ordered by neurosurgeons, and 127 (33.3%) were ordered by pediatricians. One hundred four (27.2%) patients received a diagnosis of craniosynostosis requiring operative intervention. Craniofacial surgeons and neurosurgeons were more likely than pediatricians to order CT scans that resulted in a diagnosis of craniosynostosis requiring operative intervention (P < 0.001), with no difference between craniofacial surgeons and neurosurgeons (P = 1.0). The estimated cost of obtaining an impact CT scan when ordered by neurosurgeons or craniofacial surgeons as compared to pediatricians was $2369.69 versus $13,493.75.

CONCLUSIONS

Clinicians who more frequently encounter craniosynostosis (craniofacial and neurosurgeons) had a higher likelihood of ordering CT images that resulted in a diagnosis of craniosynostosis requiring operative intervention. This study should prompt multi-disciplinary interventions aimed at improving evaluation of pretest probability before CT imaging.

Locally Affine Diffeomorphic Surface Registration and Its Application to Surgical Planning of Fronto-Orbital Advancement

Metopic craniosynostosis is a condition caused by the premature fusion of the metopic cranial suture. If untreated, it can result into brain growth restriction, increased intra-cranial pressure, visual impairment, and cognitive delay. Fronto-orbital advancement is the widely accepted surgical approach to correct cranial shape abnormalities in patients with metopic craniosynostosis, but the outcome of the surgery remains very dependent on the expertise of the surgeon because of the lack of objective and personalized cranial shape metrics to target during the intervention. We propose in this paper a locally affine diffeomorphic surface registration framework to create an optimal interventional plan personalized to each patient. Our method calculates the optimal surgical plan by minimizing cranial shape abnormalities, which are quantified using objective metrics based on a normative model of cranial shapes built from 198 healthy cases. It is guided by clinical osteotomy templates for fronto-orbital advancement, and it automatically calculates how much and in which direction each bone piece needs to be translated, rotated, and/or bent. Our locally affine framework models separately the transformation of each bone piece while ensuring the consistency of the global transformation. We used our method to calculate the optimal surgical plan for 23 patients, obtaining a significant reduction of malformations (p < 0.001) between 40.38% and 50.85% in the simulated outcome of the surgery using different osteotomy templates. In addition, malformation values were within healthy ranges (p > 0.01).

Cranial ultrasound is a reliable first step imaging in children with suspected craniosynostosis

PURPOSE

Skull radiography (SR) and Computed Tomography (CT) are still proposed as the first-line imaging choice for the diagnosis of craniosynostosis (CS) in children with abnormal head shape, but both techniques expose infants to ionizing radiation. Several studies shown that ultrasound may play an important role in the diagnosis of craniosynostosis. The aim of our study is to assess the diagnostic accuracy of cranial ultrasound scan (CUS) and confirm if it is a reliable first step imaging evaluation for the diagnosis of craniosynostosis in newborn.

METHOD

A cohort of 196 infants (122/74 males/females), with a mean age of 4 months, clinically suspected to have abnormal closure of cranial sutures, were firstly examined by CUS and then referred to neuroradiologists to perform volumetric CT scan if the suspicion of stenosis was ecographically confirmed; otherwise, a routine follow-up and physical treatment was performed, to observe the evolution of the head shape.

RESULTS

Of the 196 children studied by CUS, only two had inconclusive studies due to age limitation (>12 months). Thirty children were diagnosed with cranial synostosis at CUS and verified by CT; all the CUS results were confirmed, except two cases, that were revealed as false positives in the starting phase of the study. Twelve patients with very prominent head deformity and negative CUS underwent CT, which confirmed the CUS results in all of them; one case of closure of both temporal sutures, not studied by CUS, was documented by CT. All the 148 children with poor clinical suspicion and negative CUS underwent just a prolonged clinical follow-up. In all of them, a progressive normalization of head shape was observed, and the craniosynostosis was excluded on a clinical base.

CONCLUSIONS

CUS is a highly specific and sensitive imaging technique. In referral centers, expert hands can use it as a reliable first-step screening for infants younger than 1 year, suspected to have a craniosynostosis, thus avoiding unnecessary exposure to ionizing radiation. The "golden age" to obtain the best CUS results is under 6 months of life. Because the method is operator-dependent and there is a learning curve, a case centralization is advisable.

Craniosynostosis : Updates in Radiologic Diagnosis

The purpose of this article is to review imaging findings and to discuss the optimal imaging methods for craniosynostosis. The discussion of imaging findings are focused on ultrasonography, plain radiography, magnetic resonance imaging and computed tomography with 3-dimensional reconstruction. We suggest a strategy for imaging work-up for the diagnosis, treatment planning and follow-up to minimize or avoid ionized radiation exposure to children by reviewing the current literature.

Cranial Ultrasound as a First-Line Imaging Examination for Craniosynostosis

BACKGROUND

Radiography, typically the first-line imaging study for diagnosis of craniosynostosis, exposes infants to ionizing radiation. We aimed to compare the accuracy of cranial ultrasound (CUS) with radiography for the diagnosis or exclusion of craniosynostosis.

METHODS

Children aged 0 to 12 months who were assessed for craniosynostosis during 2011-2013 by using 4-view skull radiography and CUS of the sagittal, coronal, lambdoid, and metopic sutures were included in this prospective study. Institutional review board approval and parental informed consent were obtained. CUS and radiography were interpreted independently and blindly by 2 pediatric radiologists; conflicts were resolved in consensus. Sutures were characterized as closed, normal, or indeterminate. Correlation between CUS and radiography and interreader agreement were examined for each suture.

RESULTS

A total of 126 children (82 boys, 64.5%) ages 8 to 343 days were included. All sutures were normal on CUS and radiography in 115 patients (93.7%); craniosynostosis of 1 suture was detected in 8 (6.3%, 5 sagittal, 2 metopic, 1 coronal). In 3 cases the metopic suture was closed (n = 2) or indeterminate on CUS (n = 1) but normally closed on radiography. CUS sensitivity was 100%, specificity 98% (95% confidence interval 94%-100%). Reader agreement was 100% for sagittal, coronal, and lambdoid sutures (κ = 0.80); after consensus, disagreement remained on 3 metopic sutures.

CONCLUSIONS

In this series, CUS could be safely used as a first-line imaging tool in the investigation of craniosynostosis, reducing the need for radiographs in young children. Additional assessment may be required for accurate assessment of the metopic suture.

Identification of skull base sutures and craniofacial anomalies in children with craniosynostosis: utility of multidetector CT

PURPOSE

Craniosynostosis is a condition characterised by the premature fusion of one or more of the cranial sutures. The aim of the study was to identify, by multidetector computed tomography (CT), the involvement of vault sutures as well as of the skull base sutures (named "minor" sutures). The latter ones are involved in development of craniofacial and skull base deformities.

MATERIALS AND METHODS

We retrospectively reviewed 27 children with complex synostosis (n = 21) and anterior synostotic plagiocephaly (n = 6). High-resolution CT images with bone definition algorithm and tridimensional volume rendering reconstructions were assessed.

RESULTS

In 27 children we found different sutures involved in the synostotic process, including both major and minor skull suture synostosis, and synostosis of synchondroses. Superior orbital rim deformity, nasal root deviation, anterior endocranial axis deviation (ethmoidal axis) are found in children with coronal arch synostosis, while reduced size of the posterior fossa and Chiari 1 malformation are noted in children with lambdoid arch synostosis.

CONCLUSIONS

High-resolution CT allows an accurate identification of both "major" and "minor" skull base suture synostosis and it represents the gold standard for the diagnosis of craniostenosis and for planning the proper surgical approach.

Modeling and biomechanical analysis of craniosynostosis correction with the use of finite element method

Craniosynostosis is a skull malformation because of premature fusing of one or more cranial sutures. The most common types of craniosynostosis are scaphocephaly (with the sagittal suture fused) and trigonocephaly (with the metopic suture fused). In this paper we describe and discuss how finite element analysis and three-dimensional modeling can be used for preoperative planning of the correction of craniosynostosis and for the postoperative evaluation of the treatment results. We used the engineering software MIMICS MATERIALISE to obtain three-dimensional geometry from computed tomography scans, and applied finite element method for the sake of biomechanical analysis. These simulations help to improve the surgical treatment, making it more accurate, safer, and faster.