Intracranial volume measurement of sagittal craniosynostosis

Cephalometric Evaluation of Children with Short Stature of Genetic Etiology: A Review

Introduction: A plethora of biological molecules regulate chondrogenesis in the epiphyseal growth plate. Disruptions of the quantity and function of these molecules can manifest clinically as stature abnormalities of various etiologies. Traditionally, the growth hormone/insulin-like growth factor 1 (IGF1) axis represents the etiological centre of final stature attainment. Of note, little is known about the molecular events that dominate the growth of the craniofacial complex and its correlation with somatic stature. Aim: Given the paucity of relevant data, this review discusses available information regarding potential applications of lateral cephalometric radiography as a potential clinical indicator of genetic short stature in children. Materials and Methods: A literature search was conducted in the PubMed electronic database using the keywords: cephalometric analysis and short stature; cephalometric analysis and achondroplasia; cephalometric analysis and hypochondroplasia; cephalometric analysis and skeletal abnormalities; cephalometr* and SHOX; cephalometr* and CNP; cephalometr* and ACAN; cephalometr* and CNVs; cephalometr* and IHH; cephalometr* and FGFR3; cephalometr* and Noonan syndrome; cephalometr* and "Turner syndrome"; cephalometr* and achondroplasia. Results: In individuals with genetic syndromes causing short stature, linear growth of the craniofacial complex is confined, following the pattern of somatic short stature regardless of its aetiology. The angular and linear cephalometric measurements differ from the measurements of the average normal individuals and are suggestive of a posterior placement of the jaws and a vertical growth pattern of the face. Conclusions: The greater part of the existing literature regarding cephalometric measurements in short-statured children with genetic syndromes provides qualitative data. Furthermore, cephalometric data for individuals affected with specific rare genetic conditions causing short stature should be the focus of future studies. These quantitative data are required to potentially establish cut-off values for reference for genetic testing based on craniofacial phenotypes.

Normative reference data for intracranial volume in children: The results of CT volumetry

BACKGROUND

Intracranial volume (ICV) is an important indicator of the development of the brain and skull in children. At present, there is a lack of ICV growth standards based on large infant and children samples. Our aim was to assess the normal range of the ICV variation in Russian children using a modern automatic system for constructing the endocranial cavity (Endex) and to provide growth standards of the ICV for clinical practice.

METHODS

High-resolution head CT scans were obtained from 673 apparently healthy children (380 boys and 293 girls) aged 0-17 years and transformed into the ICV estimates using the Endex software. The open-source software RefCurv utilizing R and the GAMLSS add-on package with the LMS method was then used for the construction of smooth centile growth references for ICV according to age and sex.

RESULTS

We demonstrated that the ICVs estimates calculated using the Endex software are perfectly comparable with those obtained by a conventional technique (i.e. seed feeling). Sex-specific pediatric growth charts for ICV were constructed.

CONCLUSIONS

This study makes available for use in clinical practice ICV growth charts for the age from 0 to 17 based on a sample of 673 high-resolution CT images.

The current understanding of germline predisposition in non-syndromic sagittal craniosynostosis: a systematic review

PURPOSE

The objective of this literature review was to provide a comprehensive and up-to-date overview of the current understanding of the genetic etiology for non-syndromic sagittal craniosynostosis.

METHODS

Using the PubMed database and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we systematically reviewed relevant records on germline genetics in children with non-syndromic sagittal craniosynostosis.

RESULTS

Two hundred two records were identified, of which 25 were included following title and abstract screening and subsequent full-text review. The 25 records in combination included 829 children with non-syndromic sagittal craniosynostosis. A likely pathogenic or pathogenic germline variant was reported for 9.8% of the 827 patients for whom germline genetic testing was performed. The reported variants were distributed across 50 different genes, with more than one variant detected in 13 genes.

CONCLUSION

Based on the existing literature, genetic predisposition is likely to play a role in at least 9% of children with non-syndromic sagittal craniosynostosis. Future studies will benefit from international consensus in terms of diagnostic nomenclature and a higher level of standardization across study methodologies and bioinformatic approaches.

Posterior Cranial Vault Manifestations in Nonsyndromic Sagittal Craniosynostosis

ABSTRACT

Sagittal synostosis is the most common type of craniosynostosis. Sagittal suture fusion causes restriction of biparietal cranial vault growth, with expansion of the growing brain causing frontal bossing, an occipital bullet, and an elongated head shape. Due to the absence of studies focusing on the posterior cranial vault pattern in isolated sagittal craniosynostosis, we organized this study to characterize the posterior part of the cranial vault and its association with sagittal craniosynostosis. A retrospective study was conducted of isolated sagittal craniosynostosis patients who had undergone total cranial vault remodeling at the Cleft and Craniofacial South Australia (formerly known as the Australian Craniofacial Unit) between January 2018 and February 2020. Preoperative three-dimensional computed tomography (3D-CT) images were reviewed. The following parameters were evaluated: the cephalic index, lambdoid suture shape, lambdoid suture line pattern, presence of wormian bones along the lambdoid sutures and occipital fontanelle, presence of the mendosal suture, and angle at the tip of the join between the 2 lambdoid sutures. Thirty-nine 3D-CT scans of 32 males and 7 females were evaluated. The mean age when the patients underwent the 3D-CT imaging was 6.72 ± 7.9 months. A high prevalence of mendosal sutures (74.4%) was significantly found in sagittal craniosynostosis. Adult-like types of lambdoid suture interdigitating patterns were also significantly associated with young patients with sagittal craniosynostosis. No associations between the remaining parameters and particular synostoses were revealed.

Occult Scaphocephaly: A Forme Fruste Phenotype of Sagittal Craniosynostosis

INTRODUCTION

Latent cranial suture fusions may present with mild or absent phenotypic changes that make the clinical diagnosis challenging. Recent reports describe patients with sagittal synostosis and a normal cranial index (CI), a condition termed normocephalic sagittal craniosynostosis (NSC). The goal of this study is to evaluate the shape and intracranial volume (ICV) in a cohort of NSC patients using quantitative cranial shape analysis (CSA).

METHODS

We identified 19 patients (7.5 ± 2.28 years) between 2011 and 2016, who presented to our hospital with NSC. Cranial index and CSA were measured from the computed tomography image. Cranial shape analysis calculates the distances between the patient's cranial shape and its closest normal shape. Intracranial volume was measured and compared to an established age-matched normative database.

RESULTS

Cranial index revealed 15 (78.9%) patients within the mesocephalic range and 4 patients (21.1%) in the brachycephalic range. Detailed CSA identified 15 (78.9%) patients with subtle phenotypic changes along the scaphocephalic spectrum (ie, subtle anterior and posterior elongation with inter-parietal narrowing) and 1 patient (5.3%) with isolated overdevelopment on the posterior part of the right parietal bone. Three patients (15.8%) had a CSA close to normal. Mean ICV was 1410.5 ± 192.77cc; most patients (78.9%) fell within ±2 standard deviations.

CONCLUSION

Quantitative CSA revealed that most of the patients with NSC had cranial shape abnormalities, consistent with a forme fruste scaphocephaly that could not be otherwise recognized by clinical observation or CI. Given these findings, we propose the term occult scaphocephaly to describe this condition. The associated incidence of intracranial hypertension is unknown.

A systematic quantitative morpho-volumetric analysis in infants with sagittal craniosynostosis and relationship with the severity of scaphocephalic deformity

PURPOSE

Among patients with isolated sagittal synostosis (ISS), the head shape varies considerably in relation to the severity of the abnormality. This study aimed to quantify skull base morphometry and intracranial volume to investigate their relationships with the severity of scaphocephaly.

METHODS

We studied 66 infants with ISS identifying three groups according to the morphological severity of cranial deformity (group I: mild deformity; group II: moderate deformity; group III: severe deformity), by combining two scaphocephaly severity indices as descriptors of the relation of three morphological measurements (length, width and height) We perform a quantitative analysis using high-resolution CT images calculating following parameters: cranial fossae dimensions, supratentorial (ICV) and infratentorial (PCFV) cranial volume, supratentorial (WBV) and infratentorial (PCFBV) brain volume, ICV/WBV, PCFV/PCFBV, supratentorial and infratentorial cerebrospinal fluid (CSF).

RESULTS

In all subgroups, anterior and middle skull base lengths were increased, while posterior hemifossae lengths were unchanged. In mild subgroup, ICV/WBV was significantly different and ICV, WBV and CSF supratentorial volume increased (p < 0.05). In moderate and severe subgroups, FCPV/FCPBV was significantly different and CSF infratentorial volume was reduced (p < 0.05); FCPBV was increased only in the severe subgroup (p < 0.05).

CONCLUSION

This morpho-volumetric study provides new insights in understanding the compensatory changes occurring in infants at different stages of scaphocephaly severity. In particular, our study suggests that patients with severe deformity might have an earlier depletion of reserve mechanisms with a reduced compliance of the overall skull during encephalic growth and these patients might require early surgical cranial expansion.

Cranial growth in isolated sagittal craniosynostosis compared with normal growth in the first 6 months of age

Sagittal craniosynostosis (SCS), the most common type of premature perinatal cranial suture fusion, results in abnormal head shape that requires extensive surgery to correct. It is important to find objective and repeatable measures of severity and surgical outcome to examine the effect of timing and technique on different SCS surgeries. The purpose of this study was to develop statistical models of infant (0-6 months old) skull growth in both normative and SCS subjects (prior to surgery). Our goal was to apply these models to the assessment of differences between these two groups in overall post-natal growth patterns and sutural growth rates as a first step to develop methods for predictive models of surgical outcome. We identified 81 patients with isolated, non-syndromic SCS from Seattle Children's Craniofacial Center patient database who had a preoperative CT exam before the age of 6 months. As a control group, we identified 117 CT exams without any craniofacial abnormalities or bone fractures in the same age group. We first created population-level templates from the CT images of the SCS and normal groups. All CT images from both groups, as well as the canonical templates of both cohorts, were annotated with anatomical landmarks, which were used in a growth model that predicted the locations of these landmarks at a given age based on each population. Using the template images and the landmark positions predicted by the growth models, we created 3D meshes for each week of age up to 6 months for both populations. To analyze the growth patterns at the suture sites, we annotated both templates with additional semi-landmarks equally spaced along the metopic, coronal, sagittal and lambdoidal cranial sutures. By transferring these semi-landmarks to meshes produced from the growth model, we measured the displacement of the bone borders and suture closure rates. We found that the growth at the metopic and coronal sutures were more rapid in the SCS cohort than in the normal cohort. The antero-posterior displacement of the semi-landmarks also indicated a more rapid growth in the sagittal plane in the SCS model than in the normal model. Statistical templates and geometric morphometrics are promising tools for understanding the growth patterns in normal and synostotic populations and to produce objective and reproducible measurements of severity and outcome. Our study is the first of its kind to quantify the bone growth for the first 6 months of life in both normal and sagittal synostosis patients.

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes

Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization-using retrospective clinical spring measurements-was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young's modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application.

The unseen third dimension: a novel approach for assessing head shape severity in infants with isolated sagittal synostosis

PURPOSE

This study aimed to develop a novel approach to assess the severity of skull dysmorphology in infants with isolated sagittal synostosis (ISS) and its relationship with the surgical results.

METHODS

We divided 66 infants with ISS into three groups by combining the scaphocephalic (SSI-A) and platycephalic (VLI) indices as descriptors of the relation between length, width, and height. We evaluated each skull for morphology as hyperdolichocephalic (< 66%) versus dolichocephalic (66-77%) and as hyperplatycephalic (< 78%) versus platycephalic skull (78-85%). A score system was developed as follows: 2 points for values < 66% and < 78% and 1 point for values between 66 and 77% and 78 and 85% in SSI-A and VLI, respectively. The overall score was calculated and it was used to classify our patients on a 4-point ordinal scale, according to the severity of head shape (2 = mild, 3 = moderate, 4 = severe).

RESULTS

Thirty-two infants resulted in mild group, 17 in moderate group, and 17 in severe group. SSI-A and VLI were reduced according to the severity of ISS. We demonstrated a positive correlation between SSA-A and VLI in mild subgroup of patients while we found a negative correlation between SSA-A and VLI in moderate and in severe subgroups. Moreover, a positive correlation was found between severe subgroup and Sloan III class of surgical results.

CONCLUSION

This study describes a simple tool to better classify infants with ISS, considering the three-dimensional morphology of the skull, because it evaluates both the dolichocephalic and platycephalic component.

Intracranial volume versus static and pulsatile intracranial pressure values in children with craniosynostosis

OBJECTIVE

Reduced intracranial volume (ICV) and raised intracranial pressure (ICP) are assumed to be principal pathophysiological mechanisms in childhood craniosynostosis. This study examined the association between ICV and ICP and whether ICV can be used to estimate the ICP.

METHODS

The authors analyzed ICV and ICP measurements from children with craniosynostosis without concurrent hydrocephalus and from age-matched individuals without craniosynostosis who underwent diagnostic ICP measurement.

RESULTS

The study included 19 children with craniosynostosis (mean age 2.2 ± 1.9 years) and 12 reference individuals without craniosynostosis (mean age 2.5 ± 1.6 years). There was no difference in ICV between the patient and reference cohorts. Both mean ICP (17.1 ± 5.6 mm Hg) and mean wave amplitude (5.9 ± 2.6 mm Hg) were higher in the patient cohort. The results disclosed no significant association between ICV and ICP values in the patient or reference cohorts, and no association was seen between change in ICV and ICP values after cranial vault expansion surgery (CVES) in 5 children in whom ICV and ICP were measured before and after CVES.

CONCLUSIONS

In this cohort of children with craniosynostosis, there was no significant association between ICV and ICP values prior to CVES and no significant association between change in ICV and ICP values after CVES in a subset of patients. Therefore, ICV could not reliably estimate the ICP values. The authors suggest that intracranial hypertension in childhood craniosynostosis may not be caused by reduced ICV alone but rather by a distorted relationship between ICV and the volume of intracranial content (brain tissue, CSF, and blood).

Intracranial volume (ICV) in isolated sagittal craniosynostosis: a retrospective case-matched-control study

PURPOSE

Children with sagittal craniosynostosis (SC) are at risk of developing raised intracranial pressure (ICP). This is thought to result from cephalocranial disproportion-the restriction of normal cerebral development by a small cranial vault. It remains unclear whether intracranial volume (ICV) is altered in SC. This study offers a novel volumetric analysis of the scaphocephalic skull, comparing supratentorial (ST) volume, infratentorial (IT) volume, and total ICV of patients with sagittal synostosis to normal controls.

METHODS

ICVs of 32 consecutive patients undergoing total calvarial vault remodelling (TCVR) for isolated SC were compared to 32 age- and sex-matched normal controls. ICV was measured with manual techniques on head computerised tomographic (CT) scans using OsiriX software. A paired t test was used to compare data between cases and controls.

RESULTS

Mean total ICV, ST volume and IT volume were larger in SC than in controls, except in females > 6 months of age. There was no statistical significance. Regression analysis demonstrated larger ICVs in diseased children than in controls younger than 10 months, at which age trend lines intersected and the reverse became true for older children. This likely represents an evolving risk of cephalocranial disproportion beyond 10 months of age. The IT/ST volume ratio was conserved in scaphocephaly, and very closely approximated that of controls.

CONCLUSIONS

Sagittal craniosynostosis appears to be associated with a larger cranial vault at less than 10 months and a smaller vault at greater than 10 months, although statistical significance was not achieved.

Shape-based interpolation method in measuring intracranial volume for pre- and post-operative decompressive craniectomy using open source software

INTRODUCTION

Intracranial volume (ICV) is an important tool in the management of patients undergoing decompressive craniectomy (DC) surgery. The aim of this study was to validate ICV measurement applying the shape-based interpolation (SBI) method using open source software on computed tomography (CT) images.

METHODS

The pre- and post-operative CT images of 55 patients undergoing DC surgery were analyzed. The ICV was measured by segmenting every slice of the CT images, and compared with estimated ICV calculated using the 1-in-10 sampling strategy and processed using the SBI method. An independent t test was conducted to compare the ICV measurements between the two different methods. The calculation using this method was repeated three times for reliability analysis using the intraclass correlations coefficient (ICC). The Bland-Altman plot was used to measure agreement between the methods for both pre- and post-operative ICV measurements.

RESULTS

The mean ICV (±SD) were 1341.1±122.1ml (manual) and 1344.11±122.6ml (SBI) for the preoperative CT data. The mean ICV (±SD) were 1396.4±132.4ml (manual) and 1400.53±132.1ml (SBI) for the post-operative CT data. No significant difference was found in ICV measurements using the manual and the SBI methods (p=.983 for pre-op, and p=.960 for post-op). The intrarater ICC showed a significant correlation; ICC=1.00. The Bland-Altman plot showed good agreement between the manual and the SBI method.

CONCLUSION

The shape-based interpolation method with 1-in-10 sampling strategy gave comparable results in estimating ICV compared to manual segmentation. Thus, this method could be used in clinical settings for rapid, reliable and repeatable ICV estimations.

Modelling human skull growth: a validated computational model

During the first year of life, the brain grows rapidly and the neurocranium increases to about 65% of its adult size. Our understanding of the relationship between the biomechanical forces, especially from the growing brain, the craniofacial soft tissue structures and the individual bone plates of the skull vault is still limited. This basic knowledge could help in the future planning of craniofacial surgical operations. The aim of this study was to develop a validated computational model of skull growth, based on the finite-element (FE) method, to help understand the biomechanics of skull growth. To do this, a two-step validation study was carried out. First, an in vitro physical three-dimensional printed model and an in silico FE model were created from the same micro-CT scan of an infant skull and loaded with forces from the growing brain from zero to two months of age. The results from the in vitro model validated the FE model before it was further developed to expand from 0 to 12 months of age. This second FE model was compared directly with in vivo clinical CT scans of infants without craniofacial conditions (n = 56). The various models were compared in terms of predicted skull width, length and circumference, while the overall shape was quantified using three-dimensional distance plots. Statistical analysis yielded no significant differences between the male skull models. All size measurements from the FE model versus the in vitro physical model were within 5%, with one exception showing a 7.6% difference. The FE model and in vivo data also correlated well, with the largest percentage difference in size being 8.3%. Overall, the FE model results matched well with both the in vitro and in vivo data. With further development and model refinement, this modelling method could be used to assist in preoperative planning of craniofacial surgery procedures and could help to reduce reoperation rates.

Length of synostosis and segmented intracranial volume correlate with age in patients with non-syndromic sagittal synostosis

PURPOSE

The aim of this study is to compare the length of synostosis and segmented intracranial volume (SIV) with age in children with non-syndromic sagittal synostosis.

METHODS

Thirty-three consecutive patients (22 boys) who had been operated by cranial vault remodeling because of sagittal synostosis were compared retrospectively from 3D-CT imaging data sets obtained from volumetric CT. The mean age of the patients at preoperative CT imaging was 0.49 (range 0.13-1.3) years and at 1-year postoperative imaging 1.8 (range 1.3-3) years. The mean interval between preoperative CT imaging and surgery was 0.25 (range 0-0.8) years. Pearson's correlation and Student's t test were used in the statistical analyses.

RESULTS

Length of sagittal synostosis correlated positively with age at preoperative CT (r = 0.688, p < 0.01). Children with total synostosis (n = 9) were significantly older (mean age 0.74 vs. 0.4 years, p < 0.01) than those with partial synostosis. Of partial synostoses, 9 were located anteriorly, 3 in the middle, and 12 posteriorly. The mean synostosis ratio (synostosis length/total sagittal suture length × 100) was 83%. Preoperative SIV correlated positively with age at preoperative CT (r = 0.788, p < 0.01), whereas the 1-year postoperative SIV did not correlate with age at operation. The older the child at the time of the operation, the less the percentage SIV increased.

CONCLUSIONS

Length of sagittal synostosis and SIV increased with age.

Growth curves for intracranial volume in normal Asian children fortify management of craniosynostosis

BACKGROUND

Although the charting of normal intracranial volume (ICV) is fundamental for managing craniosynostosis, Asian norms in this regard are unknown. The purpose of this study was to establish a growth curve for ICVs in a large series of normal Asian children, providing reference values to guide corrective surgery.

METHODS

A total of 124 normal children (male, 63; female, 61) and 41 children diagnosed with craniosynostoses were analyzed. Patients aged 0-8 years presenting to the emergency room and subjected to computed tomography (CT) for head trauma served as the reference cohort. Axial CT head scan data were obtained from radiographic archives at Jichi Medical University. Imaging was done on a Siemens CT scanner (5-mm slice thickness), using a DICOM viewer to measure ICVs.

RESULTS

ICVs were plotted against age, and best-fit logarithmic curves for normal subjects were generated, without and with gender stratification. Male and female growth curves were similar in shape but diverged past the age of 1 year (male > female). ICVs of patients with craniosynostoses were plotted to male and female growth curves by disease subset, revealing the following: sagittal synostosis, near normal (or marginally larger); metopic synostosis, below normal; other non-syndromic synostoses (unilateral, bilateral, and lambdoidal) and Crouzon syndrome, near normal; Apert syndrome, above normal; and Pfeiffer syndrome, variable.

CONCLUSION

ICVs of early childhood were investigated in Asian subjects, creating growth curves that set criteria for timing, planning and goalsetting in surgical correction of craniosynostosis.

Intracranial volume (ICV) in isolated sagittal craniosynostosis measured by 3D photocephalometry: A new perspective on a controversial issue

BACKGROUND

There are still controversies regarding the intracranial volumes in patients with isolated sagittal craniosynostosis compared to a healthy population. This study aimed to compare the intracranial volume of children with sagittal synostosis and scaphocephaly to an age- and gender-matched control cohort using three-dimensional (3D) photogrammetry.

METHODS

62 boys and nine girls with sagittal craniosynostosis were included in this study. The intracranial volume was measured at the first clinical presentation. However, 3D photogrammetry was performed at children not younger than 3 months. The 3D photogrammetric data of 547 healthy boys and 287 healthy girls between the ages of 3-10 month was analyzed to establish an age- and gender-matched control group.

RESULTS

Male patients with sagittal synostosis showed a significantly reduced intracranial volume compared to the reference group. For female patients, the intracranial volume was slightly lower compared to the norm group, but not significantly.

CONCLUSIONS

Male children with sagittal synostosis showed significantly decreased intracranial volume between the age of 3 and 10 months compared to an age- and gender-matched control group. Female patients in the same age group presented a lower intracranial volume compared to the norm group. Measuring intracranial volume using 3D photogrammetry is a comparable and valuable alternative to CT scans that leads to a significant reduction of radiation exposure to the growing brain.

Effects of open and endoscopic surgery on skull growth and calvarial vault volumes in sagittal synostosis

BACKGROUND

There have been conflicting reports on how sagittal synostosis affects cranial vault volume (CVV) and which surgical approach best normalizes skull volume. In this study, we compared CVV and cranial index (CI) of children with sagittal synostosis (before and after surgery) with those of control subjects. We also compared the effect of repair type on surgical outcome.

METHODS

Computed tomography scans of 32 children with sagittal synostosis and 61 age- and sex-matched control subjects were evaluated using previously validated segmentation software for CVV and CI. Sixteen cases underwent open surgery, and 16 underwent endoscopic surgery. Twenty-seven cases had both preoperative and postoperative scans.

RESULTS

Age of subjects at computed tomography scan ranged from 1 to 9 months preoperatively and 15 to 25 months postoperatively. Mean age difference between cases and matched control subjects was 5 days. The mean CVV of cases preoperatively was nonsignificantly (17 mL) smaller than that of control subjects (P = 0.51). The mean CVV of postoperative children was nonsignificantly (24 mL) larger than that of control subjects (P = 0.51). Adjusting for age and sex, there was no significant difference in CVV between open and endoscopic cases postoperatively (β = 48 mL, P = 0.31). The mean CI increased 12% in both groups. There was no significant difference in mean postoperative CI (P = 0.18) between the 2 groups.

CONCLUSIONS

Preoperatively, children with sagittal synostosis have no significant difference in CVV compared with control subjects. Type of surgery does not seem to affect CI and CVV 1 year postoperatively. Both open and endoscopic procedures result in CVVs similar to control subjects.

The quantitative assessment of the pre- and postoperative craniosynostosis using the methods of image analysis

This paper considers the problem of the CT based quantitative assessment of the craniosynostosis before and after the surgery. First, fast and efficient brain segmentation approach is proposed. The algorithm is robust to discontinuity of skull. As a result it can be applied both in pre- and post-operative cases. Additionally, image processing and analysis algorithms are proposed for describing the disease based on CT scans. The proposed algorithms automate determination of the standard linear indices used for assessment of the craniosynostosis (i.e. cephalic index CI and head circumference HC) and allow for planar and volumetric analysis which so far have not been reported. Results of applying the introduced methods to sample craniosynostotic cases before and after the surgery are presented and discussed. The results show that the proposed brain segmentation algorithm is characterized by high accuracy when applied both in the pre- and postoperative craniosynostosis, while the introduced planar and volumetric indices for the disease description may be helpful to distinguish between the types of the disease.

The occipitofrontal circumference: reliable prediction of the intracranial volume in children with syndromic and complex craniosynostosis

OBJECT

Patients with syndromic and complex craniosynostosis are characterized by the premature fusion of one or more cranial sutures. These patients are at risk for developing elevated intracranial pressure (ICP). There are several factors known to contribute to elevated ICP in these patients, including craniocerebral disproportion, hydrocephalus, venous hypertension, and obstructive sleep apnea. However, the causal mechanism is unknown, and patients develop elevated ICP even after skull surgery. In clinical practice, the occipitofrontal circumference (OFC) is used as an indirect measure for intracranial volume (ICV), to evaluate skull growth. However, it remains unknown whether OFC is a reliable predictor of ICV in patients with a severe skull deformity. Therefore, in this study the authors evaluated the relation between ICV and OFC.

METHODS

Eighty-four CT scans obtained in 69 patients with syndromic and complex craniosynostosis treated at the Erasmus University Medical Center-Sophia Children’s Hospital were included. The ICV was calculated based on CT scans by using autosegmentation with an HU threshold < 150. The OFC was collected from electronic patient files. The CT scans and OFC measurements were matched based on a maximum amount of the time that was allowed between these examinations, which was dependent on age. A Pearson correlation coefficient was calculated to evaluate the correlations between OFC and ICV. The predictive value of OFC, age, and sex on ICV was then further evaluated using a univariate linear mixed model. The significant factors in the univariate analysis were subsequently entered in a multivariate mixed model.

RESULTS

The correlations found between OFC and ICV were r = 0.908 for the total group (p < 0.001), r = 0.981 for Apert (p < 0.001), r = 0.867 for Crouzon-Pfeiffer (p < 0.001), r = 0.989 for Muenke (p < 0.001), r = 0.858 for Saethre- Chotzen syndrome (p = 0.001), and r = 0.917 for complex craniosynostosis (p < 0.001). Age and OFC were significant predictors of ICV in the univariate linear mixed model (p < 0.001 for both factors). The OFC was the only predictor that remained significant in the multivariate analysis (p < 0.001).

CONCLUSIONS

The OFC is a significant predictor of ICV in patients with syndromic and complex craniosynostosis. Therefore, measuring the OFC during clinical practice is very useful in determining which patients are at risk for impaired skull growth.

Intracranial volume is normal in infants with sagittal synostosis

Premature sagittal synostosis results in an elongated, narrow skull shape, scaphocephaly. It has been unclear whether the intracranial volume (ICV) of these children is different from that of normal children. The aim of the present study was to precisely determine the ICV in a large cohort of children with premature sagittal synostosis and to compare it to the ICV of a sex- and age-matched control group. All patients (n = 143) with isolated sagittal synostosis registered in the Göteborg Craniofacial Registry until the end of 2012 with a preoperative CT examination were identified. For each case, a sex- and age- (±30 days) matched control was identified from children who had undergone CT for post-traumatic or neurological reasons. The ICV was measured in a semi-automatic MATLAB program with functions such as region growing, watershed, and thresholding in axial CT slices. The ICV was calculated using the Cavalieri principle. The mean (± SEM) values of ICV for children with sagittal synostosis and for corresponding controls were 866 ± 13 ml and 870 ± 15 ml, respectively. The mean ages of these groups were 173 ± 8 days and 172 ± 8 days, respectively. Subgroup analysis of sex and age at CT (≤180 days and >180 days) did not reveal any differences in ICV between cases and controls. Precise determination of ICV in addition to the use of adequate controls has made it possible to conclude that children with premature isolated sagittal synostosis have a normal ICV.

Web based brain volume calculation for magnetic resonance images

Brain volume calculations are crucial in modern medical research, especially in the study of neurodevelopmental disorders. In this paper, we present an algorithm for calculating two classifications of brain volume, total brain volume (TBV) and intracranial volume (ICV). Our algorithm takes MRI data as input, performs several preprocessing and intermediate steps, and then returns each of the two calculated volumes. To simplify this process and make our algorithm publicly accessible to anyone, we have created a web-based interface that allows users to upload their own MRI data and calculate the TBV and ICV for the given data. This interface provides a simple and efficient method for calculating these two classifications of brain volume, and it also removes the need for the user to download or install any applications.

Priorities for public health research on craniosynostosis: summary and recommendations from a Centers for Disease Control and Prevention-sponsored meeting

On June 8-9, 2006, the National Center on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention held a meeting entitled "Prioritizing a Public Health Research Agenda for Craniosynostosis". The meeting goals were to review current knowledge in the area, discuss research gaps, and identify future priorities for public health research. Participants with a broad range of expertise (including clinical and molecular genetics, cranial morphology, epidemiology, pediatrics, psychology, public health, and surgery) contributed to the development of the research agenda. Meeting participants were asked to consider public health significance and feasibility when identifying areas of priority for future public health research. Participants identified several priorities, including the need to better delineate the prevalence and phenotype of craniosynostosis (CS); to identify factors important in the causation of CS (including potentially modifiable environmental risk factors as well as genes involved in isolated CS and gene-gene and gene-environment interactions); and to better understand short- and long-term outcomes of CS (e.g., surgical, neurocognitive and neuropsychological outcomes, psychological adjustment, and social relationships) and issues related to clinical care that could affect those outcomes. The need for improved collaboration among clinical treatment centers and standardization of data collection to address these priorities was emphasized. These priorities will be used to guide future public health research on CS.