Automated Measurement of Intracranial Volume Using Three-Dimensional Photography

Morphometric analysis and outcomes following posterior cranial vault distraction in syndromic and multisuture craniosynostosis

BACKGROUND

Turribrachycephaly is a common feature in many syndromic and multisuture craniosynostoses and is traditionally treated with total cranial vault reshaping and fronto-orbital advancement. A staged approach with posterior cranial vault distraction as a primary procedure followed by anterior cranial vault reshaping has the advantage of reducing the vertical dimension of the skull in a controlled and gradual manner while expanding the cranial volume. The purpose of this study was to evaluate outcomes following posterior cranial vault expansion using distraction osteogenesis at a single tertiary pediatric center.

METHODS

This retrospective review included all cases of posterior cranial vault distraction at a single institution from 2008 to 2022 performed by one surgeon. Morphometric outcomes such as Turricephaly Index (TI) and posterior cranial volume (PCV) were assessed from pre- and postoperative computerized tomography scans for patients who underwent posterior cranial vault distraction as a primary first-stage operation. Clinical outcomes and complications were collated.

RESULTS

A total of 41 patients (25 females, 16 males; mean age 11 months) with syndromic craniosynostosis (n = 32) and nonsyndromic craniosynostosis (n = 9) were included. The main indication for posterior cranial vault distraction in this cohort was turricephaly (63%). The mean distraction distance was 25.9 mm and the mean decrease in TI was 18%. The estimated increase in PCV from distraction in this cohort was 19.7%. In this cohort of patients, 13 patients (32%) experienced complications but there were no mortalities.

CONCLUSION

Posterior cranial vault distraction osteogenesis is an effective surgical procedure to increase intracranial volume and correct turricephaly in children with syndromic and nonsyndromic craniosynostosis. This procedure is considered a safe and effective first-stage cranial operation in children with syndromic craniosynostosis with increased intracranial pressure and or turricephaly.

Data-driven cranial suture growth model enables predicting phenotypes of craniosynostosis

We present the first data-driven pediatric model that explains cranial sutural growth in the pediatric population. We segmented the cranial bones in the neurocranium from the cross-sectional CT images of 2068 normative subjects (age 0-10 years), and we used a 2D manifold-based cranial representation to establish local anatomical correspondences between subjects guided by the location of the cranial sutures. We designed a diffeomorphic spatiotemporal model of cranial bone development as a function of local sutural growth rates, and we inferred its parameters statistically from our cross-sectional dataset. We used the constructed model to predict growth for 51 independent normative patients who had longitudinal images. Moreover, we used our model to simulate the phenotypes of single suture craniosynostosis, which we compared to the observations from 212 patients. We also evaluated the accuracy predicting personalized cranial growth for 10 patients with craniosynostosis who had pre-surgical longitudinal images. Unlike existing statistical and simulation methods, our model was inferred from real image observations, explains cranial bone expansion and displacement as a consequence of sutural growth and it can simulate craniosynostosis. This pediatric cranial suture growth model constitutes a necessary tool to study abnormal development in the presence of cranial suture pathology.

Sagittal Craniosynostosis: Comparing Surgical Techniques Using 3D Photogrammetry

BACKGROUND

The aim of this study was to compare three surgical interventions for correction of sagittal synostosis-frontobiparietal remodeling (FBR), extended strip craniotomy (ESC), and spring-assisted correction (SAC)-based on three-dimensional (3D) photogrammetry and operation characteristics.

METHODS

Patients who were born between 1991 and 2019 and diagnosed with nonsyndromic sagittal synostosis who underwent FBR, ESC, or SAC and had at least one postoperative 3D photogrammetry image taken during one of six follow-up appointments until age 6 were considered for this study. Operative characteristics, postoperative complications, reinterventions, and presence of intracranial hypertension were collected. To assess cranial growth, orthogonal cranial slices and 3D photocephalometric measurements were extracted automatically and evaluated from 3D photogrammetry images.

RESULTS

A total of 322 postoperative 3D images from 218 patients were included. After correcting for age and sex, no significant differences were observed in 3D photocephalometric measurements. Mean cranial shapes suggested that postoperative growth and shape gradually normalized with higher occipitofrontal head circumference and intracranial volume values compared with normal values, regardless of type of surgery. Flattening of the vertex seems to persist after surgical correction. The authors' cranial 3D mesh processing tool has been made publicly available as a part of this study.

CONCLUSIONS

The findings suggest that until age 6, there are no significant differences among the FBR, ESC, and SAC in their ability to correct sagittal synostosis with regard to 3D photocephalometric measurements. Therefore, efforts should be made to ensure early diagnosis so that minimally invasive surgery is a viable treatment option.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Body size measuring techniques enabling stress-free growth monitoring of extreme preterm infants inside incubators: A systematic review

Introduction

Growth monitoring of preterm infants is essential for assessing the nutritional effects on their growth. The current growth monitoring techniques are too stressful, however, for the smallest preterm infants. We performed a systematic review to summarize studies on stress-free techniques for measuring the body size of preterm infants inside incubators other than the traditional calliper and tape measure-based instruments.

Methods

We searched four online literature databases: Embase, Medline, Web of Science Core Collection, and Cochrane, using search terms related to patients (neonates, infants, children) and body size measuring techniques. By means of expert judgement we assessed the techniques’ suitability for stress-free body size measurement of an infant lying in an incubator. As a criterion for suitability, we used an imaginary ideal technique.

Results

Twenty-six studies were included in this review. In 24 studies, the technique for body size measurement was related to 3D technology, and the majority of these studies acknowledged clinical superiority of 3D over 2D data. Two 3D techniques were assessed as suitable for stress-free measurement of preterm infants inside incubators. The first technique used a commercially available 3D handheld scanner which needed 3D postprocessing to derive measurement data. The second technique used a self-developed stereoscopic vision system.

Conclusions

3D volumetric parameters have higher clinical value for growth monitoring than 2D. In addition, contactless 3D measurements enable stress-free growth monitoring of even the smallest preterm infants. However, the time-consuming 3D postprocessing challenges the usability of 3D techniques. Regrettably, none of the identified suitable 3D techniques met all our requirements of an ideal all-in-one body size measuring technique for extreme preterm infants. Handheld 3D scanning might have the best properties for developing this ideal technique.

Predictive Statistical Model of Early Cranial Development

OBJECTIVE

We present a data-driven method to build a spatiotemporal statistical shape model predictive of normal cranial growth from birth to the age of 2 years.

METHODS

The model was constructed using a normative cross-sectional computed tomography image dataset of 278 subjects. First, we propose a new standard representation of the calvaria using spherical maps to establish anatomical correspondences between subjects at the cranial sutures - the main areas of cranial bone expansion. Then, we model the cranial bone shape as a bilinear function of two factors: inter-subject anatomical variability and temporal growth. We estimate these factors using principal component analysis on the spatial and temporal dimensions, using a novel coarse-to-fine temporal multi-resolution approach to mitigate the lack of longitudinal images of the same patient.

RESULTS

Our model achieved an accuracy of 1.54 ± 1.05 mm predicting development on an independent longitudinal dataset. We also used the model to calculate the cranial volume, cephalic index and cranial bone surface changes during the first two years of age, which were in agreement with clinical observations.

SIGNIFICANCE

To our knowledge, this is the first data-driven and personalized predictive model of cranial bone shape development during infancy and it can serve as a baseline to study abnormal growth patterns in the population.