Introducing Computed Tomography Standards for Age Estimation of Modern Australian Subadults Using Postnatal Ossification Timings of Select Cranial and Cervical Sites^,

Abstract

Contemporary, population-specific ossification timings of the cranium are lacking in current literature due to challenges in obtaining large repositories of documented subadult material, forcing Australian practitioners to rely on North American, arguably antiquated reference standards for age estimation. This study assessed the temporal pattern of ossification of the cranium and provides recalibrated probabilistic information for age estimation of modern Australian children. Fusion status of the occipital and frontal bones, atlas, and axis was scored using a modified two- to four-tier system from cranial/cervical DICOM datasets of 585 children aged birth to 10 years. Transition analysis was applied to elucidate maximum-likelihood estimates between consecutive fusion stages, in conjunction with Bayesian statistics to calculate credible intervals for age estimation. Results demonstrate significant sex differences in skeletal maturation (p < 0.05) and earlier timings in comparison with major literary sources, underscoring the requisite of updated standards for age estimation of modern individuals.

Apophyseal Ossification of the Iliac Crest in Forensic Age Estimation: Computed Tomography Standards for Modern Australian Subadults

“…Consistent with postprocessing protocols recommended by Lottering et al. for morphological analyses of MSCT data, MPR and volume‐rendered reconstruction (VRR) models were generated in OsiriX ® to visualize and subsequently score the degree of ossification of the iliac crest apophysis using 3D analysis. Apophyseal grading was initially conducted using the Risser sign scoring tier and associated descriptions, to complement the approach for pseudo‐radiograph assessment; however, preliminary examination revealed serious concerns regarding the application of Risser stages 1–3, as the apophyseal excursion did not proceed in the reported anterior to posterior linear pattern in our sample .…”

“…Due to the concerns discussed in Lottering et al. pertaining to partial volume effects and pseudo‐fusion of volume‐rendered reconstructions associated with threshold‐based algorithms, which lack the ability to successfully discriminate between materials with similar density properties, an orthogonal plane MPR technique is preferred for assessment of fusion status. Orthogonal plane MPR provides three perpendicular planes displayed simultaneously with graphical cues indicating their relative orientations and intersections, which can be moved within the 3D image volume to provide a cross‐sectional view at any desired location along the adjusted principal component axes.…”

“…Failure to compensate for the direction and angle of the tilt results in distortion of the DICOM data and consequently inaccurate model reconstruction; correction for the tilt (± 30 degrees) was conducted using the OsiriX ® plugin. For consistency, DICOM data were viewed with a bone algorithm at a window level of 350HU and width of 2700HU, consistent with standardized protocols employed by our laboratory . It should be acknowledged that the utility of MPR requires substantial anatomical imaging interpretation, and without a volume reconstruction, users are required to mentally transform 2D images to form a 3D impression of skeletal structures, which may introduce a certain degree of error.…”

“…Consistent with the methodological approach utilized in our previous publications , the data were analyzed as a cumulative probit model. The cumulative probit regression, the details of which are expounded in Konigsberg , has proven an efficient tool for age estimation based on ordinal developmental scores.…”

Predicting calvarial morphology in sagittal craniosynostosis

“…The three key scenarios were: Here the entire suture elements were selected and their elastic modulus was increased at the end of each interval. The metopic suture was fused at 8.5 months of age as previously described 27,28 . This was intended to model the actual in-vivo scenario.…”