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This Chapter discusses methods for assessing age in deceased individuals in different stages of preservation. In a medicolegal setting, the remains of a deceased individual may range from a small amount of material, e.g. a single tooth, to a well-preserved unidentified body. Hence, several methods covering this spectrum exist. Even though an age assessment is somewhat more reliable in sub-adults than adults, an assessment of age cannot be obtained with high accuracy and should be given as a range. In this chapter, a large range of methods for age estimation in the deceased will be described including observational and destructive procedures as well as imaging modalities. Moreover, newer methods such as DNA methylation will be mentioned.

In Denmark, post-mortem CT scanning (PMCT) was introduced over 20 years ago. The Department of Forensic Medicine, University of Copenhagen, implemented whole-body CT scanning before each autopsy in December 2002, followed by the Department at University of Southern Denmark in Odense in 2006 and at the University of Aarhus 2008. Subsequently, other equipment, including Magnetic Resonance (MR) scanners, surface scanners, photogrammetry equipment and 3D printers, were introduced in the following years. In this review, we will provide contemporary insights into the status of forensic imaging in Denmark, including requisitioned work and research. We will also discuss future directions in the field.

It is believed by many that reference data for age estimation purposes must be imaging-modality specific. A study from our department has however proven otherwise. We therefore found it interesting to investigate this further by looking at the level of agreement between different imaging modalities. The aim of this study was to investigate the level of agreement between the three radiological modalities, computed tomography (CT), magnetic resonance imaging (MRI), and digital radiography (DR), in assessing the ossification of the epiphyses of the knee. A total of 34 deceased individuals of 10–25 years of age, brought in for a medicolegal autopsy at our department, were scanned by CT, MRI, and DR. The ossification stages of the three bones of the right knee, distal femoral, proximal tibial, and proximal fibular epiphysis were assessed using the established combined staging method by Schmeling et al. and Kellinghaus et al. Analysis of the results by Cohen’s weighted kappa showed a good agreement between CT and DR (K = 0.61–0.70), and MRI and DR (K = 0.68–0.79) but only moderate agreement between CT and MRI (K = 0.55–0.57). This leads us to conclude that different radiological images cannot be used interchangeably for age estimation purposes, so reference material needs to be imaging-modality specific. However, to make a more general conclusion research on a larger population is needed.

Post-mortem computed tomography (PMCT) has been increasingly used as routine examination in forensic pathology. No recent review of the growing number of papers on the ability of PMCT to detect skull fracture exists, and original papers report sensitivities from 0.85 to 1.00. This systematic review (PROSPERO: CRD42021233264) aims to provide a meta-analysis of sensitivity and specificity of PMCT in skull fracture detection. We searched PubMed, MEDLINE and Embase for papers published between January 2000 and August 2021 reporting raw numbers, sensitivity and specificity or Abbreviated Injury Score for PMCT compared to autopsy. Papers without both PMCT and autopsy, no separate reporting of the neuro-cranium, exclusively on children, sharp trauma, gunshot or natural death as well as case reports and reviews were excluded. Two authors independently performed inclusion, bias assessment and data extraction. QUADAS-2 was used for bias assessment and a random effects models used for meta-analysis. From 4.284 hits, 18 studies were eligible and 13 included in the meta-analysis for a total of 1538 cases. All deceased were scanned on multi-slice scanners with comparable parameters. Images were evaluated by radiologists or pathologists. Intra- and inter-observer analyses were rarely reported. In summary, sensitivity of PMCT for detection of fractures in the skull base was 0.87 [0.80; 0.92] with specificity 0.96 [0.90; 0.98], and sensitivity for the vault was 0.89 [0.80; 0.94] with specificity 0.96 [0.91; 0.98]. The mixed samples are a limitation of the review.

When performing a forensic dental age assessment, mineralization disturbances of the teeth and the possible consequences these may have upon the reliability of the assessment must be taken into consideration. Furthermore, mineralization disturbances of a general character in the teeth may be seen as an indicator of more systemic insults during tooth formation and thus supplement the examination performed by the forensic pathologist. At our department the forensic dental age assessment is based upon a dental panoramic image, intra oral images of the third molars as well as a clinical photograph of the front teeth in the upper jaw. The assessment of mineralization disturbances is based upon both the clinical photograph as well as the radiological images, where the assessment of the clinical photograph functions as a quick screening for mineralization disturbances. If there are signs of disturbances of mineralization in tooth formation, it should be further examined whether the disorder has impacted tooth formation and thus root growth. This could influence the assessment of the chronological age.

When an estimate of age is needed, typically multiple indicators are present as found in skeletal or dental information. There exists a vast literature on approaches to estimate age from such multivariate data. Application of Bayes' rule has been proposed to overcome drawbacks of classical regression models but becomes less trivial as soon as the number of indicators increases. Each of the age indicators can lead to a different point estimate ("the most plausible value for age") and a prediction interval ("the range of possible values"). The major challenge in the combination of multiple indicators is not the calculation of a combined point estimate for age but the construction of an appropriate prediction interval. Ignoring the correlation between the age indicators results in intervals being too small. Boldsen et al. (2002) presented an ad-hoc procedure to construct an approximate confidence interval without the need to model the multivariate correlation structure between the indicators. The aim of the present paper is to bring under attention this pragmatic approach and to evaluate its performance in a practical setting. This is all the more needed since recent publications ignore the need for interval estimation. To illustrate and evaluate the method, Köhler et al. (1995) third molar scores are used to estimate the age in a dataset of 3200 male subjects in the juvenile age range.

A radiographic assessment of third molar development is essential for differentiating between juveniles and adolescents in forensic age estimations. As the developmental stages of third molars are highly correlated, age estimates based on a combination of a full set of third molar scores are statistically complicated. Transition analysis (TA) is a statistical method developed for estimating age at death in skeletons, which combines several correlated developmental traits into one age estimate including a 95% prediction interval. The aim of this study was to evaluate the performance of TA in the living on a full set of third molar scores. A cross sectional sample of 854 panoramic radiographs, homogenously distributed by sex and age (15.0-24.0 years), were randomly split in two; a reference sample for obtaining age estimates including a 95% prediction interval according to TA; and a validation sample to test the age estimates against actual age. The mean inaccuracy of the age estimates was 1.82 years (±1.35) in males and 1.81 years (±1.44) in females. The mean bias was 0.55 years (±2.20) in males and 0.31 years (±2.30) in females. Of the actual ages, 93.7% of the males and 95.9% of the females (validation sample) fell within the 95% prediction interval. Moreover, at a sensitivity and specificity of 0.824 and 0.937 in males and 0.814 and 0.827 in females, TA performs well in differentiating between being a minor as opposed to an adult. Although accuracy does not outperform other methods, TA provides unbiased age estimates which minimize the risk of wrongly estimating minors as adults. Furthermore, when corrected ad hoc, TA produces appropriate prediction intervals. As TA allows expansion with additional traits, i.e. stages of development of the left hand-wrist and the clavicle, it has a great potential for future more accurate and reproducible age estimates, including an estimated probability of having attained the legal age limit of 18 years.

Objectives: The developmental stages of the clavicles are important for forensic age estimation purposes in adolescents. This study compares the 4-stage system to evaluate the ossification of the medial end of the clavicle as visualized by magnetic resonance imaging (MRI) and computed tomography (CT). As several forensic institutes routinely perform CT scans, the large amount of available data may serve as reference sample for MRI in specific cases. Material and methods: This prospective study included an MRI and CT scan of 47 autopsy cases performed prior to medico-legal autopsy (age range 12.9-27.5 years). All images were scored in blind trials using a 4-stage system by a trained observer. Results: Intra-observer agreements were substantial within (MRI: K=0.685, CT: K=0.611) and between modalities (K=0.644, p

At 2.7% in 1970, the Danish medico-legal autopsy frequency was lower than recent frequencies observed in the Nordic countries (4-24%). The aim of this study was to analyse trends in the number and frequency of Danish medico-legal autopsies.