Examination of ossification of the distal radial epiphysis using magnetic resonance imaging. New insights for age estimation in young footballers in FIFA tournaments

Age Estimation Using Machine Learning Algorithms with Parameters Obtained from X-ray Images of the Calcaneus

BACKGROUND

Determination of bone age is a critical issue for forensics, surgery, and basic sciences.

AIM

This study aims to estimate age with high accuracy and precision using Machine Learning (ML) algorithms with parameters obtained from calcaneus x-ray images of healthy individuals.

METHOD

The study was carried out by retrospectively examining the foot X-ray images of 341 people aged 18-65 years. Maximum width of the calcaneus (MW), body width (BW), maximum length (MAXL), minimum length (MINL), facies articularis cuboidea height (FACH), maximum height (MAXH), and tuber calcanei width (TKW) parameters were measured from the images. The measurements were then grouped as 20-45 years of age, 46-64 years of age, 65 and older, and age estimation was made by using these at the input of ML models.

RESULTS

As a result of the ML input of the measurements obtained, a 0.85 Accuracy (Acc) rate was obtained with the Extra Tree Classifier algorithm. The accuracy rate of other algorithms was found to vary between 0.78 and 0.82. The contribution of parameters to the overall result was evaluated by using the shapley additive explanations (SHAP) analyzer of Random Forest algorithm and the MAXH parameter was found to have the highest contribution in age estimation.

CONCLUSIONS

As a result of our study, calcaneus bone was found to have high accuracy and precision in age estimations.

Skeletal age estimation of living adolescents and young adults: A pilot study on conventional radiography versus magnetic resonance imaging and staging technique versus atlas method

OBJECTIVE

To compare conventional radiography (CR) and magnetic resonance imaging (MRI) of the left hand/wrist and both clavicles for forensic age estimation of adolescents and young adults.

MATERIALS AND METHODS

CR and MRI were prospectively conducted in 108 healthy Caucasian volunteers (52 males, 56 females) aged 16 to 21 years. Skeletal development was assessed by allocating stages (wrist, clavicles) and atlas standards (hand/wrist). Inter- and intra-observer agreements were quantified using linear weighted Cohen's kappa, and descriptive statistics regarding within-stage/standard age distributions were reported.

RESULTS

Inter- and intra-observer agreements for hand/wrist CR (staging technique: 0.840-0.871 and 0.877-0.897, respectively; atlas method: 0.636-0.947 and 0.853-0.987, respectively) and MRI (staging technique: 0.890-0.932 and 0.897-0.952, respectively; atlas method: 0.854-0.941 and 0.775-0.978, respectively) were rather similar. The CR atlas method was less reproducible than the staging technique. Inter- and intra-observer agreements for clavicle CR (0.590-0.643 and 0.656-0.770, respectively) were lower than those for MRI (0.844-0.852 and 0.866-0.931, respectively). Furthermore, although shifted, wrist CR and MRI within-stage age distribution spread were similar, as were those between staging techniques and atlas methods. The possibility to apply (profound) substages to clavicle MRI rendered a more gradual increase of age distributions with increasing stages, compared to CR.

CONCLUSIONS

For age estimation based on the left hand/wrist and both clavicles, reference data should be considered anatomical structure- and imaging modality-specific. Moreover, CR is adequate for hand/wrist evaluation and a wrist staging technique seems to be more useful than an atlas method. By contrast, MRI is of added value for clavicle evaluation.

Forensische Altersdiagnostik mittels Niederfeld-Magnetresonanztomographie

Hintergrund

Ein rechtlich zulässiges medizinisches Altersfeststellungsverfahren mit möglichst schonenden und zuverlässigen Methoden bei unbegleiteten und fraglich minderjährigen Ausländern ist erforderlich, um den tatsächlich Minderjährigen den für sie gesetzlich vorgesehenen besonderen Schutz zukommen zu lassen.

Ziel der Arbeit

Studiendesign und erste Ergebnisse einer Studie zur forensischen Altersdiagnostik mittels Niederfeld-Magnetresonanztomographie werden vorgestellt.

Material und Methoden

Geplant ist die prospektive Untersuchung von 650 Studienteilnehmenden, gleichmäßig verteilt innerhalb der Altersgruppe 12 bis 24 Jahre zu je 25 Personen je Geschlecht. Es sollen Entwicklungsstadien von distalem Radius, distaler Ulna, distalem Femur und proximaler Tibia mithilfe eines 0,31-Tesla(T)-Niederfeld-MRT-Scanners erfasst und mittels Anwendung der Vieth-Klassifikation ausgewertet werden.

Ergebnisse

Nach Auswertung der Untersuchungen der bisher 487 untersuchten Studienteilnehmenden ist ersichtlich, dass die gewählten Sequenzen die für die Vieth-Klassifikation relevanten Charakteristika der Ossifikation der untersuchten Epiphysen erfassen. Die Untersuchungen erweisen sich überdies als einfach in der Durchführung.

Schlussfolgerung

Untersuchungen zur forensischen Altersschätzung am Lebenden unter Anwendung der Vieth-Klassifikation sind mit Niederfeld-MRT-Scannern bei einer Feldstärke von 0,31 T durchführbar. Es bleibt zu klären, ob die mit einem 0,31-T-Niederfeld-MRT-Scanner nachweisbaren Ossifikationsmerkmale am Handgelenk und am Knie einen zweifelsfreien Volljährigkeitsnachweis erlauben.

Forensic age assessment by 3.0 T MRI of the wrist: adaption of the Vieth classification

OBJECTIVES

In order to find a reliable method to correctly assess majority in both sexes by MRI, a study was conducted to evaluate the applicability of the recently presented Vieth classification in wrist MRI, after it had originally been proposed for knee MRI.

METHODS

After receiving a positive vote by the ethics committee, the left-hand wrists of 347 male and 348 female volunteers of German nationality in the age bracket 12-24 years were scanned. Before conducting the prospective, cross-sectional examinations, an informed consent was obtained from each volunteer. A 3.0 T MRI scanner was used, acquiring a T1 turbo spin-echo sequence (TSE) and a T2 TSE sequence with fat suppression by spectral presaturation with inversion recovery (SPIR). The images were assessed by applying the Vieth classification. Minimum, maximum, mean ± standard deviation, and median with lower and upper quartiles were defined. Intra- and interobserver agreements were determined by calculating the kappa coefficients. Differences between the sexes were analyzed using the Mann-Whitney U test.

RESULTS

By applying the unmodified Vieth classification with corresponding schematics, it was possible to assess majority in both sexes via the epiphyseal-diaphyseal fusion of the distal radius and in males also via the epiphyseal-diaphyseal fusion of the distal ulna. The Mann-Whitney U test implied significant sex-related differences for all stages. For both epiphyses, the intra- and interobserver agreement levels were very good (κ > 0.8).

CONCLUSION

If confirmed by further studies, it would be possible to determine the completion of the 18th year of life in both sexes by 3.0 T MRI of the wrist and using the Vieth classification.

KEY POINTS

• The Vieth classification allows determining majority in males and females alike based on the distal radius' epiphysis by 3.0 T MRI of the wrist. • The Vieth classification also allows determining majority in males based on the distal ulna's epiphysis by 3.0 T MRI of the wrist, but not in females. • The presented data can be deemed referential within certain discussed boundaries.

Automated age estimation of young individuals based on 3D knee MRI using deep learning

Age estimation is a crucial element of forensic medicine to assess the chronological age of living individuals without or lacking valid legal documentation. Methods used in practice are labor-intensive, subjective, and frequently comprise radiation exposure. Recently, also non-invasive methods using magnetic resonance imaging (MRI) have evaluated and confirmed a correlation between growth plate ossification in long bones and the chronological age of young subjects. However, automated and user-independent approaches are required to perform reliable assessments on large datasets. The aim of this study was to develop a fully automated and computer-based method for age estimation based on 3D knee MRIs using machine learning. The proposed solution is based on three parts: image-preprocessing, bone segmentation, and age estimation. A total of 185 coronal and 404 sagittal MR volumes from Caucasian male subjects in the age range of 13 and 21 years were available. The best result of the fivefold cross-validation was a mean absolute error of 0.67 ± 0.49 years in age regression and an accuracy of 90.9%, a sensitivity of 88.6%, and a specificity of 94.2% in classification (18-year age limit) using a combination of convolutional neural networks and tree-based machine learning algorithms. The potential of deep learning for age estimation is reflected in the results and can be further improved if it is trained on even larger and more diverse datasets.

Forensic age estimation based on fast spin-echo proton density (FSE PD)-weighted MRI of the distal radial epiphysis

Radiation exposure is a crucial factor to consider in forensic age estimation. The various magnetic resonance imaging (MRI) modalities used in forensic age estimation avoid radiation exposure. This study examined the reliability of distal radius ossification using fast spin-echo proton density (FSE PD)–weighted MRI to estimate age. Left wrist MRI findings of 532 patients aged 10–29 years were evaluated retrospectively using the five-stage system of Dedouit et al. The intra- and interobserver reliability values were κ = 0.906 and 0.869, respectively. Based on the results, the respective minimum ages estimated for stages 4 and 5 were 13.4 and 16.1 years for females, and 15.1 and 17.3 years for males; the method could not estimate an age of 18 years in any case. FSE PD MRI analysis of the distal radius epiphysis provides supportive data and can be used when evaluating the distal radius for forensic age estimation.

Bone age estimation with the Greulich-Pyle atlas using 3T MR images of hand and wrist

The age estimation of the hand bones by means of X-ray examination is a pillar of the forensic age estimation. Since the associated radiation exposure is controversial, the search for ionizing radiation-free alternatives such as MRI is part of forensic research. The aim of the current study was to use the Greulich-Pyle (GP) atlas on MR images of the hand and wrist to provide reference values for assessing the age of the hand bones. 3T hand MR images of 238 male participants between the ages of 13 and 21 were acquired using 3D gradient echo sequences (VIBE, DESS). Two readers rated the images using the X-ray-based GP atlas method. A descriptive analysis and a transitional analysis were used for the statistical processing of the data. The agreement between and within the raters was assessed. In addition, a comparison was made with the chronological age and with X-ray studies. The descriptive analysis and the transition analysis showed similar results. Both evaluations showed good agreement with X-ray studies. The comparison with the chronological age showed a difference of 0.37 and 0.54 years for the two readers. The age estimate based on the cross-validated transition analysis showed a mean error of -0.28 years. Inter- and intra-rater agreement were good. In summary, it can be concluded that age estimation of hand bones with MR images is routinely applicable with the GP atlas as an alternative without ionizing radiation. However, in order to reduce the estimation error, a multi-factorial assessment based on examinations of several body regions is still recommended.

Magnetic resonance imaging for forensic age estimation in living children and young adults: a systematic review

The use of MRI in forensic age estimation has been explored extensively during the last decade. The authors of this paper synthesized the available MRI data for forensic age estimation in living children and young adults to provide a comprehensive overview that can guide age estimation practice and future research. To do so, the authors searched MEDLINE, Embase and Web of Science, along with cited and citing articles and study registers. Two authors independently selected articles, conducted data extraction, and assessed risk of bias. They considered study populations including living subjects up to 30 years old. Fifty-five studies were included in qualitative analysis and 33 in quantitative analysis. Most studies had biases including use of relatively small European (Caucasian) populations, varying MR approaches and varying staging techniques. Therefore, it was not appropriate to pool the age distribution data. The authors found that reproducibility of staging was remarkably lower in clavicles than in any other anatomical structure. Age estimation performance was in line with the gold standard, radiography, with mean absolute errors ranging from 0.85 years to 2.0 years. The proportion of correctly classified minors ranged from 65% to 91%. Multifactorial age estimation performed better than that based on a single anatomical site. The authors found that more multifactorial age estimation studies are necessary, together with studies testing whether the MRI data can safely be pooled. The current review results can guide future studies, help medical professionals to decide on the preferred approach for specific cases, and help judicial professionals to interpret the evidential value of age estimation results.

Comparison of reliability of magnetic resonance imaging using cartilage and T1-weighted sequences in the assessment of the closure of the growth plates at the knee

Background

Growth development is traditionally evaluated with plain radiographs of the hand and wrist to visualize bone structures using ionizing radiation. Meanwhile, MRI visualizes bone and cartilaginous tissue without radiation exposure.

Purpose

To determine the state of growth plate closure of the knee in healthy adolescents and young adults and compare the reliability of staging using cartilage sequences and T1-weighted (T1W) sequence between pediatric and general radiologists.

Material and Methods

A prospective, cross-sectional study of MRI of the knee with both cartilage and T1W sequences was performed in 395 male and female healthy subjects aged between 14.0 and 21.5 years old. The growth plate of the femur and the tibia were graded using a modified staging scale by two pediatric and two general radiologists. Femur and tibia were graded separately with both sequences.

Results

The intraclass correlation was overall excellent. The inter- and intra-observer agreement for pediatric radiologists on T1W was 82% (κ = 0.73) and 77% (κ = 0.65) for the femur and 90% (κ = 0.82) and 87% (κ = 0.75) for the tibia. The inter-observer agreement for general radiologists on T1W was 69% (κ = 0.56) for the femur and 56% (κ = 0.34) for the tibia. Cohen’s kappa coefficient showed a higher inter- and intra-observer agreement for cartilage sequences than for T1W: 93% (κ = 0.86) and 89% (κ = 0.79) for the femur and 95% (κ = 0.90) and 91% (κ = 0.81) for the tibia.

Conclusion

Cartilage sequences are more reliable than T1W sequence in the assessment of the growth plate in adolescents and young adults. Pediatric radiology experience is preferable.

Forensic age assessment of the knee: proposal of a new classification system using two-dimensional ultrasound volumes and comparison to MRI

Objectives

To assess epiphyseal growth plate closure of the knee for forensic age estimation using an ultrasound (US)-based method and to compare the findings with MRI.

Methods

Thirty-three healthy male individuals (age, 14.4–19.3 years) were prospectively evaluated for epiphyseal growth plate closure of the right knee by recordings of two-dimensional US volumes and a high-resolution T1-weighted MRI sequence. The degree of epiphyseal growth plate closure was rated independently by two readers for each method using a modality specific three-point scale that differentiates between an open physis (S1), a partially closed physis (S2), and a closed physis (S3).

Results

The inter-rater agreement was high for the US (Cohen’s kappa (CK): femur 95.2%, tibia 81.3%, fibula 86.3%) and the MRI method (CK: femur 70.2%, tibia 90.8%, fibula 79.8%). The degree of growth plate closure associated positively with advancing age. The US system showed a clearer separation of median ages with lower overlap than the MRI system. Open growth plates on minors (< S3 on femur and tibia) were identified by US with higher sensitivity (1.0 vs. 0.7) and slightly lower specificity (0.7 vs. 0.85) compared with MRI. The examination time was substantially shorter on US than on MRI (2.65 ± 0.91 min vs. 24.72 ± 2.72 min; p < 0.001).

Conclusions

The US method for evaluation of growth plate closure of the knee can reliably assign male individuals to different ossification stages and identifies minors with high accuracy. More studies with larger numbers are needed to further evaluate this method.

Key Points

• US is feasible to determine the degree of epiphyseal growth plate closure of the knee, shows a high degree of reliability, and is comparable to MRI.

• US of the knee can detect open growth plates on male minors with high accuracy.

• US of the knee may be used as a fast, non-invasive imaging tool for forensic age estimation to identify male minors.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07343-1) contains supplementary material, which is available to authorized users.

Chronological Age Assessment in Young Individuals Using Bone Age Assessment Staging and Nonradiological Aspects: Machine Learning Multifactorial Approach

BACKGROUND

Bone age assessment (BAA) is used in numerous pediatric clinical settings as well as in legal settings when entities need an estimate of chronological age (CA) when valid documents are lacking. The latter case presents itself as critical as the law is harsher for adults and granted rights along with imputability changes drastically if the individual is a minor. Traditional BAA methods have drawbacks such as exposure of minors to radiation, they do not consider factors that might affect the bone age, and they mostly focus on a single region. Given the critical scenarios in which BAA can affect the lives of young individuals, it is important to focus on the drawbacks of the traditional methods and investigate the potential of estimating CA through BAA.

OBJECTIVE

This study aims to investigate CA estimation through BAA in young individuals aged 14-21 years with machine learning methods, addressing the drawbacks of research using magnetic resonance imaging (MRI), assessment of multiple regions of interest, and other factors that may affect the bone age.

METHODS

MRI examinations of the radius, distal tibia, proximal tibia, distal femur, and calcaneus were performed on 465 men and 473 women (aged 14-21 years). Measures of weight and height were taken from the subjects, and a questionnaire was given for additional information (self-assessed Tanner Scale, physical activity level, parents' origin, and type of residence during upbringing). Two pediatric radiologists independently assessed the MRI images to evaluate their stage of bone development (blinded to age, gender, and each other). All the gathered information was used in training machine learning models for CA estimation and minor versus adult classification (threshold of 18 years). Different machine learning methods were investigated.

RESULTS

The minor versus adult classification produced accuracies of 0.90 and 0.84 for male and female subjects, respectively, with high recalls for the classification of minors. The CA estimation for the 8 age groups (aged 14-21 years) achieved mean absolute errors of 0.95 years and 1.24 years for male and female subjects, respectively. However, for the latter, a lower error occurred only for the ages of 14 and 15 years.

CONCLUSIONS

This study investigates CA estimation through BAA using machine learning methods in 2 ways: minor versus adult classification and CA estimation in 8 age groups (aged 14-21 years), while addressing the drawbacks in the research on BAA. The first achieved good results; however, for the second case, the BAA was not precise enough for the classification.

The four-minute approach revisited: accelerating MRI-based multi-factorial age estimation

Objectives

This feasibility study aimed to investigate the reliability of multi-factorial age estimation based on MR data of the hand, wisdom teeth and the clavicles with reduced acquisition time.

Methods

The raw MR data of 34 volunteers—acquired on a 3T system and using acquisition times (T_A) of 3:46 min (hand), 5:29 min (clavicles) and 10:46 min (teeth)—were retrospectively undersampled applying the commercially available CAIPIRINHA technique. Automatic and radiological age estimation methods were applied to the original image data as well as undersampled data to investigate the reliability of age estimates with decreasing acquisition time. Reliability was investigated determining standard deviation (SSD) and mean (MSD) of signed differences, intra-class correlation (ICC) and by performing Bland-Altman analysis.

Results

Automatic age estimation generally showed very high reliability (SSD < 0.90 years) even for very short acquisition times (SSD ≈ 0.20 years for a total T_A of 4 min). Radiological age estimation provided highly reliable results for images of the hand (ICC ≥ 0.96) and the teeth (ICC ≥ 0.79) for short acquisition times (T_A = 16 s for the hand, T_A = 2:21 min for the teeth), imaging data of the clavicles allowed for moderate acceleration (T_A = 1:25 min, ICC ≥ 0.71).

Conclusions

The results demonstrate that reliable multi-factorial age estimation based on MRI of the hand, wisdom teeth and the clavicles can be performed using images acquired with a total acquisition time of 4 min.

Estimating forensic age via magnetic resonance imaging of the distal radial epiphysis

Magnetic resonance imaging is currently being studied extensively, but it is still far from being the frequently recommended radiological method for age estimation. In this study, we used magnetic resonance imaging (MRI) of distal radius ossification to obtain data for age estimation. Wrist MRI scans from 338 individuals, aged 10-29 years, were examined retrospectively using the staging system of Schmidt et al. and the extension of the stages as described by Timme et al. The results revealed that the minimum ages for stage 4a ossification were 16.0 years in women and 17.7 years in men, whereas those for stage 4b ossification were 16.6 and 18.2 years in women and men, respectively. Stage 5 was not detected in any patient. These results were comparable with those of a previous study using the same methodology with distal radial epiphysis ossification. Our finding regarding stage 4b ossification may provide valuable information on legally important age thresholds relevant to the use of MRI in evaluating the distal radial epiphysis in males. Further research needs to be conducted with large series in different populations to evaluate the triple banding at the distal radial epiphysis.

Forensic age diagnostics by magnetic resonance imaging of the proximal humeral epiphysis

The most commonly used radiological method for age estimation of living individuals is X-ray. Computed tomography is not commonly used due to high radiation exposure, which raises ethical concerns. This problem can be solved with the use of magnetic resonance imaging (MRI), which avoids the use of ionizing radiation. The purpose of the present study was to evaluate the utility of MRI analysis of the proximal humeral epiphyses for forensic age estimations of living individuals. In this study, 395 left proximal humeral epiphyses (patient age 12-30 years) were evaluated with fast-spin-echo proton density-weighted image (FSE PD) sequences in a coronal oblique orientation on shoulder MRI images. A five-stage scoring system was used following the method of Dedouit et al. The intra- and interobserver reliabilities assessed using Cohen's kappa statistic were κ = 0.818 and κ = 0.798, respectively. According to this study, stage five first appeared at 20 and 21 years of age in males and females, respectively. These results are not directly comparable to any other published study due to the lack of MRI data on proximal humeral head development. These findings may provide valuable information for legally important age thresholds using shoulder MRI. The current study demonstrates that MRI of the proximal humerus can support forensic age estimation. Further research is needed to establish a standardized protocol that can be applied worldwide.

Applicability of T1-weighted MRI in the assessment of forensic age based on the epiphyseal closure of the humeral head

This work investigates the value of magnetic resonance imaging analysis of proximal epiphyseal fusion in research examining the growth and development of the humerus and its potential utility in establishing forensic age estimation. In this study, 428 proximal humeral epiphyses (patient age, 12-30 years) were evaluated with T1-weighted turbo spin echo (T1 TSE) sequences in coronal oblique orientation on shoulder MRI images. A scoring system was created following a combination of the Schmeling and Kellinghaus methods. Spearman's rank correlation analysis revealed a significant positive relationship between age and ossification stage of the proximal humeral epiphysis (all subjects: rho = 0.664, p < 0.001; males: 0.631, p < 0.001; females: rho = 0.651, p < 0.001). The intra- and inter-observer reliability assessed using Cohen's kappa statistic was κ = 0.898 and κ = 0.828, respectively. The earliest age of epiphysis closure was 17 years for females and 18 years for males. MRI of the proximal humeral epiphysis can be considered advantageous for forensic age estimation of living individuals in a variety of situations, ranging from monitoring public health to estimating the age of illegal immigrants/asylum seekers, minors engaged in criminal activities, and illegal participants in competitive sports, without the danger of radiation exposure.

A 2-year follow-up MRI study for the evaluation of an age estimation method based on knee bone development

Age estimation is an actual topic in the area of forensic medicine with a special focus on the age limits of 16 and 18 years. Current research on this topic relies on retrospective data of inhomogeneous populations relating to sex, age range, and socioeconomic status. In this work, we present a 2-year follow-up study for the evaluation of an age estimation method on a prospective magnetic resonance imaging (MRI) knee data collective of a homogeneous population. The study includes 40 male subjects from northern Germany aged 14 to 21 years. Three MRI examinations were evenly acquired within 2 years for each subject. As a first evaluation, a three-stage system was used to assess the ossification status of the knee (I:"open", II:"partially ossified", III:"fully ossified"). Three raters assessed the growth plate of the distal femur, proximal tibia, and proximal fibula based on central 2D slices. A good inter-rater agreement was attained (κ = 0.84). All subjects younger than 18 years were rated as stage I and had a cumulative knee score (SKJ) ≤ 5. Based on the follow-up datasets, new parameters quantifying the intra-individual ossification process were calculated. The results of this follow-up analysis show a different start, end, and speed of each growth plate's maturation as well as an ossification peak for individuals at the age of 16. The generated MRI database provides new insights into the ossification process over time and serves as a basis for further evaluations of age estimation methods.

Reducing acquisition time for MRI-based forensic age estimation

Radiology-based estimation of a living person’s unknown age has recently attracted increasing attention due to large numbers of undocumented immigrants entering Europe. To avoid the application of X-ray-based imaging techniques, magnetic resonance imaging (MRI) has been suggested as an alternative imaging modality. Unfortunately, MRI requires prolonged acquisition times, which potentially represents an additional stressor for young refugees. To eliminate this shortcoming, we investigated the degree of reduction in acquisition time that still led to reliable age estimates. Two radiologists randomly assessed original images and two sets of retrospectively undersampled data of 15 volunteers (N = 45 data sets) applying an established radiological age estimation method to images of the hand and wrist. Additionally, a neural network-based age estimation method analyzed four sets of further undersampled images from the 15 volunteers (N = 105 data sets). Furthermore, we compared retrospectively undersampled and acquired undersampled data for three volunteers. To assess reliability with increasing degree of undersampling, intra-rater and inter-rater agreement were analyzed computing signed differences and intra-class correlation. While our findings have to be confirmed by a larger prospective study, the results from both radiological and automatic age estimation showed that reliable age estimation was still possible for acquisition times of 15 seconds.

Magnetic resonance imaging-based evaluation of ossification of the medial clavicular epiphysis in forensic age assessment

Evaluation of the degree of ossification of the medial clavicular epiphysis plays a crucial role in determining with an adequate degree of probability whether legally relevant age boundaries after the age of 17 have been crossed. In view of the need to avoid unnecessary radiation exposure, establishing non-X-ray methods for investigating the clavicle has long been a key objective in forensic age assessment research. Based on magnetic resonance imaging examinations in a large sample of healthy subjects, the current study for the first time presents statistical measures which allow inferences to be drawn for forensic age assessment in both sexes. We undertook a prospective study of a reference sample of 334 female and 335 male German volunteers aged from 12 to 24 using a 3-T MRI scanner. A 3D FFE (fast field echo) T1-weighted sequence with fat saturation was acquired. To stage ossification of the medial clavicular epiphysis, we used the clavicular ossification staging systems described by Schmeling et al. and Kellinghaus et al. Ossification stage IIIc offers a means in both sexes of demonstrating that the age of 18 has been attained prior to complete ossification of the epiphyseal plate. In both sexes, if a subject has reached ossification stage IV, it can be stated that he or she has attained the age of 21. Magnetic resonance imaging is a valid diagnostic procedure for determining the ossification stage of the medial clavicular epiphysis.

Magnetic resonance imaging of the distal radial epiphysis: a new criterion of maturity for determining whether the age of 18 has been completed?

To improve the accuracy of forensic age estimation where there is no legal basis for carrying out x-ray examinations, it would be useful to establish non-x-ray imaging techniques. The objective of this study was to provide reference data for the magnetic resonance imaging-based evaluation of the ossification stage of the distal radius. Furthermore, we tested a new criterion of the maturity of the distal radial epiphysis for determining whether an individual has completed the age of 18. We investigated 668 MRI scans of the distal radial epiphysis from 333 female and 335 male subjects ranging in age from 12 to 24. To determine the ossification stage, we used the clavicular ossification staging systems described by Schmeling et al. and Kellinghaus et al. Ossification stage IV as described by Schmeling et al. was divided into two sub-stages, IVa and IVb, depending on whether or not it was possible to identify a triple-banded meta-epiphyseal zone of calcification. All study subjects were able to be assigned to an ossification stage without ambiguity. We present statistics relating to the distribution of ossification stages divided by sex. The age of the youngest female subject assessed as ossification stage IVb was 16.8, the age of the youngest male subject 18.6. The youngest age at which female subjects were assessed as ossification stage V was 22.3; for male subjects it was 23.1. Further independent studies should be carried out to determine whether ossification stage IVb can indeed be used to reliably determine whether a male subject has completed the age of 18.

Bone age estimation based on multislice computed tomography study of the scapula

Progress in medical imaging has opened new areas of research in forensic anthropology, especially in the context of the study of bone age assessment. The study of bone age has become a useful tool for age estimation at death or age of young adult migrants in an anthropological context. We retrospectively evaluated multislice computed tomography (MSCT) explorations focused on scapulae of 232 individuals (123 males; 109 females) aged between 8 and 30 years old. Computed tomography (CT) scans were viewed in axial and multiplanar reconstructed images using OsiriX 5.9 (64 bit)®. The ossification centers of the scapula studied were as follows: acromial, sub-coracoid, glenoid, coracoid, coracoid apex, and inferior angle epiphyses. Fusion status was scored based on a five-stage system (stage 1: no ossification, stage 2: visualization of an ossification center, stage 3: partial ossification, stage 4: full ossification associated to an epiphyseal scar, and stage 5: full ossification without epiphyseal scar). Intra-observer variability was excellent, and inter-observer variability was good, demonstrating the reliability of this MSCT staging system. The fusion of scapular ossification centers was statistically associated with age (p < 0.001) but not with sex (p > 0.05). In conclusion, MSCT of the scapula is an efficient method for age assessment, which is complementary to preexisting methods particularly for specifying the 18-year threshold. Further studies with larger groups are needed to support our results.

Systematic procedure for identifying the five main ossification stages of the medial clavicular epiphysis using computed tomography: a practical proposal for forensic age diagnostics

In forensic age estimations of living individuals, computed tomography of the clavicle is widely used for determining the age of majority. To this end, the degree of ossification of the medial clavicular epiphysis can be determined by means of two classification systems complementing each other: a 5-stage system and an additional 6-stage system that further sub-classifies the stages 2 and 3. In recent years, practical experience and new data revealed that difficulties and even wrong stage determinations may occur especially when following the short descriptions of the fundamental 5-stage system only. Based on current literature, this article provides a systematic procedure for identifying the five main ossification stages by listing important preconditions and presenting an algorithm that is comprised of four specific questions. Each question is accompanied by comprehensive and detailed descriptions which specify the criteria used for differentiation. The information is subdivided into "single-slice view" and "multi-slice view." In addition, illustrative case examples and schematic drawings facilitate application of the procedure in forensic practice. The pitfalls associated with the criteria of stage determination will be discussed in detail. Eventually, two general rules will be inferred to assign correct ossification stages of the medial clavicular epiphysis by means of computed tomography.

Ages of legal importance: Implications in relation to birth registration and age assessment practices

Assessment of age is a common procedure routinely conducted in many countries following birth date disputes, particularly following asylum claims and criminal offenses. UNICEF reports that only 65% of children in the world were registered, and the numbers of children who possess an authentic birth certificate were significantly lower than those registered. Legally important ages can be categorized into defined age ranges that vary among different countries. Recently, following an increase in the number of age-specific crimes, many countries have revised their legally important ages. This article is intended to report the most recent data on the ages of legal importance in the major countries of the world and implicate its relevance to birth registration and age assessment practices.

Dental age estimation in living individuals using 3.0 T MRI of lower third molars

In order to increase the validity of age estimation in adolescents and young adults when there is no legitimation for X-ray examinations, it seems desirable to be able to assess the mineralization of third molars using X-ray-free imaging procedures. In the present study, the mineralization stages of lower third molars were determined prospectively in 269 male and 248 female individuals aged 12 to 24 years using 3.0 T MRI. The classification system of Demirjian et al. was used to determine the stages. This study presents the minima and maxima, means and standard deviations, median values, and lower and upper quartiles separately for both sexes, for the mineralization stages B-H. Statistically significant sex differences were observed for the mineralization stages C, E, F, and G, and a faster developmental rate was observed for males. It was concluded that magnetic resonance imaging is an X-ray-free alternative to orthopantomography when assessing mineralization of third molars.