Comparison of imaging planes during CT-based evaluation of clavicular ossification: a multi-center study

Machine learning and deep learning enabled age estimation on medial clavicle CT images

The medial clavicle epiphysis is a crucial indicator for bone age estimation (BAE) after hand maturation. This study aimed to develop machine learning (ML) and deep learning (DL) models for BAE based on medial clavicle CT images and evaluate the performance on normal and variant clavicles. This study retrospectively collected 1049 patients (mean± SD: 22.50±4.34 years) and split them into normal training and test sets, and variant training and test sets. An additional 53 variant clavicles were incorporated into the variant test set. The development stages of normal MCE were used to build a linear model and support vector machine (SVM) for BAE. The CT slices of MCE were automatically segmented and used to train DL models for automated BAE. Comparisons were performed by linear versus ML versus DL, and normal versus variant clavicles. Mean absolute error (MAE) and classification accuracy was the primary parameter of comparison. For BAE, the SVM had the best MAE of 1.73 years, followed by the commonly-used CNNs (1.77-1.93 years), the linear model (1.94 years), and the hybrid neural network CoAt Net (2.01 years). In DL models, SE Net 18 was the best-performing DL model with similar results to SVM in the normal test set and achieved an MAE of 2.08 years in the external variant test. For age classification, all the models exhibit superior performance in the classification of 18-, 20-, 21-, and 22-year thresholds with limited value in the 16-year threshold. Both ML and DL models produce desirable performance in BAE based on medial clavicle CT.

Forensic Diagnostics of the Skeletal Age in the Living - Backgrounds and Methodology

BACKGROUND

 The expert opinions on forensic age diagnostics requested by state institutions are used to show the exceeding of legally relevant age thresholds, especially the completed 18th year of life. According to the recommendations of the Study Group on Forensic Age Diagnostics (AGFAD), this requires - among other things - a determination of skeletal age.

METHOD

 Considering recent scientific knowledge, the current conditions and established skeletal age diagnostics methods are presented. Additionally, this review article sheds light on the influence of ethnicity and socioeconomic status, questions regarding indication, as well as alternative and future developments.

RESULTS AND CONCLUSION

 In forensic age diagnostics, particularly hand radiography and thin-slice CT of the medial clavicular epiphysis are relevant for determining skeletal age. The Atlas method of Greulich and Pyle (1959) and the clavicular stages by Schmeling et al. (2004) and Kellinghaus et al. (2010) are primarily used for this. This spectrum of methods, which is based on a very solid database, might be supplemented by MRI studies of the knee joint in the near future.

KEY POINTS

  · Determining skeletal age is an essential part of forensic age diagnostics commissioned by state authorities and courts.. · Hand radiography and CT of the medial clavicular epiphysis form the core of the spectrum of methods recommended by the Study Group of Forensic Age Diagnostics (AGFAD).. · Since the radiological studies required for forensic age diagnostics are not medically indicated, it must be ensured that the legal basis is specifically named in each case when commissioning expert opinions.. · MRI studies of the knee joint might increase the spectrum of methods in the near future..

CITATION FORMAT

· Wittschieber D, Hahnemann ML, Mentzel H. Forensic Diagnostics of the Skeletal Age in the Living - Backgrounds and Methodology. Fortschr Röntgenstr 2024; 196: 254 - 261.

Standards of practice in forensic age estimation with CT of the medial clavicular epiphysis-a systematic review

The AGFAD (Arbeitsgemeinschaft für Forensische Alterdiagnostik, Study Group on Forensic Age Diagnostics) has published several recommendations regarding both technical aspects of computed tomography (CT) of the medial clavicular epiphysis (MCE) and the process of reading and interpreting the CT images for forensic age estimations (FAE). There are, however, no published recommendations regarding CT scan protocols and no dose reference values for CT of the MCE. The objective of this analysis was to assess adherence to AGFAD recommendations among practitioners of FAE and analyse reported dose-relevant CT scan parameters with the objective of helping to establish evidence-based dose reference values for FAE. A systematic literature search was conducted in PubMed and in Google Scholar with specific MeSH terms to identify original research articles on FAE with CT of the MCE from 1997 to 2022. A total of 48 studies were included. Adherence to AGFAD recommendations among practitioners of FAE is high regarding the use of Schmeling main stages (93%), bone window (79%), ≤ 1 mm CT slices (67%), axial/coronal CT images (65%), and Kellinghaus sub-stages (59%). The reporting of CT technique and CT dose-relevant scan parameters is heterogeneous and often incomplete in the current literature. Considering the success achieved by the AGFAD in creating standards of practice of FAE in living subjects, there is potential for the AGFAD to establish standards for radiation protection in FAE as well.

[Radiological methods for age diagnostics : Clinical and forensic aspects]

Age diagnostics play an increasing role in radiology. Medical and forensic questions are indications for the application of age diagnostics. In addition to X‑rays of the hand in childhood, panoramic tomography and computed tomography are currently the standard procedures. Alternative modalities without ionizing radiation (sonography, magnetic resonance imaging) have not (yet) been established. The purpose of this article is to present the indications and methods of age diagnostics in the clinical and forensic contexts and to familiarize you with their advantages and disadvantages as well as the possibility of determining the final length.

The distal femoral epiphysis in forensic age diagnostics: studies on the evaluation of the ossification process by means of T1- and PD/T2-weighted magnetic resonance imaging

The age of majority, which corresponds to the age of 18 years in most European countries, plays a crucial role for a large number of legal decisions. Accordingly, an increasing number of requests by authorities to forensic age estimation experts comprise the question of whether the age of 18 years has been reached by an individual. In recent years, novel study data suggested that magnetic resonance imaging (MRI) of the knee might likewise allow for the determination of majority beyond reasonable doubt. However, the data basis, especially concerning the distal femoral epiphysis (DFE), is still poor. For this reason, 392 routine MRI cases of the knee (204 males and 188 females of a Western Caucasian population, aged between 12 and 25 years) were retrospectively analyzed. T1-weighted and water-selective fat-saturated PD/T2-weighted sequences, generated at 1.5 and 3.0 T clinical MR scanners, were available. Ossification stages of the DFE were determined by means of the classification system by Vieth et al. (Eur Radiol 2018; 28:3255-3262). Both the intra-observer agreement and inter-observer agreement were found to be "very good" (κ = 0.899 and κ = 0.830). The present study confirmed that MRI of the DFE is suitable to determine majority in both sexes when stage 6 is present as the study revealed minimum ages above the age of 18 years for this stage (20.40 years in males and 20.60 years in females). Accordingly, the data represent a strong support for the so far existing database. Hence, the investigation of the knee using routine MRI appears to become a realistic alternative for forensic age estimation practice in the near future.

Magnetic resonance imaging of the proximal tibial epiphysis is suitable for statements as to the question of majority: a validation study in forensic age diagnostics

Determining majority plays a key role for forensic age diagnostics in living individuals. Recent data suggest that magnetic resonance imaging (MRI) of the proximal tibial epiphysis (PTE) may be a suitable alternative or at least an additional tool to clarify whether an individual has reached majority. However, the reference data situation is still sparse. Hence, the present dual center study retrospectively analyzed routine MRI of the knee in 413 cases (214 males and 199 females) of a Western Caucasian population aged between 12 and 25 years. MRI was performed at 1.5 and 3.0 T clinical scanners using T1- and T2-weighted sequences. The classification system by Vieth et al. (Eur Radiol 2018; 28:3255-3262) was applied for determining the ossification stages of the PTE. Intra-observer agreement was "very good" (κ = 0.931), and inter-observer agreement was "good" (κ = 0.798). Minimum ages above the age of 18 years were observed with the final stage (stage 6) in either sex (20.27 years in males and 18.55 years in females). The results are not in contradiction with the previous data and can be considered a strong and valuable support of the so far existing database. Therefore, the investigation of the PTE using routine MRI (either at 1.5 or 3.0 T) could be taken into consideration for application in forensic age estimation practice in near future.

CT of the medial clavicular epiphysis for forensic age estimation: hands up?

Purpose

The aim of this study was to assess the impact of arm position in computed tomography (CT) of the clavicle performed for forensic age estimation on clavicular position, image noise, and radiation dose.

Methods and materials

Forty-seven CT scans of the medial clavicular epiphysis performed for forensic age estimation were conducted with either hands and arms held upwards (CT_HU, 28 persons) or positioned at the body (CT_HD, 19 persons). Presets were identical for both positions (70 mAs/140 kVp; Brilliance iCT, Philips). Each CT scan was reconstructed with an iterative algorithm (i-Dose 4) and evaluated at the middle of the sternoclavicular joint. Clavicular angle was measured on a.p. topograms in relation to a horizontal line. Quantitative image noise was measured in air at the level of medial clavicular epiphysis. Effective dose and scan length were recorded.

Results

Hands-up position compared with hands-down position resulted in a lower lateral body diameter (CT_HU 41.1 ± 3.6 cm vs. CT_HD 44.6 ± 3.1 cm; P = 0.03), a reduced quantitative image noise (CT_HU: 39.5 ± 9.2; CT_HD: 46.2 ± 8.3; P = 0.02), and lower CTDI_vol (5.1 ± 1.4 mGy vs. 6.7 ± 1.8 mGy; P = 0.001). Scan length was longer in patients examined with hands up (HU: 8.5 ± 3.4 cm; HD: 6.2 ± 2.1 cm; P = 0.006). Mean effective dose for CT_HU was 0.79 ± 0.32 mSv compared with 0.95 ± 0.38 mSv in CT_HD (P = 0.12). Clavicular angle was 17° ± 6° in patients with hands down and 32° ± 7° in patients with hands up (P < 0.001).

Conclusion

By elevated arm positioning, the image quality of clavicular CT scans can be improved while maintaining radiation dose compared with hands down. Clavicular position differs according to the hand position. Thus, positioning patients with elevated hands is advisable for forensic clavicular CT examinations, but multiplanar CT reconstructions should be adjusted to clavicular position and scan length should be reduced to a minimum.

Comparison of different iterative CT reconstruction techniques and filtered back projection for assessment of the medial clavicular epiphysis in forensic age estimation

PURPOSE

To assess the impact of iterative reconstruction and filtered back projection (FBP) on image quality in computed tomography (CT)-based forensic age estimation of the medial clavicular epiphysis.

METHODS AND MATERIALS

CT of the clavicle was performed in 19 patients due to forensic reasons (70 mAs/140 kVp). Raw data were reconstructed with FBP and with an iterative algorithm at level 4 and 6. Clavicular ossification stage was determined by two radiologists in consensus, firstly on FBP reconstructed images and secondly after reviewing all reconstructions including iDose 4 and 6. In addition, the 3 reconstructions were compared regarding artefacts and delineation of the meta-/epiphyseal interface. Quantitative image noise was measured.

RESULTS

Quantitative noise was lower in iDose 6 reconstructed images than in FBP (P < 0.042), but not significantly lower between iDose 4 and FBP (P = 0.127). Side by side comparison revealed lesser qualitative image noise on both iDose reconstructed images than for FBP. The meta-/epiphyseal interface delineation was rated better on both iDose levels than with FBP. In 3 of 19 patients, the clavicular ossification stage was reclassified after iterative reconstructions had been additionally reviewed.

CONCLUSION

Using iterative CT reconstruction algorithms, a reduction of image noise and an enhancement of image quality regarding the meta-/epiphyseal clavicular interface can be achieved. The study highlights the importance of image standardization as variation of reconstruction technique has impact on forensic age estimation.

Anatomic shape variants of extremitas sternalis claviculae as collected from sternoclavicular thin-slice CT-studies of 2820 male borderline-adults

Within medical age assessment practice, the indicator "medial clavicular ossification" constitutes crucial evidence capable of excluding age minority "beyond reasonable doubt" concerning age-disputed individuals doubtfully claiming children's rights during legal procedures. Yet, one of its characteristics affects the morphological variability including a fair amount of downright peculiar appearances. As a result, inexperienced examiners are tempted to classify actually not-assessable formations according to the two established developmental typologies of Schmeling et al. and Kellinghaus et al. being at the same time the most frequent systemic error of age-related clavicular taxation. Since a respective overview appears missing, the study extracts not-assessable shape variants of the medial collar bone from a large sample of 2820 male borderline-adults as seen from thin-slice, sternoclavicular computed tomography. The two already highlighted configurations "more than one, medial, secondary ossification centres" and "medial metaphyseal concavity" are found as the most commonly encountered features impeding reliable delineation of staging criteria. In accordance with previous literature, it is emphasized that "qualified" rating of extremitas sternalis claviculae within age assessment practice presupposes "knowledge about the diversity of [its] anatomic shape variants."

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.

Intraindividual incongruences of medially ossifying clavicles in borderline adults as seen from thin-slice CT studies of 2595 male persons

In the past, numerous studies have documented the possibility of intraindividual differing appearances of the paired age-marker "medial clavicular ossification" in borderline adults. However, the extent of the divergences is rarely mentioned. Against that the article describes this phenomenon from a large sample of 2595 male persons by means of thin-slice CT imaging of the sternoclavicular regions. For determining the ossification stage of the medial clavicles, the two accepted classifications by Schmeling et al. (five main stages) and Kellinghaus et al. (six substages) were applied and buildings deviating from that labelled as atypical "norm variants". The longstanding observation could be confirmed that intraindividual stage discrepancies of this age indicator are generally moderate and do not exceed one main stage or two substages of the respective classifications. It is concluded that stage determination should be scrutinized, if a dissimilarity seems to show larger differences.