Age dependence of epiphyseal ossification of the distal radius in ultrasound diagnostics

By determining the ossification stage of the distal radial epiphysis, it is possible to gain important information to help clarify the question of whether various legally relevant age limits have been exceeded. Any examination of the hand by means of projection radiography such as that used in conventional skeletal age diagnostics is strictly regulated for reasons of radiation hygiene. In many areas of the law, there are no basic legal provisions authorising the performance of X-ray examinations. The present study examines the applicability of ultrasound diagnostics in assessing ossification processes in the distal radius. To this end, the ossification stages of the distal radial epiphysis were determined in 306 female and 309 male study participants aged between 10 and 25 years. In the female gender, ossification stage III was determined at an age of 13.4 years at the earliest, and ossification stage IV at 15.0 years at the earliest. In the male gender, ossification stage III was not observed until 14.3 years, and ossification stage IV not until 15.2 years. In the practice of forensic age estimation in living persons, sonographic examination of the distal radius in areas of application with no legal basis for authorising X-ray examinations makes it possible to improve the accuracy of age diagnosis by including criteria of skeletal maturation. In view of the existing legislative basis for the use of X-rays on human subjects, the exposure of individuals to radiation can be minimised.     

Ossifikationsvorgänge des Trochanter major femoris

Background

Despite a relatively minimal level of radiation exposure, the use of x-ray radiation for the forensic estimation of chronological age of individuals is often subject to public criticism. In the recent past this has encouraged the scientific investigation of alternative imaging procedures with which the radiation-free assessment of the skeletal maturation process is possible.

Aim

The present study investigated the applicability of ultrasound diagnostics for assessing the ossification processes of the epiphysis of the greater trochanter.

Material and methods

For this purpose the epiphyseal ossification stages of 307 female and 309 male test persons between 10 and 25 years of age were determined.

Results

In the female subjects ossification stage II was found at the earliest at 10.1 years (x??=?12.2 years), ossification stage III at the earliest at 12.5 years (x??=?15.1 years) and ossification stage IV at the earliest at 13.4 years (x??=?20.8 years). In the male subjects ossification stage II was observed from 10.0 years (x??=?12.8 years), ossification stage III from 13.8 years (x??=?16.0 years) and ossification stage IV from 14.5 years (x??=?21.3 years).

Conclusion

With the legal basis as it stands at present, the sonographic examination of the femoral trochanter epiphysis allows individual radiation exposure to be kept to a minimum in the use of x-rays on humans in the forensic age estimation practice of living individuals. In areas of application where there is no legal authorization basis for radiological examinations, including a skeletal maturity criterion can increase the accuracy and reliability of age estimation.     

The iliac crest in forensic age diagnostics: evaluation of the apophyseal ossification in conventional radiography

Due to the increasing significance of forensic age estimations in the age of globalisation, novel radiographic criteria besides clavicles and hand bones may provide additional certainty for forensic age expertises. The present study analyses the suitability of the iliac crest apophysis by means of 643 pelvic radiographs of patients between 10 and 30 years of age. Retrospective assessments were carried out according to the forensically established classification and sub-classification systems modified after Kreitner et al. (Rofo 166(6):481–486, 1997) and Kellinghaus et al. (Int J Legal Med 124(4):321–325, 2010). The basic ossification stages range from 1 to 4, and the sub-stages of stage 2 and 3 range from a to c. While stage 3c was first achieved at the age of 15 by both sexes, stage 4 was first observed in females at the age of 16 and in males at the age of 17. This indicates the possibility of a valid diagnosis of both the age of 14 and the age of 16 years which represent legally relevant age thresholds in numerous countries. Applied as targeted radiography on the iliac crest, the exposure to radiation would range between other radiographic techniques recently applied. Therefore, the iliac crest apophysis appears principally suitable as novel possible criterion for forensic age estimation in the living. However, for the establishment of the iliac crest apophysis in routine diagnostics, further studies are needed focussing on the comparison of different grading systems and different radiological techniques.     

Magnetic resonance imaging of the iliac crest: age estimation in under-20 soccer players

Age assessment of living individuals represents a valuable tool in both forensic medicine and sports medicine. In soccer, age-related tournaments play an important role in guaranteeing equal chances to the competitors. However, age estimations in this field should not rely on imaging methods that include exposure to radiation. Therefore, the present study investigates the possibilities of magnetic resonance imaging (MRI) of the iliac crest apophysis for the purpose of evaluating skeletal maturation in under-20 (U-20) soccer players. To this end, gradient echo 3D sequences of the whole pelvis of 152 male tournament soccer players between 18 and 22 years of age were prospectively evaluated. A four stage classification system was applied for the assessment of the apophyseal ossification. Reliable stage determination was possible in all cases. Further sub-classification did not appear feasible due to the limitations of MRI. Analysis of the statistical parameters showed that age medians increased steadily from stage to stage. However, they did not allow for further differentiation of skeletal maturity in the cohort studied. Thus, MRI of the iliac crest appears to be generally suitable in age diagnostics of living individuals, but further investigations, especially in a cohort of individuals aged between 10 and 20 years, are needed in order to establish this method as novel criterion in sports or forensic medicine.     

The Risser sign for forensic age estimation in living individuals: a study of 643 pelvic radiographs

Due to increasing international migratory movements, forensic age estimations of living individuals in criminal proceedings are gaining increasing significance for forensic physicians and radiologists involved in delivering expert opinions. The present study examines the suitability of the radiologically well-known Risser sign grading as a possible new criterion in forensic age diagnostics. For this purpose, anteroposterior pelvic radiographs of 643 patients aged between 10 and 30 years were retrospectively evaluated by means of two different Risser sign grading systems (US and French), each with 5 stages. The left and right sides of the pelvis were assessed separately. The data was analyzed with separation of the sexes. Reliable Risser sign determination was possible in 566 cases. In both sexes, stage 4 of both the US and the French grading systems was predominantly first noted at age 14 years. In the US grading system, stage 5 was also first achieved at age 14 years in the majority of both sexes. In the French grading system, females manifested stage 5 at a minimum of 16 years, whereas in males it was first observed at 17 years. As to the nature of iliac crest maturation, interesting deviations were observed at stages 1 and 5, raising doubts about Risser’s ossification process. To conclude, both Risser sign grading systems are suitable for forensic age diagnostics, especially to determine whether the 14th year of life has been completed or not. The French Risser sign system additionally allows for statements as to the completion of the 16th year of age.     

Cameriere’s approach modified for pelvic radiographs: a novel method to assess apophyseal iliac crest ossification for the purpose of forensic age diagnostics

According to a modified method originally developed by Cameriere et al. (Int J Legal Med 120:143–146, 2006; J Forensic Sci 52:1151–1155, 2007; Forensic Sci Int 174:59–62, 2008; Forensic Sci Int 174:178–181, 2008; Forensic Sci Int 193:128.e1–128.e6, 2009), the suitability of the iliac crest apophysis (ICA) for the purpose of forensic age estimation in living individuals was investigated by means of area measurements in 643 pelvic radiographs of patients aged between 10 and 30 years. The area of the ossification centre(s) of the iliac crest and the area of the iliac wing (IW) were determined by manual segmentation. In 116 cases, area measurements were possible. ICA/IW ratios were calculated and used for regression analyses, yielding different regression equations. Depending on sex, pelvic side and ratio considered, R ² ranged between 0.20 and 0.38 and the standard error of the estimate, between 1.91 and 2.00 years. No statistical significant differences were found between the right and the left pelvic sides. In conclusion, this method is potentially applicable for forensic age estimation in living individuals. However, further studies under more standardised conditions and with higher case numbers are needed in order to decide whether the iliac crest apophysis might become suitable for routine age diagnostics.     

Ultrasound studies on the time course of clavicular ossification

When preparing forensic age estimates for living subjects over 18 years of age, it is crucial to evaluate the stage of ossification of the medial clavicular epiphysis. The establishment of radiation-free imaging techniques for assessment of clavicular ossification would be desirable in order to reduce the radiation exposure associated with forensic age estimations. In the present study, 84 right clavicles of test subjects 12–30 years of age were prospectively evaluated by means of ultrasound. Ossification stage classification was possible in 80 of the 84 medial clavicular epiphyses studied. In the remaining cases, stage classification was not possible due to the presence of developmental anomalies. The earliest ages at which the respective ossification stages were observed were 17.1 years for stage 2, 16.7 years for stage 3, and 22.5 years for stage 4. The age intervals observed for the ossification stages are consistent with the known data from radiological and computed tomography assessments. The present study results should be confirmed in a larger number of cases and with analysis of observer variability. Evaluation of medial clavicular epiphyseal ossification by ultrasound could ultimately be a rapid and economic non-ionizing diagnostic imaging procedure for forensic age estimation.     

Magnetic resonance imaging of the clavicular ossification

Assessment of the degree of ossification of the medial clavicular epiphyseal cartilage is of vital importance in forensic age diagnostics of living individuals aged more than 18 years. To date, reference studies on the assessment of clavicular ossification using imaging procedures only relate to conventional radiography and computed tomography (CT). In this study, magnetic resonance (MR) scans of 54 sternoclavicular joints of bodies aged between 6 and 40 years were evaluated prospectively. All of the examined medial clavicular epiphyseal cartilages permitted an assessment of the degree of ossification. Stage 2 was first observed at the age of 15.0 years, the earliest age at which stage 3 was observed was 16.9 years, and stage 4 was first observed at the age of 23.8 years. The observed age intervals of the respective degrees of ossification correspond to the known data from X-ray and CT scan examinations. The achieved results should be examined with a larger number of cases. A modified examination protocol is required for the MR examination of the medial clavicular epiphyseal cartilage for the purpose of forensic age diagnostics of living individuals.     

The use of magnetic resonance imaging to examine ossification of the proximal tibial epiphysis for forensic age estimation in living individuals

The establishment of radiation-free examination procedures in the field of forensic age diagnostics in living persons is to be considered of special scientific interest so as to minimize necessary exposure to X-rays while facilitating additional assessment of skeletal development in all cases. To this end, the advantages offered by magnetic resonance imaging in securing a practical application which is as unrestricted and complication-free as possible should be among the methods exploited in investigating such indicators of skeletal maturity. Within the framework of a retrospective study, we investigated the ossification status of the proximal tibial epiphysis on the MRI scans of 124 females and 166 males aged between 10 and 30 years. All the images had been generated on a 3.0 T scanner using a T1-weighted turbo spin-echo sequence. When evaluating the ossification stage, a combination of modified classifications proposed by Schmeling et al. and by Kellinghaus et al. was used. The statistical evaluation included calculation of a variety of measures to describe specific ossification stages as well as kappa coefficients to assess intra- and inter-observer agreement on diagnoses of individual stages. In forensic contexts, completion of the 14th year of life can be adequately evidenced in females with an ossification stage IV according to Schmeling et al. and in males with an ossification stage III c according to Kellinghaus et al. or an ossification stage IV according to Schmeling et al. In forensic contexts, the presence of an ossification stage IV according to Schmeling et al. can prove that the age of 16 years has been exceeded only in the male sex, whereby for age estimation purposes the diagnosis should be in line with other skeletal maturity indicators. The results available displayed a high degree of intra- and inter-observer agreement. Examination of the ossification status of the proximal tibial epiphysis using magnetic resonance imaging represents an effective additional tool for use in radiation-free forensic age diagnostics in living persons.     

Forensic age estimation in living subjects based on the ossification status of the medial clavicular epiphysis as revealed by thin-slice multidetector computed tomography

Determination of the stage of ossification of the medial clavicular epiphysis is a crucial part of age estimation in criminal proceedings when evaluating individuals with completed hand ossification. In order to ensure a maximum of accuracy in forensic age estimation practise, it is recommended to perform thin-slice CT scans; but to date there exist no reference data on the bone development of the region in question based on thin-slice computed tomography. In this retrospective study, the authors evaluated thin-slice multidetector CT images of 592 individuals aged between 10 and 35 years produced in the University Hospital of Münster. The ossification status of the medial epiphysis of the clavicle could be reliably determined in 502 cases using the classification of stages by Schmeling et al. In male individuals, stage 2 was first noted at age 14, in female individuals at age 13. Stage 3 was first achieved by male individuals at age 17, by female individuals at age 16. The occurrence of stage 4 was first found in both sexes at the age of 21. In either sex, the earliest observation of stage 5 was at age 26. The findings are basically in line with those from the only CT-based study on the subject in question using the same classification of five stages, except from the fact that in the present study, stage 5 first occurs at age 26, which is 4 or 5 years later than what was found in the CT study using 7 mm slices in the majority of cases. This vast difference may be explained through the partial volume effect occurring with thick-slice CT images by a visual deception of the epiphyseal scar occurring with stage 4.     

Study of age dependence of epiphyseal ossification of the hand skeleton

Radiological analysis of the hand skeleton is a key pillar of forensic age diagnostics in living subjects undergoing criminal proceedings. The present study investigated whether ossification stage classification of selected epiphyses of the hand could provide added value to hand radiograph analysis. Hand radiographs from 265 male and 164 female subjects aged 10–18years old who had been X-rayed due to traumatological indications were therefore assessed. Epiphyseal ossification of selected elements of the hand skeleton (ulna, radius and third metacarpal, basal phalanx, mesophalanx and telephalanx) was graded based on the criteria of the five-stage classification system of Schmeling et al. (Int J Legal Med, 118:5–8, 2004) for clavicular epiphyseal cartilage. Stage 5 (absence of the epiphyseal scar) does not occur in the radius of men before the age of 18. Stage 5 can therefore be regarded as a potential parameter for valid determination of a minimum age of 18 years for forensic age estimation in criminal proceedings.     

Studies on the time frame for ossification of the medial clavicular epiphyseal cartilage in conventional radiography

Radiological assessment of the degree of ossification of the medial clavicular epiphyseal cartilage plays a vital part in forensic age diagnosis of living adolescents and young adults. A total of 873 plain chest radiographs requested by the staff medical officer for members of staff aged 16–30 at the University Hospital Charité were evaluated retrospectively. Of these X-rays 699 permitted an assessment of ossification of at least 1 side of the clavicle. In addition to the customary stages (1: non-ossified epiphysis, 2: discernible ossification centre, 3: partial fusion, 4: total fusion) a stage 5 was also defined, characterised by the disappearance of the epiphyseal scar following total fusion. The earliest age at which stage 3 was detected in either gender was 16 years. Stage 4 was first observed in women at 20 years and in men at 21 years. In both genders, the earliest observation of stage 5 was at 26 years. It was concluded that plain chest radiographs can essentially be used to assess clavicular ossification. In practice, if overlap in posterior-anterior views impedes evaluation, a lateral view should also be taken to facilitate age estimation. In forensic practice the reference values of the present paper should be applied.     

Morphology as a cause for different classification of the ossification stage of the medial clavicular epiphysis by ultrasound, computed tomography, and macroscopy

The assessment of the ossification status of the medial clavicular epiphysis plays a decisive role in forensic age diagnostics to determine whether a person has completed his or her 18th or, respectively, 21st year of life. Currently, computed tomography is the gold standard method for age diagnostics of this kind. However, efforts are being made to establish non-ionizing methods, such as ultrasonography, predominantly, in an attempt to reduce the radiation exposure load of living persons. The present study is the first to score and to compare the ossification status of both medial clavicular epiphyses of the same subjects by sonography, computed tomography, and, in some of the cases, by macroscopy. Our study was conducted on five male corpses, ranging in age from 15.8–28.8 years. In the comparison of high-resolution sonography (frequency, 12–15 MHz) and thin slice computed tomography (slice thickness, 0.6 mm), performed separately for left and right clavicles, the results from these two methods differed in seven of ten cases. In six cases, the ossification stage of the medial clavicle, determined by sonography and classified according to Schulz et al. (2008), was scored higher than with computed tomography. In one case, it was rated lower. There was only one subject for whom both the sonographic and computed tomography findings agreed for both body sides.     

Evaluation of the radiographic visibility of the root pulp in the lower third molars for the purpose of forensic age estimation in living individuals

The question of whether an individual has reached the age of 18 is of crucial importance in forensic age estimation practice. In some countries, the age threshold of 21 years is relevant as well. A completed mineralization of third molars is not a sufficient criterion for a diagnosis of a minimum age of 18 years with the required probability. In a material of 1,198 orthopantomograms from 629 females and 569 males aged between 15 and 40 years, the visibility of the root pulp of fully mineralized lower third molars was evaluated according to stages 0, 1, 2, and 3. In females, stage 0 was first noticed at age 17.2 years, in males at age 17.6 years. In either sex, the earliest observation of stage 1 was between 21.0 and 22.4 years. Stage 2 was first achieved by males between 22.3 and 22.7 years, by females between 23.4 and 24.7 years. The occurrence of stage 3 was first found in both sexes between 25.1 and 25.9 years. These findings indicate that for stage 0, an age below 18 years cannot be excluded. However, for stage 1, the examined individual must be over 18 years of age and most probably over 21 years of age. For stages 2 and 3, the age can safely be stated to be over 21 years of age. This method may be a powerful tool for forensic dentists in age estimation in asylum and criminal proceedings.     

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.

     

Applicability of 3.0 T MRI images in the estimation of full age based on shoulder joint ossification: Single-centre study

Skeletal maturity is evaluated by many radiological methods for forensic age estimation. Direct radiography and computed tomography lead to a rise in ethical concerns due to radiation exposure. Therefore, magnetic resonance imaging (MRI) has currently been used in recent studies. In this study, the ossification stage of the shoulder joint was determined retrospectively in 178 male and 109 female individuals in the age group 12 to 30 years using 3.0 T MRI. All the images were evaluated with T1-weighted turbo spin echo (T1 TSE) sequence and T1 fast low angle shot two-dimensional sequence (T1 FL2D). The combined staging method, which was defined by Kellinghaus et al. and Schmeling et al., was used. The intra- and inter-observer agreement levels were very good (κ and κ_w). There were no significant age differences between males and females in all stages. In most of the stages, the ossification of the proximal humeral epiphyses occurred earlier in females than in males. Stage 4 did not occur in either of the sexes before the 18th birthday as the youngest patients in this stage was at 19 and 18 years of age in males and females, respectively. We concluded that evaluating the ossification of the proximal humeral epiphysis with MRI imaging for forensic age estimation may be beneficial. Evaluating the same anatomical structure with different MRI sequences may be useful for accurate staging diagnosis.     

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.

     

Studies on the time frame for ossification of the medial epiphysis of the clavicle as revealed by CT scans

The authors retrospectively analyzed 629 CT images of patients aged between 15 and 30 years produced during multiple trauma diagnostics at the Unfallkrankenhaus Berlin. For the purposes of this study, the authors reliably determined the ossification status of the medial epiphysis of the clavicle in 556 cases, using the classification of stages by Schmeling et al. In both sexes, stage 2 was first noted at age 15. In male patients, the earliest occurrence of stage 3 was noted at age 17, in female patients at age 16. Stage 4 was first achieved by both sexes at age 21. Stage 5 was first noted in female patients at age 21 and in male patients at age 22, which is 4 or 5 years earlier than was observed by a comparable study using conventional radiographs. The partial-volume effect in computed tomography using the thick slice scanning mode was discussed as a possible explanation for this early visualization. The question of how slice thickness affects the age intervals between ossification stages identified by CT examinations should be examined in additional studies.     

Age estimation of Chinese children based on second molar maturity

In forensic medicine and many other fields, age estimation by the use of teeth is of great importance for the purpose of individual identification. In the past, however, age estimation based on the second molar mineralization was scarcely performed. In this study, a total of 1657 panoramic radiographs taken from 834 males and 823 females of northern Chinese origin in the age bracket 5 to 25 years were assessed. The mineralization status of the second molars was determined using the classification described by Demirjian et al. Results showed that the left and right, as well as maxillary and mandibular second molars were generally at similar stages of mineralization. The maxillary left second molars (27) at stage D, mandibular left second molars (37) at stages C, D, F, and G, and mandibular right second molars (47) at stages D, F, and G showed a significantly lower average age in female subjects than in male subjects. In males, fully developed second molars first appeared with 12 years of age; in females, stage H occurred with 11 years at the earliest. One male individual and one female individual with second molars showing stage G were 23 years old. It was concluded that second molars showing stage H do not exclude an age under 14 years and that second molars showing stage G do not exclude an age above 18 years.

     

Determination of skeletal maturity by ultrasound: a preliminary report

Objective Replacement of radiography by sonography for determination of skeletal maturity.Design Sonographic and radiographie evaluation of the maturation of the iliac bone apophysis (Risser's sign) and evaluation of the distal radial epiphyses.Patients 64 children and adolescents with idiopathic scoliosis, aged from 5 to 19 years.Results Sonograms with corresponding radiographs were available for the hand and wrist in 36 cases and for the iliac bone in 28 cases. Comparison of sonographic with radiological data revealed sonography to have a sensitivity for qualifying the status of the distal radial epiphysis of 93.1%. Specificity was 100%, accuracy 94.4% for investigation of the distal radial epiphysis. Overall accuracy for correct determination of Risser's stage by ultrasound (in comparison with the radiographie standard) was 89.2%.Conclusions These findings suggest that ultrasound is a useful and highly acceptable tool for bone age determination in clinical routine or screening studies and will help to reduce ionizing radiation to children and adolescents.Scientific Award in Pédiatrie Orthopaedics 1995 of the German- Austrian-Swiss Ped. Orthopaedic Association