Age estimation of living individuals and the analysis of the phenomenon of long bone compression after epiphyseal closure based on non-invasive MRI image sequences of the knee.

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Age estimation of living individuals especially the differentiation between adolescent and adult is an important part of asylum and criminal law. Therefore examinations of the body, radiography of the hand as well as odontology inspections were used. Due to radiation protection radiography can only use in case of criminal law. Beside this constraint most of the published methods should be rated critically in case of applying them to any individual. This is due to the fact that most of the age estimation methods are based on the statistical analysis of groups that covers only a subset of the population related to social status or origin. Non-invasive imaging techniques, like the magnetic resonance imaging (MRI), enable the assessment of the ossification process of epiphyses growth. Here, the correlation between the grade of the growth process and the age of the individuals is calculated and used for actual age-estimation. But, in most cases the manual assessment is time-consuming and the grading is not clear. This can lead to user dependent results and misclassification. Also the use of image analysis methods for automatic and robust age estimation enabling the evaluation of a greater number of datasets is not published yet. Another biological phenomenon is the length reduction of long bones after the completed growth process. In the last years this shrinkage was incidentally described but without measuring the longitudinal length. In 2012 the first study was published using a Knemometer for longitudinal measuring. Here, the shrinkage after complete closing of the epiphysis of the proximal tibia was documented for the first time. The aim of this project is the evaluation of the epiphyses ossification in the knee based on MRI image sequences to establish a new method for age estimation. A new method should be developed which enables an automatic and robust classification of the grade of ossification using 3D MRI datasets. The applicability of this procedure should be investigated for the differentiation between adolescent and adult analyzing a large collective of datasets. Additionally, the phenomenon of long bone compression should be proofed. Therefore, a new data base including 3D MRI image data, longitudinal measurement and characteristic parameters (e.g. weight and height) for each subject should be acquired and analyzed several times over a period of 3 years. Then, the length of the tibia should be calculated using computer based methods on MRI image data. Afterwards these results should be compared to the Knemometer values proving the quality of the computer based methods. Furthermore, non-linear registration should be evaluated to localize the area of long bone shrinkage. Finally, it should be investigated which of the extracted image parameters are relevant for forensic age estimation (16 and 18) and how precise the majority age can be identified.