Forensic Age Determination Using MRI Scans of the Ankle: Applying Two Classifications to Assess Ossification

Abstract In forensic age determination, e.g. for legal proceedings, exceeded age limits may be relevant. To investigate age-related differences in skeletal development, the recommendations of the Study Group on Forensic Age Diagnostics (AGFAD) rely on imaging techniques using ionizing radiation (including orthopantomograms and radiographs of the hand). Vieth et al. and Ottow et al. have proposed MRI classifications for epi-/diaphyseal fusion of the knee joint to determine different age limits. The aim of the present study was to verify whether these two classifications could also be applied to MRI of the ankle. MRI images of the ankle from 333 patients (160 female, 173 male) ranging in age from 10 to 28 years were retrospectively analyzed. T1-weighted turbo spin-echo (TSE) sequences and T2-weighted fat-suppressed sequences were analyzed for the two classifications. The different ossification stages of the two classifications were determined and the corresponding chronological ages were assigned. In addition, gender-specific differences were analyzed. Intra- and inter-observer variability was determined using Cohen’s kappa. With the classification of Ottow et al., the completion of the 14th year of life could be determined in both sexes. With the classification of Vieth et al, the completion of the 14th year of life could be determined in both sexes and the 18th year of life in male patients. Intra-observer and inter-observer variability was very good and good, respectively (κ > 0.87 and κ > 0.72). In the present study, it was also possible to use both classifications for MRI of the ankle joint. The method offers the potential of an alternative or at least supplementary radiation-free assessment criterion in forensic age estimation.