Forensic age estimation in living adolescents with CT imaging of the clavicula-impact of low-dose scanning on readers' confidence

Objectives Computed tomography (CT) imaging of the clavicula displays the reference standard for forensic bone age diagnostics in adolescents and young adults. Consequently, highest efforts on radiation reduction are warranted. Therefore, the aim of this study was to investigate the feasibility of low-dose (LD) CT imaging of the clavicula for age estimation in living adolescents. Methods A total of 207 non-contrast chest CT of 144 patients born between 1988 and 2012, performed in 2018 due to various clinical indications, were included in this retrospective study. The mean patient age was 16.9 +/- 6.6 years. Patients were divided into a LD (n = 146) and standard-dose (SD;n = 61) group. Image quality, confidence levels, and ossification stages (using the 5-stage classification including the subgroups 2a-3c) were assessed by two radiologists independently. Radiation dose was determined via dosimetry software. Results Dose simulation withz-axis reduction to depict the clavicula only resulted in a median exposure of 0.1 mSv (IQR: 0.0) in LD compared with 0.9 mSv (IQR: 0.6) in SD (p < 0.001). The median image quality was rated by both readers significantly worse in LD compared with SD on a Likert scale ranging from 1 to 4 with a median of 3 (IQR: 1) versus 4 (IQR: 0;p < 0.001 for both readers). There was an almost perfect agreement for the ossification stages between both readers with a Cohen's kappa of 0.83 (p < 0.001). Median confidence levels of both readers were not significantly different between LD and SD in the decisive subgroups 2a-3c. Conclusions Low-dose CT imaging of the clavicula for age estimation in living adolescents is possible without loss of readers' confidence.