Validation of post mortem dental CT for disaster victim identification Thomas D. Ruder a,b,c,n , Yannick A. Thali a,d , Saiful N.A. Rashid e,f , Michael T. Mund a,g , Michael J. Thali a , Gary M. Hatch h , Angi M. Christensen i , Sandra Somaini j , Garyfalia Ampanozi a,c a Institute of Forensic Medicine, Department of Forensic Medicine and Imaging, University of Zurich, CH-8057 Zurich, Switzerland b Institute of Diagnostic, Interventional, and Pediatric Radiology, University Hospital Bern, CH-3010 Bern, Switzerland c Center of Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, CH-3012 Bern, Switzerland d Institute of Radiology, Cantonal Hospital Lucerne, CH-6000 Lucerne, Switzerland e Department of Imaging, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, Malaysia f National Institute of Forensic Medicine, Hospital Kuala Lumpur, Malaysia g JDMT Medical Services AG, CH-8330 Pfäffikon, Switzerland h Radiology-Pathology Center for Forensic Imaging, Departments of Radiology and Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87102, USA i Federal Bureau of Investigation Laboratory, Quantico, VA 22135, USA j Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern, CH-3010 Bern, Switzerland article info Article history: Received 27 November 2015 Accepted 25 January 2016 Available online 31 January 2016 Keywords: Forensic radiology Forensic identification Dental identification Post mortem CT Post mortem dental-CT abstract The objective of this study was to test the accuracy and inter-reader variability of comparative radiologic identification based on dental post mortem computed tomography (PMCT) and ante mortem (AM) dental radiographs. Five raters with varying degrees of expertize and experience independently compared 115 dental PMCT images to 114 AM dental radiographs to identify matching pairs (n ¼98), unmatched PMCT images (n ¼17), and unmatched AM radiographs (n ¼16). Levels of confidence (LOC) and number of concordant features (NOCF) of matched pairs were documented. Accuracy of matches/exclusions, interrater corre- lation coefficient and correlation between correct matches/exclusions, LOC and NOCF were calculated for all raters. Mean accuracy was 92% for matches and 80% for exclusions. Interrater correlation coefficient re- garding LOC and NOCF were 0.623 and 0.907 respectively. LOC were correlated with NOCF of matched pairs but accuracy of matches/exclusions was neither correlated to LOC nor to NOCF. This study shows that visual comparison of PMCT images with AM dental radiographs is a reliable method for identification. Accuracy of identification using PMCT/AM dental radiographs was as high as in comparable studies using post mortem (PM) dental radiographs/AM dental radiographs. Raters with practical experience in forensic identification and experience with the imaging modality (in this case: dental PMCT) achieved higher accuracy than inexperienced raters. Match accuracy did not correlate with subjective confidence or number of concordant features. It is advised to work in teams rather than in- dividually when dealing with real cases in forensic identification, to minimize subjective interpretation and avoid confirmation bias. & 2016 Elsevier Ltd. All rights reserved. 1. Introduction Identification of the dead is a fundamental part of forensic investigation [1]. Individual identification relies on comparison of ante mortem (AM) and post mortem (PM) data, typically finger- prints, DNA samples, or dental records [2]. Interpol offers general guidelines for victim identification in mass disasters [2]. However there are no internationally recognized guidelines in isolated cases and the procedure differs as a function of local conventions, availability of experts, and the scenario [3]. In the past 15 years, the use of post mortem computed tomo- graphy (PMCT) in forensic death investigations increased [4] and its potential for disaster victim identification was put to the test both in actual and simulated mass disaster scenarios [5–7]. Today, Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jofri Journal of Forensic Radiology and Imaging http://dx.doi.org/10.1016/j.jofri.2016.01.006 2212-4780/& 2016 Elsevier Ltd. All rights reserved. n Correspondence to: Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, CH-8057 Zurich, Switzerland. E-mail addresses: thomas.ruder@irm.uzh.ch, thomas_ruder@hotmail.com (T.D. Ruder). Journal of Forensic Radiology and Imaging 5 (2016) 25–30