Forensic Imaging for Causal Investigation of Death
A 63-year-old man was found in the street after overrun by a car. An emergency physician stated the on-site death. According to the whole setting of the accident and after hearing both the car driver and witnesses, when being overrun, the man was lying on the street already. As usual in such cases, one of the first debated questions was if the death occurred prior or subsequent to the overrun.\nA postmortem CT imaging of the whole body was done prior to the autopsy. The examinations were performed on a 128-slice dual-source CT system (Somatom Definition Flash, Siemens AG, Forchheim, Germany). The examination started with anterior-posterior and lateral scout views. The parameters were for the entire body including the head pitch 0.35, gantry rotation time 1.0 seconds, tube voltage 120 kV, effective tube current time product 550 mAs_eff and field of view 50 cm. Image reconstructions were performed using the filtered backprojection. Reconstructed images where transferred for further processing, reformatting and displaying to the syngo multimodality work place (Syngo MMWP, Siemens AG, Forchheim, Germany). The subsequent consensus report of two radiologists (one board-certified radiologist with substantial experiences of clinical CT reporting for more than 20 years and one resident with 2 years experiences of clinical CT reporting as well as each with one year experience in postmortem imaging), revealed as the main findings multiple bone fractures of the skull, ribs, vertebrae and extremities as well as a distinct laceration of the spleen. All this lesions were without any relevant surrounding hemorrhage which would have been expected under these circumstances. In the duodenum, a round radiopaque formation was found which was reminiscent of a conglomeration of ingested tablets which indicates medication intake before death (). The radiologic report concluded that the man was overrun postmortem, after having died shortly before due to another reason, presumably as a consequence of intoxication.\nThe subsequent autopsy was done on the following day by two forensic pathologists being unaware of the radiologic report. In the autopsy report, the stomach and duodenum were documented to contain a brownish friable mass. However, a blister of zopiclone tablets was found in the personal belongings of the man (zopiclone AbZ, 7.5 mg), containing altogether fourteen tablets, nine of them having been removed. Indeed, zopiclone could be identified with the toxicological analysis of the stomach content and urine. Additionally, blood samples were collected from the saphenous vein. The blood concentration of zopiclone was 507 ng/mL and with regard to products of decomposition which might influence the result, the blood concentration of zopiclone was estimated to approximately 660 ng/mL at the time of death (therapeutic concentration in the serum is considered 10 to 50 ng/mL). In addition, a blood alcohol concentration of 1.39‰ was measured. A laceration of the spleen as well as multiple fractures in various regions of the body were also documented, however all with almost no surrounding hemorrhage. Zopiclone and alcohol intoxication were concluded as cause of death, followed by a subsequent overrun accident.\nAfter autopsy, the forensic pathologists got access to the radiological report.\nComputed tomography images were consulted for second reading as a radiopaque formation, which was described in the radiological report, had not been found during the autopsy. Both radiologists independently considered the radiopaque formation to be located within the duodenum, most probably within a duodenal diverticulum. The density of the formation was documented with 90 Hounsfield units (HU).\nTo further examine the observed finding, zopiclone tablets were scanned with the same CT scanner which was used for the postmortem imaging. First, one tablet was put in a bottle, filled with water, and scanned directly, the same procedure was repeated with an aggregate of five tablets, scanned directly and after one hour. In vitro imaging of these tablets revealed nearly the same density (88 HU) as above measured within the radiopaque formation (). This was true for both, the scans of the single tablet and the aggregate of five tablets.\nThe final forensic report revealed zopiclone in combination with alcohol intoxication as the cause of death followed by an overrun accident based on the autopsy results, including toxicological analysis and supported by the CT findings in combination with the in vitro scans of zopiclone.